Methods of identifying immunoglobulin associated with adverse reactions

Abstract

The present disclosure relates to methods of identifying and reducing anti-Fc epsilon Receptor I (FcεRI) immunoglobulins (Ig) associated with adverse reactions from plasma or a fraction thereof, formulations and uses of the anti-FcεRI Ig reduced plasma protein product thereof.

Description

[0001] CSL Behring AG P540 HL / AK 29.03.2024 METHODS OF IDENTIFYING IMMUNOGLOBULIN ASSOCIATED WITH ADVERSE REACTIONS FIELD The present disclosure relates to methods of identifying and reducing anti-Fc epsilon Receptor I (FcεRI) immunoglobulins (Ig) associated with adverse reactions from plasma or a fraction thereof, formulations and uses of the anti-FcεRI Ig reduced plasma protein product thereof. BACKGROUND Immunoglobulins (Ig) are one of the most abundant proteins in plasma and are responsible for complement activation, opsonisation and toxin neutralisation. Plasma derived Ig has become a major plasma product and world-wide demand is increasing. Human Ig products, both hyperimmune (or “specific”) and normal (or “nonspecific”), predominantly consist of IgG. IgG purified from human plasma is used for prophylactic prevention of infections in immunodeficient patients, replacement therapy for antibody deficiencies in patients, and the treatment of conditions relating to immune deficiencies, inflammatory and autoimmune diseases and acute infections in patients. A list of FDA approved Igs is provided at http: / / www.fda.gov / vaccines-blood-biologics / approved-blood-products / immune-globulins. There are currently several commercial intravenous IG (IVIG) products (typically 5 % or 10 % (w / v) stabilised solutions) available including Privigen® (CSL Behring), Flebogamma® (Grifols), Gamunex®-C (Grifols), Gammagard® (Takeda), and Octagam® (Octapharma). More recently, subcutaneous IG (SCIG) administration has become available. Commercial SCIG products (typically 10 %, 16.5 % or 20 % (w / v) stabilised solutions) include Hizentra® (CSL Behring), Gamunex®-C (Grifols), Xembify® (Grifols), Cutaquig® (Octapharma) and Cuvitru® (Takeda). Other Ig products are administered intramuscularly (IMIG). Whilst immunoglobulin therapy is effective and generally well tolerated, various adverse effects have been reported over the years. Subject to the immunoglobulin product, the majority of these events, such as rash, flushing, headache, malaise, fever, chills, fatigue and lethargy, are transient and mild. However, some side effects, such as immediate hypersensitivity reactions (including urticaria and pruritis), thrombosis, arrhythmia, aseptic meningitis, and hemolytic anemia are serious. These adverse effects, with varying degrees of severity, are associated with specific immunoglobulin preparations and individual patient susceptibility. Whilst assessment of patient risk factors, reducing infusion rates and switching between IVIG and SCIG can minimize adverse effects, it is unknown what components in the plasma and Ig products are causing these adverse reactions and sometimes increased frequency of adverse events can result in withdrawal of Ig products from distribution. Indeed, excessive numbers of hypersensitivity reactions involving specific lots of Ig occurs episodically and unpredictably leading to withdrawals of product lots and quarantine of manufacturing intermediaries that can adversely affect IG supply (Product Safety Update; International blood / plasma news, p100, February 2023). It will therefore be apparent to the skilled person that there is a need in the art for methods of identifying and reducing components from plasma that cause adverse reactions in subjects from plasma sample or fractions thereof. SUMMARY The present disclosure is based on the inventors identification of an immunoglobulin (Ig) associated with adverse reactions in subjects. In particular, through statistical analysis of plasma donations, the inventors identified a single plasma donor associated with hypersensitivity reactions. The inventors subsequently found that plasma from this donor was capable of inducing both mast cell and basophil degranulation through activation of the Fc epsilon Receptor I (FcεRI) mediated pathway. The inventors further identified that activation of the FcεRI mediated pathway was immunoglobulin (Ig) G driven. Somewhat surprisingly, purified IgG products derived from plasma of a donor associated with hypersensitivity reactions, did not clearly induce mast cell or basophil degranulation in vitro through activation of the FcεRI mediated pathway. It was only by identifying the individual plasma donor associated with the hypersensitivity reactions that the inventors were able to determine why the purified IgG products were causing adverse reactions in subjects. Accordingly, the findings by the inventors provide the basis for a method of identifying anti-Fc epsilon Receptor I (FcεRI) immunoglobulin (Ig) in a plasma sample or a fraction thereof. The present disclosure also provides a method of detecting anti-Fc epsilon Receptor I (FcεRI) immunoglobulin (Ig) in a plasma sample or a fraction thereof. The present disclosure further provides a method of screening a plasma sample or a fraction thereof for anti-Fc epsilon Receptor I (FcεRI) immunoglobulin (Ig). The present disclosure provides a method comprising contacting a plasma sample or a fraction thereof with a reagent that binds to an anti-Fc epsilon Receptor I (FcεRI) immunoglobulin (Ig) in a plasma sample or a fraction thereof and detecting binding of the reagent. In one example, the reagent binds directly to the anti-FcεRI Ig in the plasma sample or fraction thereof. In one example, the reagent binds indirectly to the anti-FcεRI Ig in the plasma sample or fraction thereof. In one example, the reagent is a ligand comprising FcεRI or fragment or epitope thereof. For example, the fragment of FcεRI comprises an α-chain of FcεRI. In one example, the FcεRI fragment is a functional fragment. For example, the FcεRI functional fragment is a fragment of FcεRI that when bound to the anti-FcεRI Ig activates a FcεRI mediated signalling pathway. In one example, the method comprises contacting a plasma sample or a fraction thereof with a ligand comprising FcεRI or fragment or epitope thereof that binds to the anti-FcεRI Ig in the plasma sample or fraction thereof. For example, binding of the anti-FcεRI Ig in the plasma sample or fraction thereof to the FcεRI or fragment or epitope thereof results in the formation of complex. In one example, the method further comprises detecting the complex, wherein the presence of the complex is indicative of the presence of the anti-FcεRI Ig in the plasma sample or fraction thereof. The present disclosure provides a method of detecting anti-Fc epsilon Receptor I (FcεRI) immunoglobulin (Ig) in a plasma sample or a fraction thereof, the method comprising: (i) contacting the sample to a ligand which binds to the anti-FcεRI Ig in the sample to thereby form a complex; and (ii) detecting the complex, wherein presence of the complex is indicative of the presence of the anti-FcεRI Ig in the plasma sample or fraction thereof. The present disclosure also provides a method of screening a plasma sample or a fraction thereof for an anti-Fc epsilon Receptor I (FcεRI) immunoglobulin (Ig), the method comprising: (i) contacting the sample to a ligand which binds to the anti-FcεRI Ig in the sample to thereby form a complex; and (ii) detecting the complex, wherein presence of the complex is indicative of the presence of the anti-FcεRI Ig in the plasma sample or fraction thereof. The present disclosure further provides a method of identifying a plasma sample or a fraction thereof suitable for administration to a subject, the method comprising: (i) contacting the sample to a ligand which binds to the anti-Fc epsilon Receptor I (FcεRI) immunoglobulin (Ig) in the sample to thereby form a complex; and (ii) detecting the complex, wherein presence of the complex is indicative of the presence of the anti-FcεRI Ig in the plasma sample or fraction thereof, wherein the presence of anti-FcεRI Ig in the plasma sample or fraction thereof indicates the plasma sample or fraction thereof is not suitable for administration to the subject. The present disclosure provides a method of screening a plasma sample or a fraction thereof to determine suitability for administration to a subject, the method comprising: (i) contacting the sample to a ligand which binds to an anti-Fc epsilon Receptor I (FcεRI) immunoglobulin (Ig) in the sample to thereby form a complex; and (ii) detecting the complex, wherein presence of the complex is indicative of the presence of the anti-FcεRI Ig in the plasma sample or fraction thereof, wherein the presence of anti-FcεRI Ig in the plasma sample or fraction thereof indicates the plasma sample or fraction thereof is not suitable for administration to the subject. The present disclosure further provides a method of identifying a plasma sample or a fraction thereof for use in producing an immunoglobulin (Ig) preparation for administration to a subject, the method comprising: (i) contacting the sample to a ligand which binds to the anti-Fc epsilon Receptor I (FcεRI) Ig in the sample to thereby form a complex; and (ii) detecting the complex, wherein presence of the complex is indicative of the presence of the anti-FcεRI Ig in the plasma sample or fraction thereof, wherein the presence of anti-FcεRI Ig in the plasma sample or fraction thereof indicates the plasma sample or fraction thereof is not suitable for use in producing an Ig preparation for administration to the subject. The present disclosure also provides a method of screening a plasma sample or a fraction thereof for use in producing an immunoglobulin (Ig) preparation for administration to a subject, the method comprising: (i) contacting the sample to a ligand which binds to the anti-Fc epsilon Receptor I (FcεRI) Ig in the sample to thereby form a complex; and (ii) detecting the complex, wherein presence of the complex is indicative of the presence of the anti-FcεRI Ig in the plasma sample or fraction thereof, wherein the presence of anti-FcεRI Ig in the plasma sample or fraction thereof indicates the plasma sample or fraction thereof is not suitable for use in producing an Ig preparation for administration to the subject. The present disclosure provides a method of detecting an anti-Fc epsilon Receptor I (FcεRI) immunoglobulin (Ig) in a plasma sample or a fraction thereof, the method comprising: (i) contacting the sample to a ligand which binds to the anti-FcεRI Ig in the sample to thereby form a complex; and (ii) detecting the complex with a detection protein comprising a detectable label, wherein presence of the detectable label is indicative of the presence of the anti- FcεRI Ig in the plasma sample or fraction thereof. The present disclosure provides a method of screening a plasma sample or a fraction thereof for an anti-Fc epsilon Receptor I (FcεRI) immunoglobulin (Ig), the method comprising: (i) contacting the sample to a ligand which binds to the anti-FcεRI Ig in the sample to thereby form a complex; and (ii) detecting the complex with a detection protein comprising a detectable label, wherein presence of the detectable label is indicative of the presence of the anti- FcεRI Ig in the plasma sample or fraction thereof. The present disclosure provides a method of identifying a plasma sample or a fraction thereof suitable for administration to a subject, the method comprising: (i) contacting the sample to a ligand which binds to an anti-Fc epsilon Receptor I (FcεRI) immunoglobulin (Ig) in the sample to thereby form a complex; and (ii) detecting the complex with a detection protein comprising a detectable label, wherein presence of the detectable label is indicative of the presence of the anti- FcεRI Ig in the plasma sample or fraction thereof, wherein the presence of anti- FcεRI Ig in the plasma sample or fraction thereof indicates the plasma sample or fraction thereof is not suitable for administration to the subject. The present disclosure provides a method of screening a plasma sample or a fraction thereof to determine suitability for administration to a subject, the method comprising: (i) contacting the sample to a ligand which binds to an anti-Fc epsilon Receptor I (FcεRI) immunoglobulin Ig in the sample to thereby form a complex; and (ii) detecting the complex with a detection protein comprising a detectable label, wherein presence of the detectable label is indicative of the presence of the anti- FcεRI Ig in the plasma sample or fraction thereof, wherein the presence of anti- FcεRI Ig in the plasma sample or fraction thereof indicates the plasma sample or fraction thereof is not suitable for administration to the subject. The present disclosure provides a method of detecting anti-Fc epsilon Receptor I (FcεRI) immunoglobulin (Ig) in a plasma sample or a fraction thereof, the method comprising: (i) immobilising a ligand comprising FcεRI or fragment or epitope thereof onto a solid surface; (ii) contacting the sample to the ligand immobilised on the solid surface, wherein the immobilised ligand binds to the anti-FcεRI Ig in the sample to thereby form a complex; (iii) contacting the complex with a detection protein comprising an antibody variable region, wherein the detection protein binds to the anti-FcεRI Ig and wherein the detection protein comprises a detectable label; and (iv) detecting the label, wherein presence of the detectable label is indicative of the presence of the anti-FcεRI Ig in the plasma sample or fraction thereof. The present disclosure provides a method of detecting anti-Fc epsilon Receptor I (FcεRI) immunoglobulin (Ig) in a plasma sample or a fraction thereof, the method comprising: (i) immobilising a ligand comprising FcεRI or fragment or epitope thereof onto a solid surface; (ii) contacting the sample to the ligand immobilised on the solid surface, wherein the immobilised ligand binds to the anti-FcεRI Ig in the sample to thereby form a complex; (iii) contacting the complex with a detection protein comprising an antibody variable region, wherein the detection protein binds to the anti-FcεRI Ig; and (iv) contacting the detection protein with an antibody that binds thereto and comprises a detectable label; and (v) detecting the label, wherein presence of the detectable label is indicative of the presence of the anti-FcεRI Ig in the plasma sample or fraction thereof. The present disclosure provides a method of screening a plasma sample or a fraction thereof for anti-Fc epsilon Receptor I (FcεRI) immunoglobulin (Ig), the method comprising: (i) immobilising a ligand comprising FcεRI or fragment or epitope thereof onto a solid surface; (ii) contacting the sample to the ligand immobilised on the solid surface, wherein the immobilised ligand binds to the anti-FcεRI Ig in the sample to thereby form a complex; (iii) contacting the complex with a detection protein comprising an antibody variable region, wherein the detection protein binds to the anti-FcεRI Ig and wherein the detection protein comprises a detectable label; and (iv) detecting the label, wherein presence of the detectable label is indicative of the presence of the anti-FcεRI Ig in the plasma sample or fraction thereof. The present disclosure provides a method of screening a plasma sample or a fraction thereof for anti-Fc epsilon Receptor I (FcεRI) immunoglobulin (Ig), the method comprising: (i) immobilising a ligand comprising FcεRI or fragment or epitope thereof onto a solid surface; (ii) contacting the sample to the ligand immobilised on the solid surface, wherein the immobilised ligand binds to the anti-FcεRI Ig in the sample to thereby form a complex; (iii) contacting the complex with a detection protein comprising an antibody variable region, wherein the detection protein binds to the anti-FcεRI Ig; and (iv) contacting the detection protein with an antibody that binds thereto and comprises a detectable label; and (v) detecting the label, wherein presence of the detectable label is indicative of the presence of the anti-FcεRI Ig in the plasma sample or fraction thereof. The present disclosure provides a method of identifying a plasma sample or a fraction thereof suitable for administration to a subject, the method comprising: (i) immobilising a ligand comprising FcεRI or fragment or epitope thereof onto a solid surface; (ii) contacting the sample to the ligand immobilised on the solid surface, wherein the immobilised ligand binds to the anti-FcεRI Ig in the sample to thereby form a complex; (iii) contacting the complex with a detection protein comprising an antibody variable region, wherein the detection protein binds to the anti-FcεRI Ig and wherein the detection protein comprises a detectable label; and (iv) detecting the label, wherein presence of the detectable label is indicative of the presence of the anti-FcεRI Ig in the plasma sample or fraction thereof, wherein the presence of anti-FcεRI Ig in the plasma sample or fraction thereof indicates the plasma sample or fraction thereof is not suitable for administration to the subject. The present disclosure provides a method of identifying a plasma sample or a fraction thereof suitable for administration to a subject, the method comprising: (i) immobilising a ligand comprising FcεRI or fragment or epitope thereof onto a solid surface; (ii) contacting the sample to the ligand immobilised on the solid surface, wherein the immobilised ligand binds to the anti-FcεRI Ig in the sample to thereby form a complex; (iii) contacting the complex with a detection protein comprising an antibody variable region, wherein the detection protein binds to the anti-FcεRI Ig; and (iv) contacting the detection protein with an antibody that binds thereto and comprises a detectable label; and (v) detecting the label, wherein presence of the detectable label is indicative of the presence of the anti-FcεRI Ig in the plasma sample or fraction thereof, wherein the presence of anti-FcεRI Ig in the plasma sample or fraction thereof indicates the plasma sample or fraction thereof is not suitable for administration to the subject. The present disclosure provides a method of screening a plasma sample to determine suitability for administration to a subject, the method comprising: (i) immobilising a ligand comprising FcεRI or fragment or epitope thereof onto a solid surface; (ii) contacting the sample to the ligand immobilised on the solid surface, wherein the immobilised ligand binds to the anti-FcεRI Ig in the sample to thereby form a complex; (iii) contacting the complex with a detection protein comprising an antibody variable region, wherein the detection protein binds to the anti-FcεRI Ig and wherein the detection protein comprises a detectable label; and (iv) detecting the label, wherein presence of the detectable label is indicative of the presence of the anti-FcεRI Ig in the plasma sample or fraction thereof, wherein the presence of anti-FcεRI Ig in the plasma sample or fraction thereof indicates the plasma sample or fraction thereof is not suitable for administration to the subject. The present disclosure provides a method of screening a plasma sample to determine suitability for administration to a subject, the method comprising: (i) immobilising a ligand comprising FcεRI or fragment or epitope thereof onto a solid surface; (ii) contacting the sample to the ligand immobilised on the solid surface, wherein the immobilised ligand binds to the anti-FcεRI Ig in the sample to thereby form a complex; (iii) contacting the complex with a detection protein comprising an antibody variable region, wherein the detection protein binds to the anti-FcεRI Ig; and (iv) contacting the detection protein with an antibody that binds thereto and comprises a detectable label; and (v) detecting the label, wherein presence of the detectable label is indicative of the presence of the anti-FcεRI Ig in the plasma sample or fraction thereof, wherein the presence of anti-FcεRI Ig in the plasma sample or fraction thereof indicates the plasma sample or fraction thereof is not suitable for administration to the subject. The present disclosure provides a method of identifying a subject suitable for plasma donation for the production of an immunoglobulin (Ig) preparation, the method comprising: (i) contacting a plasma sample or fraction thereof from the subject to a ligand which binds to the anti-FcεRI Ig in the sample to thereby form a complex; and (ii) detecting the complex, wherein presence of the complex is indicative of the presence of the anti-FcεRI Ig in the plasma sample or fraction thereof, wherein the presence of anti-FcεRI Ig in the plasma sample or fraction thereof indicates the subject is not suitable for plasma donation for the production of the Ig preparation. The present disclosure provides a method of screening for a subject suitable for plasma donation for the production of an immunoglobulin (Ig) preparation, the method comprising: (i) contacting a plasma sample or fraction thereof from the subject to a ligand which binds to an anti-Fc epsilon Receptor I (FcεRI) immunoglobulin (Ig) in the sample to thereby form a complex; and (ii) detecting the complex, wherein presence of the complex is indicative of the presence of the anti-FcεRI Ig in the plasma sample or fraction thereof, wherein the presence of anti-FcεRI Ig in the plasma sample or fraction thereof indicates the subject is not suitable for plasma donation for the production of the Ig preparation. The present disclosure provides a method of identifying a subject suitable for plasma donation for the production of an immunoglobulin (Ig) preparation, the method comprising: (i) contacting a plasma sample or fraction thereof from the subject to a ligand which binds to an anti-Fc epsilon Receptor I (FcεRI) immunoglobulin (Ig) in the sample to thereby form a complex; and (ii) detecting the complex with a detection protein comprising a detectable label, wherein presence of a detectable label is indicative of the presence of the anti- FcεRI Ig in the plasma sample or fraction thereof, wherein the presence of anti- FcεRI Ig in the plasma sample or fraction thereof indicates the subject is not suitable for plasma donation for the production of the Ig preparation. The present disclosure provides a method of screening for a subject suitable for plasma donation for the production of an immunoglobulin (Ig) preparation, the method comprising: (i) contacting a plasma sample or fraction thereof from the subject to a ligand which binds to an anti-Fc epsilon Receptor I (FcεRI) immunoglobulin (Ig) in the sample to thereby form a complex; and (ii) detecting the complex with a detection protein comprising a detectable label, wherein presence of a detectable label is indicative of the presence of the anti- FcεRI Ig in the plasma sample or fraction thereof, wherein the presence of anti- FcεRI Ig in the plasma sample or fraction thereof indicates the subject is not suitable for plasma donation for the production of the Ig preparation. In one example, the ligand comprises FcεRI or fragment or epitope thereof. For example, the fragment of FcεRI comprises an α-chain of FcεRI. In one example, the FcεRI fragment is a functional fragment. For example, the FcεRI functional fragment is a fragment of FcεRI that when bound to the anti-FcεRI Ig activates a FcεRI mediated signalling pathway. In some examples, the anti-FcεRI Ig binds to an epitope of FcεRI and activates a FcεRI mediated signalling pathway. In one example, the anti-FcεRI Ig binds to an α-chain of the FcεRI and activates a FcεRI mediated signalling pathway. In one example, the anti-FcεRI Ig binds to an epitope of FcεRI and activates another immunological signalling pathway. For example, the anti-FcεRI Ig binds to an epitope of FcεRI and activates an IgE mediated signalling pathway. In another example, the anti-FcεRI Ig binds to an epitope of FcεRI and activates an IgG mediated signalling pathway. In one example, the anti-FcεRI Ig binds to an epitope of FcεRI an IgE mediated signalling pathway and another immunological signalling pathway. In one example, the anti-FcεRI Ig binds to an epitope of FcεRI an IgG mediated signalling pathway and another immunological signalling pathway. In some examples, the anti-FcεRI Ig binds to an epitope of FcεRI and activates an IgE mediated signalling pathway and an IgG mediated signalling pathway. In one example, the anti-FcεRI Ig binds to an epitope of FcεRI and activates a FcεRI mediated signalling pathway, an IgE mediated signalling pathway, and an IgG mediated signalling pathway. In one example, the anti-FcεRI Ig binds to an epitope of FcεRI and activates a FcεRI mediated signalling pathway and an IgE mediated signalling pathway. In one example, the anti-FcεRI Ig binds to an epitope of FcεRI and activates a FcεRI mediated signalling pathway and an IgG mediated signalling pathway. In one example, activation of the FcεRI mediated signalling pathway induces basophil and / or mast cell activation and / or degranulation. In another example, activation of the FcεRI mediated signalling pathway induces basophil activation. In yet another example, activation of the FcεRI mediated signalling pathway induces basophil degranulation. In another example, activation of the FcεRI mediated signalling pathway induces basophil activation and degranulation. In a further example, activation of the FcεRI mediated signalling pathway induces mast cell activation. In yet a further example, activation of the FcεRI mediated signalling pathway induces mast cell degranulation. In one example, activation of the FcεRI mediated signalling pathway induces mast cell activation and degranulation. In a further example, activation of the FcεRI mediated signalling pathway induces basophil and mast cell activation and degranulation. The present disclosure also provides a method of detecting anti-Fc epsilon Receptor I (FcεRI) immunoglobulin (Ig) in a plasma sample or a fraction thereof, the method comprising detecting basophil and / or mast cell activation and / or degranulation induced by the plasma sample or fraction thereof, wherein the basophil and / or mast cell activation and / or degranulation is indicative of the presence of the anti-FcεRI Ig in the plasma sample or fraction thereof. The present disclosure provides a method of screening a plasma sample or a fraction thereof for anti-Fc epsilon Receptor I (FcεRI) immunoglobulin (Ig), the method comprising detecting basophil and / or mast cell activation and / or degranulation induced by the plasma sample or fraction thereof, wherein the basophil and / or mast cell activation and / or degranulation is indicative of the presence of anti-FcεRI Ig in the plasma sample or fraction thereof. The present disclosure also provides a method of screening a plasma sample or a fraction thereof for use in producing an immunoglobulin (Ig) preparation for administration to a subject, the method comprising detecting basophil and / or mast cell activation and / or degranulation induced by the plasma sample or fraction thereof, wherein the basophil and / or mast cell activation and / or degranulation is indicative of the presence of anti-FcεRI Ig in the plasma sample or fraction thereof, wherein the presence of anti-FcεRI Ig in the plasma sample or fraction thereof indicates the plasma sample or fraction thereof is not suitable for use in producing the Ig preparation for administration to the subject. The present disclosure further provides a method of identifying a plasma sample or a fraction thereof suitable for administration to a subject, the method comprising detecting basophil and / or mast cell activation and / or degranulation induced by the plasma sample or fraction thereof, wherein the basophil and / or mast cell activation and / or degranulation is indicative of the presence of anti-FcεRI Ig in the plasma sample or fraction thereof, wherein the presence of anti-FcεRI Ig in the plasma sample or fraction thereof indicates the plasma sample or fraction thereof is not suitable for administration to the subject. The present disclosure further provides a method of identifying a plasma sample or a fraction thereof for use in producing an immunoglobulin (Ig) preparation for administration to a subject, the method comprising detecting basophil and / or mast cell activation and / or degranulation induced by the plasma sample or fraction thereof, wherein the proportion of basophil and / or mast cell activation and / or degranulation is indicative of the presence of anti-FcεRI Ig in the plasma sample or fraction thereof, wherein the presence of anti-FcεRI Ig in the plasma sample or fraction thereof indicates the plasma sample or fraction thereof is not suitable for use in producing the Ig preparation for administration to the subject. In one example, the anti-FcεRI Ig is an anti-FcεRI IgG and / or an anti-FcεRI IgE. In one example, the anti-FcεRI Ig is an anti-FcεRI IgG and an anti-FcεRI IgE. In one example, the anti-FcεRI Ig is an anti-FcεRI IgG or an anti-FcεRI IgE. In another example, the anti-FcεRI Ig is an anti-FcεRI IgG. In a further example, the anti-FcεRI Ig is an anti-FcεRI IgE. In one example, the anti-FcεRI Ig induces a hypersensitivity reaction in a subject. In one example, the ligand is immobilised on a solid surface. In another example, the method further comprises immobilising the FcεRI ligand onto a solid surface. In one example, the method further comprises the protein complex being contacted with the detection protein comprising an antibody variable region, wherein the detection protein binds to the anti-FcεRI Ig, and wherein the detection protein comprises the detectable label. In one example, the method further comprises the protein complex being contacted with the detection protein comprising an antibody variable region, wherein the detection protein binds to the anti-FcεRI Ig, and contacting the detection protein with an antibody that binds thereto and comprises a detectable label. In one example, the detection protein is an anti-IgG and / or an anti-IgE. In one example, the detection protein is an anti-IgG and an anti-IgE. In one example, the detection protein is an anti-IgG or an anti-IgE. In another example, the detection protein is an anti-IgG. In a further example, the detection protein is an anti-IgE. In one example, the detectable label is selected from the group consisting of a radiolabel, an enzyme, a fluorescent label, a luminescent label, a bioluminescent label, a magnetic label, a prosthetic group and a contrast agent. The skilled person will appreciate from the disclosure herein that in methods of screening and / or identifying a plasma sample or fraction thereof suitable for administration and / or for use in producing an Ig preparation described herein, the plasma sample or fraction thereof is not suitable for administration or use if the anti-FcεRI IgG is present in a detectable amount. For example, presence of anti-FcεRI Ig in the plasma sample or fraction thereof in a detectable amount indicates the plasma sample or fraction thereof is not suitable for administration to the subject. In another example, presence of anti-FcεRI Ig in the plasma sample or fraction thereof in a detectable amount indicates the plasma sample or fraction thereof is not suitable for use in producing the Ig preparation for administration to the subject. Methods of detecting the presence of anti-FcεRI Ig will be apparent to the skilled person and / or described herein. For example, the presence of a detectable amount of anti-FcεRI Ig is determined directly by determining the level of anti-FcεRI Ig in the plasma sample or fraction thereof. In another example, the presence of a detectable amount of anti-FcεRI Ig is determined indirectly by determining the proportion of basophil and / or mast cell activation and / or degranulation induced by the plasma sample or fraction thereof. In one example, the method comprises determining the level of the anti-FcεRI Ig in the plasma sample or fraction thereof. In one example, the method comprises determining the level of anti-FcεRI IgG in the plasma sample or fraction thereof. For example, the method comprises determining a detectable amount of anti-FcεRI IgG in the plasma sample or fraction thereof. In one example, the detectable amount of anti-FcεRI IgG in the plasma sample or fraction thereof is at least 40 μg / mL. In one example, the detectable amount of anti-FcεRI IgG in the plasma sample or fraction thereof is at least 45 μg / mL. In one example, the detectable amount of anti-FcεRI IgG in the plasma sample or fraction thereof is at least 50 μg / mL. For example, if the anti-FcεRI IgG is present in the plasma sample or fraction thereof at a concentration of at least 40 μg / mL (i.e., in a detectable amount), the plasma sample or fraction thereof is not suitable for administration to the subject or for use in producing an Ig preparation for administration to the subject. In one example, if the anti-FcεRI IgG is present in the plasma sample or fraction thereof at a concentration of less than 40 μg / mL (i.e., not in a detectable amount), the plasma sample or fraction thereof is suitable for administration to the subject or for use in producing an Ig preparation for administration to the subject. In one example, the method comprises determining the level of anti-FcεRI IgE in the plasma sample or fraction thereof. For example, the method comprises determining a detectable amount of anti-FcεRI IgE in the plasma sample or fraction thereof. In one example, the detectable amount of anti-FcεRI IgE in the plasma sample or fraction thereof is at least 0.1 kU / L. In one example, the detectable amount of anti-FcεRI IgE in the plasma sample or fraction thereof is at least 0.5 kU / L. In one example, the detectable amount of anti-FcεRI IgE in the plasma sample or fraction thereof is at least 1 kU / L. For example, if the anti-FcεRI IgE is present in the plasma sample or fraction thereof at a concentration of at least 0.1 kU / L (i.e., in a detectable amount), the plasma sample or fraction thereof is not suitable for administration to the subject or for use in producing an Ig preparation for administration to the subject. In one example, if the anti-FcεRI IgE is present in the plasma sample or fraction thereof at a concentration of less than 0.1 kU / L (i.e., not in a detectable amount), the plasma sample or fraction thereof is suitable for administration to the subject or for use in producing an Ig preparation for administration to the subject. In one example, the method further comprises determining the proportion of basophil and / or mast cell activation and / or degranulation induced by the plasma sample or fraction thereof. In one example, the method further comprises determining the proportion of basophil and mast cell activation and / or degranulation induced by the plasma sample or fraction thereof. In one example, the method further comprises determining the proportion of basophil or mast cell activation and / or degranulation induced by the plasma sample or fraction thereof. In another example, the method further comprises determining the proportion of basophil activation and / or degranulation induced by the plasma sample or fraction thereof. In a further example, the method further comprises determining the proportion of mast cell activation and / or degranulation induced by the plasma sample or fraction thereof. In one example, the proportion of basophil and / or mast cell activation and / or degranulation following exposure to the plasma sample or fraction thereof is determined by determining the proportion of basophil and / or mast cells expressing one or more markers selected from the group consisting of CD63, CD203c, CD107a and combinations thereof. In one example, the proportion of basophil and mast cell activation following exposure to the plasma sample or fraction thereof is determined by determining the proportion of basophil and mast cells expressing one or more markers selected from the group consisting of CD63, CD203c, CD107a and combinations thereof. In one example, the proportion of basophil activation following exposure to the plasma sample or fraction thereof is determined by determining the proportion of basophil expressing one or more markers selected from the group consisting of CD63, CD203c and combinations thereof. In one example, the proportion of mast cell activation following exposure to the plasma sample or fraction thereof is determined by determining the proportion of mast cells expressing CD107a. In one example, the method comprises determining the proportion of basophils expressing CD63 following exposure to the plasma sample or fraction thereof. For example, the method comprises determining a detectable amount of anti-FcεRI Ig in the plasma sample or fraction thereof by determining the proportion of basophils expressing CD63 following exposure to the plasma sample or fraction thereof. In one example, the proportion of basophils expressing CD63 following exposure to the plasma sample or fraction thereof is more than 5 %. For example, the proportion of basophils expressing CD63 is relative to the total proportion of basophils being exposed to the plasma sample or fraction thereof. In one example, a detectable amount of anti-FcεRI Ig is present in the plasma sample or fraction thereof if at least 5 % of a population of basophils express CD63 following exposure to the plasma sample or fraction thereof. In one example, the method comprises determining the proportion of basophils expressing CD203c following exposure to the plasma sample or fraction thereof. For example, the method comprises determining a detectable amount of anti-FcεRI Ig in the plasma sample or fraction thereof by determining the proportion of basophils expressing CD203c following exposure to the plasma sample or fraction thereof. In one example, the proportion of basophils expressing CD203c following exposure to the plasma sample or fraction thereof is more than 5 %. For example, the proportion of basophils expressing CD203c is relative to the total proportion of basophils being exposed to the plasma sample or fraction thereof. In one example, a detectable amount of anti-FcεRI Ig is present in the plasma sample or fraction thereof if at least 5 % of a population of basophils express CD203c following exposure to the plasma sample or fraction thereof. In one example, the method comprises determining the proportion of mast cells expressing CD107a following exposure to the plasma sample or fraction thereof. For example, the method comprises determining a detectable amount of anti-FcεRI Ig in the plasma sample or fraction thereof by determining the proportion of mast cells expressing CD107a following exposure to the plasma sample or fraction thereof. In one example, the proportion of mast cells expressing CD107a following exposure to the plasma sample or fraction thereof is more than 5 %. For example, the proportion of mast cells expressing CD107a is relative to the total proportion of mast cells being exposed to the plasma sample or fraction thereof. In one example, a detectable amount of anti-FcεRI Ig is present in the plasma sample or fraction thereof if at least 5 % of a population of mast cells express CD107a following exposure to the plasma sample or fraction thereof. In one example, the plasma sample or fraction thereof is selected from the group consisting of a human blood plasma sample, an IgG intermediate product, an intravenous immunoglobulin G (IVIG), a subcutaneous immunoglobulin G (SCIG), a cryo-rich plasma, a cryo-poor plasma, a Supernatant I (SN I), a Cohn Fraction II (Fr II), a Cohn Fraction II+III (Fr II+III), a Cohn Fraction I+II+III (FrI+II+III), a Kistler / Nitschmann Precipitate A (KN A), a Kistler / Nitschmann Precipitate B (KN B), a Kistler / Nitschmann Precipitate of Supernatant B (KN B+1), and combinations thereof. In one example, the plasma sample or fraction thereof is a human blood plasma sample from one or more subjects. In one example, the method further comprises administering the plasma sample or fraction thereof to a subject if the anti-FcεRI Ig is not present. For example, the anti-FcεRI Ig is not present in a detectable amount. In one example, the method further comprises including the plasma sample or fraction thereof into a pooled blood plasma sample if the anti-FcεRI Ig is not present. For example, the plasma sample or fraction thereof is included into a pooled blood plasma sample if the anti-FcεRI Ig is not present in a detectable amount. In one example, the method further comprises excluding the plasma sample or fraction thereof from a pooled blood plasma sample if the anti-FcεRI Ig is present. For example, the plasma sample or fraction thereof is excluded from a pooled blood plasma sample if the anti-FcεRI Ig is present in a detectable amount. The inventors’ findings also provide the basis for a method of preparing an anti-Fc epsilon Receptor I (FcεRI) immunoglobulin (Ig) reduced preparation from a plasma sample or a fraction thereof, the method comprising detecting anti-FcεRI Ig in the plasma sample or fraction thereof according to any method described herein and producing an anti-FcεRI Ig reduced preparation. The present disclosure also provides a method of preparing an anti-Fc epsilon Receptor I (FcεRI) immunoglobulin (Ig) reduced preparation from a plasma sample or a fraction thereof, the method comprising binding the anti-FcεRI Ig to a chromatography resin comprising a ligand which binds to the anti-FcεRI Ig in the plasma sample or fraction thereof and collecting the anti-FcεRI Ig reduced preparation. The present disclosure also provides a method of preparing an anti-Fc epsilon Receptor I (FcεRI) immunoglobulin (Ig) reduced preparation from a plasma sample or a fraction thereof, the method comprising: (i) loading the plasma sample or fraction thereof onto an chromatography resin comprising a ligand which binds to the anti-FcεRI Ig in the plasma sample or fraction thereof; and (ii) collecting the anti-FcεRI Ig reduced preparation. In one example, the chromatography resin is an affinity chromatography resin. For example, a continuous affinity chromatography resin. The present disclosure provides a method of preparing an anti-Fc epsilon Receptor I (FcεRI) immunoglobulin (Ig) reduced preparation from a plasma sample or a fraction thereof, the method comprising: (i) loading the plasma sample or fraction thereof onto an affinity chromatography resin comprising a ligand which binds to the anti-FcεRI Ig in the plasma sample or fraction thereof; and (ii) collecting an anti-FcεRI Ig reduced preparation. In one example, the ligand is immobilized to a matrix of the chromatography resin. In one example, the ligand comprises FcεRI or fragment or epitope thereof. For example, the fragment of FcεRI comprises an α-chain of FcεRI. In one example, the FcεRI fragment is a functional fragment. For example, the FcεRI functional fragment is a fragment of FcεRI that when bound to the anti-FcεRI Ig activates a FcεRI mediated signalling pathway. In one example, the method further comprises detecting the presence of anti-FcεRI Ig in the plasma sample or fraction thereof by performing a method of detecting as described herein. In one example, the anti-FcεRI Ig reduced preparation induces reduced activation of a FcεRI mediated signalling pathway relative to a preparation wherein the level of the anti-FcεRI Ig is not reduced. In one example, the anti-FcεRI Ig reduced preparation does not induce activation of a FcεRI mediated signalling pathway. In one example, the anti-FcεRI Ig reduced preparation induces reduced basophil and mast cell activation and / or degranulation relative to a preparation wherein the level of the anti-FcεRI Ig is not reduced. In one example, the anti-FcεRI Ig reduced preparation induces reduced basophil activation relative to a preparation wherein the level of the anti-FcεRI Ig is not reduced. In one example, the anti-FcεRI Ig reduced preparation induces reduced mast cell activation relative to a preparation wherein the level of the anti-FcεRI Ig is not reduced. In one example, the anti-FcεRI Ig reduced preparation does not induce basophil and / or mast cell activation and / or degranulation. In one example, the basophil and / or mast cell activation and / or degranulation following exposure to the anti-FcεRI Ig reduced preparation is determined by a method described herein. For example, the method comprises determining the proportion of basophil and / or mast cells expressing one or more markers selected from the group consisting of CD63, CD203c, CD107a and combinations thereof. In another example, the basophil activation following exposure to the anti-FcεRI Ig reduced preparation is determined by determining the proportion of basophil expressing one or more markers selected from the group consisting of CD63, CD203c and combinations thereof. In a further example, the mast cell activation following exposure to the anti-FcεRI Ig reduced preparation is determined by determining the proportion of mast cells expressing CD107a. In one example, the method comprises determining the proportion of basophils expressing CD63 following exposure to the anti-FcεRI Ig reduced preparation. For example, the method comprises determining whether a detectable amount of anti-FcεRI Ig is present in the anti- FcεRI Ig reduced preparation by determining the proportion of basophils expressing CD63 following exposure to the anti-FcεRI Ig reduced preparation. In one example, the proportion of basophils expressing CD63 following exposure to the anti-FcεRI Ig reduced preparation is less than 5 %. For example, the proportion of basophils expressing CD63 is relative to the total proportion of basophils being exposed to the anti-FcεRI Ig reduced preparation. In one example, a detectable amount of anti-FcεRI Ig is present in the anti-FcεRI Ig reduced preparation if at least 5 % of a population of basophils express CD63 following exposure to the anti-FcεRI Ig reduced preparation. In one example, no detectable amount of anti-FcεRI Ig is present in the anti-FcεRI Ig reduced preparation if less than 5 % of a population of basophils express CD63 following exposure to the anti-FcεRI Ig reduced preparation. In one example, the method comprises determining the proportion of basophils expressing CD203c following exposure to the anti-FcεRI Ig reduced preparation. For example, the method comprises determining whether a detectable amount of anti-FcεRI Ig is present in the anti- FcεRI Ig reduced preparation by determining the proportion of basophils expressing CD203c following exposure to the anti-FcεRI Ig reduced preparation. In one example, the proportion of basophils expressing CD203c following exposure to the anti-FcεRI Ig reduced preparation is less than 5%. For example, the proportion of basophils expressing CD203c is relative to the total proportion of basophils being exposed to the anti-FcεRI Ig reduced preparation. In one example, a detectable amount of anti-FcεRI Ig is present in the anti-FcεRI Ig reduced preparation if at least 5 % of a population of basophils express CD203c following exposure to the anti-FcεRI Ig reduced preparation. In one example, no detectable amount of anti-FcεRI Ig is present in the anti-FcεRI Ig reduced preparation if less than 5 % of a population of basophils express CD203c following exposure to the anti-FcεRI Ig reduced preparation. In one example, the method comprises determining the proportion of mast cells expressing CD107a following exposure to the anti-FcεRI Ig reduced preparation. For example, the method comprises determining whether a detectable amount of anti-FcεRI Ig is present in the anti- FcεRI Ig reduced preparation by determining the proportion of mast cells expressing CD107a following exposure to the anti-FcεRI Ig reduced preparation. In one example, the proportion of mast cells expressing CD107a following exposure to the anti-FcεRI Ig reduced preparation is less than 5 %. For example, the proportion of mast cells expressing CD107a is relative to the total proportion of mast cells being exposed to the anti-FcεRI Ig reduced preparation. In one example, a detectable amount of anti-FcεRI Ig is present in the anti-FcεRI Ig reduced preparation if at least 5 % of a population of mast cells express CD107a following exposure to the anti-FcεRI Ig reduced preparation. In one example, no detectable amount of anti-FcεRI Ig is present in the anti-FcεRI Ig reduced preparation if less than 5 % of a population of mast cells express CD107a following exposure to the anti-FcεRI Ig reduced preparation. In one example, the anti-FcεRI Ig reduced preparation comprises less than 40 μg / mL of an anti-FcεRI IgG and less than 0.1 kU / L of an anti-FcεRI IgE. In one example, the method comprises determining the level of anti-FcεRI IgG in the anti-FcεRI Ig reduced preparation. For example, the method comprises determining if a detectable amount of anti-FcεRI IgG is present in the anti-FcεRI Ig reduced preparation. In one example, the detectable amount of anti-FcεRI IgG in the anti-FcεRI Ig reduced preparation is at least 40 μg / mL. In another example, the anti-FcεRI Ig reduced preparation comprises less than 40 μg / mL of an anti-FcεRI IgG. In one example, the level of anti-FcεRI IgG in the anti-FcεRI Ig reduced preparation is less than 35 μg / mL. In one example, the level of anti-FcεRI IgG in the anti-FcεRI Ig reduced preparation is less than 30 μg / mL. In one example, the level of anti- FcεRI IgG in the anti-FcεRI Ig reduced preparation is less than 35 μg / mL. In one example, the level of anti-FcεRI IgG in the anti-FcεRI Ig reduced preparation is less than 20 μg / mL. In one example, the level of anti-FcεRI IgG in the anti-FcεRI Ig reduced preparation is less than 15 μg / mL. In one example, the level of anti-FcεRI IgG in the anti-FcεRI Ig reduced preparation is less than 10 μg / mL. In one example, the level of anti-FcεRI IgG in the anti-FcεRI Ig reduced preparation is less than 5 μg / mL. In one example, if the anti-FcεRI IgG is present in the anti- FcεRI Ig reduced preparation at a concentration of less than 40 μg / mL (i.e., not in a detectable amount), the anti-FcεRI Ig reduced preparation is suitable for administration to the subject. In one example, the method comprises determining the level of anti-FcεRI IgE in the anti-FcεRI Ig reduced preparation. For example, the method comprises determining if a detectable amount of anti-FcεRI IgE is present in the anti-FcεRI Ig reduced preparation. In one example, the detectable amount of anti-FcεRI IgE in the anti-FcεRI Ig reduced preparation is at least 0.1 kU / L. In one example, the anti-FcεRI Ig reduced preparation comprises less than 0.1 kU / L of an anti-FcεRI IgE. In one example, the level of anti-FcεRI IgE in the anti-FcεRI Ig reduced preparation is less than 0.01 kU / L. In one example, the level of anti-FcεRI IgE in the anti-FcεRI Ig reduced preparation is less than 0.05 kU / L. In one example, the level of anti-FcεRI IgE in the anti-FcεRI Ig reduced preparation is less than 0.001 kU / L. In one example, the level of anti- FcεRI IgE in the anti-FcεRI Ig reduced preparation is less than 0.005 kU / L. In one example, if the anti-FcεRI IgE is present in the anti-FcεRI Ig reduced preparation at a concentration of less than 0.1 kU / L (i.e., not in a detectable amount), the anti-FcεRI Ig reduced preparation is suitable for administration to the subject. In one example, the anti-FcεRI Ig reduced preparation is an anti-FcεRI Ig reduced IgG preparation. In one example, the affinity chromatography resin further comprises a blood group A antigen and a blood group B antigen immobilized to the matrix of the affinity chromatography resin. In another example, the affinity chromatography resin further comprises a blood group A antigen. In a further example, the affinity chromatography resin further comprises a blood group B antigen. In one example, the affinity chromatography resin is a continuous affinity chromatography resin. For example, the continuous affinity chromatography resin comprises a ligand which binds to anti-FcεRI Ig. In one example, the affinity chromatography resin is a continuous affinity chromatography resin comprising a ligand which binds to anti-FcεRI Ig, a blood group A antigen and a blood group B antigen. In one example, the affinity chromatography resin is a continuous affinity chromatography resin comprising a ligand which binds to anti-FcεRI Ig and a blood group A antigen immobilized to a matrix of the affinity chromatography resin. In one example, the affinity chromatography resin is a continuous affinity chromatography resin comprising a ligand which binds to anti-FcεRI Ig and a blood group B antigen immobilized to a matrix of the affinity chromatography resin. The present disclosure provides an affinity chromatography resin comprising a ligand which binds to anti-FcεRI Ig and optionally, a blood group A antigen and / or a blood group B antigen. For example, the disclosure provides a continuous affinity chromatography resin comprising a ligand which binds to anti-FcεRI Ig and optionally, a blood group A antigen and / or a blood group B antigen. In one example, the affinity chromatography is continuous affinity chromatography comprising: (i) a first affinity chromatography resin comprising a ligand which binds to anti-FcεRI Ig immobilized to a matrix of the first affinity chromatography resin; and (ii) a second affinity chromatography resin comprising a blood group A antigen and a blood group B antigen immobilized to a matrix of the second affinity chromatography resin. In one example, the affinity chromatography is continuous affinity chromatography comprising: (i) a first affinity chromatography resin comprising a ligand which binds to anti-FcεRI Ig immobilized to a matrix of the first affinity chromatography resin; and (ii) a second affinity chromatography resin comprising a blood group A antigen immobilized to a matrix of the second affinity chromatography resin. In one example, the affinity chromatography is continuous affinity chromatography comprising: (i) a first affinity chromatography resin comprising a ligand which binds to anti-FcεRI Ig immobilized to a matrix of the first affinity chromatography resin; and (ii) a second affinity chromatography resin comprising a blood group B antigen immobilized to a matrix of the second affinity chromatography resin. In one example, the affinity chromatography is continuous affinity chromatography comprising: (i) a first affinity chromatography resin comprising a blood group A antigen and a blood group B antigen immobilized to a matrix of the first affinity chromatography resin; and (ii) a second affinity chromatography resin comprising a ligand which binds to anti- FcεRI Ig immobilized to a matrix of the second affinity chromatography resin. In one example, the affinity chromatography is continuous affinity chromatography comprising: (i) a first affinity chromatography resin comprising a blood group A antigen immobilized to a matrix of the first affinity chromatography resin; and (ii) a second affinity chromatography resin comprising a ligand which binds to anti- FcεRI Ig immobilized to a matrix of the second affinity chromatography resin. In one example, the affinity chromatography is continuous affinity chromatography comprising: (i) a first affinity chromatography resin comprising a blood group B antigen immobilized to a matrix of the first affinity chromatography resin; and (ii) a second affinity chromatography resin comprising a ligand which binds to anti- FcεRI Ig immobilized to a matrix of the second affinity chromatography resin. In one example, the ligand comprises FcεRI or fragment or epitope thereof. For example, the fragment of FcεRI comprises an α-chain of FcεRI. In one example, the FcεRI fragment is a functional fragment. For example, the FcεRI functional fragment is a fragment of FcεRI that when bound to the anti-FcεRI Ig activates a FcεRI mediated signalling pathway. In one example, the method further comprises one or more steps selected from a group consisting of ethanol precipitation, octanoid acid fractionation, ion exchange chromatography, viral inactivation, viral filtration, ultrafiltration / diafiltration and combinations thereof. The findings further provide the basis for a pharmaceutical composition comprising the anti- FcεRI Ig reduced preparation or the anti-FcεRI Ig reduced IgG plasma preparation, comprising polyclonal IgG, as well as the use of the pharmaceutical composition for treating, preventing and / or delaying progression of a condition (e.g., primary immunodeficiency disease, chronic inflammatory demyelinating polyneuropathy, and chronic immune thrombocytopenic purpura) in a subject. The present disclosure provides a pharmaceutical composition comprising an anti-Fc epsilon Receptor I (FcεRI) immunoglobulin (Ig) reduced IgG preparation produced by a method described herein. In one example, the polyclonal IgG is selected from the group consisting of Hizentra® (CSL Behring), Privigen® (CSL Behring), Flebogamma® (Grifols), Gamunex®-C (Grifols), Gammagard® (Takeda), and Octagam® (Octapharma). Gamunex®-C (Grifols), Xembify® (Grifols), Cutaquig® (Octapharma) and Cuvitru® (Takeda). In one example, the anti-FcεRI Ig reduced preparation comprises an undetectable amount of anti-FcεRI Ig. For example, the anti-FcεRI Ig reduced preparation comprises less than 40 μg / mL of anti-FcεRI IgG and / or less than 0.1 kU / L of anti-FcεRI IgE. In one example, the anti-FcεRI Ig reduced preparation comprises less than 40 μg / mL of anti-FcεRI IgG. In one example, the anti-FcεRI Ig reduced preparation comprises less than 35 μg / mL of anti-FcεRI IgG. In one example, the anti-FcεRI Ig reduced preparation comprises less than 30 μg / mL of anti-FcεRI IgG. In one example, the anti-FcεRI Ig reduced preparation comprises less than 25 μg / mL of anti-FcεRI IgG. In one example, the anti-FcεRI Ig reduced preparation comprises less than 20 μg / mL of anti-FcεRI IgG. In one example, the anti-FcεRI Ig reduced preparation comprises less than 15 μg / mL of anti-FcεRI IgG. In one example, the anti-FcεRI Ig reduced preparation comprises less than 10 μg / mL of anti-FcεRI IgG. In one example, the anti-FcεRI Ig reduced preparation comprises less than 5 μg / mL of anti-FcεRI IgG. In one example, the anti-FcεRI Ig reduced preparation comprises less than 0.1 kU / L of anti-FcεRI IgE. In one example, the anti-FcεRI Ig reduced preparation comprises less than 0.01 kU / L of anti-FcεRI IgE. In one example, the anti-FcεRI Ig reduced preparation comprises less than 0.005 kU / L of anti-FcεRI IgE. In one example, the anti-FcεRI Ig reduced preparation comprises less than 0.001 kU / L of anti-FcεRI IgE. In one example, the anti-FcεRI Ig reduced IgG preparation comprises an undetectable amount of anti-FcεRI Ig. For example, the anti-FcεRI Ig reduced IgG preparation comprises less than 40 μg / mL of anti-FcεRI IgG and / or less than 0.1 kU / L of anti-FcεRI IgE. In one example, the anti-FcεRI Ig reduced IgG preparation comprises less than 40 μg / mL of anti-FcεRI IgG. In one example, the anti-FcεRI Ig reduced IgG preparation comprises less than 35 μg / mL of anti- FcεRI IgG. In one example, the anti-FcεRI Ig reduced IgG preparation comprises less than 30 μg / mL of anti-FcεRI IgG. In one example, the anti-FcεRI Ig reduced IgG preparation comprises less than 25 μg / mL of anti-FcεRI IgG. In one example, the anti-FcεRI Ig reduced IgG preparation comprises less than 20 μg / mL of anti-FcεRI IgG. In one example, the anti- FcεRI Ig reduced IgG preparation comprises less than 15 μg / mL of anti-FcεRI IgG. In one example, the anti-FcεRI Ig reduced IgG preparation comprises less than 10 μg / mL of anti- FcεRI IgG. In one example, the anti-FcεRI Ig reduced IgG preparation comprises less than 5 μg / mL of anti-FcεRI IgG. In one example, the anti-FcεRI Ig reduced IgG preparation comprises less than 0.1 kU / L of anti-FcεRI IgE. In one example, the anti-FcεRI Ig reduced IgG preparation comprises less than 0.01 kU / L of anti-FcεRI IgE. In one example, the anti-FcεRI Ig reduced IgG preparation comprises less than 0.005 kU / L of anti-FcεRI IgE. In one example, the anti-FcεRI Ig reduced IgG preparation comprises less than 0.001 kU / L of anti-FcεRI IgE. In one example, the anti-FcεRI Ig reduced preparation does not induce activation of the FcεRI mediated signalling pathway. For example, the anti-FcεRI Ig reduced preparation does not induce basophil and / or mast cell activation and / or degranulation. In one example, the anti- FcεRI Ig reduced preparation does not induce a detectable amount of basophil and / or mast cell activation and / or degranulation. It will be apparent from the disclosure herein that basophil and / or mast cell activation and / or degranulation is determined by determining the proportion of basophils expressing CD63 and / or CD203c and / or mast cells expressing CD107a.In one example, the proportion of basophils expressing CD63 following exposure to the anti-FcεRI Ig reduced IgG preparation is less than 5 %, the proportion of basophils expressing CD203c following exposure to the anti- FcεRI Ig reduced IgG preparation is less than 5 % and / or the proportion of mast cells expressing CD107a following exposure to the anti-FcεRI Ig reduced IgG preparation is less than 5 % of the total population of basophils and / or mast cells exposed to the anti-FcεRI Ig reduced IgG preparation. In another example, the proportion of basophils expressing CD63 following exposure to the anti-FcεRI Ig reduced IgG preparation is less than 5 % of the total population of basophils exposed to the anti-FcεRI Ig reduced IgG preparation. In a further example, the proportion of basophils expressing CD203c following exposure to the anti-FcεRI Ig reduced IgG preparation is less than 5 % of the total population of basophils exposed to the anti-FcεRI Ig reduced IgG preparation. In one example, the proportion of mast cells expressing CD107a following exposure to the anti-FcεRI Ig reduced IgG preparation is less than 5 % of the total population of mast cells exposed to the anti-FcεRI Ig reduced IgG preparation. In one example, the proportion of basophils expressing CD63 following exposure to the anti-FcεRI Ig reduced IgG preparation is less than 5 % of the total population of basophils exposed to the anti-FcεRI Ig reduced IgG preparation and / or the proportion of basophils expressing CD203c following exposure to the anti-FcεRI Ig reduced IgG preparation is less than 5 % of the total population of basophils exposed to the anti-FcεRI Ig reduced IgG preparation. In one example, the proportion of basophils expressing CD63 following exposure to the anti-FcεRI Ig reduced IgG preparation is less than 5 % of the total population of basophils exposed to the anti-FcεRI Ig reduced IgG preparation and / or the proportion of mast cells expressing CD107a following exposure to the anti-FcεRI Ig reduced IgG preparation is less than 5 % of the total population of mast cells exposed to the anti-FcεRI Ig reduced IgG preparation. In one example, the proportion of basophils expressing CD203c following exposure to the anti-FcεRI Ig reduced IgG preparation is less than 5 % of the total population of basophils exposed to the anti-FcεRI Ig reduced IgG preparation and / or the proportion of mast cells expressing CD107a following exposure to the anti-FcεRI Ig reduced IgG preparation is less than 5 % of the total population of mast cells exposed to the anti-FcεRI Ig reduced IgG preparation. In one example, the proportion of basophils expressing CD63 following exposure to the anti-FcεRI Ig reduced IgG preparation is less than 5 % of the total population of basophils exposed to the anti-FcεRI Ig reduced IgG preparation, the proportion of basophils expressing CD203c following exposure to the anti-FcεRI Ig reduced IgG preparation is less than 5 % of the total population of basophils exposed to the anti-FcεRI Ig reduced IgG preparation and / or the proportion of mast cells expressing CD107a following exposure to the anti-FcεRI Ig reduced IgG preparation is less than 5 % of the total population of mast cells exposed to the anti-FcεRI Ig reduced IgG preparation. The present disclosure also provides a pooled IgG preparation, wherein the pooled IgG preparation comprises a detectable amount of an anti-Fc epsilon Receptor I (FcεRI) immunoglobulin (Ig). It will be apparent to the skilled person from the disclosure herein that the pooled IgG preparation with detectable amount of an anti-FcεRI Ig has not been subjected to any method of the present disclosure. Accordingly, the present disclosure also provides a method of detecting anti-FcεRI Ig in a pooled IgG preparation. The present disclosure also provides a method of treating, preventing and / or delaying progression of a condition relating to an immune deficiency, an inflammatory disease, an autoimmune disease and / or an acute infection in a subject, the method comprising administering the anti-FcεRI Ig reduced preparation, the anti-FcεRI Ig reduced IgG preparation or the pharmaceutical composition described herein. For example, the disclosure provides a method of treating a condition relating to an immune deficiency, an inflammatory disease, an autoimmune disease and / or an acute infection in a subject, the method comprising administering the anti-FcεRI Ig reduced preparation, the anti-FcεRI Ig reduced IgG preparation or the pharmaceutical composition described herein. The disclosure also provides a method of preventing a condition relating to an immune deficiency, an inflammatory disease, an autoimmune disease and / or an acute infection in a subject, the method comprising administering the anti-FcεRI Ig reduced preparation, the anti-FcεRI Ig reduced IgG preparation or the pharmaceutical composition described herein. The disclosure further provides a method of delaying progression of a condition relating to an immune deficiency, an inflammatory disease, an autoimmune disease and / or an acute infection in a subject, the method comprising administering the anti-FcεRI Ig reduced preparation, the anti-FcεRI Ig reduced IgG preparation or the pharmaceutical composition described herein. The present disclosure also provides the anti-FcεRI Ig reduced preparation, the anti-FcεRI Ig reduced IgG preparation or the pharmaceutical composition described herein for use in treating, preventing and / or delaying progression of a condition relating to an immune deficiency, an inflammatory disease, an autoimmune disease and / or an acute infection in a subject. The disclosure also provides the anti-FcεRI Ig reduced preparation, the anti-FcεRI Ig reduced IgG preparation or the pharmaceutical composition described herein for use in treating of a condition relating to an immune deficiency, an inflammatory disease, an autoimmune disease and / or an acute infection in a subject. The disclosure also provides the anti-FcεRI Ig reduced preparation, the anti-FcεRI Ig reduced IgG preparation or the pharmaceutical composition described herein for use in preventing of a condition relating to an immune deficiency, an inflammatory disease, an autoimmune disease and / or an acute infection in a subject. The disclosure also provides the anti-FcεRI Ig reduced preparation, the anti-FcεRI Ig reduced IgG preparation or the pharmaceutical composition described herein for use in delaying progression of a condition relating to an immune deficiency, an inflammatory disease, an autoimmune disease and / or an acute infection in a subject. The present disclosure also provides use of the anti-FcεRI Ig reduced preparation, the anti- FcεRI Ig reduced IgG preparation or the pharmaceutical composition described herein for treating, preventing and / or delaying progression of a condition relating to an immune deficiency, an inflammatory disease, an autoimmune disease and / or an acute infection in a subject. The present disclosure also provides use of the anti-FcεRI Ig reduced preparation, the anti-FcεRI Ig reduced IgG preparation or the pharmaceutical composition described herein for treating a condition relating to an immune deficiency, an inflammatory disease, an autoimmune disease and / or an acute infection in a subject. The present disclosure also provides use of the anti-FcεRI Ig reduced preparation, the anti-FcεRI Ig reduced IgG preparation or the pharmaceutical composition described herein for preventing a condition relating to an immune deficiency, an inflammatory disease, an autoimmune disease and / or an acute infection in a subject. The present disclosure also provides use of the anti-FcεRI Ig reduced preparation, the anti-FcεRI Ig reduced IgG preparation or the pharmaceutical composition described herein for delaying progression of a condition relating to an immune deficiency, an inflammatory disease, an autoimmune disease and / or an acute infection in a subject. The present disclosure also provides use of the anti-FcεRI Ig reduced preparation, the anti- FcεRI Ig reduced IgG preparation or the pharmaceutical composition described herein in the manufacture of a medicament for the treatment, prevention and / or delayed progression of an immune deficiency, an inflammatory disease, an autoimmune disease and / or an acute infection in a subject. The present disclosure also provides use of the anti-FcεRI Ig reduced preparation, the anti-FcεRI Ig reduced IgG preparation or the pharmaceutical composition described herein in the manufacture of a medicament for the treatment of an immune deficiency, an inflammatory disease, an autoimmune disease and / or an acute infection in a subject. The present disclosure also provides use of the anti-FcεRI Ig reduced preparation, the anti-FcεRI Ig reduced IgG preparation or the pharmaceutical composition described herein in the manufacture of a medicament for the prevention of an immune deficiency, an inflammatory disease, an autoimmune disease and / or an acute infection in a subject. The present disclosure also provides use of the anti-FcεRI Ig reduced preparation, the anti-FcεRI Ig reduced IgG preparation or the pharmaceutical composition described herein in the manufacture of a medicament for delaying progression of an immune deficiency, an inflammatory disease, an autoimmune disease and / or an acute infection in a subject. The present disclosure also provides a method of preparing an immunoglobulin (Ig) preparation from a plasma sample or a fraction thereof, the Ig preparation having reduced adverse reactions in a subject, the method comprising detecting the presence of anti-FcεRI Ig in the plasma sample or fraction thereof according to any method described herein and producing an Ig preparation having reduced adverse reactions. In one example, the condition is selected from the group consisting of primary immunodeficiency disease, chronic inflammatory demyelinating polyneuropathy and chronic immune thrombocytopenic purpura. In one example, the condition is primary immunodeficiency disease. In another example, the condition is chronic inflammatory demyelinating polyneuropathy. In a further example, the condition is chronic immune thrombocytopenic purpura. The present disclosure also provides a method of preparing an immunoglobulin (Ig) preparation from a plasma sample or a fraction thereof, the Ig preparation having reduced adverse reactions in a subject, the method comprising determining the proportion of basophil and / or mast cell activation and / or degranulation following exposure to the plasma sample or fraction thereof; (i) including the plasma sample or fraction thereof into the Ig preparation if the proportion of basophils expressing CD63 following exposure to the plasma sample or fraction thereof is less than 1 %, less than 2 %, less than 3 %, less than 4 % or less than 5 % of the total population of basophils exposed to the plasma sample or fraction thereof; (ii) excluding the plasma sample or fraction thereof into the Ig preparation if the proportion of basophils expressing CD63 following exposure to the plasma sample or fraction thereof is more than 5 %, more than 6 %, more than 7 %, more than 8 %, more than 9 %, more than 10 %, more than 11 %, more than 12 %, more than 13 %, more than 14 % or more than 15 % of the total population of basophils exposed to the plasma sample or fraction thereof; (iii) including the plasma sample or fraction thereof into the Ig preparation if the proportion of basophils expressing CD203c following exposure to the plasma sample or fraction thereof is less than 1 %, less than 2 %, less than 3 %, less than 4 % or less than 5 % of the total population of basophils exposed to the plasma sample or fraction thereof; (iv) excluding the plasma sample or fraction thereof into the Ig preparation if the proportion of basophils expressing CD203c following exposure to the plasma sample or fraction thereof is more than 5 %, more than 6 %, more than 7 %, more than 8 %, more than 9 %, more than 10 %, more than 11 %, more than 12 %, more than 13 %, more than 14 % or more than 15 % of the total population of basophils exposed to the plasma sample or fraction thereof; (v) including the plasma sample or fraction thereof into the Ig preparation if the proportion of mast cells expressing CD107a following exposure to the plasma sample or fraction thereof is less than 1 %, less than 2 %, less than 3 %, less than 4 % or less than 5 % of the total population of mast cells exposed to the plasma sample or fraction thereof; and / or (vi) excluding the plasma sample or fraction thereof into the Ig preparation if the proportion of mast cells expressing CD107a following exposure to the plasma sample or fraction thereof is more than 5 %, more than 6 %, more than 7 %, more than 8 %, more than 9 %, more than 10 %, more than 11 %, more than 12 %, more than 13 %, more than 14 % or more than 15 % of the total population of mast cells exposed to the plasma sample or fraction thereof. The present disclosure also provides methods for identifying a plasma donation suitable for the production of an Ig preparation. BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a graphical representation of a MRGPRX2 receptor-mediated activation profile for Cortistatin 14 (A, positive control), single plasma Donors (B, C, including Donor Z), affected (D, F) and non-affected products (E, G). Figure 2 is a graphical representation of a Hoxb8 mast cell activation by IVIG. Non- affected lots labelled as Ctrl-P. Affected lots labelled as AE-P (A) or unlabelled (B). Formulation buffer is used as negative control (data not shown). Figure 3 is a graphical representation of a Hoxb8 mast cell activation by SCIG. Non- affected lots labelled as Ctrl-H. Affected lots labelled as AE-H (A) or unlabelled (B). Formulation buffer is used as negative control (data not shown). Figure 4 is a graphical representation of mast cell activation profiles for 17 tested single Donor plasma (A, B). Plasma 1 sample is from designated donor Z. The arrow indicates the activation signal for Plasma 1. Figure 5 is a graphical representation of mast cell activation profiles profiles for untreated (A), IgG depleted (B) and IgE depleted plasma (C) from donors 1, 2 and 3. The exclamation marks indicate abrogation of Hoxb8 mast cell activation. Figure 6 is a graphical representation of mast cell activation profiles with blocking of IgG binding to FcγRIIb by Fc-based anti-CD16 / 32 antibody. Dotted line highlights the 5 % threshold. Figure 7 is a graphical representation of mast cell activation profiles with blocking of IgE binding to FcεRIα by soluble FcεRIα. The exclamation marks indicate partial abrogation of Hoxb8 mast cell activation. Dotted line highlights the 5 % threshold. Figure 8 is a graphical representation of mast cell activation profiles with a cell intrinsic block by targeting BTK with Ibrutinib. The exclamation marks indicate abrogation of Hoxb8 mast cell activation. Dotted line highlights the 5 % threshold. Figure 9 is a graphical representation of mast cell activation profiles with blocking of C5a- dependent mast cell activation by use of C5aR antagonist. Dotted line highlights the 5 % threshold. Figure 10 is a graphical representation of activation of basophil degranulation (CD63+) by IVIG using basophils Donors 1 (A), 2 (B), 3 (C). Non-affected lots labelled as Ctrl-P. Affected lots labelled as AE-P or unlabelled. Upper dotted line highlights the 5 % threshold, lower dotted line highlights the baseline. Figure 11 is a graphical representation of activation of basophil degranulation (CD63+) by SCIG using basophils from basophil Donors 1 (A), 2 (B), 3 (C). Non-affected lots labelled as Ctrl-H. Affected lots labelled as AE-H. Upper dotted line highlights the 5 % threshold, lower dotted line highlights the baseline. Figure 12 is a graphical representation of activation of basophil degranulation (CD63+) by individual plasma samples using basophils Donors 1 (A), 2 (B), 3 (C). Plasma 1 sample is from designated donor Z. The arrows indicate the activation signal for Plasma 1 for all basophils donors at undiluted condition. Upper dotted line highlights the 5 % threshold, lower dotted line highlights the baseline. Figure 13 is a graphical representation of activation of basophil degranulation, CD63+ (A) and CD203c+ (B) without IL-3 by individual plasma samples using basophils from Donor 1. Dotted line highlights the 5 % threshold. Figure 14 is a graphical representation of activation of basophil degranulation CD63+ (A) and CD203c+ (B) without IL-3 by individual plasma samples using basophils from basophil Donor 2. Dotted line highlights the 5 % threshold. Figure 15 is a graphical representation of activation of basophil degranulation CD63+ (A) and CD203c+ (B) without IL-3 by individual plasma samples using basophils from basophil Donor 3. Dotted line highlights the 5 % threshold. Figure 16 is a graphical representation of activation of basophil degranulation (CD203c+) by SCIG (A) and IVIG (B) using basophils Donor 1. Upper dotted line highlights the 5 % threshold, lower dotted line highlights the baseline. The exclamation mark indicates activation signal exceeding threshold. For each lot the activation of basophil degranulation is plotted from left to right at a concentration of SCIG (A) or of IVIG (B) as used in the assay of 2, 20, 200, 2000, 20000, and 40000 µg / mL. For each lot on the right hand side in each panel, the activation for the 2000 µg / mL SCIG (A) or of IVIG (B) concentration spiked with anti-FcεRI is plotted as stimulation control. Figure 17 is a graphical representation of activation of basophil degranulation (CD203c+) by SCIG (A) and IVIG (B) using basophils Donor 2. Upper dotted line highlights the 5 % threshold, lower dotted line highlights the baseline. For each lot the activation of basophil degranulation is plotted from left to right at a concentration of SCIG (A) or of IVIG (B) as used in the assay of 2, 20, 200, 2000, 20000, and 40000 µg / mL. For each lot on the right hand side in each panel, the activation for the 2000 µg / mL SCIG (A) or of IVIG (B) concentration spiked with anti-FcεRI is plotted as stimulation control. Figure 18 is a graphical representation of activation of basophil degranulation (CD203c+) by SCIG (A) and IVIG (B) using basophils Donor 3. Upper dotted line highlights the 5 % threshold, lower dotted line highlights the baseline. For each lot the activation of basophil degranulation is plotted from left to right at a concentration of SCIG (A) or of IVIG (B) as used in the assay of 2, 20, 200, 2000, 20000, and 40000 µg / mL. For each lot on the right hand side in each panel, the activation for the 2000 µg / mL SCIG (A) or of IVIG (B) concentration spiked with anti-FcεRI is plotted as stimulation control. Figure 19 is a graphical representation of basophil degranulation (CD203c+) by individual plasma samples using basophils Donors 1 (A), 2 (B), 3 (C). Upper dotted line highlights the 5 % threshold, lower dotted line highlights the baseline, spiked means anti-FcεRI (stimulation control). For each plasma sample using basophils Donors 1 (A), 2 (B), 3 (C), the basophil degranulation is plotted from left to right for the following tested plasma dilutions: undiluted, 1:10, 1:100, 1:1000, 1:10000, and 1:100000. For each plasma sample tested, on the right hand side in each panel a 1:10 dilution spiked with anti-FcεRI is plotted as stimulation control. Figure 20 is a graphical representation of basophil degranulation profiles (CD203c+) for untreated, IgG depleted, IgG enriched and IgE depleted plasma from donors 1 (A, D, G), 2 (B, E, H) and 3 (C, F, I). Plasma 1 sample is from designated donor Z. The arrows indicate abrogation of the activation signal for Plasma 1 for all basophils donors for IgG depleted plasma. Upper dotted line highlights the 5 % threshold, lower dotted line highlights the baseline, spiked means anti-FcεRI (stimulation control). DETAILED DESCRIPTION General Throughout this specification, unless specifically stated otherwise or the context requires otherwise, reference to a single step, composition of matter, group of steps or group of compositions of matter shall be taken to encompass one and a plurality (i.e., one or more) of those steps, compositions of matter, groups of steps or groups of compositions of matter. Those skilled in the art will appreciate that the present disclosure is susceptible to variations and modifications other than those specifically described. It is to be understood that the disclosure includes all such variations and modifications. The disclosure also includes all of the steps, features, compositions and compounds referred to or indicated in this specification, individually or collectively, and any and all combinations or any two or more of said steps or features. The present disclosure is not to be limited in scope by the specific examples described herein, which are intended for the purpose of exemplification only. Functionally-equivalent products, compositions and methods are clearly within the scope of the present disclosure. Any example of the present disclosure herein shall be taken to apply mutatis mutandis to any other example of the disclosure unless specifically stated otherwise. Unless specifically defined otherwise, all technical and scientific terms used herein shall be taken to have the same meaning as commonly understood by one of ordinary skill in the art (for example, in immunology, immunohistochemistry, protein chemistry, and biochemistry). Unless otherwise indicated, the recombinant protein, cell culture, and immunological techniques utilised in the present disclosure are standard procedures, well known to those skilled in the art. Such techniques are described and explained throughout the literature in sources such as, J. Perbal, A Practical Guide to Molecular Cloning, John Wiley and Sons (1984), J. Sambrook et al. Molecular Cloning: A Laboratory Manual, Cold Spring Harbour Laboratory Press (1989), T.A. Brown (editor), Essential Molecular Biology: A Practical Approach, Volumes 1 and 2, IRL Press (1991), D.M. Glover and B.D. Hames (editors), DNA Cloning: A Practical Approach, Volumes 1-4, IRL Press (1995 and 1996), and F.M. Ausubel et al. (editors), Current Protocols in Molecular Biology, Greene Pub. Associates and Wiley- Interscience (1988, including all updates until present), Ed Harlow and David Lane (editors) Antibodies: A Laboratory Manual, Cold Spring Harbour Laboratory, (1988), and J.E. Coligan et al. (editors) Current Protocols in Immunology, John Wiley & Sons (including all updates until present). The term “and / or”, e.g., “X and / or Y” shall be understood to mean either “X and Y” or “X or Y” and shall be taken to provide explicit support for both meanings or for either meaning. Throughout this specification the word “comprise”, or variations such as “comprises” or “comprising”, will be understood to imply the inclusion of a stated element, integer or step, or group of elements, integers or steps, but not the exclusion of any other element, integer or step, or group of elements, integers or steps. Selected Definitions The term “immunoglobulin (Ig)” shall be taken to mean a protein or antibody present in the serum and cells of the immune system. There are several types of Ig, for example, IgG, IgE, IgM, IgD, IgA, and IgY. As used herein, “an anti-Fc epsilon Receptor I (FcεRI) immunoglobulin (Ig)” or “anti-FcεRI Ig” shall be understood to refer to any Ig that binds to the FcεRI, a fragment thereof or an epitope of FcεRI. As used herein the term “FcεRI mediated signaling pathway” refers to crosslinking of the FcεRI leading to basophil and / or mast cell activation and / or degranulation. The term “plasma” shall refer to the straw-coloured / pale yellow component of blood obtained from one or more blood donor(s). Methods of obtaining plasma from a donor will be apparent to a skilled person and / or described herein. For example, plasma is obtained by removing red blood cells from donated blood. For example, plasma is obtained by plasmapheresis. The term “plasma sample” or “fraction thereof” shall refer to plasma which has been fractionated to isolate one or more desirable protein components from the plasma. For example, plasma may be fractionated to isolate cryo-precipitates (proteins that precipitate out of solution when a unit of fresh frozen plasma is slowly thawed in the cold) and cryosupernatant (also known as cryo-poor plasma). For example, plasma may be fractionated by ethanol precipitation to produce IgG-containing Oncley fractions, Cohn fractions, ammonium sulphate precipitates, or Precipitate A (KN A) from plasma as described in US patent 3,301,842. Plasma fractions include II+III precipitate produced according to Cohn methods such as Method 6, Cohn et. al. J. Am; Chem. Soc., 68 (3), 459-475 (1946), Method 9, Oncley et al. J. Am; Chem. Soc., 71, 541-550 (1946), or the I+II+III precipitate, Method 10, Cohn et.al. J. Am; Chem. Soc., 72, 465-474 (1950); as well as the method of Deutsch et.al. J. Biol. Chem.164, 109-118 (1946) or the Precipitate-A of Nitschmann and Kistler Vox Sang.7, 414-424 (1962); Helv. Chim. Acta 37, 866-873 (1954). For example, the plasma may be fractionated by octanoic acid fractionation as described in European application 893450. Typically, Cohn Fractions, Kistler / Nitschmann Precipitate A (KN A) exist as a suspended paste. Other purification techniques including chromatography may be used. As used herein, an “IgG intermediate product” refers to any material obtained between the manufacturing steps. For example, supernatants or fractions of the starting material. As used herein “mast cells” shall be understood to refer to granulated tissue-resident cells known for host cell response, allergic response, and vascular homeostasis. As used herein “basophils” shall be understood to refer to the largest type of granulocyte representing about 0.5 % to 1 % of circulating white blood cells. Their activation and degranulation is involved in inflammatory reactions during immune response, as well as in the formation of acute and chronic allergic diseases. The term “protein” shall be taken to include a single polypeptide chain, i.e., a series of contiguous amino acids linked by peptide bonds or a series of polypeptide chains covalently or non-covalently linked to one another (i.e., a polypeptide complex). For example, the series of polypeptide chains can be covalently linked using a suitable chemical or a disulfide bond. Examples of non-covalent bonds include hydrogen bonds, ionic bonds, Van der Waals forces, and hydrophobic interactions. The term “polypeptide” or “polypeptide chain” will be understood from the foregoing paragraph to mean a series of contiguous amino acids linked by peptide bonds. The skilled artisan will be aware that an “antibody” is generally considered to be a protein that comprises a variable region made up of a plurality of polypeptide chains, e.g., a polypeptide comprising a light chain variable region (VL) and a polypeptide comprising a heavy chain variable region (VH). An antibody also generally comprises constant domains, some of which can be arranged into a constant region, which includes a constant fragment or fragment crystallizable (Fc), in the case of a heavy chain. A VHand a VLinteract to form a Fv comprising an antigen binding region that is capable of specifically binding to one or a few closely related antigens. Generally, a light chain from mammals is either a κ light chain or a λ light chain and a heavy chain from mammals is α, δ, ε, γ, or μ. Antibodies can be of any type (e.g., IgG, IgE, IgM, IgD, IgA, and IgY), class (e.g., IgG1, IgG2, IgG3, IgG4, IgA1and IgA2) or subclass. The term “antibody” also encompasses humanized antibodies, primatized antibodies, human antibodies, synhumanized antibodies and chimeric antibodies. As used herein, “variable region" refers to the portions of the light and / or heavy chains of an antibody as defined herein that is capable of specifically binding to an antigen and includes amino acid sequences of complementarity determining regions (CDRs); i.e., CDRl, CDR2, and CDR3, and framework regions (FRs). Exemplary variable regions comprise three or four FRs (e.g., FR1, FR2, FR3 and optionally FR4) together with three CDRs. VH refers to the variable region of the heavy chain. VL refers to the variable region of the light chain. As used herein, the term “detect” or “detecting” refers to the identification of the presence or existence of an anti-FcεRI Ig in a plasma sample. As used herein, the term “contact” or “contacting” is used to refer to a direct or indirect interaction or association between a ligand or reagent described herein and a molecule. For example, a ligand (such as FcεRI or fragment or epitope thereof) either directly or indirectly binds to an anti-FcεRI Ig in a plasma sample or fraction thereof. The term also encompasses the interaction between e.g a first protein (such as a detection protein) with e.g., a second molecule (such as an antibody). As used herein, the term “binds” in reference to the interaction of a protein with an antigen means that the interaction is dependent upon the presence of a particular structure (e.g., an antigenic determinant or epitope) on the antigen. For example, an antibody recognizes and binds to a specific protein structure rather than to proteins generally. If an antibody binds to epitope "A", the presence of a molecule containing epitope “A” (or free, unlabeled “A”), in a reaction containing labeled “A” and the antibody, will reduce the amount of labeled “A” bound to the antibody. As used herein, the term “specifically binds” or “binds specifically” shall be taken to mean that an antibody of the disclosure reacts or associates more frequently, more rapidly, with greater duration and / or with greater affinity with a particular antigen (e.g., S protein or RBD) than it does with alternative antigens. For example, an antibody binds to S protein or RBD with materially greater affinity (e.g., 20 fold or 40 fold or 60 fold or 80 fold to 100 fold or 150 fold or 200 fold greater affinity) avidity, more readily, and / or with greater duration than it binds to other antigens, e.g., to antigens commonly recognized by polyreactive natural antibodies (i.e., by naturally occurring antibodies known to bind a variety of antigens naturally found in humans). Generally, but not necessarily, reference to binding means specific binding, and each term shall be understood to provide explicit support for the other term. As used herein, the term “epitope” (syn. “antigenic determinant”) shall be understood to mean a region of protein to which a protein comprising an antibody variable region binds. This term is not necessarily limited to the specific residues or structure to which the protein makes contact. For example, this term includes the region spanning amino acids contacted by the protein and / or 5-10 or 2-5 or 1-3 amino acids outside of this region. In some examples, the epitope comprises a series of discontinuous amino acids that are positioned close to one another when the protein is folded, i.e., a “conformational epitope”. The skilled artisan will also be aware that the term "epitope" is not limited to peptides or polypeptides. For example, the term “epitope” includes chemically active surface groupings of molecules such as sugar side chains, phosphoryl side chains, or sulfonyl side chains, and, in certain examples, may have specific three dimensional structural characteristics, and / or specific charge characteristics. The term “affinity chromatography resin” shall be taken to mean a resin comprising an affinity chromatography ligand (e.g. FcεRI, or fragment or epitope thereof) attached to a matrix as would be apparent to the skilled artisan and / or as described herein. The term “ligand” shall be understood to mean a molecule immobilised to a matrix of the chromatography column which interacts anti-FcεRI Ig. For example, the ligand comprises a FcεRI or fragment or epitope thereof. In one example, the ligand is a FcεRI or fragment or epitope thereof. In another example, the ligand is a FcεRI antibody or fragment thereof. In a further example, the ligand is a FcεRI DNA aptamer. The term “matrix” shall be taken to mean a support to which molecules may be attached, directly or indirectly. The matrix may include any substrate material that is capable of providing physical support for the compositions described herein. The materials may be naturally occurring, synthetic, or a modification of a naturally occurring material. Suitable matrix materials may include glass fibers, polyester, cellulose, rayon, silicon, a silicon wafer chip, graphite, mirrored surfaces, laminates, membranes, ceramics, plastics (including polymers such as, e.g., poly(vinyl chloride), cyclo-olefin copolymers, agarose gels or beads, polyacrylamide, polyacrylate, polyethylene, polypropylene, poly(4-methylbutene), polystyrene, polymethacrylate, poly(ethylene terephthalate), polytetrafluoroethylene (PTFE or Teflon®), nylon, poly(vinyl butyrate)), germanium, gallium arsenide, gold, silver, Langmuir Blodgett films, a flow through chip, etc., either used by themselves or in conjunction with other materials. Additional rigid materials may be considered, such as glass, which includes silica and further includes, for example, glass that is available as Bioglass. Other materials that may be employed include porous materials, such as, for example, controlled pore glass beads, crosslinked beaded Sepharose® or agarose resins, or copolymers of crosslinked bis- acrylamide and azalactone. The term “pharmaceutical composition” shall be taken to mean a formulation of Ig with compounds generally accepted in the art for the delivery of Ig to mammals. Exemplary compounds include all pharmaceutically acceptable carriers, diluents or excipients thereof. The term “treat” or “treatment” or “treating” shall be taken to mean administering a therapeutically effective amount of Ig such that one or more symptoms or characteristics of the condition is reduced in the subject or that the subject is no longer clinically diagnosed with the condition. The term “preventing”, “prevent” or “prevention” includes providing prophylaxis with respect to occurrence or recurrence of a specified condition in a subject. A subject may be predisposed to or at risk of developing a condition but has not yet been diagnosed with the condition. As used herein, the phrase “delaying progression of” includes reducing or slowing down the progression of a condition in a subject and / or more than one symptom of the condition. The term “condition” shall be taken to mean a state of being or health status of a subject in need of treatment with Ig. The term “subject” shall be taken to mean any animal including humans, for example a mammal. Exemplary subjects include but are not limited to humans and non-human primates. For example, the subject is a human. Fc epsilon Receptor I (FcεRI) The present disclosure provides a method of identifying an anti-Fc epsilon Receptor I (FcεRI) immunoglobulin (Ig) in a plasma sample or a fraction thereof. As used herein, the term “Fc epsilon Receptor I (FcεRI)” shall be understood to refer to an antigen present on mast cells, basophils, epidermal Langerhans cells, eosinophils and other antigen-presenting cells. FcεRI is multimeric receptor and a member of a family of related antigen / Fc receptors which have conserved structural features and similar roles in initiating intracellular signalling cascades. In humans, two types of FcεRI are expressed on the cell surface, a tetrameric receptor consisting of an α-chain, a β-chain and a homodimeric γ-chain (αβγ2) and a trimeric receptor consisting of an α-chain and a homodimeric γ-chain (αγ2). FcεRI is responsible for the activation and degranulation of mast cells and basophils. Antigenic crosslinking for example, through IgE and / or IgG binding, of the FcεRI initiates multiple signalling pathways, referred to as “FcεRI mediated signalling pathway”, which control diverse effector responses. These include the secretion of allergic mediators and induction of cytokine gene transcription, resulting in secretion of molecules such as interleukin-4, interleukin-6, tumour-necrosis factor-α and granulocyte-macrophage colony-stimulating factor. FcεRI is therefore central to the induction and maintenance of an allergic response. Detecting, Identifying and Screening for anti-FcεRI Ig The present disclosure provides a method of detecting an anti-FcεRI Ig in a plasma sample or a fraction thereof. In addition, the present disclosure provides a method of screening for an anti-FcεRI Ig in a plasma sample or a fraction thereof. The present disclosure also provides methods of identifying a plasma sample or a fraction thereof suitable for administration to a subject. The present disclosure also provides methods of identifying a plasma sample or fraction thereof for use in producing an immunoglobulin (Ig) preparation for administration to a subject. Furthermore, the present disclosure provides methods of screening a plasma sample or a fraction thereof to determine suitability for administration to a subject. The present disclosure also provides methods of screening a plasma sample or a fraction thereof for use in producing an immunoglobulin (Ig) preparation for administration to a subject. It will be apparent to the skilled person that a plasma sample or fraction thereof that comprises a detectable amount of an anti-FcεRI Ig is not suitable for administration to the subject and / or for use in producing an Ig preparation for administration to the subject. As used herein, a “detectable amount” shall be understood to mean any quantity or amount of anti-FcεRI Ig that induces activation of the FcεRI mediated signalling pathway. It will be apparent to the skilled person from the disclosure herein that anti-FcεRI Ig may still be present in a plasma sample or fraction thereof, but is in an amount that is insufficient to induce activation of the FcεRI mediated signalling pathway. For example, activation of the FcεRI mediated signalling pathway can occur when there is more than 40 μg / mL of an anti-FcεRI IgG in a sample and / or more than 0.1 kU / L of an anti-FcεRI IgE in a sample. In one example, activation of the FcεRI mediated signalling pathway can occur when the proportion of basophils expressing CD63 following exposure to a sample is more than 5 % of the total population of basophils exposed to the sample and / or the proportion of basophils expressing CD203c following exposure to a sample is more than 5 % of the total population of basophils exposed to the sample and / or the proportion of mast cells expressing CD107a following exposure to a sample is more than 5 % of the total population of mast cells exposed to the sample. For example, the proportion of basophils expressing CD63 and / or CD203c is relative to the total proportion of basophils being exposed to the plasma sample or fraction thereof. In one example, the proportion of mast cells expressing CD107a is relative to the total proportion of mast cells being exposed to the plasma sample or fraction thereof. In alternative examples, a plasma sample or fraction thereof that does not comprise a detectable amount of an anti-FcεRI Ig is suitable for administration to the subject. For example, the method further comprises administering the plasma sample to a subject if anti-FcεRI Ig is not present or not detectable in the plasma sample or fraction thereof. The present disclosure further provides methods for identifying a subject suitable for plasma donation for the production of an Ig preparation. Additionally, the present disclosure provides methods of screening for a subject suitable for plasma donation for the production of an Ig preparation. The present disclosure also provides methods for identifying a plasma donation suitable for the production of an Ig preparation. It will be apparent to the skilled person that a plasma sample or fraction thereof from the subject that exhibits a detectable amount of an anti-FcεRI Ig is indicative that the subject is not a suitable candidate for plasma donation for the production of an Ig preparation. Furthermore, a plasma sample or fraction thereof that exhibits a detectable amount of an anti-FcεRI Ig is indicative that the plasma sample or fraction thereof is not suitable for production of an Ig preparation. In alternative examples, a plasma sample or fraction thereof from the subject that does not comprise a detectable amount of an anti-FcεRI Ig is indicative that the subject is a suitable candidate for plasma donation for the production of an Ig preparation. Furthermore, a plasma sample or fraction thereof that does not exhibit a detectable amount of an anti-FcεRI Ig is indicative that the plasma sample or fraction thereof is suitable for production of an Ig preparation. For example, the method further comprises donating the plasma sample or fraction thereof for the production of an Ig preparation if a detectable amount of the anti-FcεRI Ig is not present. Such methods of detecting, screening and / or identifying will be apparent to the skilled person and / or are described herein. Exemplary methods for detecting, screening and / or identifying an anti-FcεRI Ig in a plasma sample or a fraction thereof or subject use ligands which bind to the anti-Fc epsilon Receptor I (FcεRI) Ig (e.g., a FcεRI or fragment or epitope thereof) and include a lateral flow assay and an ELISA. Methods of determining the levels of anti-FcεRI Ig will be apparent to the skilled person and / or described herein. In one example, the method comprises performing an enzyme-linked immunosorbent assay (ELISA). In a further example, the method comprises performing an fluorescence linked immunosorbent assay (FLISA). In another example, the method comprises performing a lateral flow immunoassay. Enzyme-linked immunosorbent assay (ELISA) and Fluorescence Linked Immunosorbent Assay (FLISA) The present disclosure provides an ELISA or FLISA for detecting, identifying and / or screening an anti-FcεRI Ig in a plasma sample or a fraction thereof, the assay comprising a ligand (e.g., a FcεRI or fragment or epitope thereof). Standard solid-phase ELISA or FLISA formats are particularly useful in determining the concentration of a protein (e.g., an antibody or Ig) from a variety of samples. In one form such an assay involves immobilizing a biological sample onto a solid matrix. A ligand (e.g., a FcεRI or fragment or epitope thereof) that specifically binds to a protein (i.e., anti-FcεRI Ig) within a plasma sample of fraction thereof is brought into direct contact with the immobilized ligand, and forms a direct bond with any of its target protein present in said sample. This ligand is generally labeled with a detectable reporter molecule, such as for example, a fluorescent label (e.g. FITC or Texas Red) or a fluorescent semiconductor nanocrystal (as described in US 6,306,610) in the case of a FLISA or an enzyme (e.g. horseradish peroxidase (HRP), alkaline phosphatase (AP) or β-galactosidase) in the case of an ELISA, or alternatively a labeled protein or antibody can be used that binds to the first antibody. Following washing to remove any unbound protein the label is detected either directly, in the case of a fluorescent label, or through the addition of a substrate, such as for example hydrogen peroxide, TMB, or toluidine, or 5-bromo-4-chloro-3-indol-beta-D- galaotopyranoside (x-gal) in the case of an enzymatic label. Such ELISA or FLISA based systems are suitable for quantification of the amount of a protein in a sample, by calibrating the detection system against known amounts of a standard to which the ligand binds, such as for example, the anti-FcεRI Ig. The skilled person will understand that the method of the present disclosure is suitable for use on a capture enzyme-linked immunosorbent assay (ELISA) or enzyme immunoassay (EIA). As used herein, the term “ELISA” or “sandwich ELISA” or “capture ELISA” or “EIA” refers to immobilizing a ligand (specific for the anti-FcεRI Ig) onto a matrix, such as, for example, a membrane, a polystyrene or polycarbonate microwell, a polystyrene or polycarbonate dipstick or a glass support, followed by addition of an amount of a plasma sample. The molecule is then “bound” or “captured”. The captured anti-FcεRI Ig is detected by the detection protein or detection antibody which can be covalently linked to an enzyme, or can itself be detected by addition of a secondary protein or antibody which is linked to an enzyme. It will be apparent to the skilled person that the assay formats described herein are amenable to high throughput formats, such as, for example automation of screening processes or a microarray format as described in Mendoza et al., 1999. Furthermore, variations of the above- described assay will be apparent to those skilled in the art, such as, for example, a competitive ELISA. Lateral flow assays The present disclosure provides a lateral flow assay for detecting and / or screening an anti- FcεRI Ig in a plasma sample or a fraction thereof, the assay comprising a ligand, and a lateral flow assay device. Lateral flow assays, also known as “immunochromatographic strip tests” operate on the same principles as enzyme-linked immunosorbent assays (ELISA). In essence, these tests run a liquid sample along the surface of a membrane or filter paper with reactive molecules that show a visual positive or negative result depending on the presence of a particular analyte (e.g., an anti-FcεRI Ig). A lateral flow assay device is a test system for the detection of analytes or components of interest in a sample, for example, to detect the presence of an anti-FcεRI Ig in a plasma sample or a fraction thereof. A lateral flow assay device is a device configured to receive a sample at a sample region and to provide for the sample to move laterally, via, e.g. wicking, by capillary action from the sample region to a detection region. In certain examples, the lateral flow assay device further comprises one or more conjugation region(s), wherein the lateral flow assay device is configured to provide for lateral flow of a sample from a sample region to one or more conjugation region(s) prior to reaching a detection region. In related examples of a lateral flow assay device, a sample region is in contact with a conjugation region and the conjugation region is in contact with one end of a detection region such that the lateral flow assay device is configured to allow a sample to flow from the sample region to a conjugation region and finally to a detection region. In certain examples of the lateral flow assay device, the device further comprises an absorbent region in contact with a detection region such that the device is configured to allow the flow of a sample from a sample region to a detection region and finally to the absorbent region. A lateral assay device typically has a matrix onto which an optional sample region, an optional conjugation region, the detection region, and an optional absorbent region are mounted. The matrix (“backing card”) provides support for the pads and membranes of the actual assay but are otherwise not involved in the reaction or flow of the sample and analyte. Backing cards are for example made of polyvinylchloride (PVC). The assembly of pads and membranes on the backing card will typically be in a plastic housing although this is not required. The housing may have more than one opening (“sample port”) over the sample pad for application of the sample. The control and test zones are visible (e.g. via an opening or window) to detect or measure the bound label. The housing prevents the user from applying the sample anywhere except the sample pad. The housing also serves to protect the strip from inadvertent splash onto the membrane. External labelling on the housing can also be used to indicate the position of test and control lines and provide other information. Housings can be obtained as off-the- shelf cassettes or custom-designed to fit around the strip. Internal pins and bars can be used to hold the strip in place relative to the sample port and viewing window. They hold the materials in fluid communication with one another while the test strip is running. The “sample region”, if present, receives the sample upon application and promotes the even distribution of the sample onto the detection region or conjugation region, if present. It may also influence the rate at which liquid enters the detection region, preventing flooding of the device. In addition, the sample pad may also comprise additional components such as proteins, detergents, viscosity enhancers and buffer salts in order to process the sample (e.g. separation of sample components in the case of blood samples, removal of interferences, adjustment of pH, increasing the viscosity, solubilising components and / or preventing non- specific binding between conjugate and analyte or other components or to the reaction membrane). The “conjugate region” or “conjugation region”, if present, comprises a dried and mobilisable composition comprising the labelled antibody or labelled protein. When sample flows into the conjugation region, the labelled antibody or labelled protein lifts off the conjugate region material, and moves with the sample front into the detection region. If applicable, the conjugation region will also comprise the dried and mobilisable control conjugate. In other examples, the lateral flow assay device does not comprise a separate conjugation region. In such examples, the sample is mixed with a composition comprising the labelled antibody or labelled protein disclosed herein in a separate container, prior to migration along the lateral flow assay device. Such devices may be referred to as lateral flow assay dipsticks. For example, a plasma sample or fraction thereof from a subject may be contacted with the composition described herein in a separate container to create a mixed solution, and then a lateral flow assay device comprising a detection region may be dipped into the solution such that it migrates along the detection region to the test and control zones. The “detection region” is typically a membrane which comprises a test zone and control zone comprising irreversibly bound capture reagents, including an antibody or protein, an antibody against the labelled protein or labelled antibody, or a capture reagent such as streptavidin. Typically, the reaction membrane is made from a polymer such as nitrocellulose, polyvinylidene fluoride, nylon or polyethersulfone. Nitrocellulose is an exemplary option for the reaction membrane. Nitrocellulose membranes bind proteins (such as antibodies or biotin- binding proteins) electrostatically through interaction of the strong dipole of the nitrate esters with strong dipoles of the peptide bonds within the protein. The lateral flow assay device may also comprise an “absorbent region” or “absorption region”. The absorbent region is placed at the distal end of the detection region and reserves the remaining sample. It wicks the fluid through the membrane and collects the processed liquid. Moreover, it increases the total volume of sample that can enter the detection region. Suitable materials for a sample region, conjugation region, or a detection region that may be comprised in a lateral flow assay device described herein include, but are not limited to organic or inorganic polymers, and natural and synthetic polymers, including glass fiber, cellulose, nylon, cross-linked dextran, various chromatographic papers and nitrocellulose. It will be appreciated that suitable materials will enable a sample to flow laterally, via capillary action, along the device described herein. In certain examples, the detection region is a nitrocellulose membrane. In certain examples, a sample region and a conjugation region may be composed of the same material. In certain examples, a lateral flow assay device comprises a sample region in capillary contact with a detection region. Suitable commercially available materials will be known to the skilled person. Commercially available materials may be used for a sample region, conjugation region, and / or detection region that may be comprised in a lateral flow assay device described herein. The lateral flow assay device may further comprise a sample filter membrane applied to the sample region. The sample filter membrane may be composed of any suitable material including, but not limited to, a hydrophobic material capable of filtering out cells (for example blood cells) from fluids. Suitable sample membranes will be apparent to the skilled person and may have, for example, a filter size of about 0.22 μm to about 10 μm. In one example, a sample is applied to the sample region of a lateral flow assay device and the device is then incubated. Incubation comprises allowing the device to remain at a temperature, for example room temperature (e.g. about 20 °C to about 25 °C), such that the sample flows from the sample region to the detection region. In examples further comprising a conjugation region, incubation comprises allowing a lateral flow device to remain at a temperature, for example room temperature (e.g. about 20 °C to about 25 °C), such that the sample flows from the sample region to the conjugation region followed by the detection region. In one example, the lateral flow assay device is incubated after applying a sample to the sample region for about 2 minutes to about 20 minutes, about 2 minutes to about 15 minutes, or about 2 minutes to about 10 minutes. For example, the lateral flow assay device is incubated for about 10 minutes to about 15 minutes after applying a sample to the sample region. In one example, the lateral flow assay device may further comprise a control component immobilized in the control zone of the detection region. In one example, the detection region of a lateral flow assay device is configured such that the sample flows past a test zone before the control zone. In one example, the assay may further comprise inspection of the signal of a control line to confirm valid operation of a lateral flow assay device. Inspection may comprise visual confirmation of signal on a control line. In one example, assessing comprises a quantitative measurement of the molecules captured on a test zone and / or control zone. In one example, assessing may comprise semi-quantitative or qualitative assessment of a test zone, e.g. detection of a signal above a pre-determined threshold. Suitable means of assessing a test zone will depend on the signal generated by a test zone. For example, detection may be optical, thermal, magnetic or electrochemical. In one example, assessing may comprise quantitatively or qualitatively measuring the signal from, for example, a fluorescent dye or a colloidal metal. Assessing may be carried out visually. Assessing may be carried out by a smartphone. In certain examples, assessing may comprise use of a portable fluorescence meter. Commercially available devices for measuring a signal from a lateral flow assay device will be familiar to the skilled person. Detectable Labels As used herein, a “detectable label” is a molecular or atomic tag or marker that generates or can be induced to generate an optical or other signal or product that can be detected visually or by using a suitable detector. Detectable labels are well known in the art and include, for example, a radiolabel, an enzyme, a fluorescent label, a luminescent label, a bioluminescent label, a magnetic label, a prosthetic group, a contrast agent and an ultrasound agent. Fluorescent labels commonly used include Alexa, cyanine such as Cy5 and Cy5.5, and indocyanine, and fluorescein isothiocyanate (FITC), but they are not so limited. Fluorescent labels useful in the practice of the present disclosure can include, also without limitation, 1,5 IAEDANS; 1,8-ANS; 4-Methylumbelliferone; 5-carboxy-2,7-dichlorofluorescein; 5- Carboxyfluorescein (5-FAM); 5-Carboxynapthofluorescein (pH 10); 5- Carboxytetramethylrhodamine (5-TAMRA); 5-FAM (5-Carboxyfluorescein); 5-HAT (Hydroxy Tryptamine); 5-Hydroxy Tryptamine (HAT); 5-ROX (carboxy-X-rhodamine); 5-TAMRA (5- Carboxytetramethylrhodamine); 6-Carboxyrhodamine 6C; 6-CR 6G; 6-JOE; 7-Amino-4- methylcoumarin; 7-Aminoactinomycin D (7-AAD); 7-Hydroxy-4-methylcoumarin; 9-Amino-6- chloro-2-methoxyacridine; ABQ; Acid Fuchsin; ACMA (9-Amino-6-chloro-2-methoxyacridine); Acridine Orange+DNA; Acridine Orange+RNA; Acridine Orange, both DNA & RNA; Acridine Red; Acridine Yellow; Acriflavin; Acriflavin Feulgen SITSA; Aequorin (Photoprotein); Alexa Fluor 350; Alexa Fluor 430; Alexa Fluor 488; Alexa Fluor 532; Alexa Fluor 546; Alexa Fluor 568; Alexa Fluor 594; Alexa Fluor 633; Alexa Fluor 647; Alexa Fluor 660; Alexa Fluor 680; Alizarin Complexon; Alizarin Red; Allophycocyanin (APC); AMC, AMCA-S; AMCA (Aminomethylcoumarin); AMCA-X; Aminoactinomycin D; Aminocoumarin; Aminomethylcoumarin (AMCA); Anilin Blue; Anthrocyl stearate; APC (Allophycocyanin); APC- Cy7; APTRA-BTC=Ratio Dye, Zn2+; APTS; Astrazon Brilliant Red 4G; Astrazon Orange R; Astrazon Red 6B; Astrazon Yellow 7 GLL; Atabrine; ATTO-TAG CBQCA; ATTO-TAG FQ; Auramine; Aurophosphine G; Aurophosphine; BAO 9 (Bisamninophenyloxadiazole); BCECF (high pH); BCECF (low pH); Berberine Sulphate; Beta Lactamase; BFP blue shifted GFP (Y66H); Blue Fluorescent Protein; BFP / GFP FRET Bimane; Bisbenzamnide; Bisbenzimide (Hoechst); bis-BTC=Ratio Dye, Zn2+; Blancophor FFG; Blancophor SV; BOBO-1; BOBO-3; Bodipy 492 / 515; Bodipy 493 / 503; Bodipy 500 / 510; Bodipy 505 / 515; Bodipy 530 / 550; Bodipy 542 / 563; Bodipy 558 / 568; Bodipy 564 / 570; Bodipy 576 / 589; Bodipy 581 / 591; Bodipy 630 / 650- X; Bodipy 650 / 665-X; Bodipy 665 / 676; Bodipy Fl; Bodipy FL ATP; Bodipy Fl-Ceramide; Bodipy R6G SE; Bodipy TMR; Bodipy TMR-X conjugate; Bodipy TMR-X, SE; Bodipy TR; Bodipy TR ATP; Bodipy TR-X SE; BO-PRO-1; BO-PRO-3; Brilliant Sulphoflavin FF; BTC-Ratio Dye Ca2+; BTC-5N-atio Dye, Zn2+; Calcein; Calcein Blue; Calcium Crimson; Calcium Green; Calcium Green-1 Ca2+Dye; Calcium Green-2 Ca2+; Calcium Green-5N Ca2+; Calcium Green-C18 Ca2+; Calcium Orange; Calcofluor White; Carboxy-X-rhodamine (5-ROX); Cascade Blue; Cascade Yellow 399; Catecholamine; CCF2 (GeneBlazer); CFDA; CFP--Cyan Fluorescent Protein; CFP / YFP; FRET; Chlorophyll; Chromomycin A; Chromomycin A; CL-NERF (Ratio Dye, pH); CMFDA; Coelenterazine; Coelenterazine cp (Ca2+Dye); Coelenterazine f; Coelenterazine fcp; Coelenterazine h; Coelenterazine hcp; Coelenterazine ip; Coelenterazine n; Coelenterazine O; Coumarin Phalloidin; C-phycocyanine; CPM Methylcoumarin; CTC; CTC Formazan; Cy2; Cy3.1 8; Cy3.5; Cy3; Cy5.1 8; Cy5.5; Cy5; Cy7; Cyan GFP; cyclic AMP Fluorosensor (FiCRhR); CyQuant Cell Proliferation Assay; Dabcyl; Dansyl; Dansyl Amine; Dansyl Cadaverine; Dansyl Chloride; Dansyl DHPE; Dansyl fluoride; DAPI; Dapoxyl; Dapoxyl 2; Dapoxyl 3; DCFDA; DCFH (Dichlorodihydrofluorescein Diacetate); DDAO; DHR (Dihydorhodamine 123); Di-4-ANEPPS; Di-8-ANEPPS (non-ratio); DiA (4-Di-16-ASP); Dichlorodihydrofluorescein Diacetate (DCFH); DiD-Lipophilic Tracer; DiD (DiIC18(5)); DIDS; Dihydorhodamine 123 (DHR); DiI (DiIC18(3)); Dinitrophenol; DiO (DiOC18(3)); DiR; DiR (DiIC18(7)); DM-NERF (high pH); DNP; Dopamine; DsRed; Red fluorescent protein; DTAF; DY-630-NHS; DY-635-NHS; EBFP; ECFP; EGFP; ELF 97; Eosin; Erythrosin; Erythrosin ITC; Ethidium Bromide; Ethidium homodimer-1 (EthD-1); Euchrysin; EukoLight; Europium (III) chloride; EYFP; Fast Blue; FDA; Feulgen (Pararosaniline); FIF (Formaldehyde Induced Fluorescence); FITC; FITC Antibody; Flazo Orange; Fluo-3; Fluo-4; Fluorescein (FITC); Fluorescein Diacetate; Fluoro-Emerald; Fluoro-Gold (Hydroxystilbamidine); Fluor-Ruby; FluorX; FM 1-43; FM 4-46; Fura Red (high pH); Fura Red / Fluo-3; Fura-2, high calcium; Fura- 2, low calcium; Fura-2 / BCECF; Genacryl Brilliant Red B; Genacryl Brilliant Yellow 10GF; Genacryl Pink 3G; Genacryl Yellow 5GF; GeneBlazer (CCF2); GFP (S65T); GFP red shifted (rsGFP), GFP wild type, non-UV excitation (wtGFP); GFP wild type, UV excitation (wtGFP); GFPuv; Gloxalic Acid; Granular Blue; Haematoporphyrin; Hoechst 33258; Hoechst 33342; Hoechst 34580; HPTS; Hydroxycoumarin; Hydroxystilbamidine (FluoroGold); Hydroxytryptamine; Indo-1, high calcium; Indo-1, low calcium; Indodicarbocyanine (DiD); Indotricarbocyanine (DiR); Intrawhite Cf; JC-1; JO-JO-1; JO-PRO-1; LaserPro; Laurodan; LDS 751 (DNA); LDS 751 (RNA); Leucophor PAF; Leucophor SF; Leucophor WS; Lissamine Rhodamine; Lissamine Rhodamine B; LIVE / DEAD Kit Animal Cells, Calcein / Ethidium homodimer; LOLO-1; LO-PRO-1; Lucifer Yellow; Lyso Tracker Blue; Lyso Tracker Blue-White; Lyso Tracker Green; Lyso Tracker Red; Lyso Tracker Yellow; LysoSensor Blue, LysoSensor Green; LysoSensor Yellow / Blue; Mag Green; Magdala Red (Phloxin B); Mag-Fura Red; Mag- Fura-2; Mag-Fura-5; Mag-Indo-1; Magnesium Green; Magnesium Orange; Malachite Green; Marina Blue; Maxilon Brilliant Flavin 10 GFF; Maxilon Brilliant Flavin 8 GFF; Merocyanin; Methoxycoumarin; Mitotracker Green FM; Mitotracker Orange; Mitotracker Red; Mitramycin; Monobromobimane; Monobromobimane (mBBr-GSH); Monochlorobimane; MPS (Methyl Green Pyronine Stilbene); NBD; NBD Amine; Nile Red; Nitrobenzoxadidole; Noradrenaline; Nuclear Fast Red; Nuclear Yellow; Nylosan Brilliant Iavin E8G; Oregon Green; Oregon Green 488-X; Oregon Green; Oregon Green 488; Oregon Green 500; Oregon Greene 514; Pacific Blue; Pararosaniline (Feulgen); PBFI; PE-Cy5; PE-Cy7; PerCP; PerCP-Cy5.5; PE-TexasRed [Red 613]; Phloxin B (Magdala Red); Phorwite AR; Phorwite BKL; Phorwite Rev; Phorwite RPA; Phosphine 3R; PhotoResist; Phycoerythrin B [PE]; Phycoerythrin R [PE]; PKH26 (Sigma); PKH67; PMIA; Pontochrome Blue Black; POPO-1; POPO-3; PO-PRO-1; PO-PRO-3; Primuline; Procion Yellow; Propidium Iodide (PI); PyMPO; Pyrene; Pyronine; Pyronine B; Pyrozal Brilliant Flavin 7GF; QSY 7; Quinacrine Mustard; Red 613 [PE-TexasRed]; Resorufin; RH 414; Rhod-2; Rhodamine; Rhodamine 110; Rhodamine 123; Rhodamine 5 GLD; Rhodamine 6G; Rhodamine B; Rhodamine B 200; Rhodamine B extra; Rhodamine BB; Rhodamine BG; Rhodamine Green; Rhodamine Phallicidine; Rhodamine Phalloidine; Rhodamine Red; Rhodamine WT; Rose Bengal; R-phycocyanine; R-phycoerythrin (PE); rsGFP; S65A; S65C; S65L; S65T; Sapphire GFP; SBFI; Serotonin; Sevron Brilliant Red 2B; Sevron Brilliant Red 4G; Sevron Brilliant Red B; Sevron Orange; Sevron Yellow L; sgBFP; sgBFP (super glow BFP); sgGFP; sgGFP (super glow GFP); SITS; SITS (Primuline); SITS (Stilbene Isothiosulphonic Acid); SNAFL calcein; SNAFL-1; SNAFL-2; SNARF calcein; SNARF1; Sodium Green; SpectrumAqua; SpectrumGreen; SpectrumOrange; Spectrum Red; SPQ (6-methoxy-N-(3-sulfopropyl)quinolinium); Stilbene; Sulphorhodamine B can C; Sulphorhodamine G Extra; SYTO 11; SYTO 12; SYTO 13; SYTO 14; SYTO 15; SYT; SYTO 17; SYTO 18; SYTO 20; SYTO 21; SYTO 22; SYTO 23; SYTO 24; SYTO 25; SYTO 40; SYTO 41; SYTO 42; SYTO 43; SYTO 44; SYTO 45; SYTO 59; SYTO 60; SYTO 61; SYTO 62; SYTO 63; SYTO 64; SYTO 80; SYTO 81; SYTO 82; SYTO 83; SYTO 84; SYTO 85; SYTOX Blue; SYTOX Green; SYTOX Orange; Tetracycline; Tetramethylrhodamine (TRITC); Texas Red; Texas Red-X conjugate; Thiadicarbocyanine (DiSC3); Thiazine Red R; Thiazole Orange; Thioflavin 5; Thioflavin S; Thioflavin TCN; Thiolyte; Thiozole Orange; Tinopol CBS (Calcofluor White); TMR; TO-PRO-1; TO-PRO-3; TO-PRO-5; TOTO-1; TOTO-3; TriColor (PE-Cy5); TRITC (TetramethylRodamine-IsoThioCyanate); True Blue; TruRed; Ultralite; Uranine B; Uvitex SFC; wt GFP; WW 781; X-Rhodamine; XRITC; Xylene Orange; Y66F; Y66H; Y66W; Yellow GFP; YFP; YO-PRO-1; YO-PRO-3; YOYO-1; and YOYO-3. In one example, a detectable label is an enzyme. Examples of enzymes useful in the disclosure include, without limitation, alkaline phosphatase and horseradish peroxidase. Alternatively, or in addition, the enzyme can be, for example, luciferase. The enzyme can be linked to the antibody by conventional chemical methods, or it can be expressed together with the antibody as a fusion protein. In one example, the enzyme is horseradish peroxidase. Radioisotopes useful as detectable labels in the disclosure are well known in the art and can include3H,11C,18F,35S,64Cu,67Ga,68Ga,99mTc,111In,123I,124I,125I, and131I. Analysis of effector cells Methods of determining the proportion of basophil and / or mast cell activation and / or basophil and / or mast cell degranulation of the disclosure will be apparent to the skilled person and / or described herein. For example, the proportion can be determined using ELISA, FLISA or a lateral flow assay. Briefly, basophil and / or mast cells are incubated with the plasma sample or fraction thereof for a suitable period time. Cells are then fixed and the proportion of basophil and / or mast cell activation and / or basophil and / or mast cell degranulation relative to the total proportion of basophil and / mast cells being exposed to the sample is analysed using flow cytometry. As used herein, the term “proportion” in reference to a basophil and / or mast cell activation shall be understood to refer to a measure of an activation marker. As used herein, the term “activation” shall be understood to mean the stimulation of a cell (e.g., basophils and / or mast cells) by exposure to activation markers, such as a cellular or soluble ligand, which results in a change in the morphology or behaviour of the cell. For example, upon activation of the cell, the cell upregulates the activation markers. In some examples, the activation markers are selected from the group consisting of CD63, CD203c, CD107a and combinations thereof. As used herein the term “degranulation” shall be taken to mean the process by which cytoplasmic granules are released from cells (e.g., of mast cells and / or basophils). In some examples, activation of the cell leads to degranulation. In other examples, activation of the cell does not lead to degranulation. For example, activation of the cell leads to increased cytokine production without degranulation. In one example, basophil activation following exposure to the plasma sample or fraction thereof can be determined using basophil activation tests known in the art. For example, the test is a basophil activation test. The test uses activation markers to measure the proportion of activation and / or degranulation of basophils. For example, the activation marker is CD63. In another example, the activation marker is CD203c. CD63 and CD203c are useful markers for flow cytometric quantification of in vitro activated basophils. In some examples, the basophils are activated human basophils. In one example, the proportion of basophil activation is determined using flow cytometry. In one example, the proportion of basophil activation is determined by incubating basophils with a plasma sample or fraction thereof and quantifying the proportion of CD63 expressing basophils in the total population of basophils using flow cytometry. In another example, the proportion of basophil activation is determined by incubating basophils with a plasma sample or fraction thereof and quantifying the proportion of CD203c expressing basophils in the total population of basophils using flow cytometry. In one example, basophil activation is measured by the presence of interleuklin-3 (IL-3). In another example, basophil activation is measured by the absence of IL-3. In another example, mast cell activation following exposure to the plasma sample or fraction thereof can be determined using mast cell activation assays known in the art. For example, the assay is a Hoxb8 mast cell activation test. The assay uses activation markers to measure the proportion of activation and / or degranulation of mast cells. For example, the activation marker is CD107a. CD107a is a useful marker flow cytometric quantification of in vitro activated mast cells. In some examples, the mast cells are Hoxb8 mast cells. In one example, the proportion of mast cell activation is determined by incubating mast cells with a plasma sample or fraction thereof and quantifying the proportion of CD107a expressing mast cells in the total population of mast cells using flow cytometry. Briefly, the basophils or mast cells are incubated with the plasma sample or fraction thereof. Detecting activation of the cells is done by detecting the proportion of cells expressing an activation marker (e.g., CD63, CD203c and / or CD107a). The proportion of activation (i.e., the proportion of cells expressing the activation marker in the total population of cells) is then quantified using flow cytometry. It will be apparent to the skilled person from the disclosure herein that methods of determining basophil and / or mast cell activation and / or degranulation are performed in vitro. In one example, the method comprises determining a detectable amount of anti-FcεRI Ig in the plasma sample or fraction thereof by determining the proportion of basophils expressing CD63 following exposure to the plasma sample or fraction thereof. In one example, a detectable amount of anti-FcεRI Ig is present in the plasma sample or fraction thereof if at least 5 % of a population of basophils express CD63 following exposure to the plasma sample or fraction thereof. For example, the proportion of basophils expressing CD63 following exposure to the plasma sample or fraction thereof is more than 5 %, more than 6 %, more than 7 %, more than 8 %, more than 9 %, more than 10 %, more than 11 %, more than 12 %, more than 13 %, more than 14 % or more than 15 % of the total population of basophils exposed to the plasma sample or fraction thereof. In one example, the method comprises determining a detectable amount of anti-FcεRI Ig in the plasma sample or fraction thereof by determining the proportion of basophils expressing CD203c following exposure to the plasma sample or fraction thereof. In one example, a detectable amount of anti-FcεRI Ig is present in the plasma sample or fraction thereof if at least 5 % of a population of basophils express CD203c following exposure to the plasma sample or fraction thereof. For example, the proportion of basophils expressing CD203c following exposure to the plasma sample or fraction thereof is more than 5 %, more than 6 %, more than 7 %, more than 8 %, more than 9 %, more than 10 %, more than 11 %, more than 12 %, more than 13 %, more than 14 % or more than 15 % of the total population of basophils exposed to the plasma sample or fraction thereof. In one example, the method comprises determining a detectable amount of anti-FcεRI Ig in the plasma sample or fraction thereof by determining the proportion of mast cells expressing CD107a following exposure to the plasma sample or fraction thereof. In one example, a detectable amount of anti-FcεRI Ig is present in the plasma sample or fraction thereof if at least 5 % of a population of mast cells express CD107a following exposure to the plasma sample or fraction thereof. For example, the proportion of mast cells expressing CD107a following exposure to the plasma sample or fraction thereof is more than 5 %, more than 6 %, more than 7 %, more than 8 %, more than 9 %, more than 10 %, more than 11 %, more than 12 %, more than 13 %, more than 14 % or more than 15 % of the total population of mast cells exposed to the plasma sample or fraction thereof. Methods of Preparing anti-FcεRI Ig Reduced Preparations The present disclosure provides a method of preparing an anti-FcεRI Ig reduced preparation from a plasma or a fraction thereof using a chromatography resin. For example, the disclosure provides a method of preparing an anti-FcεRI Ig reduced preparation from a plasma or a fraction thereof using an affinity chromatography resin. The affinity resin of the present disclosure comprises a ligand capable of specifically binding to an anti-FcεRI Ig. As used herein, the terms “reduced” and “depleted” are used interchangeably and shall be understood to mean an Ig preparation wherein the amount of anti-FcεRI Ig has been decreased relative to an Ig preparation where the anti-FcεRI Ig has not been reduced or depleted and in an amount sufficient to prevent activation of the FcεRI mediated signalling pathway. As would be appreciated by the skilled person by the disclosure herein, the anti-FcεRI Ig need not be reduced or depleted 100 % but only in in an amount to prevent activation of the FcεRI mediated signalling pathway. As used herein, the terms “reduced basophil activation” and “reduced mast cell activation” shall be understood to mean an Ig preparation where the amount of anti-FcεRI Ig is reduced such that the activation of the basophil or mast cell is decreased. As would be appreciated by the skilled person reduced basophil activation or reduced mast cell activation need not refer to 100% decrease in the activation, but merely a decrease relative to an Ig preparation where the anti-FcεRI Ig has not been reduced or depleted. Suitable affinity chromatography resins will be apparent to the skilled person and / or described herein. In one example, the resin comprises a ligand comprising a FcεRI or fragment or epitope thereof. In another example, the resin comprises a ligand comprising a FcεRI antibody or fragment thereof. The skilled person will be aware that ligands based on FcεRI are capable of specifically binding to all types of anti-FcεRI Ig (i.e., IgG and IgE). Continuous affinity chromatography In some examples, the affinity chromatography is continuous affinity chromatography. The term “continuous affinity chromatography” shall be taken to mean a chromatographic method comprising one or more column(s) packed with identical affinity resins, wherein each column comprises one or more zones. A zone is a column, or a region of a column, comprising the resin where one or more chromatography steps can be performed. For example, a zone is selected from a group consisting of an equilibration zone, a binding zone, a wash zone, an elution zone, a stripping zone, or a combination thereof. Continuous affinity chromatography comprising more than one column involves the columns being connected in an arrangement that allows the columns to be operated in series and / or in parallel. In principle, IgG may be loaded on a first and / or subsequent columns while other columns (or other zones of a column) are going through an equilibration, wash, elution, and / or regeneration simultaneously. Examples of continuous affinity chromatography will be apparent to the skilled person and / or described herein. Examples of columns which may be used to perform the continuous chromatography method will be apparent to the skilled person and / or described herein. For example, the continuous chromatography method may be performed using Tricorn 5 / 100 (Cytiva). In another example, the continuous chromatography method may be performed using BioSMB PD System (Sartorius). Simulated moving bed (SMB) chromatography In one example, the continuous affinity chromatography is simulated moving bed (SMB) chromatography. The term “simulated moving bed chromatography” or “SMB chromatography” refers to a chromatography method first described in US patent 2,985,589. Examples of SMB chromatography setup and / or apparatus will be apparent to the skilled person and / or described herein. The concept of simulated moving bed involves the use of multiple smaller columns (rather than one large column) containing a solid absorbent (e.g. affinity resin) and performing one or more continuous chromatography steps (i.e. equilibration, binding, washing, eluting or stripping) simultaneously on different columns in a continuous loop. An example of a SMB chromatography set up has columns arranged into four sections with one or more columns per section. Two inlet streams (feed and eluent) and two outlet streams (extract and raffinate) are directed in alternating order to and from the column ring. The inlet and outlet positions are switched at regular time intervals in the direction of the liquid flow, thus simulating counter-current movement of columns. A feed (containing adsorbable components (extract)) is loaded onto one or more columns of the SMB chromatography setup, and the extract binds to the resin within the columns. Meanwhile, less adsorbed components (raffinate) in the feed pass through the column. The raffinate may be loaded onto one or more subsequent column(s) or removed from the SMB chromatography system as waste. An eluent is loaded onto the column to collect the extract. For example, an eluate may be collected from a first column while more feed is loaded onto one or more subsequent column(s). Suitable wash and elution buffers having the characteristics of the present disclosure will be apparent to the skilled person and / or described herein. In one example, the wash buffer comprises 20 mM sodium dihydrogen phosphate, 145 mM sodium chloride and is at a pH of 7.4. The resin in SMB chromatography may undergo multiple cycles (e.g. 50 cycles) of resin equilibration, IgG loading, binding, elution, stripping, sanitising, and / or regeneration per batch of plasma sample or fraction thereof used. Multiple batch runs (e.g.4 to 10 batches) may be performed using SMB chromatography. The total life time of the resin in SMB chromatography can be in the range of 200 to 500 cycles (if not more) before the resin is unusable. Resin regeneration is generally performed to allow multiple uses of the resin. Periodic counter-current chromatography (PCC) In one example, the continuous affinity chromatography is periodic counter-current chromatography (PCC). Examples of PCC setup and / or apparatus will be apparent to the skilled person and / or described herein. The concept of PCC involves the use of multiple columns containing a solid absorbent (e.g. affinity resin) and performing the chromatography steps in parallel in a quasi-continuous manner. The buffers used in binding, washing, and / or elution steps flow counter-current to the affinity resin. An example of PCC setup involves the use of two columns. In a first step, a sample is loaded onto a first column above the DBC of the resin so that unbound product (e.g. IgG) breaks through the first column and is captured by the second column. In a second step, the first column is washed, eluted, cleaned and / or re-equilibrated independently of the second column being loaded with a further sample. In a third step, an additional sample is loaded onto the second column above the DBC of the resin so that unbound product breaks through the second column and is captured by the first column. In a fourth step, the second column is washed, eluted, cleaned and / or re-equilibrated independently of the first column being loaded with a further sample. The process steps are continuously cycled between the two columns. Another example of PCC setup involves the use of multiple columns. For example, a variation of the above PCC setup can involve use of multiple columns to capture unbound product which simulates use of a large column. Continuous counter-current tangential chromatography (CCTC) In one example, the continuous affinity chromatography is continuous counter-current tangential chromatography (CCTC). Examples of CCTC setup and / or apparatus will be apparent to the skilled person and / or described herein. The concept of CCTC involves using the affinity resin in a slurry form where the slurry is continuously directed through a number of static mixers and hollow fiber membranes which separate the fluid phase from the resin. CCTC is ordinarily performed at low pressures (e.g. <70kPa). An example of a CCTC process involves binding, first wash, second wash, elution, stripping and / or equilibration steps. Sample (e.g. plasma sample or fraction thereof) and the affinity resin is passed through static mixers and hollow fiber membranes in a binding step. Impurities are removed in the flow through of the hollow fiber membranes in the washing step, while resin bound product (i.e. IgG) is retained by the membrane. The hollow fibres retain the resin and allow the product to flow through in the elution step. The resins are stripped and / or equilibrated and process repeated. Continuous counter-current spiral chromatography (CCSC) In one example, the continuous affinity chromatography is continuous counter-current spiral chromatography (CCSC). Examples of CCSC setup and / or apparatus will be apparent to the skilled person and / or described herein. The concept of CCSC involves the use of a compact rotating coil separation column mounted onto a centrifuge rotary frame. There are two separation column designs currently available: the spiral disk assembly and the spiral tube support assembly. An exemplary CCSC process involves a coiled separation column revolving around a central axis of the centrifuge while it synchronously rotates about its own axis (at e.g., 1,000 to 1,200 rpm). A mobile phase can be passed through the centrifuge rotor without rotary seals, and a large amount of a stationary phase is retained while the two phases are mixed along the length of the column to produce a highly efficient solute separation. Buffers The present disclosure provides an affinity chromatography method using buffers which enable efficient Ig binding to, and collection from, the resin. Generally, plasma sample or fraction thereof are at a neutral pH (pH of about 7.4). The resin is equilibrated with an equilibration buffer and / or washed with a wash buffer having a buffering range which covers the neutral pH. Suitable wash buffers comprise buffering agents having a dissociation constant (pKa) between 6.8 and 8.5 at 25 °C. An exemplary buffering agent of the equilibration and / or wash buffer is sodium dihydrogen phosphate, where the phosphoric acid component of sodium dihydrogen phosphate has three dissociation constants (pKa: 2.16, 7.21 and 12.32). Phosphoric acid has a dissociation constant at about the pH of an elution and / or stripping buffer used in the continuous affinity chromatography method. However, phosphoric acid does not have a dissociation constant between the pH of the equilibration and / or wash buffer (higher pH) and the elution and / or stripping buffer (lower pH) used in the affinity chromatography method. This enables a fast switch between wash and elution steps, and stripping and equilibration steps, giving more defined peaks and shorter chromatography phases. An advantage of using such equilibration and / or wash buffers is that smaller buffer volumes can be used, thereby increasing the efficiency of the affinity chromatography method. Other suitable buffering agents of the equilibration and / or wash buffer include imidazole (pKa: 7.0), Tris (pKa: 8.30), glycylglycine (pKa: 8.40), MOPS (pKa: 7.2), PIPES (pKa: 6.8), TES (pKa: 7.40), Bicine (pKa: 8.35), HEPES (pKa: 7.55), EPPS (pKa:8.00), HEPPSO (pKa: 7.85), MOBS (pKa: 7.60), POPSO (pKa: 7.78), TAPSO (pKa: 7.61), Tricine (pKa: 8.05), TEA (pKa: 7.76). Chromatography resin The present disclosure provides a method preparing an anti-Fc epsilon Receptor I (FcεRI) immunoglobulin (Ig) reduced preparation from a plasma sample or a fraction thereof using a continuous chromatography resin. In one example, the resin of the present disclosure comprises a ligand capable of specifically binding to an anti-Fc epsilon Receptor I (FcεRI) immunoglobulin (Ig). In one example, the method further comprises use of an affinity chromatography resin to remove anti-A and anti-B antibodies. In one example, the method further comprises use of an affinity chromatography resin to remove anti-A antibodies. In one example, the method further comprises use of an affinity chromatography resin to remove anti-B antibodies. Suitable chromatography resins will be apparent to the skilled person and / or described in US2009 / 074749 incorporated herein by reference. In one example, the resin comprises a mixture of supports whose matrixes are grafted with oligosaccharide groups which have antigenic similarity with blood groups A and B. An exemplary resin is Glycosorb Abo®(Glycorex Transplantation AS). Additional purification steps As would be understood by the skilled person additional steps may be performed before or after the continuous chromatography step. In one example, the additional steps may be performed before the continuous chromatography step. In one example, the additional steps may be performed after the continuous chromatography step. In one example, the method further comprises one or more steps selected from a group consisting of ethanol precipitation, octanoic acid fractionation, ion exchange chromatography, viral inactivation, viral filtration and ultrafiltration / diafiltration. Additional purification steps will be apparent to the skilled person and / or described herein. In one example, the method further comprises ethanol precipitation. For example, cold ethanol may be used to isolate and enrich the anti-FcεRI Ig reduced preparation by removing albumin and α- and β-globulins from the plasma sample or fractions thereof. For example, as described in WO2011 / 149472. In one example, the method further comprises octanoic acid fractionation. Octanoic acid may be used to remove of plasma lipids and plasma proteins (other than IgG). For example, as described in WO2011 / 131787. In one example, the method further comprises ion exchange chromatography. For example, anion exchange chromatography may be used to remove IgA, remaining IgM and other plasma components (other than IgG). The anion exchanger can be a resin-based anion exchanger, an anion exchange membrane adsorber, or any other format of anion exchanger with a positively charged substrate for capturing negatively charged particles. In one example, the anion exchanger is an anion exchange membrane adsorber. In another example, the anion exchanger is a resin-based anion exchanger. In a further example, the anion exchanger is a monolithic anion exchanger. In one example, the method further comprises anion exchange chromatography using a resin- based anion exchanger. For example, the anion exchange chromatography resin is a strong anion exchanger. In one example, the strong anion exchange resin comprises a matrix consisting of a poly(styrene-divinylbenzene) matrix. In one example, the strong anion exchanger comprises a quaternized polyethyleneimine functional group. Suitable resin-based anion exchanges will be apparent to the skilled person and include, for example, POROSTMHQ 50. In one example, the anion exchange chromatography step is performed in flow through mode. In another example, the anion exchange chromatography step is performed in bind-and-elute mode. In one example, the anion exchange chromatography step comprises a buffer selected from the group consisting of sodium citrate, 2-(N-morpholino)ethanesulfonic acid (MES) buffer, sodium dihydrogen phosphate, Bis-Tris, phosphate, L-histidine and combinations thereof. In one example, the anion exchange chromatography step comprises a buffer comprising MES buffer. In another example, the anion exchange chromatography step comprises phosphate buffer. In one example, the method further comprises viral inactivation. For example, viral inactivation may be effected by adjusting the solution to low pH. Low pH may be a pH of between 2 to 4. In one example, low pH viral inactivation is performed in the presence of caprylate. In another example, viral inactivation may be effected by contacting the plasma sample or fraction thereof, or the anti-FcεRI Ig reduced preparation or the pharmaceutical composition comprising the anti-FcεRI Ig reduced preparation with n-Octyl-β-D-Glucopyranoside (OG), thereby forming an OG-IgG mixture. In a further example, low pH viral inactivation is performed in the presence of N,N-Dimethylmyristylamine N-oxide (TDAO). In a further example, viral inactivation may be effected by exposing the protein mixture, plasma or plasma fraction, a protein reduced preparation or composition (e.g., a plasma protein reduced preparation e.g., an IgG-reduced preparation) to a solvent-detergent inactivation step. Suitable solvent-detergent treatments would be apparent to the skilled person and include, for example environmentally friendly detergents. Exemplary environmentally friendly detergents suitable for use in the present disclosure and in particular for use in inactivating lipid enveloped viruses include N,N-Dimethylmyristylamine N-oxide (TDAO), polysorbate 80 (PS80), polyoxyethylene (10) isooctylcyclohexyl ether (TRITON® X-100-reduced), and a non-ionic surfactant prepared from glucose and alcohol (e.g., SimulsolTMformulations). In one example, the detergent is N,N-Dimethylmyristylamine N-oxide (TDAO). In one example, the detergent is polysorbate 80. In another example, the detergent is polyoxyethylene (10) isooctylcyclohexyl ether (TRITON® X-100-reduced). In a further example, the detergent is a non-ionic surfactant prepared from glucose and alcohol. In one example, the method further comprises viral filtration. For example, viral filtration membranes of pore sizes from 1-20 nm may be used to remove microbes and viruses from a solution or eluate or pharmaceutical composition. An exemplary nanofilter is Planova 20 (Planova).Exemplary nanofilters include Planova S20N (Asahi), Virosart HC (Sartorius) and Planova 20N (Asahi). In one example, the method further comprises ultrafiltration / diafiltration. An exemplary ultrafiltration / diafiltration membrane is Pellicon 2 Cassettes (Millipore) or Polyethersulfone or Hydrosart cassettes (Sartorius). Analysis of the Anti-FcεRI Ig Reduced Preparation In one example, the activity of the anti-FcεRI Ig reduced preparation is assessed. Methods of determining yield, purity and IgG subclass distribution will be apparent to the skilled person and / or described herein. In one example, purity is determined by SDS-PAGE and MALDI-TOF-MS peptide fingerprint analysis. Briefly, purified plasma protein products or pharmaceutical compositions described herein are loaded onto a suitable SDS-PAGE gel (e.g. 8-16% TRIS-glycine), along with a protein size marker and a positive control for the protein of interest (e.g., IgG such as IVIG) under reduced and non-reduced conditions. Proteins are separated based on size and protein bands of interest are isolated, processed and analysed by MALDI-TOF-MS. In another example, impurities in the anti-FcεRI Ig reduced preparation or pharmaceutical composition described herein are measured in an Enzyme-Linked Immunosorbent Assay (ELISA) using impurity (e.g. IgA) specific antibodies. For example, the ELISA is performed using commercially available methods. In one example, purity, yield and / or subclass distribution of IgG is determined by nephelometry. In one example, the anti-FcεRI Ig reduced preparation comprises a purity of more than 95 % Ig. For example, the anti-FcεRI Ig reduced preparation comprises a purity of more than 96 % Ig. In another example, the anti-FcεRI Ig reduced preparation comprises a purity of more than 97 % Ig. In another example, the anti-FcεRI Ig reduced preparation comprises a purity of more than 98 % Ig. In another example, the anti-FcεRI Ig reduced preparation comprises a purity of more than 99 % Ig. Stability of plasma and plasma fraction The stability of the plasma sample or fraction thereof for loading onto a chromatography resin described herein can be determined by assessing the pro-coagulant activity, proteolytic activity and particle size of the plasma sample or fraction thereof. Methods for assessing pro-coagulant activity, proteolytic activity and particle size will be apparent to a skilled person and / or described herein. Briefly, the plasma or plasma fraction is freeze / thawed in one or more cycles, stored at between 2 °C and 32 °C (e.g.2 °C, 10 °C, 18 °C, 21 °C, 28 °C or 32 °C) for 24 or up to 48 hrs and analysed using one or more of the methods described below. In one example, the plasma sample or fraction thereof is thawed in one or more cycles at a temperature of 32 °C, stored for 24 or up to 48 hours and analysed using one or more of the methods described below. In another example, the plasma sample or fraction thereof is thawed in one or more cycles at a temperature of 32 °C, stored for 24 or up to 48 hours and analysed using one or more of the methods described below and then cooled and stored at a temperature of 21 °C. In one example, the plasma sample or fraction thereof is thawed at a temperature of 32 °C and at a temperature of 21 °C before the continuous chromatography. In one example, the pro-coagulant activity in the plasma sample or fraction thereof can be determined using an in vitro coagulation assay, e.g., activated partial thromboplastin time (NaPTT) assay. The NaPTT assay measures the rate at which one or more coagulation factors (e.g., fibrinogen, prothrombin, proaccelerin, anti-hemophilic factor, Stuart-Prower factor, plasma thromboplastin antecedent and Hegeman factor) are activated or form in plasma sample or fraction thereof, when coagulation activators (e.g. silica, kaolin, ellagic acid) are added to the assay. In one example, proteolytic activity in the plasma sample or fraction thereof can be assessed by measuring the activity of thrombin, general serine proteases, kallikrein, plasmin and FXa e.g. using commercially available kits, such as thrombin activity assay kit (S-2238), general serine protease assay kit (S-2288), kallikrein activity assay kit (S-2302), plasmin activity assay kit (S-2251) and FXa activity kit (S-2765). In one example, the size of any particles in the plasma sample or fraction thereof is assessed by microflow imaging (MFI) and polydispersity index is calculated. Calculation of the polydispersity index will be apparent to the skilled person. Pharmaceutical Compositions Anti-FcεRI Ig reduced plasma preparations and anti- FcεRI Ig reduced IgG preparations of the disclosure are useful for formulations into a pharmaceutical composition for parenteral, such as intravenous administration or subcutaneous administration, for therapeutic and prophylactic treatment. A pharmaceutical composition of present invention according to a preferred embodiment comprises the anti-FcεRI Ig reduced preparation or the anti-FcεRI Ig reduced IgG plasma preparation. The compositions for administration will commonly comprise a solution of the anti-FcεRI Ig reduced preparation or anti-FcεRI Ig reduced IgG preparation of the disclosure dissolved in a pharmaceutically acceptable carrier, such as an aqueous carrier. A variety of aqueous carriers can be used, e.g., buffered saline and the like. The compositions may contain pharmaceutically acceptable carriers as required to approximate physiological conditions such as pH adjusting and buffering agents, toxicity adjusting agents and the like, for example, sodium acetate, sodium chloride, potassium chloride, calcium chloride, sodium lactate and the like. The concentration of the Ig in the pharmaceutical composition of the present disclosure in these formulations can vary widely, and will be selected primarily based on fluid volumes, viscosities, body weight and the like in accordance with the particular mode of administration selected and the patient's needs. The vehicles may contain minor amounts of additives that enhance isotonicity and chemical stability, e.g., buffers and preservatives. For example, the pharmaceutical composition comprises proline as a stabilising agent. Suitable pharmaceutical compositions in accordance with the disclosure will generally include an amount of the anti-FcεRI Ig reduced preparation of the present disclosure admixed with an acceptable pharmaceutical carrier, such as a sterile aqueous solution, to give a range of final concentrations, depending on the intended use. The techniques of preparation are generally known in the art as exemplified by Remington's Pharmaceutical Sciences, 16th Ed. Mack Publishing Company, 1980. For example, the total Ig concentration of the pharmaceutical composition is 1 to 5 % w / v, 5 to 15 % w / v, or 8 to 12 % w / v. For example, the total Ig concentration of the pharmaceutical composition is 1 %, or 2 %, or 3 %, or 4 %, or 5 %, or 6 %, or 7 %, or 8 %, or 9 %, or 10 %, or 11 %, or 12 %, or 13 %, or 14 %, or 15 % w / v. For intravenous use, 1 % w / v (i.e.10g Ig / L) may be used. For intravenous use, 10 % w / v (i.e.100g Ig / L) may be used. For subcutaneous administration, a higher concentration may be used. For example, 15 to 35 % w / v, or 20 to 30 % w / v. In one example, the total Ig concentration of the pharmaceutical composition is 16 %, or 17 %, or 18 %, or 19 %, or 20 %, or 21 %, or 22 %, or 23 %, or 24 %, or 25 %, or 26 % w / v. Anti-FcεRI Ig reduced Ig Preparations The present disclosure provides an anti-Fc epsilon Receptor I (FcεRI) immunoglobulin (Ig) reduced preparation, comprising polyclonal IgG. The present disclosure also provides an anti-Fc epsilon Receptor I (FcεRI) immunoglobulin (Ig) reduced IgG preparation, comprising polyclonal IgG. In one example, the polyclonal IgG is present in an amount from 5 to 25 % (w / v). In one example, the polyclonal IgG is present in an amount from 6 to 15 % (w / v). In one example, the polyclonal IgG is present in an amount from about 8 to 12 % (w / v). In one example, the polyclonal IgG is present in an amount of about 10 % (w / v). The final protein concentration will depend on various factors, such as the administration route, the type of condition to be treated, etc. The skilled person will be able to determine the optimal protein concentration for the intended application. For example, for intravenous infusion, the polyclonal IgG is present in an amount from about 15 to 20 % (w / v). In one example, the polyclonal IgG is present in an amount from about 8 to 12 % (w / v). In another example, the polyclonal IgG is present in an amount of about 20 % (w / v). For subcutaneous administration a higher dosage may be chosen, for instance about 15 to 20 % (w / v). In one example, the polyclonal IgG is present in an amount of about 20 % (w / v). The immunoglobulins can be isolated from human or animal blood or produced by other means, for instance by recombinant DNA technology or hybridoma technology. In one example, the immunoglobulin is obtained from blood plasma, typically from a pool of blood plasma from many donors. In order to obtain the immunoglobulins from plasma, the plasma is subjected to alcohol fractionation, which may be combined with other purification techniques like chromatography, adsorption or precipitation as described herein. However, other processes can also be used. The pharmaceutical compositions of the disclosure are formulated by methods known in the art. In the case of an IgG solution, the pH of the final preparation is adjusted to a relatively high but acidic pH, namely in the range of about pH 4.2 to 5.4. It has been found that this pH range is particularly useful for improving the storage of characteristics of polyclonal IgG preparations. In one example, the pH is from about 4.6 to 5.0. In an example, the pH is 4.8. In other examples, the pharmaceutical composition further comprises a stabilizer. In one example, the stabilizer is more than one amino acid. For example, the amino acids are selected from the group consisting of non-polar and basic amino acids. In some examples, the amino acid is selected from the group consisting of histidine, arginine, lysine, ornithine, isoleucine, valine, methionine, glycine and proline. In one example, the stabilizer is proline. For example, the proline is L-proline. The amount of proline in the pharmaceutical composition ranges from about 10 to about 2000 mmol / l. In some examples, the amount of proline in the pharmaceutical composition ranges from about 50 to about 1000 mmol / l. In other examples, the amount of proline in the pharmaceutical composition ranges from about 100 to 500 mmol / l. In one example, the amount of L-proline in the pharmaceutical composition ranges from about 200 mmol / L to 300 mmol / L. For example, the amount of L-proline in the preparation ranges from about 225 mmol / L to 275 mmol / L. In one example, the amount of L-proline in the pharmaceutical composition ranges from about 240 mmol / L to 260 mmol / L. For example, the amount of L-proline in the pharmaceutical composition ranges from about 250 mmol / L. In further examples, the amount of proline in the pharmaceutical composition is about 250 mmol / l. In one example, the final concentration of proline is between 200 mM to 400 mM. In one example, the final concentration of proline is 250 mM. In one example, the proline is L-proline. In another example, the proline is a proline equivalent (e.g., proline analogues). In other examples, the stabilizer is present in the pharmaceutical composition at a concentration of more than 200 mM. In some examples, the stabilizer is present in the pharmaceutical composition at a concentration between 200 mM and 400 mM. In another examples, the stabilizer is present in the pharmaceutical composition at a concentration between 200 mM and 300 mM. In further examples, the stabilizer is present in the pharmaceutical composition at a concentration of 250 mM. In one example, the pharmaceutical composition comprises a pH of between 4 and 5.5. For example, the pharmaceutical composition comprises a pH of between 4.5 and 5.0. In one example, the pharmaceutical composition comprises a pH of between 4.6 and 5.0. For example, the pharmaceutical composition comprises a pH of 4.6. In one example, the pharmaceutical composition or Ig preparation or anti-FcεRI Ig reduced preparation comprises a pH of 4.7. In another example, the pharmaceutical composition comprises a pH of 4.8. In a further example, the pharmaceutical composition comprises a pH of 4.9. In one example, the pharmaceutical composition comprises a pH of 5.0. In one example, the pharmaceutical composition comprises 100 mg / mL of total human plasma protein. In one example, the pharmaceutical composition comprises 20 g / 100 mL of total human plasma protein. In one example, the pharmaceutical composition comprises a purity of more than 95 % immunoglobulin G (IgG). For example, the pharmaceutical composition comprises a purity of more than 96 % immunoglobulin G (IgG). In another example, the pharmaceutical composition comprises a purity of more than 97 % immunoglobulin G (IgG). In another example, the pharmaceutical composition comprises a purity of more than 98 % immunoglobulin G (IgG). In another example, the pharmaceutical composition comprises a purity of more than 99 % immunoglobulin G (IgG). In one example, the pharmaceutical composition or the anti-FcεRI Ig reduced preparation comprises an IgG1 subclass distribution of more than 60 %. For example, the pharmaceutical composition or the anti-FcεRI Ig reduced preparation comprises an IgG1 subclass distribution of more than 65 %. In one example, the pharmaceutical composition or the anti-FcεRI Ig reduced preparation comprises an IgG2 subclass distribution of less than 30 %. For example, the pharmaceutical composition or the anti-FcεRI Ig reduced preparation comprises an IgG2 subclass distribution of less than 28 %. In one example, the pharmaceutical composition or the anti-FcεRI Ig reduced preparation comprises an IgG3 subclass distribution of less than 5 %. For example, the pharmaceutical composition or the anti-FcεRI Ig reduced preparation comprises an IgG3 subclass distribution of less than 4 %. In one example, the pharmaceutical composition or the anti-FcεRI Ig reduced preparation comprises an IgG4 subclass distribution of less than 5 %. For example, the pharmaceutical composition or the anti-FcεRI Ig reduced preparation comprises an IgG4 subclass distribution of less than 3 %. In one example, the pharmaceutical composition or anti-FcεRI Ig reduced preparation comprises an IgG subclass distribution that is similar to that of normal human plasma, for example 69 % IgG1, 26 % IgG2, 3 % IgG3and 2 % IgG4. In one example, the pharmaceutical composition comprises a nominal osmolality of between about 300 mOsm / kg and 400 mOsm / kg. In one example, the pharmaceutical composition comprises a nominal osmolality of 380 mOsm / kg. For example, the pharmaceutical composition comprises a nominal osmolality of between about 300 mOsm / kg and 350 mOsm / kg. In one example, the pharmaceutical composition comprises a nominal osmolality of 320 mOsm / kg. In one example, the pharmaceutical composition comprises a sodium content of ≤ 1 mmol / L. In one example, the pharmaceutical composition comprises an IgA content of ≤ 0.05 mg / mL. For example, the pharmaceutical composition comprises an IgA content of ≤ 0.04 mg / mL, or ≤ 0.03 mg / mL. In one example, the pharmaceutical composition comprises an IgA content of ≤ 0.025 mg / mL. In one example, the pharmaceutical composition comprises an IgA content of ≤ 0.01 mg / mL. For example, the pharmaceutical composition comprises an IgA content of ≤ 0.009 mg / mL. In one example, the pharmaceutical composition comprises an IgA content of ≤ 0.1 mg / g IgG. In one example, the pharmaceutical composition comprises an IgA content of ≤0.09 mg / g IgG. In one example, the pharmaceutical composition comprises an IgM content of ≤ 10 mg / L. For example, an IgM content of ≤ 10 mg / L, ≤ 9 mg / L, ≤ 8 mg / L, ≤ 7 mg / L, ≤ 6 mg / L, ≤ 5 mg / L, ≤ 4 mg / L, ≤ 3 mg / L, ≤ 2 mg / L. In one example, the pharmaceutical composition comprises an IgM content of ≤ 2 mg / L. In one example, the pharmaceutical composition comprises an IgM content of ≤ 1 mg / L. In one example, the pharmaceutical composition comprises an IgM content of ≤ 0.5 mg / L. For example, the pharmaceutical composition comprises an IgM content of <0.17 mg / L. In one example, the pharmaceutical composition comprises an IgM content of ≤ 2 µg / g IgG. In one example, the pharmaceutical composition comprises an IgM content of ≤ 1.9 µg / g IgG. In one example, the pharmaceutical composition comprises an albumin content of ≤ 0.50 mg / mL. For example, the pharmaceutical composition comprises an albumin content of ≤ 0.40 mg / mL. In one example, the pharmaceutical composition or anti-FcεRI Ig reduced Ig preparation comprises an albumin content of ≤ 0.30 mg / mL. In one example, the pharmaceutical composition comprises an albumin content of ≤ 0.20 mg / mL. In one example, the pharmaceutical composition comprises an albumin content of ≤ 0.10 mg / mL. For example, the pharmaceutical composition comprises an albumin content of ≤ 0.09 mg / mL. In one example, the pharmaceutical composition comprises an albumin content of ≤ 0.08 mg / mL. In one example, the pharmaceutical composition comprises an albumin content of ≤ 0.07 mg / mL. In one example, the pharmaceutical composition comprises an albumin content of ≤ 1 mg / g IgG. In one example, the pharmaceutical composition comprises an albumin content of ≤ 0.80 mg / g IgG. In one example, the pharmaceutical composition comprises a Prekallikrein activator (PKA) level of ≤ 35 IU / mL. In one example, the pharmaceutical composition comprises a Prekallikrein activator (PKA) level of ≤ 30 IU / mL. In one example, the pharmaceutical composition comprises a Prekallikrein activator (PKA) level of ≤ 50 IU / mL. In one example, the pharmaceutical composition comprises a Prekallikrein activator (PKA) level of ≤ 20 IU / mL. For example, the pharmaceutical composition comprises a Prekallikrein activator (PKA) level of ≤ 15 IU / mL. In one example, the pharmaceutical composition comprises a Prekallikrein activator (PKA) level of ≤ 10 IU / mL. In one example, the anti-FcεRI Ig reduced preparation comprises polyclonal IgG at an amount of 10 % (w / v), proline at a concentration of 250 mM, and a pH of 4.8. In one example, the anti-FcεRI Ig reduced preparation comprises polyclonal IgG at an amount of 20% (w / v), proline at a concentration of 250 mM, PS80 at an amount of 20 µg / mL, and a pH of 4.8. Exemplary methods of purifying Ig processes are described in WO2015 / 000886, exemplary IgG products are described in WO2016 / 087569, both of which are incorporated herein by reference. The present disclosure also provides a pooled IgG preparation, wherein the pooled IgG preparation comprises a detectable amount of an anti-Fc epsilon Receptor I (FcεRI) immunoglobulin (Ig). It will be apparent to the skilled person from the disclosure herein that the pooled IgG preparation with a detectable amount of an anti-FcεRI Ig has not been subjected to any method of the present disclosure. Accordingly, the present disclosure also provides a method of detecting anti-FcεRI Ig in a pooled IgG preparation. In one example, the pooled IgG preparation comprises other isotypes such IgA and IgM. In one example, the pooled IgG preparation comprises IgA. In one example, the pooled IgG preparation comprises other isotypes IgM. Method of use As discussed herein, the present disclosure provides a method of treating, preventing and / or delaying progression of a condition relating to a primary or secondary immune deficiency, an inflammatory disease, an autoimmune disease or an acute infection in a subject, comprising administering an anti-FcεRI Ig reduced preparation, an anti-FcεRI Ig reduced IgG preparation or a pharmaceutical formulation to the subject. The present disclosure also provides an anti-FcεRI Ig reduced preparation or an anti-FcεRI Ig reduced IgG preparation or a pharmaceutical composition described herein for use in treating, preventing and / or delaying progression of a condition relating to an immune deficiency, an inflammatory disease, an autoimmune disease and / or an acute infection in a subject. The present disclosure further provides an anti-FcεRI Ig reduced preparation or an anti-FcεRI Ig reduced IgG preparation or a pharmaceutical composition described herein in the manufacture of a medicament for treating, preventing and / or delaying progression of a condition relating to an immune deficiency, an inflammatory disease, an autoimmune disease and / or an acute infection in a subject. In one example, the condition is selected from a group consisting of primary immunodeficiency disease (PI), chronic inflammatory demyelinating polyneuropathy (CIDP), chronic immune thrombocytopenic purpura (ITP) and combinations thereof. In one example the condition is primary immunodeficiency disease (PI). In one example, the condition is chronic inflammatory demyelinating polyneuropathy (CIDP). In one example, the condition is chronic immune thrombocytopenic purpura (ITP). In another example, the condition is selected from the group consisting of congenital agammaglobulinaemia and hypogammaglobulinaemia, common variable immunodeficiency, severe combined immunodeficiency, allogenic bone marrow transplant, chronic lymphocytic leukaemia, pediatric HIV, kidney transplant with a high antibody recipient or with an ABO incompatible donor, chronic fatigue syndrome, Clostridium difficile colitis, Graves' ophthalmopathy, muscular dystrophy, inclusion body myositis, Lambert-Eaton syndrome, Lupus erythematosus, multifocal motor neuropathy, myasthenia gravis, neonatal alloimmune thrombocytopenia, Parvovirus B19 infection, pemphigus, post-transfusion purpura, renal transplant rejection, spontaneous Abortion Miscarriage, stiff person syndrome, opsoclonus Myoclonus, severe sepsis and septic shock in critically ill adults, toxic epidermal necrolysis, chronic lymphocytic leukemia, multiple myeloma, X-linked agammaglobulinemia, hypogammaglobulinemia, RRMS, IgG subclass deficiencies with recurrent infections and combinations thereof. In further examples, the treatment further comprises a replacement therapy in myeloma or chronic lymphocytic leukaemia with severe secondary hypogammaglobulinaemia and recurrent infections. In other examples, the condition is selected from a group consisting of autoimmune diseases and certain neurological diseases, such as Rheumatoid arthritis, Systemic Lupus Erythematosus (SLE), Antiphospholipid syndrome, immune thrombocytopenia (ITP), Kawasaki disease, Guillain Barre syndrome (GBS), multiple sclerosis (MS), chronic inflammatory demyelinating polyneuropathy (CIDP), multifocal motor neuropathy (MMN), myasthenia gravis (MG), skin blistering diseases, scleroderma, Dermatomyositis, Polymyositis, Alzheimer's Disease, Parkinson's Disease, Alzheimer's Disease related to Downs Syndrome, cerebral amyloid angiopathy, Dementia with Lewy bodies, Fronto-temporal lobar degeneration, vascular dementia, cell and organ transplant and combinations thereof. In some examples, the pharmaceutical composition is present in a vial, a prefilled syringe or an autoinjector device. The present disclosure also provides a prefilled syringe comprising the pharmaceutical composition described herein. The present disclosure also provides an autoinjector device comprising the pharmaceutical composition described herein. In one example, the composition of the disclosure is administered subcutaneously to the subject in need thereof. In another example, the composition of the disclosure is administered intravenously to the subject in need thereof. In one example, the composition of the disclosure is self-administered. In one example, the composition of the disclosure is self-administered subcutaneously. In one example, the composition of the disclosure is provided in a pre-filled syringe. In one example, the composition of the disclosure is self-administered subcutaneously, with a pre-filled syringe. In one example of any method described herein, the subject is a mammal, for example a primate such as a human. Kits Another example of the disclosure provides kits containing a FcεRI or fragment or epitope thereof for use in any method described herein (e.g. detecting an anti-FcεRI Ig in a plasma sample or a fraction thereof). In one example, the panel or kit as described herein is for ex vivo analysis. In one example, the kit is suitable for use with a whole blood sample, a plasma sample or fraction thereof. Reagents for particular types of assays can also be provided in the kits. In one example, the kits comprise a device, such as a lateral flow assay device, an analytical rotor, or an electrochemical, optical, or opto-electronic sensor, or a plate (e.g., a plate suitable for an ELISA assay). In examples in which the kit comprises a lateral flow assay device, a ligand (e.g., FcεRI or fragment or epitope thereof) may be contained within the kit separate to the device, or it may be comprised within the device itself, for example it may be dried on to a conjugate region within the device. In addition, the kit includes various diluents and buffers, labelled conjugates or other agents for performing the methods described above, and other signal-generating reagents, such as enzyme substrates, cofactors and chromogens. Other components of the kit can easily be determined by one of skill in the art. Such components may include coating reagents, indicator charts for colorimetric comparisons, disposable gloves, decontamination instructions, applicator sticks or containers, a sample preparatory cup, etc. In one example, a kit comprises buffers or other reagents appropriate for constituting a reaction medium in which the composition disclosed herein is contacted with the sample. In one example, the kit further comprise an instruction or package insert with instructions for detecting and / or screening an anti-FcεRI Ig in a plasma sample or a fraction thereof. For example, in certain examples, the kit comprises an instruction indicating how to use the kit detect an anti-FcεRI Ig, or to screen and / or identify plasma samples suitable for administration to a subject, or identify subjects suitable and / or unsuitable for plasma donation for the production of an Ig preparation. In one example, the kit comprises an instruction indicating how to prepare a sample. In one example, the kit provides instructions for contacting the sample with a ligand disclosed herein (i.e., FcεRI or fragment or epitope thereof) in any order prior to analysing the sample for the presence of an anti-FcεRI Ig. The kit may also provide instructions for optimization of buffers, optimization of the ratios of the various components, optimization of dilution of the sample, and optimization of the order of the mixture and application steps (e.g., mix all components prior to application, mix only certain components and apply others separately). The invention is further disclosed in the following numbered paragraphs: 1. A method of detecting an anti-Fc epsilon Receptor I (FcεRI) immunoglobulin (Ig) in a plasma sample or a fraction thereof, the method comprising: (i) contacting the sample to a ligand which binds to the anti-FcεRI Ig in the sample to thereby form a complex; and (ii) detecting the complex, wherein presence of the complex is indicative of the presence of the anti-FcεRI Ig in the plasma sample or fraction thereof. A method of screening a plasma sample or a fraction thereof for an anti-Fc epsilon Receptor I (FcεRI) immunoglobulin (Ig), the method comprising: (i) contacting the sample to a ligand which binds to the anti-FcεRI Ig in the sample to thereby form a complex; and (ii) detecting the complex, wherein presence of the complex is indicative of the presence of the anti-FcεRI Ig in the plasma sample or fraction thereof. A method of identifying a plasma sample or a fraction thereof suitable for administration to a subject, the method comprising: (i) contacting the sample to a ligand which binds to the anti-Fc epsilon Receptor I (FcεRI) immunoglobulin (Ig) in the sample to thereby form a complex; and (ii) detecting the complex, wherein presence of the complex is indicative of the presence of the anti-FcεRI Ig in the plasma sample or fraction thereof, wherein the presence of anti-FcεRI Ig in the plasma sample or fraction thereof indicates the plasma sample or fraction thereof is not suitable for administration to the subject. A method of screening a plasma sample or a fraction thereof to determine suitability for administration to a subject, the method comprising: (i) contacting the sample to a ligand which binds to an anti-Fc epsilon Receptor I (FcεRI) immunoglobulin (Ig) in the sample to thereby form a complex; and (ii) detecting the complex, wherein presence of the complex is indicative of the presence of the anti-FcεRI Ig in the plasma sample or fraction thereof, wherein the presence of anti-FcεRI Ig in the plasma sample or fraction thereof indicates the plasma sample or fraction thereof is not suitable for administration to the subject. A method of identifying a plasma sample or a fraction thereof for use in producing an immunoglobulin (Ig) preparation for administration to a subject, the method comprising: (i) contacting the sample to a ligand which binds to the anti-Fc epsilon Receptor I (FcεRI) Igin the sample to thereby form a complex; and (ii) detecting the complex, wherein presence of the complex is indicative of the presence of the anti-FcεRI Ig in the plasma sample or fraction thereof, wherein the presence of anti-FcεRI Ig in the plasma sample or fraction thereof indicates the plasma sample or fraction thereof is not suitable for use in producing an Ig preparation for administration to the subject. 6. A method of screening a plasma sample or a fraction thereof for use in producing an immunoglobulin (Ig) preparation for administration to a subject, the method comprising: (i) contacting the sample to a ligand which binds to an anti-Fc epsilon Receptor I (FcεRI) Ig in the sample to thereby form a complex; and (ii) detecting the complex, wherein presence of the complex is indicative of the presence of the anti-FcεRI Ig in the plasma sample or fraction thereof, wherein the presence of anti-FcεRI Ig in the plasma sample or fraction thereof indicates the plasma sample or fraction thereof is not suitable for use in producing an Ig preparation for administration to the subject. 7. The method of any one of paragraphs 1 to 6, wherein the method further comprises administering the plasma sample or fraction thereof to the subject if the anti-FcεRI Ig is not present in a detectable amount. 8. The method of any one of paragraphs 1 to 8, wherein the method further comprises including the plasma sample or fraction thereof into a pooled blood plasma sample if the anti-FcεRI Ig is not present in a detectable amount. 9. The method of any one of paragraphs 1 to 8, wherein the method further comprises excluding the plasma sample or fraction thereof from a pooled blood plasma sample if the anti-FcεRI Ig is present in a detectable amount. 10. The method of any one of paragraphs 1 to 9, wherein the method further comprises contacting the complex with a detection protein. 11. The method of paragraph 10, wherein the detection protein comprises a detectable label, wherein presence of the detectable label is indicative of the presence of a detectable amount of anti-FcεRI Ig in the plasma sample or fraction thereof. 12. The method of paragraphs 10 or 11, wherein the detection protein comprises an antibody variable region that binds to the anti-FcεRI Ig. 13. The method of paragraph 10, wherein the method further comprises contacting the detection protein with an antibody that binds thereto and comprises a detectable label. 14. A method of detecting an anti-Fc epsilon Receptor I (FcεRI) immunoglobulin (Ig) in a plasma sample or a fraction thereof, the method comprising: (i) contacting the sample to a ligand which binds to the anti-FcεRI Ig in the sample to thereby form a complex; and (ii) detecting the complex with a detection protein comprising a detectable label, wherein presence of a detectable label is indicative of the presence of the anti- FcεRI Ig in the plasma sample or fraction thereof. 15. A method of screening a plasma sample or a fraction thereof for an anti-Fc epsilon Receptor I (FcεRI) immunoglobulin (Ig), the method comprising: (i) contacting the sample to a ligand which binds to the anti-FcεRI Ig in the sample to thereby form a complex; and (ii) detecting the complex with a detection protein comprising a detectable label, wherein presence of a detectable label is indicative of the presence of the anti- FcεRI Ig in the plasma sample or fraction thereof. 16. A method of identifying a plasma sample or a fraction thereof suitable for administration to a subject, the method comprising: (i) contacting the sample to a ligand which binds to an anti-Fc epsilon Receptor I (FcεRI) immunoglobulin (Ig) in the sample to thereby form a complex; and (ii) detecting the complex with a detection protein comprising a detectable label, wherein presence of a detectable label is indicative of the presence of the anti- FcεRI Ig in the plasma sample or fraction thereof, wherein the presence of anti- FcεRI Ig in the plasma sample or fraction thereof indicates the plasma sample or fraction thereof is not suitable for administration to the subject. 17. A method of screening a plasma sample or a fraction thereof to determine suitability for administration to a subject, the method comprising: (i) contacting the sample to a ligand which binds to an anti-Fc epsilon Receptor I (FcεRI) immunoglobulin Ig in the sample to thereby form a complex; and (ii) detecting the complex with a detection protein comprising a detectable label, wherein presence of a detectable label is indicative of the presence of the anti- FcεRI Ig in the plasma sample or fraction thereof, wherein the presence of anti- FcεRI Ig in the plasma sample or fraction thereof indicates the plasma sample or fraction thereof is not suitable for administration to the subject. 18. A method of identifying a plasma sample or a fraction thereof for use in producing an immunoglobulin (Ig) preparation for administration to a subject, the method comprising: (i) contacting the sample to a ligand which binds to an anti-Fc epsilon Receptor I (FcεRI) immunoglobulin (Ig) in the sample to thereby form a complex; and (ii) detecting the complex with a detection protein comprising a detectable label, wherein presence of a detectable label is indicative of the presence of the anti- FcεRI Ig in the plasma sample or fraction thereof, wherein the presence of anti- FcεRI Ig in the plasma sample or fraction thereof indicates the plasma sample or fraction thereof is not suitable for use in producing an Ig preparation for administration to a subject administration to the subject. 19. A method of screening a plasma sample or fraction thereof for use in producing an immunoglobulin (Ig) preparation for administration to a subject, the method comprising: (i) contacting the sample to a ligand which binds to an anti-Fc epsilon Receptor I (FcεRI) immunoglobulin Ig in the sample to thereby form a complex; and (ii) detecting the complex with a detection protein comprising a detectable label, wherein presence of a detectable label is indicative of the presence of the anti- FcεRI Ig in the plasma sample or fraction thereof, wherein the presence of anti- FcεRI Ig in the plasma sample or fraction thereof indicates the plasma sample or fraction thereof is not suitable for use in producing an Ig preparation for administration to a subject administration to the subject. 20. The method of any one of paragraphs 14 to 19, wherein the method further comprises contacting the complex with a detection protein. 21. The method of any one of paragraphs 14 to 20, wherein the detection protein comprises an antibody variable region that binds to the anti-FcεRI Ig. 22. The method of any one of paragraphs 1 to 21, wherein the ligand is immobilised onto a solid surface. 23. The method of any one of paragraphs 1 to 22, wherein the method further comprises immobilising the ligand onto a solid surface. 24. A method of detecting an anti-Fc epsilon Receptor I (FcεRI) immunoglobulin (Ig) in a plasma sample or a fraction thereof, the method comprising: (i) immobilising a ligand comprising a FcεRI or fragment or epitope thereof onto a solid surface; (ii) contacting the sample to the ligand immobilised on the solid surface, wherein the immobilised ligand binds to the anti-FcεRI Ig in the sample to thereby form a complex; (iii) contacting the complex with a detection protein comprising an antibody variable region, wherein the detection protein binds to the anti-FcεRI Ig and wherein the detection protein comprises a detectable label; and (iv) detecting the label, wherein presence of the detectable label is indicative of the presence of the anti-FcεRI Ig in the plasma sample or fraction thereof. 25. A method of detecting an anti-Fc epsilon Receptor I (FcεRI) immunoglobulin (Ig) in a plasma sample or a fraction thereof, the method comprising: (i) immobilising a ligand comprising a FcεRI or fragment or epitope thereof onto a solid surface; (ii) contacting the sample to the ligand immobilised on the solid surface, wherein the immobilised ligand binds to the anti-FcεRI Ig in the sample to thereby form a complex; (iii) contacting the complex with a detection protein comprising an antibody variable region, wherein the detection protein binds to the anti-FcεRI Ig; (iv) contacting the detection protein with an antibody that binds thereto and comprises a detectable label; and (v) detecting the label, wherein presence of the detectable label is indicative of the presence of the anti-FcεRI Ig in the plasma sample or fraction thereof. 26. A method of screening a plasma sample or a fraction thereof for an anti-Fc epsilon Receptor I (FcεRI) immunoglobulin (Ig), the method comprising: (i) immobilising a ligand comprising a FcεRI or fragment or epitope thereof onto a solid surface; (ii) contacting the sample to the ligand immobilised on the solid surface, wherein the immobilised ligand binds to the anti-FcεRI Ig in the sample to thereby form a complex; (iii) contacting the complex with a detection protein comprising an antibody variable region, wherein the detection protein binds to the anti-FcεRI Ig and wherein the detection protein comprises a detectable label; and (iv) detecting the label, wherein presence of the detectable label is indicative of the presence of the anti-FcεRI Ig in the plasma sample or fraction thereof. 27. A method of screening a plasma sample or a fraction thereof for an anti-Fc epsilon Receptor I (FcεRI) immunoglobulin (Ig), the method comprising: (i) immobilising a ligand comprising a FcεRI or fragment or epitope thereof onto a solid surface; (ii) contacting the sample to the ligand immobilised on the solid surface, wherein the immobilised ligand binds to the anti-FcεRI Ig in the sample to thereby form a complex; (iii) contacting the complex with a detection protein comprising an antibody variable region, wherein the detection protein binds to the anti-FcεRI Ig; (iv) contacting the detection protein with an antibody that binds thereto and comprises a detectable label; and (v) detecting the label, wherein presence of the detectable label is indicative of the presence of the anti-FcεRI Ig in the plasma sample or fraction thereof. 28. A method of identifying a plasma sample or a fraction thereof suitable for administration to a subject, the method comprising: (i) immobilising a ligand comprising a FcεRI or fragment or epitope thereof onto a solid surface; (ii) contacting the sample to the ligand immobilised on the solid surface, wherein the immobilised ligand binds to the anti-FcεRI Ig in the sample to thereby form a complex; (iii) contacting the complex with a detection protein comprising an antibody variable region, wherein the detection protein binds to the anti-FcεRI Ig and wherein the detection protein comprises a detectable label; and (iv) detecting the label, wherein presence of the detectable label is indicative of the presence of the anti-FcεRI Ig in the plasma sample or fraction thereof, wherein the presence of anti-FcεRI Ig in the plasma sample or fraction thereof indicates the plasma sample or fraction thereof is not suitable for administration to the subject. 29. A method of identifying a plasma sample or a fraction thereof suitable for administration to a subject, the method comprising: (i) immobilising a ligand comprising a FcεRI or fragment or epitope thereof onto a solid surface; (ii) contacting the sample to the ligand immobilised on the solid surface, wherein the immobilised ligand binds to the anti-FcεRI Ig in the sample to thereby form a complex; (iii) contacting the complex with a detection protein comprising an antibody variable region, wherein the detection protein binds to the anti-FcεRI Ig; (iv) contacting the detection protein with an antibody that binds thereto and comprises a detectable label; and (v) detecting the label, wherein presence of the detectable label is indicative of the presence of the anti-FcεRI Ig in the plasma sample or fraction thereof, wherein the presence of anti-FcεRI Ig in the plasma sample or fraction thereof indicates the plasma sample or fraction thereof is not suitable for administration to the subject. 30. A method of screening a plasma sample or a fraction thereof to determine suitability for administration to a subject, the method comprising: (i) immobilising a ligand comprising a FcεRI or fragment or epitope thereof onto a solid surface; (ii) contacting the sample to the ligand immobilised on the solid surface, wherein the immobilised ligand binds to the anti-FcεRI Ig in the sample to thereby form a complex; (iii) contacting the complex with a detection protein comprising an antibody variable region, wherein the detection protein binds to the anti-FcεRI Ig and wherein the detection protein comprises a detectable label; and (iv) detecting the label, wherein presence of the detectable label is indicative of the presence of the anti-FcεRI Ig in the plasma sample or fraction thereof, wherein the presence of anti-FcεRI Ig in the plasma sample or fraction thereof indicates the plasma sample or fraction thereof is not suitable for administration to the subject. 31. A method of screening a plasma sample or a fraction thereof to determine suitability for administration to a subject, the method comprising: (i) immobilising a ligand comprising a FcεRI or fragment or epitope thereof onto a solid surface; (ii) contacting the sample to the ligand immobilised on the solid surface, wherein the immobilised ligand binds to the anti-FcεRI Ig in the sample to thereby form a complex; (iii) contacting the complex with a detection protein comprising an antibody variable region, wherein the detection protein binds to the anti-FcεRI Ig; (iv) contacting the detection protein with an antibody that binds thereto and comprises a detectable label; and (v) detecting the label, wherein presence of the detectable label is indicative of the presence of the anti-FcεRI Ig in the plasma sample or fraction thereof, wherein the presence of anti-FcεRI Ig in the plasma sample or fraction thereof indicates the plasma sample or fraction thereof is not suitable for administration to the subject. A method of identifying a plasma sample or a fraction thereof for use in producing an immunoglobulin (Ig) preparation for administration to a subject, the method comprising: (i) immobilising a ligand comprising a FcεRI or fragment or epitope thereof onto a solid surface; (ii) contacting the sample to the ligand immobilised on the solid surface, wherein the immobilised ligand binds to the anti-FcεRI Ig in the sample to thereby form a complex; (iii) contacting the complex with a detection protein comprising an antibody variable region, wherein the detection protein binds to the anti-FcεRI Ig and wherein the detection protein comprises a detectable label; and (iv) detecting the label, wherein presence of the detectable label is indicative of the presence of the anti-FcεRI Ig in the plasma sample or fraction thereof, wherein the presence of anti-FcεRI Ig in the plasma sample or fraction thereof indicates the plasma sample or fraction thereof is not suitable for use in producing an Ig preparation for administration to the subject. A method of identifying a plasma sample or a fraction thereof for use in producing an immunoglobulin (Ig) preparation for administration to a subject, the method comprising: (i) immobilising a ligand comprising a FcεRI or fragment or epitope thereof onto a solid surface; (ii) contacting the sample to the ligand immobilised on the solid surface, wherein the immobilised ligand binds to the anti-FcεRI Ig in the sample to thereby form a complex; (iii) contacting the complex with a detection protein comprising an antibody variable region, wherein the detection protein binds to the anti-FcεRI Ig; (iv) contacting the detection protein with an antibody that binds thereto and comprises a detectable label; and (v) detecting the label, wherein presence of the detectable label is indicative of the presence of the anti-FcεRI Ig in the plasma sample or fraction thereof, wherein the presence of anti-FcεRI Ig in the plasma sample or fraction thereof indicates the plasma sample or fraction thereof is not suitable for use in producing an Ig preparation for administration to the subject. A method of screening a plasma sample or a fraction thereof for use in producing an immunoglobulin (Ig) preparation for administration to a subject, the method comprising: (i) immobilising a ligand comprising a FcεRI or fragment or epitope thereof onto a solid surface; (ii) contacting the sample to the ligand immobilised on the solid surface, wherein the immobilised ligand binds to the anti-FcεRI Ig in the sample to thereby form a complex; (iii) contacting the complex with a detection protein comprising an antibody variable region, wherein the detection protein binds to the anti-FcεRI Ig and wherein the detection protein comprises a detectable label; and (iv) detecting the label, wherein presence of the detectable label is indicative of the presence of the anti-FcεRI Ig in the plasma sample or fraction thereof, wherein the presence of anti-FcεRI Ig in the plasma sample or fraction thereof indicates the plasma sample or fraction thereof is not suitable for use in producing an Ig preparation for administration to the subject. A method of screening a plasma sample or a fraction thereof for use in producing an immunoglobulin (Ig) preparation for administration to a subject, the method comprising: (i) immobilising a ligand comprising a FcεRI or fragment or epitope thereof onto a solid surface; (ii) contacting the sample to the ligand immobilised on the solid surface, wherein the immobilised ligand binds to the anti-FcεRI Ig in the sample to thereby form a complex; (iii) contacting the complex with a detection protein comprising an antibody variable region, wherein the detection protein binds to the anti-FcεRI Ig; (iv) contacting the detection protein with an antibody that binds thereto and comprises a detectable label; and (v) detecting the label, wherein presence of the detectable label is indicative of the presence of the anti-FcεRI Ig in the plasma sample or fraction thereof, wherein the presence of anti-FcεRI Ig in the plasma sample or fraction thereof indicates the plasma sample or fraction thereof is not suitable for use in producing Ig preparation for administration to the subject. 36. The method of any one of paragraphs 13 to 35, wherein if the label is not detected, the anti-FcεRI Ig is not present in a detectable amount. 37. The method of paragraph 36, wherein the method further comprises administering the plasma sample or fraction thereof to a subject if the anti-FcεRI Ig is not present in a detectable amount. 38. The method of paragraph 36, wherein the method further comprises including the plasma sample or fraction thereof into a pooled blood plasma sample if the anti-FcεRI Ig is not present in a detectable amount. 39. The method of paragraph 36, wherein the method further comprises excluding the plasma sample or a fraction thereof from a pooled blood plasma sample if the anti- FcεRI Ig is present in a detectable amount. 40. A method of identifying a subject suitable for plasma donation for the production of an immunoglobulin (Ig) preparation, the method comprising: (i) contacting a plasma sample or fraction thereof from the subject to a ligand which binds to the anti-FcεRI Ig in the sample to thereby form a complex; and (ii) detecting the complex, wherein presence of the complex is indicative of the presence of the anti-FcεRI Ig in the plasma sample or fraction thereof. 41. A method of screening for a subject suitable for plasma donation for the production of an immunoglobulin (Ig) preparation, the method comprising: (i) contacting a plasma sample or fraction thereof from the subject to a ligand which binds to an anti-Fc epsilon Receptor I (FcεRI) immunoglobulin (Ig) in the sample to thereby form a complex; and (ii) detecting the complex, wherein presence of the complex is indicative of the presence of the anti-FcεRI Ig in the plasma sample or fraction thereof. 42. The method of paragraph 40 or 41, wherein the subject is suitable for plasma donation if the anti-FcεRI Ig is not present. 43. The method of any one of paragraphs 40 or 41, wherein the subject is not suitable for plasma donation if the anti-FcεRI Ig is present. 44. The method of any one of paragraphs 40 to 43, wherein the method further comprises contacting the complex with a detection protein. 45. The method of paragraph 44, wherein the detection protein comprises an antibody variable region, wherein the detection protein binds to the anti-FcεRI Ig. 46. The method of paragraph 44 or 45, wherein the detection protein comprises a detectable label, wherein presence of the detectable label is indicative of the presence of the anti-FcεRI Ig in the plasma sample or fraction thereof. 47. The method of paragraph 46, wherein the method further comprises detecting the label, wherein presence of the detectable label is indicative of the presence of the anti-FcεRI Ig in the plasma sample or fraction thereof. 48. The method of paragraphs 44 or 45, wherein the method further comprises contacting the detection protein with an antibody that binds thereto and comprises a detectable label. 49. A method of identifying a subject suitable for plasma donation for the production of an immunoglobulin (Ig) preparation, the method comprising: (i) contacting a plasma sample or fraction thereof from the subject to a ligand which binds to an anti-Fc epsilon Receptor I (FcεRI) immunoglobulin (Ig) in the sample to thereby form a complex; and (ii) detecting the complex with a detection protein comprising a detectable label, wherein presence of a detectable label is indicative of the presence of the anti- FcεRI Ig in the plasma sample or fraction thereof, wherein the presence of anti- FcεRI Ig in the plasma sample or fraction thereof indicates the subject is suitable for plasma donation for the production of an Ig preparation. 50. A method of screening for a subject suitable for plasma donation for the production of an immunoglobulin (Ig) preparation, the method comprising: (i) contacting a plasma sample or fraction thereof from the subject to a ligand which binds to an anti-Fc epsilon Receptor I (FcεRI) immunoglobulin (Ig) in the sample to thereby form a complex; and (ii) detecting the complex with a detection protein comprising a detectable label, wherein presence of a detectable label is indicative of the presence of the anti- FcεRI Ig in the plasma sample or fraction thereof, wherein the presence of anti- FcεRI Ig in the plasma sample or fraction thereof indicates the subject is suitable for plasma donation for the production of an Ig preparation. 51. The method of any one of paragraphs 40 to 50, wherein the ligand is immobilised onto a solid surface. 52. The method of any one of paragraphs 40 to 51, wherein the method further comprises immobilising the ligand onto a solid surface. 53. The method of any one of paragraphs 49 to 52, wherein the subject is suitable for plasma donation if the anti-FcεRI Ig is not present in a detectable amount. 54. The method of any one of paragraphs 49 to 52, wherein the subject is not suitable for plasma donation if the anti-FcεRI Ig is present in a detectable amount. 55. The method of any one of paragraphs 1 to 54, wherein the method is an enzyme-linked immunosorbent assay (ELISA). 56. The method of any one of paragraphs 1 to 54, wherein the method is a fluorescence- linked immunosorbent assay (FLISA). 57. The method of any one of paragraphs 1 to 54, wherein the method is a lateral flow assay. 58. The method of any one of paragraphs 1 to 57, wherein the anti-FcεRI Ig binds to an epitope of FcεRI and activates a FcεRI mediated signalling pathway. 59. The method of any one of paragraphs 1 to 58, wherein the anti-FcεRI Ig binds to an α- chain of the FcεRI and activates a FcεRI mediated signalling pathway. 60. The method of any one of paragraphs 1 to 59, wherein a detectable amount of an anti- FcεRI Ig in the plasma sample or fraction thereof activates the FcεRI mediated signalling pathway. 61. The method of paragraph 59 or 60, wherein activation of the FcεRI mediated signalling pathway induces basophil activation. 62. The method of any one of paragraphs 1 to 61, wherein activation of the FcεRI mediated signalling pathway induces mast cell activation. 63. The method of any one of paragraphs 1 to 62, wherein activation of the FcεRI mediated signalling pathway induces basophil degranulation. 64. The method of any one of paragraphs 1 to 63, wherein activation of the FcεRI mediated signalling pathway induces mast cell degranulation. 65. A method comprising contacting a plasma sample or a fraction thereof with a reagent that binds to an anti-Fc epsilon Receptor I (FcεRI) immunoglobulin (Ig) in the plasma sample or a fraction thereof and detecting binding of the reagent. 66. The method of paragraph 65, wherein the reagent binds directly to the anti-FcεRI Ig in the plasma sample or fraction thereof. 67. The method of paragraph 65, wherein the reagent binds indirectly to the anti-FcεRI Ig in the plasma sample or fraction thereof. 68. The method of paragraph 65 or 66, wherein the reagent comprises a ligand comprising FcεRI or fragment or epitope thereof. 69. A method of detecting anti-Fc epsilon Receptor I (FcεRI) immunoglobulin (Ig) in a plasma sample or a fraction thereof, the method comprising determining the proportion of basophil and / or mast cell activation and / or degranulation induced by the plasma sample or fraction thereof, wherein presence of a basophil and / or mast cell activation and / or degranulation is indicative of the presence of the anti-FcεRI Ig in the plasma sample or fraction thereof. 70. The method of any one of paragraphs 1 to 69, wherein the anti-FcεRI Ig is an anti- FcεRI IgG and an anti-FcεRI IgE. 71. The method of any one of paragraphs 1 to 70, wherein the anti-FcεRI Ig is an anti- FcεRI IgG. 72. The method of paragraph 70 or 71, wherein the anti-FcεRI IgG is an IgG1. 73. The method of paragraph 70 or 71, wherein the anti-FcεRI IgG is an IgG2. 74. The method of paragraph 70 or 71, wherein the anti-FcεRI IgG is an IgG3. 75. The method of paragraph 70 or 71, wherein the anti-FcεRI IgG is an IgG4. The method of any one of paragraphs 1 to 69, wherein the anti-FcεRI Ig is an anti- FcεRI IgE. 77. The method of any one of paragraphs 1 to 69, wherein the anti-FcεRI Ig is an anti- FcεRI IgM. 78. The method of any one of paragraphs 1 to 69, wherein the anti-FcεRI Ig is an anti- FcεRI IgA. 79. The method of any one of paragraphs 1 to 78, wherein the ligand comprises a FcεRI or fragment or epitope thereof. 80. The method of any one of paragraphs 1 to 78, wherein the ligand is a FcεRI or fragment or epitope thereof. 81. The method of any one of paragraphs 1 to 78, wherein the ligand comprises a FcεRI antibody or fragment thereof. 82. The method of any one of paragraphs 1 to 78, wherein the ligand comprises a FcεRI DNA aptamer. 83. The method of any one of paragraphs 1 to 82, wherein the detection protein is an anti- IgG antibody. 84. The method of paragraph 83, wherein the detection protein is an anti-IgG1 antibody. 85. The method of paragraph 83, wherein the detection protein is an anti-IgG2 antibody. 86. The method of paragraph 83, wherein the detection protein is an anti-IgG3 antibody. 87. The method of paragraph 84, wherein the detection protein is an anti-IgG4 antibody. 88. The method of any one of paragraphs 1 to 82, wherein the detection protein is an anti- IgE antibody. 89. The method of any one of paragraphs 1 to 82, wherein the detection protein is an anti- IgM antibody. 90. The method of any one of paragraphs 1 to 82, wherein the detection protein is an anti- IgA antibody. 91. The method of any one of paragraphs 1 to 90, wherein the detectable label is selected from the group consisting of a radiolabel, an enzyme, a fluorescent label, a luminescent label, a bioluminescent label, a magnetic label, a prosthetic group and a contrast agent. 92. The method of any one of paragraphs 1 to 91, wherein the detectable label is a radiolabel. 93. The method of any one of paragraphs 1 to 91, wherein the detectable label is an enzyme. 94. The method of any one of paragraphs 1 to 91, wherein the detectable label is a fluorescent label. 95. The method of any one of paragraphs 1 to 91, wherein the detectable label is a luminescent label. 96. The method of any one of paragraphs 1 to 91, wherein the detectable label is a bioluminescent label. 97. The method of any one of paragraphs 1 to 91, wherein the detectable label is a magnetic label. 98. The method of any one of paragraphs 1 to 91, wherein the detectable label is a prosthetic group. 99. The method of any one of paragraphs 1 to 91, wherein the detectable label is a contrast agent. 100. The method of any one of paragraphs 1 to 99, the method further comprising determining the level of the anti-FcεRI Ig in the plasma sample or fraction thereof. 101. The method of paragraph 98 or 99, wherein the method further comprises administering the plasma sample or fraction thereof to the subject if the level of anti- FcεRI IgG is below a detectable amount. 102. The method of paragraph 100 or 101, wherein the anti-FcεRI Ig is an anti-FcεRI IgG. 103. The method of paragraph 101 or 102, wherein the detectable amount of anti-FcεRI IgG in the plasma sample or fraction thereof is at least 40 μg / mL. 104. The method of paragraph 100, wherein the anti-FcεRI Ig is an anti-FcεRI IgE. 105. The method of paragraph 104, wherein the detectable amount of anti-FcεRI IgE in the plasma sample or fraction thereof is at least 0.1 kU / L. 106. The method of any one of paragraphs 1 to 105, wherein the method further comprises determining the proportion of basophil activation induced by the plasma sample or fraction thereof. 107. The method of paragraph 106, wherein the proportion of basophil activation following exposure to the plasma sample or fraction thereof is determined by determining the proportion of basophils expressing one or more markers selected from the group consisting of CD63, CD203c and combinations thereof in the total population of basophils exposed to the plasma sample or fraction thereof. 108. The method of paragraphs 106 or 107, wherein the proportion of basophil activation following exposure to the plasma sample or fraction thereof is determined by determining the proportion of basophils expressing CD63 in the total population of basophils exposed to the plasma sample or fraction thereof. 109. The method of paragraphs 106 or 107, wherein the proportion of basophil activation following exposure to the plasma sample or fraction thereof is determined by determining the proportion of basophils expressing CD203c in the total population of basophils exposed to the plasma sample or fraction thereof. 110. The method of paragraphs 106 or 107, wherein the proportion of basophil activation following exposure to the plasma sample or fraction thereof is determined by determining the proportion of basophils expressing CD63 and CD203c in the total population of basophils exposed to the plasma sample or fraction thereof. 111. The method of any one of paragraphs 106 to 110, wherein the proportion of basophil activation induced by the plasma sample or fraction thereof indicates whether a detectable amount of anti-FcεRI Ig is present in the plasma sample or fraction. 112. The method of paragraphs 111, wherein a detectable amount of anti-FcεRI Ig is present in the plasma sample or fraction if the proportion of basophils expressing CD63 following exposure to the plasma sample or fraction thereof is more than 5 %, more than 6 %, more than 7 %, more than 8 %, more than 9 %, more than 10 %, more than 11 %, more than 12 %, more than 13 %, more than 14 % or more than 15 % of the total population of basophils exposed to the plasma sample or fraction thereof. 113. The method of paragraphs 111 or 112, wherein a detectable amount of anti-FcεRI Ig is present in the plasma sample or fraction if the proportion of basophils expressing CD63 following exposure to the plasma sample or fraction thereof is more than 5 % of the total population of basophils exposed to the plasma sample or fraction thereof. 114. The method of paragraphs 111 or 112, wherein a detectable amount of anti-FcεRI Ig is present in the plasma sample or fraction if the proportion of basophils expressing CD63 following exposure to the plasma sample or fraction thereof is more than 6 % of the total population of basophils exposed to the plasma sample or fraction thereof. 115. The method of paragraphs 111 or 112, wherein a detectable amount of anti-FcεRI Ig is present in the plasma sample or fraction if the proportion of basophils expressing CD63 following exposure to the plasma sample or fraction thereof is more than 7 % of the total population of basophils exposed to the plasma sample or fraction thereof. The method of paragraphs 111 or 112, wherein a detectable amount of anti-FcεRI Ig is present in the plasma sample or fraction if the proportion of basophils expressing CD63 following exposure to the plasma sample or fraction thereof is more than 8 % of the total population of basophils exposed to the plasma sample or fraction thereof. The method of paragraphs 111 or 112, wherein a detectable amount of anti-FcεRI Ig is present in the plasma sample or fraction if the proportion of basophils expressing CD63 following exposure to the plasma sample or fraction thereof is more than 9 % of the total population of basophils exposed to the plasma sample or fraction thereof. The method of paragraphs 111 or 112, wherein a detectable amount of anti-FcεRI Ig is present in the plasma sample or fraction if the proportion of basophils expressing CD63 following exposure to the plasma sample or fraction thereof is more than 10 % of the total population of basophils exposed to the plasma sample or fraction thereof. The method of paragraphs 111 or 112, wherein a detectable amount of anti-FcεRI Ig is present in the plasma sample or fraction if the proportion of basophils expressing CD63 following exposure to the plasma sample or fraction thereof is more than 11 % of the total population of basophils exposed to the plasma sample or fraction thereof. The method of paragraphs 111 or 112, wherein a detectable amount of anti-FcεRI Ig is present in the plasma sample or fraction if the proportion of basophils expressing CD63 following exposure to the plasma sample or fraction thereof is more than 12 % of the total population of basophils exposed to the plasma sample or fraction thereof. The method of paragraphs 111 or 112, wherein a detectable amount of anti-FcεRI Ig is present in the plasma sample or fraction if the proportion of basophils expressing CD63 following exposure to the plasma sample or fraction thereof is more than 13 % of the total population of basophils exposed to the plasma sample or fraction thereof. The method of paragraphs 111 or 112, wherein a detectable amount of anti-FcεRI Ig is present in the plasma sample or fraction if the proportion of basophils expressing CD63 following exposure to the plasma sample or fraction thereof is more than 14 % of the total population of basophils exposed to the plasma sample or fraction thereof. 123. The method of paragraphs 111 or 112, wherein a detectable amount of anti-FcεRI Ig is present in the plasma sample or fraction if the proportion of basophils expressing CD63 following exposure to the plasma sample or fraction thereof is more than 15 % of the total population of basophils exposed to the plasma sample or fraction thereof. 124. The method of paragraphs 111 or 112, wherein the method further comprises administering the plasma sample or fraction thereof to the subject if the anti-FcεRI Ig is not present in a detectable amount in the plasma sample or fraction thereof. 125. The method of paragraph 124, wherein the anti-FcεRI Ig is not present in a detectable amount if the proportion of basophils expressing CD63 following exposure to the plasma sample or fraction thereof is less than 5 % of the total population of basophils exposed to the plasma sample or fraction thereof. 126. The method of paragraph 111, wherein a detectable amount of anti-FcεRI Ig is present in the plasma sample or fraction if the proportion of basophils expressing CD203c following exposure to the plasma sample or fraction thereof is more than 5 %, more than 6 %, more than 7 %, more than 8 %, more than 9 %, more than 10 %, more than 11 %, more than 12 %, more than 13 %, more than 14 % or more than 15 % of the total population of basophils exposed to the plasma sample or fraction thereof. 127. The method of paragraphs 111 or 126, wherein a detectable amount of anti-FcεRI Ig is present in the plasma sample or fraction if the proportion of basophils expressing CD203c following exposure to the plasma sample or fraction thereof is more than 5 % of the total population of basophils exposed to the plasma sample or fraction thereof. 128. The method of paragraphs 111 or 126, wherein a detectable amount of anti-FcεRI Ig is present in the plasma sample or fraction if the proportion of basophils expressing CD203c following exposure to the plasma sample or fraction thereof is more than 6 % of the total population of basophils exposed to the plasma sample or fraction thereof. 129. The method of paragraphs 111 or 126, wherein a detectable amount of anti-FcεRI Ig is present in the plasma sample or fraction if the proportion of basophils expressing CD203c following exposure to the plasma sample or fraction thereof is more than 7 % of the total population of basophils exposed to the plasma sample or fraction thereof. The method of paragraphs 111 or 126, wherein a detectable amount of anti-FcεRI Ig is present in the plasma sample or fraction if the proportion of basophils expressing CD203c following exposure to the plasma sample or fraction thereof is more than 8 % of the total population of basophils exposed to the plasma sample or fraction thereof. The method of paragraphs 111 or 126, wherein a detectable amount of anti-FcεRI Ig is present in the plasma sample or fraction if the proportion of basophils expressing CD203c following exposure to the plasma sample or fraction thereof is more than 9 % of the total population of basophils exposed to the plasma sample or fraction thereof. The method of paragraphs 111 or 126, wherein a detectable amount of anti-FcεRI Ig is present in the plasma sample or fraction if the proportion of basophils expressing CD203c following exposure to the plasma sample or fraction thereof is more than 10 % of the total population of basophils exposed to the plasma sample or fraction thereof. The method of paragraphs 111 or 126, wherein a detectable amount of anti-FcεRI Ig is present in the plasma sample or fraction if the proportion of basophils expressing CD203c following exposure to the plasma sample or fraction thereof is more than 11 % of the total population of basophils exposed to the plasma sample or fraction thereof. The method of paragraphs 111 or 126, wherein a detectable amount of anti-FcεRI Ig is present in the plasma sample or fraction if the proportion of basophils expressing CD203c following exposure to the plasma sample or fraction thereof is more than 12 % of the total population of basophils exposed to the plasma sample or fraction thereof. The method of paragraphs 111 or 126, wherein a detectable amount of anti-FcεRI Ig is present in the plasma sample or fraction if the proportion of basophils expressing CD203c following exposure to the plasma sample or fraction thereof is more than 13 % of the total population of basophils exposed to the plasma sample or fraction thereof. The method of paragraphs111 or 126, wherein a detectable amount of anti-FcεRI Ig is present in the plasma sample or fraction if the proportion of basophils expressing CD203c following exposure to the plasma sample or fraction thereof is more than 14 % of the total population of basophils exposed to the plasma sample or fraction thereof. The method of paragraphs 111 or 126, wherein a detectable amount of anti-FcεRI Ig is present in the plasma sample or fraction if the proportion of basophils expressing CD203c following exposure to the plasma sample or fraction thereof is more than 15 % of the total population of basophils exposed to the plasma sample or fraction thereof. The method of paragraphs 111 or 124, wherein the anti-FcεRI Ig is not present in a detectable amount if the proportion of basophils expressing CD203c following exposure to the plasma sample or fraction thereof is less than 5 %. The method of any one of paragraphs 106 to 138, wherein the proportion of basophil activation is determined by incubating basophils with the plasma sample or fraction thereof and quantifying the proportion of CD63 expressing basophils and / or the proportion of CD203c expressing basophils in the total population of basophils using flow cytometry. The method of any one of paragraphs 1 to 139, wherein the method further comprises determining the proportion of mast cell activation induced by the plasma sample or fraction thereof. The method of paragraph 141, wherein the proportion of mast cell activation following exposure to the plasma sample or fraction thereof is determined by determining the proportion of mast cells expressing CD107a in the total population of mast cells exposed to the plasma sample or fraction thereof. The method of any paragraph 141 or 142, wherein the proportion of mast cell activation induced by the plasma sample or fraction thereof indicates whether a detectable amount of anti-FcεRI Ig is present in the plasma sample or fraction. The method of paragraph 143, wherein a detectable amount of anti-FcεRI Ig is present in the plasma sample or fraction if the proportion of mast cells expressing CD107a following exposure to the plasma sample or fraction thereof is more than 5 %, more than 6 %, more than 7 %, more than 8 %, more than 9 %, more than 10 %, more than 11 %, more than 12 %, more than 13 %, more than 14 % or more than 15 % of the total population of mast cells exposed to the plasma sample or fraction thereof. The method of paragraphs 143 or 144, wherein a detectable amount of anti-FcεRI Ig is present in the plasma sample or fraction if the proportion of mast cells expressing CD107a following exposure to the plasma sample or fraction thereof is more than 5 % of the total population of mast cells exposed to the plasma sample or fraction thereof. The method of paragraphs 143 or 144, wherein a detectable amount of anti-FcεRI Ig is present in the plasma sample or fraction if the proportion of mast cells expressing CD107a following exposure to the plasma sample or fraction thereof is more than 6 % of the total population of mast cells exposed to the plasma sample or fraction thereof. The method of paragraphs 143 or 144, wherein a detectable amount of anti-FcεRI Ig is present in the plasma sample or fraction if the proportion of mast cells expressing CD107a following exposure to the plasma sample or fraction thereof is more than 7 % of the total population of mast cells exposed to the plasma sample or fraction thereof. The method of paragraphs 143 or 144, wherein a detectable amount of anti-FcεRI Ig is present in the plasma sample or fraction if the proportion of mast cells expressing CD107a following exposure to the plasma sample or fraction thereof is more than 8 % of the total population of mast cells exposed to the plasma sample or fraction thereof. The method of paragraphs 143 or 144, wherein a detectable amount of anti-FcεRI Ig is present in the plasma sample or fraction if the proportion of mast cells expressing CD107a following exposure to the plasma sample or fraction thereof is more than 9 % of the total population of mast cells exposed to the plasma sample or fraction thereof. The method of paragraphs 143 or 144, wherein a detectable amount of anti-FcεRI Ig is present in the plasma sample or fraction if the proportion of mast cells expressing CD107a following exposure to the plasma sample or fraction thereof is more than 10 % of the total population of mast cells exposed to the plasma sample or fraction thereof. The method of paragraphs 143 or 144, wherein a detectable amount of anti-FcεRI Ig is present in the plasma sample or fraction if the proportion of mast cells expressing CD107a following exposure to the plasma sample or fraction thereof is more than 11 % of the total population of mast cells exposed to the plasma sample or fraction thereof. The method of paragraphs 143 or 144, wherein a detectable amount of anti-FcεRI Ig is present in the plasma sample or fraction if the proportion of mast cells expressing CD107a following exposure to the plasma sample or fraction thereof is more than 12 % of the total population of mast cells exposed to the plasma sample or fraction thereof. The method of paragraphs 143 or 144, wherein a detectable amount of anti-FcεRI Ig is present in the plasma sample or fraction if the proportion of mast cells expressing CD107a following exposure to the plasma sample or fraction thereof is more than 13 % of the total population of mast cells exposed to the plasma sample or fraction thereof. The method of paragraphs 143 or 144, wherein a detectable amount of anti-FcεRI Ig is present in the plasma sample or fraction if the proportion of mast cells expressing CD107a following exposure to the plasma sample or fraction thereof is more than 14 % of the total population of mast cells exposed to the plasma sample or fraction thereof. The method of paragraphs 143 or 144, wherein a detectable amount of anti-FcεRI Ig is present in the plasma sample or fraction if the proportion of mast cells expressing CD107a following exposure to the plasma sample or fraction thereof is more than 15 % of the total population of mast cells exposed to the plasma sample or fraction thereof. The method of paragraph 143 or 144, wherein the anti-FcεRI Ig is not present in the plasma sample or fraction in a detectable amount if the proportion of mast cells expressing CD107a following exposure to the plasma sample or fraction thereof is less than 5 %. The method of any one of paragraphs 143 to 156, wherein the proportion of mast cell activation is determined by incubating mast cells with the plasma sample or fraction thereof and quantifying the proportion of CD107a expressing mast cells in the total population of mast cells using flow cytometry The method of any one of paragraphs 1 to 157, wherein the plasma sample or fraction thereof is selected the group consisting of a human blood plasma sample, an IgG intermediate product, an intravenous immunoglobulin G (IVIG), a subcutaneous immunoglobulin G (SCIG), a cryo-rich plasma, a cryo-poor plasma, a Supernatant I (SN I), a Cohn Fraction II (Fr II), a Cohn Fraction II+III (Fr II+III), a Cohn Fraction I+II+III (FrI+II+III), a Kistler / Nitschmann Precipitate A (KN A), a Kistler / Nitschmann Precipitate B (KN B), a Kistler / Nitschmann Precipitate of Supernatant B (KN B+1), and combinations thereof. 159. The method of any one of paragraphs 1 to 158, wherein the plasma sample or fraction thereof is a human blood plasma sample. 160. The method of any one of paragraphs 1 to 158, wherein the plasma sample or fraction thereof is an IgG intermediate product. 161. The method of any one of paragraphs 1 to 158, wherein the plasma sample or fraction thereof is an intravenous immunoglobulin G (IVIG). 162. The method of any one of paragraphs 1 to 158, wherein the plasma sample or fraction thereof is a subcutaneous immunoglobulin G (SCIG). 163. The method of any one of paragraphs 1 to 158, wherein the plasma sample or fraction thereof is a cryo-poor plasma. 164. The method of any one of paragraphs 1 to 158, wherein the plasma sample or fraction thereof is a Supernatant I (SN I). 165. The method of any one of paragraphs 1 to 158, wherein the plasma sample or fraction thereof is a Cohn Fraction II (Fr II). 166. The method of any one of paragraphs 1 to 158, wherein the plasma sample or fraction thereof is a Cohn Fraction II+III (Fr II+III). 167. The method of any one of paragraphs 1 to 158, wherein the plasma sample or fraction thereof is a Cohn Fraction I+II+III (FrI+II+III). 168. The method of any one of paragraphs 1 to 158, wherein the plasma sample or fraction thereof is a Kistler / Nitschmann Precipitate A (KN A). 169. The method of any one of paragraphs 1 to 158, wherein the plasma sample or fraction thereof is a Kistler / Nitschmann Precipitate B (KN B). 170. The method of any one of paragraphs 1 to 158, wherein the plasma sample or fraction thereof is a Kistler / Nitschmann Precipitate of Supernatant B (KN B+1). 171. The method of any one of paragraphs 1 to 170, wherein the plasma sample or fraction thereof is a human blood plasma sample from one or more subjects. 172. An affinity chromatography resin comprising a ligand which binds to anti-FcεRI Ig immobilized to a matrix of the affinity chromatography resin. 173. The affinity chromatography resin of paragraph 172, wherein the resin further comprises a blood group A antigen and a blood group B antigen immobilized to the matrix of the affinity chromatography resin. 174. A method of preparing an anti-Fc epsilon Receptor I (FcεRI) immunoglobulin (Ig) reduced preparation from a plasma sample or a fraction thereof, the method comprising binding the anti-FcεRI Ig to an affinity chromatography resin comprising a ligand which binds to the anti-FcεRI Ig in the plasma sample or fraction thereof and collecting the anti-FcεRI Ig reduced preparation. 175. The method of paragraph 174, wherein the method further comprises loading the plasma sample or fraction thereof onto the affinity chromatography resin. 176. A method of preparing an anti-Fc epsilon Receptor I (FcεRI) immunoglobulin (Ig) reduced preparation from a plasma sample or a fraction thereof, the method comprising: (i) loading the plasma sample or fraction thereof onto an affinity chromatography resin comprising a ligand which binds to the anti-FcεRI Ig in the plasma sample or fraction thereof immobilized to a matrix of the affinity chromatography resin; and (ii) collecting the anti-FcεRI Ig reduced preparation. 177. The method of any one of paragraphs 174 to 176, wherein the method further comprises a wash and / or elution step. 178. The method of any one of paragraphs 174 to 177, wherein the method further comprises an elution step. 179. The method of any one of paragraphs 174 to 178, wherein the method further comprises a wash step. 180. The method of any one of paragraphs 174 to 179, wherein the anti-FcεRI Ig binds to an α-chain of the FcεRI and activates a FcεRI mediated signalling pathway. 181. The method of any one of paragraphs 174 to 180, wherein the anti-FcεRI Ig reduced preparation induces reduced activation of a FcεRI mediated signalling pathway relative to a preparation wherein the anti-FcεRI Ig is not reduced. 182. The method of any one of paragraphs 174 to 181, wherein the anti-FcεRI Ig is not present in a detectable amount in the anti-FcεRI Ig reduced preparation. 183. The method of paragraph 182, wherein the anti-FcεRI Ig reduced preparation induces reduced activation of a FcεRI mediated signalling pathway relative to a preparation wherein the anti-FcεRI Ig is not reduced. 184. The method of any one of paragraphs 174 to 182, wherein the anti-FcεRI Ig is not present in a detectable amount and the anti-FcεRI Ig reduced preparation induces reduced basophil activation relative to a preparation wherein the anti-FcεRI Ig is not reduced. 185. The method of any one of paragraphs 174 to 182, wherein the anti-FcεRI Ig is not present in a detectable amount and the anti-FcεRI Ig reduced preparation induces reduced mast cell activation relative to a preparation wherein the anti-FcεRI Ig is not reduced. 186. The method of any one of paragraphs 174 to 184, wherein basophil activation following exposure to the anti-FcεRI Ig reduced preparation is determined by determining the proportion of basophils expressing one or more markers selected from the group consisting of CD63, CD203c and combinations thereof. 187. The method of paragraph 186, wherein basophil activation is determined by determining the proportion of basophils expressing CD63 following exposure to the anti-FcεRI Ig reduced preparation. 188. The method of paragraph 186, wherein basophil activation is determined by determining the proportion of basophils CD203c following exposure to the anti-FcεRI Ig reduced preparation. 189. The method of paragraph 186, wherein basophil activation is determined by determining the proportion of basophils expressing CD63 and CD203c following exposure to the anti-FcεRI Ig reduced preparation. 190. The method of any one of paragraphs 186, 187 or 189, wherein the proportion of basophils expressing CD63 following exposure to the anti-FcεRI Ig reduced preparation is less than 1 %, less than 2 %, less than 3 %, less than 4 % or less than 5 % of the total population of basophils exposed to the anti-FcεRI Ig reduced preparation. 191. The method of any one of paragraphs 186, 187, 189 or 190, wherein the proportion of basophils expressing CD63 following exposure to the anti-FcεRI Ig reduced preparation is less than 5 % of the total population of basophils exposed to the anti-FcεRI Ig reduced preparation. 192. The method of any one of paragraphs 186, 187, 189 to 191, wherein the proportion of basophils expressing CD63 following exposure to the anti-FcεRI Ig reduced preparation less than 4 % of the total population of basophils exposed to the anti-FcεRI Ig reduced preparation. 193. The method of any one of paragraphs 186, 187, 189 to 192, wherein the proportion of basophils expressing CD63 following exposure to the anti-FcεRI Ig reduced preparation is less than 3 % of the total population of basophils exposed to the anti-FcεRI Ig reduced preparation. 194. The method of any one of paragraphs 186, 187, 189 to 193, wherein the proportion of basophils expressing CD63 following exposure to the anti-FcεRI Ig reduced preparation is less than 2 % of the total population of basophils exposed to the anti-FcεRI Ig reduced preparation. The method of any one of paragraphs 186, 187, 189 to 194, wherein the proportion of basophils expressing CD63 following exposure to the anti-FcεRI Ig reduced preparation is less than 1 % of the total population of basophils exposed to the anti-FcεRI Ig reduced preparation. The method of any one of paragraphs 186, 187 or 189, wherein the method further comprises administering the anti-FcεRI Ig reduced preparation to the subject if the proportion of basophils expressing CD63 following exposure to the anti-FcεRI Ig reduced preparation is less than 5 % of the total population of basophils exposed to the anti-FcεRI Ig reduced preparation. The method of any one of paragraphs 186, 187 or 189, wherein the method or use further comprises including the anti-FcεRI Ig reduced preparation into a pooled blood plasma sample if the proportion of basophils expressing CD63 following exposure to the anti-FcεRI Ig reduced preparation is less than 5 % of the total population of basophils exposed to the anti-FcεRI Ig reduced preparation. The method of any one of paragraphs 186, 187 or 189, wherein the method or use further comprises excluding the anti-FcεRI Ig reduced preparation from a pooled blood plasma sample if the proportion of basophils expressing CD63 following exposure to the anti-FcεRI Ig reduced preparation is more than 5 % of the total population of basophils exposed to the anti-FcεRI Ig reduced preparation. The method of any one of paragraphs 186, 187 or 189, wherein the proportion of basophils expressing CD203c following exposure to the anti-FcεRI Ig reduced preparation is less than 1 %, less than 2 %, less than 3 %, less than 4 % or less than 5 % of the total population of basophils exposed to the anti-FcεRI Ig reduced preparation. The method of any one of paragraphs 186, 187, 189 or 199, wherein the proportion of basophils expressing CD203c following exposure to the anti-FcεRI Ig reduced preparation is less than 5 % of the total population of basophils exposed to the anti- FcεRI Ig reduced preparation. The method of any one of paragraphs186, 187, 189, 199 or 200, wherein the proportion of basophils expressing CD203c following exposure to the anti-FcεRI Ig reduced preparation is less than 4 % of the total population of basophils exposed to the anti- FcεRI Ig reduced preparation. 202. The method of any one of paragraphs 186, 187, 189, 199 to 201, wherein the proportion of basophils expressing CD203c following exposure to the anti-FcεRI Ig reduced preparation is less than 3 % of the total population of basophils exposed to the anti- FcεRI Ig reduced preparation. 203. The method of any one of paragraphs 186, 187, 189, 199 to 202, wherein the proportion of basophils expressing CD203c following exposure to the anti-FcεRI Ig reduced preparation is less than 2 % of the total population of basophils exposed to the anti- FcεRI Ig reduced preparation. 204. The method of any one of paragraphs186, 187, 189, 199 to 203, wherein the proportion of basophils expressing CD203c following exposure to the anti-FcεRI Ig reduced preparation is less than 1 % of the total population of basophils exposed to the anti- FcεRI Ig reduced preparation. 205. The method of any one of paragraphs 186, 187 or 189, wherein the method further comprises administering the anti-FcεRI Ig reduced preparation to the subject if the proportion of basophils expressing CD203c following exposure to the anti-FcεRI Ig reduced preparation is less than 5 % of the total population of basophils exposed to the anti-FcεRI Ig reduced preparation. 206. The method of any one of paragraphs 186, 187 or 189, wherein the method further comprises including the anti-FcεRI Ig reduced preparation into a pooled blood plasma sample if the proportion of basophils expressing CD203c following exposure to the anti- FcεRI Ig reduced preparation is less than 5 % of the total population of basophils exposed to the anti-FcεRI Ig reduced preparation. 207. The method of any one of paragraphs 186, 187 or 189, wherein the method further comprises excluding the anti-FcεRI Ig reduced preparation from a pooled blood plasma sample if the proportion of basophils expressing CD203c following exposure to the anti- FcεRI Ig reduced preparation is more than 5 % of the total population of basophils exposed to the anti-FcεRI Ig reduced preparation. 208. The method of any one of paragraphs 185 to 207, wherein mast cell activation following exposure to the anti-FcεRI Ig reduced preparation is determined by determining the proportion of mast cells expressing CD107a. 209. The method of paragraph 208, wherein the proportion of mast cells expressing CD107a following exposure to the anti-FcεRI Ig reduced preparation is less than 1 %, less than 2 %, less than 3 %, less than 4 % or less than 5 % of the total population of mast cells exposed to the anti-FcεRI Ig reduced preparation. 210. The method of paragraph 208 or 210, wherein the proportion of mast cells expressing CD107a following exposure to the anti-FcεRI Ig reduced preparation is less than 5 % of the total population of mast cells exposed to the anti-FcεRI Ig reduced preparation. 211. The method of paragraph 208 to 210, wherein the proportion of mast cells expressing CD107a following exposure to the anti-FcεRI Ig reduced preparation is less than 4 % of the total population of mast cells exposed to the anti-FcεRI Ig reduced preparation. 212. The method of paragraph 208 to 211, wherein the proportion of mast cells expressing CD107a following exposure to the anti-FcεRI Ig reduced preparation is less than 3 % of the total population of mast cells exposed to the anti-FcεRI Ig reduced preparation. 213. The method of paragraph 208 to 212, wherein the proportion of mast cells expressing CD107a following exposure to the anti-FcεRI Ig reduced preparation is less than 2 % of the total population of mast cells exposed to the anti-FcεRI Ig reduced preparation. 214. The method of paragraph 208 to 213, wherein the proportion of mast cells expressing CD107a following exposure to the anti-FcεRI Ig reduced preparation is less than 1 % of the total population of mast cells exposed to the anti-FcεRI Ig reduced preparation. 215. The method of paragraph 208 to 214, wherein the method further comprises administering the anti-FcεRI Ig reduced preparation to the subject if the proportion of mast cells expressing CD107a following exposure to the anti-FcεRI Ig reduced preparation is less than 5 % of the total population of mast cells exposed to the anti- FcεRI Ig reduced preparation. 216. The method of paragraph 208 to 214, wherein the method further comprises including the anti-FcεRI Ig reduced preparation into a pooled blood plasma sample if the proportion of mast cells expressing CD107a following exposure to the anti-FcεRI Ig reduced preparation is less than 5 % of the total population of mast cells exposed to the anti-FcεRI Ig reduced preparation. 217. The method of paragraph 208 to 214, wherein the method further comprises excluding the anti-FcεRI Ig reduced preparation from a pooled blood plasma sample if the proportion of mast cells expressing CD107a following exposure to the anti-FcεRI Ig reduced preparation is more than 5 % of the total population of mast cells exposed to the anti-FcεRI Ig reduced preparation. 218. The method of any one of paragraphs 186 to 198, wherein the proportion of basophil activation is determined by incubating basophils with the anti-FcεRI Ig reduced preparation and quantifying the proportion of CD63 expressing basophils in the total population of basophils using flow cytometry. 219. The method of any one of paragraphs 199 to 207, wherein the proportion of basophil activation is determined by incubating basophils with the anti-FcεRI Ig reduced preparation and quantifying the proportion of CD203c expressing basophils in the total population of basophils using flow cytometry. 220. The method of any one of paragraphs 208 to 217, wherein the proportion of mast cell activation is determined by incubating mast cells with the anti-FcεRI Ig reduced preparation and quantifying the proportion of CD107a expressing mast cells in the total population of mast cells using flow cytometry. 221. The method of any one of paragraphs 174 to 220, wherein the anti-FcεRI Ig reduced preparation comprises less than 40 μg / mL of an anti-FcεRI IgG. 222. The method of any one of paragraphs 174 to 221, wherein the anti-FcεRI Ig reduced preparation comprises less than 35 μg / mL of an anti-FcεRI IgG. 223. The method of any one of paragraphs 174 to 222, wherein the anti-FcεRI Ig reduced preparation comprises less than 30 μg / mL of an anti-FcεRI IgG. 224. The method of any one of paragraphs 174 to 223, wherein the anti-FcεRI Ig reduced preparation comprises less than 25 μg / mL of an anti-FcεRI IgG. 225. The method of any one of paragraphs 174 to 224, wherein the anti-FcεRI Ig reduced preparation comprises less than 20 μg / mL of an anti-FcεRI IgG. 226. The method of any one of paragraphs 174 to 225, wherein the anti-FcεRI Ig reduced preparation comprises less than 15 μg / mL of an anti-FcεRI IgG. 227. The method of any one of paragraphs 174 to 226, wherein the anti-FcεRI Ig reduced preparation comprises less than 10 μg / mL of an anti-FcεRI IgG. 228. The method of any one of paragraphs 174 to 227, wherein the anti-FcεRI Ig reduced preparation comprises less than 5 μg / mL of an anti-FcεRI IgG. 229. The method of any one of paragraphs 174 to 228, wherein the anti-FcεRI Ig reduced preparation comprises between 0-39.9 μg / mL of an anti-FcεRI IgG. 230. The method of any one of paragraphs 174 to 229, wherein the anti-FcεRI Ig reduced preparation comprises between 0-30 μg / mL of an anti-FcεRI IgG. 231. The method of any one of paragraphs 174 to 230, wherein the anti-FcεRI Ig reduced preparation comprises between 0-20 μg / mL of an anti-FcεRI IgG. 232. The method of any one of paragraphs 174 to 231, wherein the anti-FcεRI Ig reduced preparation comprises between 0-10 μg / mL of an anti-FcεRI IgG. 233. The method of any one of paragraphs 174 to 232, wherein the anti-FcεRI Ig reduced preparation comprises less than 0.1 kU / L of an anti-FcεRI IgE. 234. The method of any one of paragraphs 174 to 233, wherein the anti-FcεRI Ig reduced preparation comprises less than 0.05 kU / L of an anti-FcεRI IgE. 235. The method of any one of paragraphs 174 to 234, wherein the anti-FcεRI Ig reduced preparation comprises less than 0.01 kU / L of an anti-FcεRI IgE. 236. The method of any one of paragraphs 174 to 235, wherein the anti-FcεRI Ig reduced preparation comprises less than 0.001 kU / L of an anti-FcεRI IgE. 237. The method of any one of paragraphs 174 to 236, wherein the anti-FcεRI Ig reduced preparation comprises 0 kU / L of an anti-FcεRI IgE. 238. The method of any one of paragraphs 174 to 237, wherein the anti-FcεRI Ig reduced preparation between 0-0.1 kU / L of an anti-FcεRI IgE. 239. The method of any one of paragraphs 174 to 238, wherein the anti-FcεRI Ig reduced preparation between 0.050.1 kU / L of an anti-FcεRI IgE. 240. The method of any one of paragraphs 174 to 239, wherein the affinity chromatography resin further comprises a blood group A antigen immobilized to the matrix of the affinity chromatography resin. 241. The method of any one of paragraphs 174 to 240, wherein the affinity chromatography resin is a continuous affinity chromatography resin. 242. The method of paragraphs 240 or 241, wherein the affinity chromatography is continuous affinity chromatography comprising: (i) a first affinity chromatography resin comprising a ligand which binds to anti-FcεRI Ig immobilized to a matrix of the first affinity chromatography resin; and (ii) a second affinity chromatography resin comprising a blood group A antigen immobilized to a matrix of the second affinity chromatography resin. 243. The method of paragraphs 240 or 241, wherein the affinity chromatography is continuous affinity chromatography comprising: (i) a first affinity chromatography resin comprising a blood group A antigen immobilized to a matrix of the second affinity chromatography resin; and (ii) a second affinity chromatography resin comprising a ligand which binds to anti- FcεRI Ig immobilized to a matrix of the first affinity chromatography resin. 244. The method of any one of paragraphs 174 to 243, wherein the affinity chromatography resin further comprises a blood group B antigen immobilized to the matrix of the affinity chromatography resin. 245. The method of paragraph 244, wherein the affinity chromatography is continuous affinity chromatography comprising: (i) a first affinity chromatography resin comprising a ligand which binds to anti-FcεRI Ig immobilized to a matrix of the first affinity chromatography resin; and (ii) a second affinity chromatography resin comprising a blood group B antigen immobilized to a matrix of the second affinity chromatography resin. 246. The method of paragraph 244, wherein the affinity chromatography is continuous affinity chromatography comprising: (i) a first affinity chromatography resin comprising blood group B antigen immobilized to a matrix of the second affinity chromatography resin; and (ii) a second affinity chromatography resin comprising a ligand which binds to anti- FcεRI Ig immobilized to a matrix of the first affinity chromatography resin. 247. The method of any one of paragraphs 174 to 239, wherein the affinity chromatography resin further comprises a blood group A antigen and a blood group B antigen immobilized to the matrix of the affinity chromatography resin. 248. The method of paragraph 247, wherein the affinity chromatography is continuous affinity chromatography comprising: (i) a first affinity chromatography resin comprising a ligand which binds to anti-FcεRI Ig immobilized to a matrix of the first affinity chromatography resin; and (ii) a second affinity chromatography resin comprising a blood group A antigen and a blood group B antigen immobilized to a matrix of the second affinity chromatography resin. 249. The method of paragraph 247, wherein the affinity chromatography is continuous affinity chromatography comprising: (i) a first affinity chromatography resin comprising a blood group A antigen and a blood group B antigen immobilized to a matrix of the second affinity chromatography resin; and (ii) a second affinity chromatography resin comprising a ligand which binds to anti- FcεRI Ig immobilized to a matrix of the first affinity chromatography resin. 250. The method of any one of paragraphs 1 to 249, wherein the ligand which binds to anti- FcεRI Ig comprises a FcεRI or fragment or epitope thereof. 251. The method of any one of paragraphs 1 to 250, wherein the method further comprises one or more steps selected from a group consisting of ethanol precipitation, octanoid acid fractionation, ion exchange chromatography, viral inactivation, viral filtration, ultrafiltration / diafiltration and combinations thereof. 252. The method of paragraph 251, wherein the method further comprises the step of ethanol precipitation. 253. The method of paragraph 251 or 252, wherein the method further comprises the step of octanoid acid fractionation. 254. The method of any one of paragraphs 251 to 253, wherein the method further comprises the step of ion exchange chromatography. 255. The method of any one of paragraphs 251 to 254, wherein the method further comprises the step of viral inactivation. 256. The method of any one of paragraphs 251 to 255, wherein the method further comprises the step of viral filtration. 257. The method of any one of paragraphs 1 to 256, wherein the method further comprises the step of ultrafiltration / diafiltration. 258. An anti-Fc epsilon Receptor I (FcεRI) immunoglobulin (Ig) reduced IgG preparation, comprising polyclonal IgG. 259. The anti-FcεRI Ig reduced IgG preparation of paragraph 258, wherein the polyclonal IgG is selected from the group consisting of Hizentra® (CSL Behring), Privigen® (CSL Behring), Flebogamma® (Grifols), Gamunex®-C (Grifols), Gammagard® (Takeda), and Octagam® (Octapharma), Xembify® (Grifols), Cutaquig® (Octapharma) and Cuvitru® (Takeda). 260. The anti-FcεRI Ig reduced IgG preparation of paragraph 258 or 259, wherein the preparation further comprises a stabilizer comprising proline, has a pH of about 4.2 to about 5.4 The anti-FcεRI Ig reduced IgG preparation of paragraph 260, wherein the proline is present at a concentration of 250 mM, and wherein the pH is 4.8. The anti-FcεRI Ig reduced IgG preparation of any one of paragraphs 258 to 261, further comprising 20 µg / mL PS80, wherein the proline is present at a concentration of 250 mM, and wherein the pH is 4.8. The anti-FcεRI Ig reduced IgG preparation of any one of paragraphs 258 to 262, wherein the anti-FcεRI Ig reduced IgG preparation comprises no detectable amount of anti-FcεRI Ig and induces reduced activation of an FcεRI mediated signalling pathway relative to an IgG preparation wherein anti-FcεRI Ig is not reduced. The anti-FcεRI Ig reduced IgG preparation of any one of paragraphs 258 to 263, wherein the anti-FcεRI Ig reduced IgG preparation comprises no detectable amount of anti-FcεRI Ig and induces reduced basophil activation relative to a preparation wherein the anti-FcεRI Ig is not reduced. The anti-FcεRI Ig reduced IgG preparation of any one of paragraphs 258 to 264, wherein the anti-FcεRI Ig reduced IgG preparation comprises no detectable amount of anti-FcεRI Ig and induces reduced mast cell activation relative to a preparation wherein the anti-FcεRI Ig is not reduced. The anti-FcεRI Ig reduced IgG preparation of any one of paragraphs 258 to 265, wherein the anti-FcεRI Ig reduced IgG preparation comprises less than 40 μg / mL, less than 35 μg / mL, less than 30 μg / mL, less than 25 μg / mL, less than 20 μg / mL, less than 15 μg / mL, less than 10 μg / mL or less than 5 μg / mL of an anti-FcεRI IgG. The anti-FcεRI Ig reduced IgG preparation of paragraph 266, wherein the anti-FcεRI Ig reduced IgG preparation comprises less than 40 μg / mL of anti-FcεRI IgG. The anti-FcεRI Ig reduced IgG preparation of paragraph 266, wherein the anti-FcεRI Ig reduced IgG preparation comprises less than 35 μg / mL of anti-FcεRI IgG. The anti-FcεRI Ig reduced IgG preparation of paragraph 266, wherein the anti-FcεRI Ig reduced IgG preparation comprises less than 30 μg / mL of anti-FcεRI IgG. 270. The anti-FcεRI Ig reduced IgG preparation of paragraph 266, wherein the anti-FcεRI Ig reduced IgG preparation comprises less than 25 μg / mL of anti-FcεRI IgG. 271. The anti-FcεRI Ig reduced IgG preparation of paragraph 266, wherein the anti-FcεRI Ig reduced IgG preparation comprises less than 20 μg / mL of anti-FcεRI IgG. 272. The anti-FcεRI Ig reduced IgG preparation of paragraph 266, wherein the anti-FcεRI Ig reduced IgG preparation comprises less than 15 μg / mL of anti-FcεRI IgG. 273. The anti-FcεRI Ig reduced IgG preparation of paragraph 266, wherein the anti-FcεRI Ig reduced IgG preparation comprises less than 10 μg / mL of anti-FcεRI IgG. 274. The anti-FcεRI Ig reduced IgG preparation of paragraph 266, wherein the anti-FcεRI Ig reduced IgG preparation comprises less than 5 μg / mL of anti-FcεRI IgG. 275. The anti-FcεRI Ig reduced IgG preparation of paragraph 266, wherein the anti-FcεRI Ig reduced IgG preparation comprises less than 1 μg / mL of anti-FcεRI IgG. 276. The anti-FcεRI Ig reduced IgG preparation of paragraph 266, wherein the anti-FcεRI Ig reduced IgG preparation comprises between 1 and 40 μg / mL of anti-FcεRI IgG. 277. The anti-FcεRI Ig reduced IgG preparation of paragraph 266, wherein the anti-FcεRI Ig reduced IgG preparation comprises between 1 and 35 μg / mL of anti-FcεRI IgG. 278. The anti-FcεRI Ig reduced IgG preparation of paragraph 266, wherein the anti-FcεRI Ig reduced IgG preparation comprises between 1 and 30 μg / mL of anti-FcεRI IgG. 279. The anti-FcεRI Ig reduced IgG preparation of paragraph 266, wherein the anti-FcεRI Ig reduced IgG preparation comprises between 1 and 25 μg / mL of anti-FcεRI IgG. 280. The anti-FcεRI Ig reduced IgG preparation of paragraph 266, wherein the anti-FcεRI Ig reduced IgG preparation comprises between 1 and 20 μg / mL of anti-FcεRI IgG. 281. The anti-FcεRI Ig reduced IgG preparation of paragraph 266, wherein theanti-FcεRI Ig reduced IgG preparation comprises between 1 and 15 μg / mL of anti-FcεRI IgG. 282. The anti-FcεRI Ig reduced IgG preparation of paragraph 266, wherein the anti-FcεRI Ig reduced IgG preparation comprises between 1 and 10 μg / mL of anti-FcεRI IgG. 283. The anti-FcεRI Ig reduced IgG preparation of paragraph 266, wherein the anti-FcεRI Ig reduced IgG preparation comprises between 1 and 5 μg / mL of anti-FcεRI IgG. 284. The anti-FcεRI Ig reduced IgG preparation of any one of paragraphs 258 to 283, wherein the anti-FcεRI Ig reduced IgG preparation comprises less than 0.1 kU / L, less than 0.05 kU / L, less than, 0.01 kU / L or less than 0.001 kU / L of anti-FcεRI IgE. 285. The anti-FcεRI Ig reduced IgG preparation of paragraph 284, wherein the anti-FcεRI Ig reduced IgG preparation comprises less than 0.1 kU / L of anti-FcεRI IgE. 286. The anti-FcεRI Ig reduced IgG preparation of paragraph 284, wherein the anti-FcεRI Ig reduced IgG preparation comprises less than 0.05 kU / L of anti-FcεRI IgE. 287. The anti-FcεRI Ig reduced IgG preparation of paragraph 284, wherein the anti-FcεRI Ig reduced IgG preparation comprises less than 0.01 kU / L of anti-FcεRI IgE. 288. The anti-FcεRI Ig reduced IgG preparation of paragraph 284, wherein the anti-FcεRI Ig reduced IgG preparation comprises less than 0.001 kU / L of anti-FcεRI IgE. 289. The anti-FcεRI Ig reduced IgG preparation of paragraph 284, wherein the anti-FcεRI Ig reduced IgG preparation comprises between 0.001 and 0.1 kU / L of anti-FcεRI IgE. 290. The anti-FcεRI Ig reduced IgG preparation of paragraph 284, wherein the anti-FcεRI Ig reduced IgG preparation comprises between 0.001 and 0.05 kU / L of anti-FcεRI IgE. 291. The anti-FcεRI Ig reduced IgG preparation of paragraph 284, wherein the anti-FcεRI Ig reduced IgG preparation comprises between 0.001 and 0.01 kU / L of anti-FcεRI IgE. 292. The anti-FcεRI Ig reduced IgG preparation of any one of paragraphs 258 to 291, wherein basophil activation following exposure to the anti-FcεRI Ig reduced IgG preparation is determined by determining the proportion of basophils expressing one or more markers selected from the group consisting of CD63, CD203c and combinations thereof. 293. The anti-FcεRI Ig reduced IgG preparation of any one of paragraphs 258 to 292, wherein basophil activation following exposure to the anti-FcεRI Ig reduced IgG preparation is determined by determining the proportion of basophils expressing CD63. 294. The anti-FcεRI Ig reduced IgG preparation of any one of paragraphs 258 to 293, wherein basophil activation following exposure to the anti-FcεRI Ig reduced IgG preparation is determined by determining the proportion of basophils expressing CD203c. 295. The anti-FcεRI Ig reduced IgG preparation of any one of paragraphs 258 to 294, wherein basophil activation following exposure to the anti-FcεRI Ig reduced IgG preparation is determined by determining the proportion of basophils expressing CD63 and CD203c. 296. The anti-FcεRI Ig reduced IgG preparation of any one of paragraphs 292, 293 and 295, wherein the proportion of basophils expressing CD63 following exposure to the anti- FcεRI Ig reduced IgG preparation is less than 1 %, less than 2 %, less than 3 %, less than 4 % or less than 5 % of the total population of basophils exposed to the anti-FcεRI Ig reduced IgG preparation. 297. The anti-FcεRI Ig reduced IgG preparation of any one of paragraph 292, 293, 295 or 296, wherein the proportion of basophils expressing CD63 following exposure to the anti-FcεRI Ig reduced IgG preparation is less than 1 % of the total population of basophils exposed to the anti-FcεRI Ig reduced IgG preparation. 298. The anti-FcεRI Ig reduced IgG preparation of any one of paragraph 292, 293, 295 or 296, wherein the proportion of basophils expressing CD63 following exposure to the anti-FcεRI Ig reduced IgG preparation is less than 2 % of the total population of basophils exposed to the anti-FcεRI Ig reduced IgG preparation. 299. The anti-FcεRI Ig reduced IgG preparation of any one of paragraph 292, 293, 295 or 296, wherein the proportion of basophils expressing CD63 following exposure to the anti-FcεRI Ig reduced IgG preparation is less than 3 % of the total population of basophils exposed to the anti-FcεRI Ig reduced IgG preparation. The anti-FcεRI Ig reduced IgG preparation of any one of paragraph 292, 293, 295 or 296, wherein the proportion of basophils expressing CD63 following exposure to the anti-FcεRI Ig reduced IgG preparation is less than 4 % of the total population of basophils exposed to the anti-FcεRI Ig reduced IgG preparation. The anti-FcεRI Ig reduced IgG preparation of paragraph any one of paragraph 292, 293, 295 or 296, wherein the proportion of basophils expressing CD63 following exposure to the anti-FcεRI Ig reduced IgG preparation is less than 5 % of the total population of basophils exposed to the anti-FcεRI Ig reduced IgG preparation. The anti-FcεRI Ig reduced IgG preparation of any one of paragraphs any one of paragraph 292, 293, 295 to 301, wherein the proportion of basophil activation is determined by incubating basophils with the anti-FcεRI Ig reduced IgG preparation and quantifying the proportion of CD63 expressing basophils in the total population of basophils using flow cytometry. The anti-FcεRI Ig reduced IgG preparation of any one of paragraphs 292, 294 or 295, wherein the proportion of basophils expressing CD203c following exposure to the anti- FcεRI Ig reduced IgG preparation is less than 1 %, less than 2 %, less than 3 %, less than 4 % or less than 5 % of the total population of basophils exposed to the anti-FcεRI Ig reduced IgG preparation. The anti-FcεRI Ig reduced IgG preparation of any one of paragraphs 292, 294, 295 or 303, wherein the proportion of basophils expressing CD203c following exposure to the anti-FcεRI Ig reduced IgG preparation is less than 1 % of the total population of basophils exposed to the anti-FcεRI Ig reduced IgG preparation. The anti-FcεRI Ig reduced IgG preparation of any one of paragraphs 292, 294, 295 or 303, wherein the proportion of basophils expressing CD203c following exposure to the anti-FcεRI Ig reduced IgG preparation is less than 2 % of the total population of basophils exposed to the anti-FcεRI Ig reduced IgG preparation. The anti-FcεRI Ig reduced IgG preparation of any one of paragraphs 292, 294, 295 or 303, wherein the proportion of basophils expressing CD203c following exposure to the anti-FcεRI Ig reduced IgG preparation is less than 3 % of the total population of basophils exposed to the anti-FcεRI Ig reduced IgG preparation. The anti-FcεRI Ig reduced IgG preparation of any one of paragraphs 292, 294, 295 or 303, wherein the proportion of basophils expressing CD203c following exposure to the anti-FcεRI Ig reduced IgG preparation is less than 4 % of the total population of basophils exposed to the anti-FcεRI Ig reduced IgG preparation. The anti-FcεRI Ig reduced IgG preparation of any one of paragraphs 292, 294, 295 or 303, wherein the proportion of basophils expressing CD203c following exposure to the anti-FcεRI Ig reduced IgG preparation is less than 5 % of the total population of basophils exposed to the anti-FcεRI Ig reduced IgG preparation. The anti-FcεRI Ig reduced IgG preparation of any one of paragraphs 292, 294, 295 or 303, wherein the proportion of basophil activation is determined by incubating basophils with the anti-FcεRI Ig reduced IgG preparation and quantifying the proportion of CD203c expressing basophils in the total population of basophils using flow cytometry. The anti-FcεRI Ig reduced IgG preparation of any one of paragraphs 258 to 291, wherein mast cell activation following exposure to the anti-FcεRI Ig reduced IgG preparation is determined by determining the proportion of mast cells expressing CD107a. The anti-FcεRI Ig reduced IgG preparation of paragraph 310, wherein the proportion of mast cells expressing CD107a following exposure to the anti-FcεRI Ig reduced IgG preparation is less than 1 %, less than 2 %, less than 3 %, less than 4 % or less than 5 % of the total population of mast cells exposed to the anti-FcεRI Ig reduced IgG preparation. The anti-FcεRI Ig reduced IgG preparation of paragraphs 310 or 311, wherein the proportion of mast cells expressing CD107a following exposure to the anti-FcεRI Ig reduced IgG preparation is less than 1 % of the total population of basophils exposed to the anti-FcεRI Ig reduced IgG preparation. The anti-FcεRI Ig reduced IgG preparation of paragraphs 310 or 311, wherein the proportion of mast cells expressing CD107a following exposure to the anti-FcεRI Ig reduced IgG preparation is less than 2 % of the total population of basophils exposed to the anti-FcεRI Ig reduced IgG preparation. 314. The anti-FcεRI Ig reduced IgG preparation of paragraphs 310 or 311, wherein the proportion of mast cells expressing CD107a following exposure to the anti-FcεRI Ig reduced IgG preparation is less than 3 % of the total population of basophils exposed to the anti-FcεRI Ig reduced IgG preparation. 315. The anti-FcεRI Ig reduced IgG preparation of paragraphs 310 or 311, wherein the proportion of mast cells expressing CD107a following exposure to the anti-FcεRI Ig reduced IgG preparation is less than 4 % of the total population of basophils exposed to the anti-FcεRI Ig reduced IgG preparation. 316. The anti-FcεRI Ig reduced IgG preparation of paragraphs 310 or 311, wherein the proportion of mast cells expressing CD107a following exposure to the anti-FcεRI Ig reduced IgG preparation is less than 5 % of the total population of basophils exposed to the anti-FcεRI Ig reduced IgG preparation. 317. The anti-FcεRI Ig reduced IgG preparation of any one of paragraphs 310 to 316, wherein the proportion of mast cell activation is determined by incubating mast cells with the anti-FcεRI Ig reduced IgG preparation and quantifying the proportion of CD107a expressing mast cells in the total population of mast cells using flow cytometry. 318. A pharmaceutical composition comprising the anti-Fc epsilon Receptor I (FcεRI) immunoglobulin (Ig) reduced preparation produced by a method of any one of paragraphs 174 to 257. 319. A pharmaceutical composition comprising the anti-Fc epsilon Receptor I (FcεRI) immunoglobulin (Ig) reduced IgG preparation of any one of paragraphs 258 to 317. 320. A pooled IgG preparation, wherein the pooled IgG preparation comprises a detectable amount of an anti-Fc epsilon Receptor I (FcεRI) immunoglobulin (Ig). 321. The pooled IgG preparation of paragraph 320, wherein the detectable amount of anti- FcεRI Ig comprises more than 40 μg / mL, more than 45 μg / mL, more than 50 μg / mL, more than 55 μg / mL or more than 60 μg / mL of anti-FcεRI IgG. 322. The pooled IgG preparation of any one of paragraphs 320 or 321, wherein the detectable amount of anti-FcεRI Ig comprises more than 40 μg / mL of anti-FcεRI IgG. 323. The pooled IgG preparation of any one of paragraphs 320 to 322, wherein the detectable amount of anti-FcεRI Ig comprises more than 45 μg / mL of anti-FcεRI IgG. 324. The pooled IgG preparation of any one of paragraphs 320 to 323, wherein the detectable amount of anti-FcεRI Ig comprises more than 50 μg / mL of anti-FcεRI IgG. 325. The pooled IgG preparation of any one of paragraphs 320 to 324, wherein the detectable amount of anti-FcεRI Ig comprises more than 55 μg / mL of anti-FcεRI IgG. 326. The pooled IgG preparation of any one of paragraphs 320 to 325, wherein the detectable amount of anti-FcεRI Ig comprises more than 60 μg / mL of anti-FcεRI IgG. 327. The pooled IgG preparation of any one of paragraphs 320 to 326, wherein the detectable amount of anti-FcεRI Ig comprises more than 0.1 kU / L, more than 0.5 kU / L, more than, 1 kU / L or more than 1.5 kU / L of anti-FcεRI IgE. 328. The pooled IgG preparation of any one of paragraphs 320 to 327, wherein the detectable amount of anti-FcεRI Ig comprises more than 0.1 kU / L of anti-FcεRI IgE. 329. The pooled IgG preparation of any one of paragraphs 320 to 328, wherein the detectable amount of anti-FcεRI Ig comprises more than 0.5 kU / L of anti-FcεRI IgE. 330. The pooled IgG preparation of any one of paragraphs 320 to 329, wherein the detectable amount of anti-FcεRI Ig comprises more than 1 kU / L of anti-FcεRI IgE. 331. The pooled IgG preparation of any one of paragraphs 320 to 330, wherein the detectable amount of anti-FcεRI Ig comprises more than 1.5 kU / L of anti-FcεRI IgE. 332. The pooled IgG preparation of any one of paragraphs 320 to 331, wherein the detectable amount of anti-FcεRI Ig comprises between 0.1 and 5 kU / L of anti-FcεRI IgE. 333. The pooled IgG preparation of any one of paragraphs 320 to 332, wherein basophil activation following exposure to the pooled IgG preparation is determined by determining the proportion of basophils expressing one or more markers selected from the group consisting of CD63, CD203c and combinations thereof. 334. The pooled IgG preparation of any one of paragraphs 320 to 333, wherein basophil activation following exposure to the pooled IgG preparation is determined by determining the proportion of basophils expressing CD63. 335. The pooled IgG preparation of any one of paragraphs 320 to 333, wherein basophil activation following exposure to the pooled IgG preparation is determined by determining the proportion of basophils expressing CD203c. 336. The pooled IgG preparation of any one of paragraphs 320 to 333, wherein basophil activation following exposure to the pooled IgG preparation is determined by determining the proportion of basophils expressing CD63 and CD203c. 337. The pooled IgG preparation of any one of paragraphs 320 to 334 or 336, wherein the proportion of basophils expressing CD63 following exposure to the pooled IgG preparation is more than 5 %, more than 6 %, more than 7 %, more than 8 %, more than 9%, more than 10% of the total population of basophils exposed to the pooled IgG preparation. 338. The pooled IgG preparation of any one of paragraphs 320 to 334 or 336 to 337, wherein the proportion of basophils expressing CD63 following exposure to the pooled IgG preparation is more than 5 % of the total population of basophils exposed to the pooled IgG preparation. 339. The pooled IgG preparation of any one of paragraphs 320 to 334 or 336 to 338, wherein the proportion of basophils expressing CD63 following exposure to the pooled IgG preparation is more than 6 % of the total population of basophils exposed to the pooled IgG preparation. 340. The pooled IgG preparation of any one of paragraphs 320 to 334 or 336 to 339, wherein the proportion of basophils expressing CD63 following exposure to the pooled IgG preparation is more than 7 % of the total population of basophils exposed to the pooled IgG preparation. 341. The pooled IgG preparation of any one of paragraphs 320 to 334 or 336 to 340, wherein the proportion of basophils expressing CD63 following exposure to the pooled IgG preparation is more than 8 % of the total population of basophils exposed to the pooled IgG preparation. 342. The pooled IgG preparation of any one of paragraphs 320 to 334 or 336 to 341, wherein the proportion of basophils expressing CD63 following exposure to the pooled IgG preparation is more than 9 % of the total population of basophils exposed to the pooled IgG preparation. 343. The pooled IgG preparation of any one of paragraphs 320 to 334 or 336 to 342, wherein the proportion of basophils expressing CD63 following exposure to the pooled IgG preparation is more than 10 % of the total population of basophils exposed to the pooled IgG preparation. 344. The method of any one of paragraphs 320 to 334 or 336 to 342, wherein the proportion of basophil activation is determined by incubating basophils with a plasma sample or fraction thereof and quantifying the proportion of CD63 expressing basophils in the total population of basophils using flow cytometry. 345. The pooled IgG preparation of any one of paragraphs 320 to 333 or 335, wherein the proportion of basophils expressing CD203c following exposure to the pooled IgG preparation is more than 5 %, more than 6 %, more than 7 %, more than 8 %, more than 9% or more than 10%% of the total population of basophils exposed to the pooled IgG preparation. 346. The pooled IgG preparation of any one of paragraphs 320 to 333, 335 or 345, wherein the proportion of basophils expressing CD203c following exposure to the pooled IgG preparation is more than 5 % of the total population of basophils exposed to the pooled IgG preparation. 347. The pooled IgG preparation of any one of paragraphs 320 to 333, 335 or 345 to 346, wherein the proportion of basophils expressing CD203c following exposure to the pooled IgG preparation is more than 6 % of the total population of basophils exposed to the pooled IgG preparation. 348. The pooled IgG preparation of any one of paragraphs 320 to 333, 335 or 345 to 347, wherein the proportion of basophils expressing CD203c following exposure to the pooled IgG preparation is more than 7 % of the total population of basophils exposed to the pooled IgG preparation. The pooled IgG preparation of any one of paragraphs 320 to 333, 335 or 345 to 348, wherein the proportion of basophils expressing CD203c following exposure to the pooled IgG preparation is more than 8 % of the total population of basophils exposed to the pooled IgG preparation. The pooled IgG preparation of any one of paragraphs 320 to 333, 335 or 345 to 349, wherein the proportion of basophils expressing CD203c following exposure to the pooled IgG preparation is more than 9 % of the total population of basophils exposed to the pooled IgG preparation. The pooled IgG preparation of any one of paragraphs 320 to 333, 335 or 345 to 350, wherein the proportion of basophils expressing CD203c following exposure to the pooled IgG preparation is more than 10 % of the total population of basophils exposed to the pooled IgG preparation. The pooled IgG preparation of any one of paragraphs any one of paragraphs 320 to 333, 335 or 345 to 351, wherein the proportion of basophil activation is determined by incubating basophils with the pooled IgG preparation and quantifying the proportion of CD203c expressing basophils in the total population of basophils using flow cytometry. The pooled IgG preparation of any one of paragraphs 320 to 352, wherein mast cell activation following exposure to the pooled IgG preparation is determined by determining the proportion of mast cells expressing CD107a in the total population of mast cells exposed to the pooled IgG preparation. The pooled IgG preparation of paragraph 353, wherein the proportion of mast cells expressing CD107a following exposure to the pooled IgG preparation is more than 5 %, more than 6 %, more than 7 %, more than 8 %, more than 9 % or more than 10 % of the total population of mast cells exposed to the pooled IgG preparation. The pooled IgG preparation of paragraphs 353 or 354, wherein the proportion of mast cells expressing CD107a following exposure to the pooled IgG preparation is more than 5 % of the total population of mast cells exposed to the pooled IgG preparation. 356. The pooled IgG preparation of any one of paragraphs 353 or 354, wherein the proportion of mast cells expressing CD107a following exposure to the pooled IgG preparation is more than 6 % of the total population of mast cells exposed to the pooled IgG preparation. 357. The pooled IgG preparation of any one of paragraphs 353 or 354, wherein the proportion of mast cells expressing CD107a following exposure to the pooled IgG preparation is more than 7 % of the total population of mast cells exposed to the pooled IgG preparation. 358. The pooled IgG preparation of any one of paragraphs 353 or 354, wherein the proportion of mast cells expressing CD107a following exposure to the pooled IgG preparation is more than 8 % of the total population of mast cells exposed to the pooled IgG preparation. 359. The pooled IgG preparation of any one of paragraphs 353 or 354, wherein the proportion of mast cells expressing CD107a following exposure to the pooled IgG preparation is more than 9 % of the total population of mast cells exposed to the pooled IgG preparation. 360. The pooled IgG preparation of any one of paragraphs 353 or 354, wherein the proportion of mast cells expressing CD107a following exposure to the pooled IgG preparation is more than 10 % of the total population of mast cells exposed to the pooled IgG preparation. 361. The pooled IgG preparation of any one of paragraphs 353 to 360, wherein the proportion of mast cell activation is determined by incubating mast cells with the pooled IgG preparation and quantifying the proportion of CD107a expressing mast cells in the total population of mast cells using flow cytometry. 362. A method of treating, preventing and / or delaying progression of a condition in a subject, the method comprising administering the pharmaceutical composition of paragraph 318 or 319 or the anti-FcεRI Ig reduced IgG preparation of any one of paragraphs 320 to 361. 363. The pharmaceutical composition of paragraphs 318 or 319 or the anti-FcεRI Ig reduced IgG preparation of any one of paragraphs 320 to 361 for use in treating, preventing and / or delaying progression of a condition in a subject. 364. Use of the pharmaceutical composition of paragraphs 318 or 319 or the anti-FcεRI Ig reduced IgG preparation of any one of paragraphs 320 to 361 in the manufacture of a medicament for treating, preventing and / or delaying progression of a condition in a subject. 365. The method of paragraph 362, or the pharmaceutical composition or the anti-FcεRI Ig reduced IgG preparation of paragraph 363, or the use of paragraph 364 wherein the condition relates to an immune deficiency, an inflammatory disease, an autoimmune disease or an acute infection. 366. The method or the pharmaceutical composition or the anti-FcεRI Ig reduced IgG preparation or the use of paragraph 365, wherein the immune deficiency is selected from the group consisting of congenital agammaglobulinaemia, congenital hypogammaglobulinaemia, common variable immunodeficiency, severe combined immunodeficiency, allogenic bone marrow transplant, chronic lymphocytic leukaemia, pediatric HIV, kidney transplant with a high antibody recipient or with an ABO incompatible donor, chronic fatigue syndrome, Clostridium difficile colitis, Graves' ophthalmopathy, muscular dystrophy, inclusion body myositis, Lambert-Eaton syndrome, Lupus erythematosus, multifocal motor neuropathy, myasthenia gravis, neonatal alloimmune thrombocytopenia, Parvovirus B19 infection, pemphigus, post- transfusion purpura, renal transplant rejection, spontaneous Abortion Miscarriage, stiff person syndrome, opsoclonus Myoclonus, severe sepsis and septic shock in critically ill adults, toxic epidermal necrolysis, chronic lymphocytic leukemia, multiple myeloma, X-linked agammaglobulinemia, hypogammaglobulinemia, RRMS, IgG subclass deficiencies with recurrent infections, and combinations thereof. 367. The method or the pharmaceutical composition or the anti-FcεRI Ig reduced IgG preparation or the use of paragraph 365, wherein the inflammatory disease or autoimmune disease is selected from the group consisting of Rheumatoid arthritis, Systemic Lupus Erythematosus (SLE), Antiphospholipid syndrome, immune thrombocytopenia (ITP), Kawasaki disease, Guillain Barre syndrome (GBS), multiple sclerosis (MS), chronic inflammatory demyelinating polyneuropathy (CIDP), multifocal motor neuropathy (MMN), myasthenia gravis (MG), skin blistering diseases, scleroderma, Dermatomyositis, Polymyositis, Alzheimer’s Disease, Parkinson’s Disease, Alzheimer's Disease related to Downs Syndrome, cerebral amyloid angiopathy, Dementia with Lewy bodies, Fronto-temporal lobar degeneration, vascular dementia, cell and organ transplant and combinations thereof. A method of preparing an immunoglobulin (Ig) preparation from a plasma sample or a fraction thereof, the Ig preparation having reduced adverse reactions in a subject, the method comprising determining the proportion of basophil and / or mast cell activation following exposure to the plasma sample or fraction thereof; (i) including the plasma sample or fraction thereof in the Ig preparation if the proportion of basophils expressing CD63 following exposure to the plasma sample or fraction thereof is less than 1 %, less than 2 %, less than 3 %, less than 4 % or less than 5 % of the total population of basophils exposed to the plasma sample or fraction thereof; (ii) excluding the plasma sample or fraction thereof from the Ig preparation if the proportion of basophils expressing CD63 following exposure to the plasma sample or fraction thereof is more than 5 %, more than 6 %, more than 7 %, more than 8 %, more than 9 %, more than 10 %, more than 11 %, more than 12 %, more than 13 %, more than 14 % or more than 15 % of the total population of basophils exposed to the plasma sample or fraction thereof; (iii) including the plasma sample or fraction thereof in the Ig preparation if the proportion of basophils expressing CD203c following exposure to the plasma sample or fraction thereof is less than 1 %, less than 2 %, less than 3 %, less than 4 % or less than 5 % of the total population of basophils exposed to the plasma sample or fraction thereof; (iv) excluding the plasma sample or fraction thereof from the Ig preparation if the proportion of basophils expressing CD203c following exposure to the plasma sample or fraction thereof is more than 5 %, more than 6 %, more than 7 %, more than 8 %, more than 9 %, more than 10 %, more than 11 %, more than 12 %, more than 13 %, more than 14 % or more than 15 % of the total population of basophils exposed to the plasma sample or fraction thereof; (v) including the plasma sample or fraction thereof in the Ig preparation if the proportion of mast cells expressing CD107a following exposure to the plasma sample or fraction thereof is less than 1 %, less than 2 %, less than 3 %, less than 4 % or less than 5 % of the total population of mast cells exposed to the plasma sample or fraction thereof; (vi) excluding the plasma sample or fraction thereof from the Ig preparation if the proportion of mast cells expressing CD107a following exposure to the plasma sample or fraction thereof is more than 5 %, more than 6 %, more than 7 %, more than 8 %, more than 9 %, more than 10 %, more than 11 %, more than 12 %, more than 13 %, more than 14 % or more than 15 % of the total population of mast cells exposed to the plasma sample or fraction thereof; and / or (v) including the plasma sample or fraction thereof into the Ig preparation if the plasma sample or fraction thereof comprises less than a detectable amount of Ig causing adverse reactions, wherein the detectable amount of the Ig causing adverse reactions is less than 40 μg / mL, less than 35 μg / mL, less than 30 μg / mL, less than 25 μg / mL, less than 20 μg / mL, less than 15 μg / mL, less than 10 μg / mL or less than 5 μg / mL. 369. The method of paragraph 368, wherein the adverse reaction is a hypersensitivity reaction (HSR). 370. The method of paragraph 369, wherein the HSR is selected from the group consisting of pruritus, erythema, urticaria, swelling and combinations thereof. 371. The method of any one of paragraphs 368 to 370, wherein the adverse reaction occurs at the infusion site, during infusion, shortly after infusion or combinations thereof. The present disclosure includes the following non-limiting Examples. EXAMPLES Example 1: Donor commonality analysis: Data driven donor Z investigation A series of hypersensitivity reaction related adverse events (HSR-AE) reports became known for certain SCIG product lots. As the hypersensitivity signals received for these IgG lots all had similar signals, a data-driven investigation focusing specifically on determining whether there was a plasma donor introducing a biochemical signal into the finished product that may trigger hypersensitivity related reactions (HSR-AE) in patients was initiated. In the following this donor is referred to as “donor Z” and the data-driven investigation is referred to as the “donor Z investigation”. Methodology Approach It was assumed that donor Z was the exclusive cause for the observed HSR-AEs, and that most or all donations of donor Z lead to HSR-AE reports for the respective IgG lots. Under these strong assumptions, it was apparent that donor Z had to have contributed to all withdrawn lots. As such, only one donor who contributed to all affected lots (a “common donor”) was sought out. At the initial stage of the first four withdrawn lots, but also at 5, 6 or more withdrawn lots, hundreds of donors were still common donors and additional insights were necessary to identify donor Z. To resolve this issue, the following considerations and implications were postulated. Based on the assumption of exactly one donor Z, all other common donors were understood as common donors by chance in the sense that their donations ended up in the same finished products (FPs) as for donor Z by chance. 1. The likelihood for any given donor to have donations in all the withdrawn FPs increases ceteris paribus strongly with the number of donations that this donor made. It implies that most of the common donors are regular and frequent plasma donors featuring a high number of donations. However, as only a minority of manufactured IgG lots were associated with HSR-AE reports and voluntary withdrawals, this low relative frequency is largely incompatible with regular and frequent donors. 2. With only one donor Z, but hundreds of common donors by chance, a decisive difference between the two groups had to exist, while all “random” common donors looked roughly similar. It was expected a one-vs-all clustering for the common donors when looking at one or multiple suitable metrics. These metrics were constructed and the evidence and confidence level of each analysis carefully assessed. Scoring of donations A donation was scored as “positive” if it contributed to a FP that was voluntarily withdrawn because of HSR-AEs. A donation was scored as “negative” if it (a) contributed to a FP which was not withdrawn because of HSR-AEs and is completely used up or (b) is currently in the market, has not been withdrawn because of HSR-AEs, and in addition had already been long enough on the market such that one can expect that HSR-AEs, if triggered by this lot, would have already been reported. Specific details about the implementation of this last condition are provided below under Analysis. All donations that were not scored as “positive” or “negative” were scored as “undecided”. This category subsumes all donations for which an HSR-AE- based scoring is not possible as these donations are either not yet processed to FPs, are manufactured to FPs but have not yet been distributed to patients or have not been long enough with patients to expect under normal circumstances the return of reports about HSR- AEs. Metrics Based on the scored donations, the following two metrics were calculated separately for each donor. The number of negatively scored donations per donor is a suitable metric to assess the number of contraindications for a given donor to be the donor Z. Thus, it allows to differentiate between the actual donor Z and all other donors that happen to be included in the withdrawn lots by random chance. Ceteris paribus, a lower number of negatively scored donations increases the likelihood of a given donor to be the donor Z. The positive donation ratio (pdr) is defined as # ^^^^^^^^ ^^^^^^^^^ ^^^ = # ^^^^^^^^ ^^^^^^^^^ + # ^^^^^^^^ ^^^^^^^^^ and is the ratio of donations scored as positive amongst all donations for which an HSR-AE- based scoring is available. As such, it excludes the number of undecided donations that do not bear any information with respect to HSR-AEs. In contrast to the previous metric, this metric is independent of the number of donations for which an HSR-AE -based scoring is available and constitutes a second suitable metric to assess the likelihood of a given donor to be donor Z. Ceteris paribus, a higher positive donation ratio increases the likelihood of a given donor to be donor Z. Data In order to construct the donation trace for all donors associated with withdrawn IVIG and SCIG lots, three sets of data were necessary. The donation data set (or data set 1) provides information on the donations from the collection of each donation up to their pooling as well as additional meta information such as donor and center ID. The lot trace data (or data set 2) provides information about the processing of the pools until the stage of FPs, both in terms of unique IDs of all intermediates and FPs as well as date stamps associated with each processing step. In addition, the so-called Ex Warehouse date provides information at which date FPs were shipped from the warehouses towards the respective markets and affiliates. The distribution data set (or data set 3) provides information about the distribution date which specifies the time point when a lot was first distributed in the market. Analysis Scoring details The donor Z investigation was based on four voluntarily withdrawn IgG lots due to HSR-AE reports and required the scoring of all donations into the three categories positive, negative, and undecided. In particular, for FPs, the difference between a negative and an undecided scoring is if one can expect that under normal circumstances HSR-AE reports for this lot, if existing, should have already been received. If yes, the lot is scored as negative, if no, then undecided. In order to specify this time period, it was have calculated the maximum duration between distribution date and withdrawal date as based on the initial four withdrawn lots. This resulted in 88 days and given that this period is the maximum over the 4 lots investigated and includes in addition the period from the receipt of the first HSR-AE reports until the formal withdrawal decision, it was considered a conservative estimate of the time it usually takes to receive HSR-AE reports for any given IgG lot. While most, but not all lots feature a distribution date, in addition the period between Ex Warehouse date and withdrawal was calculated as 365 days. This latter estimate was utilized for the scoring of donations only if the distribution date of the respective lot was not available. Common donor analysis The common donor analysis was run on the initial four withdrawn lots and revealed a total of 674 common donors but no actionable insights. Once HSR-AE reports for the fifth lot were confirmed, the common donor analysis was re-evaluated on the five lots with confirmed HSR- AE reports. Across these five lots, a total of 311 common donors remained and additional investigations were required to obtain actionable insights. Table 1 presents the 25 most likely donor Z candidates among the 311 common donors, where the 25 most likely donor Z candidates were identified as those common donors that satisfied more than one of the two conditions: ^ Among the 15 donors with the lowest number of negative donations ^ Among the 15 donors with the highest positive donation ratio As five donors met both conditions, this results in the total of 25 donors for which a donation hold was proposed. Investigating the 25 donors displayed in Table 1 more closely, it became clear that there was more evidence for donor D1 being donor Z than for any of the other 24 donor Z candidates as reflected by the positive donation rate and the number of negative donations. This combination made donor D1 a donor Z candidate of higher interest than the other 24 donors and triggered a closer investigation of the temporal pattern of the donations.

[0002] Table 1: The 25 most likely donor Z candidates as based on the first five voluntarily withdrawn IgG lots. The table lists per DonorID the two metrics and additional statistics, sorted by negative donations. Confirmation through verifiable predictions Based on the analyses presented, 311 common donors were classified across the first five withdrawn lots into 286 common donors of lower interest and 25 donors of higher interest. This latter group was subdivided into 24 donors of medium interest and one donor of high interest (donor D1). This classification was only qualitative and lacked the ability to provide truly probabilistic insights, thus uncertainty remained as to whether donor D1 was truly donor Z. The aim shifted towards the confirmation of donor D1 candidate as donor Z. Ideally, the confirmation comes thereby from an independently verifiable prediction as there is a clear discrepancy in the confidence associated with (a) being able to state that one donor satisfies the relevant criteria only after HSR-AE reports have received and (b) true predictions that allow for an independent verification and are highly unlikely to be correctly issued without having truly identified donor Z. Consequently, under the working hypothesis that donor D1 is donor Z it was predicted which lots were expected next to receive elevated levels of HSR-AE reports and analyzed to this end the distribution dates of all IgG lots associated with donor D1. By applying the herewith presented working hypothesis it was predicted that specific lots were the next lots for which HSR-AE reports were to be expected as they had recently been distributed in the market and were associated with donor D1. Soon after issuing these predictions, HSR-AE reports were received for all predicted lots. This provided a very high level of confidence in the hypothesis of donor D1 being donor Z and led to corresponding pre-emptive voluntary withdrawals and a distribution hold, respectively, for all IgG lots with plasma contributions from donor D1. Example 2: Functional Testing To experimentally support the hypothesis of single plasma donor (“Donor Z”) contribution to certain lots of IVIG and SCIG products affected by hypersensitivity adverse events, functional cell-based assays were used to test relevant product lots as well as plasma samples from different donors. Materials Equipment, chemicals and sample preparation All the equipment and Material used in this study are reported in Table 2. Table 2: Equipment and Materials Cryo depletion of plasma samples Citrated plasma donations were thawed at 0 °C, 100 mL distributed in two 50 mL falcon tubes and spun down at 14970 g for 30 min at 0 °C. The obtained white pellet recovered weighed from 0.9-2.5 g. The supernatant was separated by means of pipette and stored at -70 °C for further analysis. Enriched IgG plasma fractions Donor plasma samples were selectively depleted for IgG according to Kober et al. PLos One (2022) 17(1): e0262162 using Capture Select™ FcXP matrix purchased from Thermo. However, the FcXP resin volumes were adapted to 1 mL to fit purification of IgG from plasma volumes of 5 mL. The resin was washed with an equal volume of PBS pH 7.4 and separated by centrifugation twice, incubated with the plasma sample for 60 minutes at 4 °C on an overhead shaker. After centrifugation at 1000 rpm for 1 minute, the supernatant was collected and the resin washed twice by adding 1 mL of PBS pH 7.4, centrifugation for 1 minute at 1000 rpm and discarding the supernatant. For elution of the bound IgG fraction, the resin was mixed with 1 mL acetate buffer pH 4.0 (20 mM acetate, 50 mM NaCl), let stand for a few minutes, centrifugated at 1000 rpm for 1 minute and the supernatant collected. The elution was repeated 7-12 times. Completeness of elution was assessed by measuring the IgG concentration in the eluted fractions with a Nanodrop spectrophotometer. The capture and elution process was repeated on the sample plasma sample 4 times using a freshly regenerated resin each time. The combined eluates were subsequently concentrated with Centriprep Centrifugal filters with a cutoff of 30 kDa to original donor plasma IgG level. IVIG / SCIG immunoglobulin product The IVIG product tested was a 10 % (w / v) plasma derived polyvalent IgG preparation. The SCIG product tested was a 20 % (w / v) plasma derived polyvalent IgG preparation. Reduced IgG plasma fractions Donor plasma samples were selectively reduced for IgE using Capture Select™ IgE affinity matrix purchased from Thermo. The resin (0.5-2.5 mL) was washed with an equal volume of PBS pH 7.4 and separated by centrifugation twice, incubated with 5 mL plasma sample for 45 minutes at 4 °C on an overhead shaker. After centrifugation at 1000 rpm for 1 minute, the supernatant was collected. The reduction procedure was repeated on the supernatant using 0.5 mL of fresh resin. IVIG buffer (250 mM proline) 450 mL water for injection was placed in a glass bottle and 25 mL of 5M proline solution added. After mixing the pH was adjusted to 4.8 by addition of 0.2M HCl (ca. 100 μL) and filled to 500 mL with water for injection. The solution was then sterile filtered, filled in 50 mL glass vials and closed with the same stopper in sterile conditions. SCIG buffer (250 mM proline, 20 mg / L PS80) 450 mL water for injection was placed in a glass bottle, 25 mL of 5M proline solution and 100 μL of 10 % polysorbate 80 added. After mixing the pH was adjusted to 4.8 by addition of 0.2M HCl (ca. 100 μL) and filled to 500 mL with water for injection. The solution was then sterile filtered, filled in 50 mL glass vials and closed with the same stopper in sterile conditions. Methods Activation of Mas related G protein-coupled receptor X2 (MRGPRX2) The PathHunter MRGPRX2 Bioassay kit from Eurofins Discovery was used for detecting cell- based functional activation of the specific GPCR. The in vitro assay includes: ^ 00144PathHunter CHO-K1 MRGPRX2 Bioassay Cells (genetically engineered CHOK1; ^ cell line transgenic for the human MRGPRX2 coupled to β-galactosidase (β-Gal); ^ different reagents; ^ Cortistatin-14 as stimulation control; and ^ 96-Well White, Clear Flat-Bottom, TC-Treated, Sterile Plates with Lid2. Briefly, cells were seeded in a 96-well plate and products or plasma added in duplicates. The experiment was performed with 10 dilutions using fixed 3-fold dilution steps and top testing concentrations of 20 mg / mL for IVIG, 40 mg / ml for SCIG and 20 % of the initial concentration for single Donor plasma. For results evaluation, data were normalized to the maximal and minimal values, a dose response curve is obtained and EC50 is calculated using CBIS data analysis suite (ChemInnovation, CA). Percentage of activity is reported as follow: % Activity =100 % x (mean RFU of test sample - mean RFU of vehicle control) / (mean MAX RFU control ligand - mean RFU of vehicle control). Mast-cell activation and degranulation assay Hoxb8 Mast Cell Activation Test (FAST-PASE) from ATANIS Biotech AG was used for detecting mast cell activation and degranulation. After incubation of Hoxb8 Mast Cell with products (i.e., IVIG or SCIG) or donor plasma, the activation was determined by flow cytometric quantification of a lysosome associated membrane protein that gets exposed to the surface upon degranulation (i.e. CD107a). The in vitro based assay includes: ^ ATANIS proprietary Hoxb8 mast cell line (genetically engineered homeobox B8 (Hoxb8)-immortalized progenitor line from the bone marrow of mice that are transgenic for the human high-affinity IgE receptor (FcεRIα); ^ different reagents; ^ anti-FcεRIα as stimulation control; ^ 96-well round bottom plate. Activating anti-FcεRIα antibodies Briefly, 50,000 Hoxb8 mast cells were seeded in a 96-well round bottom plate and incubated overnight at 37 °C with 5 % CO2. The Hoxb8 mast cells were then challenged with different concentrations of products or donor plasma (in technical duplicates) were then incubated for 25 minutes at 37 °C with 5 % CO2. The experiment was performed with 6 dilutions, fixed 10- fold dilution steps and top testing concentration of 50,000 μg / ml for products while for single donor plasma 6 dilutions, fixed 10- or 2-fold dilution steps and undiluted top testing concentration. For results evaluation, data for both positive control and activators are reported as percentage of activated mast cells (%CD107a+ cells). Reactivity of differently processed plasma Briefly, 50,000 Hoxb8 mast cells were seeded in a 96-well round bottom plate with different concentrations of naïve plasma, IgG depleted, IgG enriched and IgE depleted sera. Assessing activation pathway Blocking IgG binding to FcgRIIb by Fc-based anti-CD16 / 32 antibody Briefly, the donor plasma was pre-incubated with a FcεRIα antibody or a medium with an anti- mouse CD16 / 32 antibody for 30 minutes at 4 °C. The pre-incubated mix was transferred to the Hoxb8 mast cells incubated for 25 minutes at 37 °C. Blocking IgE binding to FcεRIα by preincubation of plasma with soluble FcεRIα Briefly, the donor plasma was pre-incubated with a FcεRIα antibody or a medium with a soluble FcεRIα for 30 minutes at 4 °C. The pre-incubated mix was transferred to the Hoxb8 mast cells incubated for 25 minutes at 37 °C. Cell intrinsic block of mast cell activation by targeting BTK with Ibrutinib Briefly, the mast cells were pre-incubated with inhibitor Ibrutinib (PCI32765) (2x final concentration) for 15 minutes at 37 °C. Equal volume of the undiluted plasma samples or anti- FcεRIα antibody (2x of final concentration) for control activation or medium were then added for 25 min at 37 °C. Blocking C5a-dependent mast cell activation by use of C5aR Antagonist Briefly, the mast cells were pre-incubated with inhibitor C5aR antagonist (PMX-53) (2x final concentration) for 15 minutes at 37 °C. Equal volume of the undiluted plasma samples or medium were then added for 25 min at 37 °C. Basophil activation test (BAT) In vitro basophil activation tests (i.e. BAT) were performed using both products and donor plasma as ...

Claims

CSL Behring AG P540 HL / am 28.03.2024 Claims 1. A method of detecting an anti-Fc epsilon Receptor I (FcεRI) immunoglobulin (Ig) in a plasma sample or a fraction thereof, the method comprising: (i) contacting the sample to a ligand which binds to the anti-FcεRI Ig in the sample to thereby form a complex; and (ii) detecting the complex, wherein presence of the complex is indicative of the presence of the anti-FcεRI Ig in the plasma sample or fraction thereof.

2. The method of claim 1, wherein the anti-FcεRI Ig binds to an epitope of FcεRI and activates a FcεRI mediated signalling pathway.

3. The method of claim 1 or claim 2, wherein the anti-FcεRI Ig binds to an α-chain of the FcεRI and activates a FcεRI mediated signalling pathway.

4. The method of any one of claims 1 to 3, wherein activation of the FcεRI mediated signalling pathway induces basophil and / or mast cell activation and / or degranulation.

5. The method of any one of claims 1 to 4, wherein the anti-FcεRI Ig is an anti-FcεRI IgG and / or an anti-FcεRI IgE.

6. The method of any one of claims 1 to 5, wherein the ligand comprises a FcεRI or fragment or epitope thereof.

7. The method of any one of claims 1 to 6, wherein the detection protein comprises an antibody variable region that binds to the anti-FcεRI Ig.

8. The method of any one of claims 1 to 7, the method further comprising determining the level of the anti-FcεRI Ig in the plasma sample or fraction thereof.

9. The method of claim 8, wherein the anti-FcεRI IgG in the plasma sample or fraction thereof is present in a detectable amount, wherein the detectable amount of anti-FcεRI Ig is at least 40 μg / mL.- 2 - 10. The method of claim 8 or claim 9, wherein the anti-FcεRI IgE in the plasma sample or fraction thereof is present in a detectable amount, wherein the detectable amount of anti- FcεRI IgE is at least 0.1 kU / L.

11. The method of any one of claims 1 to 10, wherein the method further comprises determining the proportion of basophil and / or mast cell activation induced by the plasma sample or fraction thereof.

12. The method of claim 11, wherein the proportion of basophil and / or mast cell activation following exposure to the plasma sample or fraction thereof is determined by determining the proportion of basophil and / or mast cells expressing one or more markers selected from the group consisting of CD63, CD203c, CD107a and combinations thereof.

13. The method of claim 12, wherein the proportion of basophils expressing CD63 following exposure to the plasma sample or fraction thereof is more than 5 % of the total population of basophils exposed to the plasma sample or fraction thereof.

14. The method of claim 12 or claim 13, wherein the proportion of basophils expressing CD203c following exposure to the plasma sample or fraction thereof is more than 5 % of the total population of basophils exposed to the plasma sample or fraction thereof.

15. The method of any one of claims 12 to 14, wherein the proportion of mast cells expressing CD107a following exposure to the plasma sample or fraction thereof is more than 5% of the total population of mast cells exposed to the plasma sample or fraction thereof.

16. The method of any one of claims 1 to 15, wherein the plasma sample or fraction thereof is selected the group consisting of a human blood plasma sample, an IgG intermediate product, an intravenous immunoglobulin G (IVIG), a subcutaneous immunoglobulin G (SCIG), a cryo-rich plasma, a cryo-poor plasma, a Supernatant I (SN I), a Cohn Fraction II (Fr II), a Cohn Fraction II+III (Fr II+III), a Cohn Fraction I+II+III (FrI+II+III), a Kistler / Nitschmann Precipitate A (KN A), a Kistler / Nitschmann Precipitate B (KN B), a Kistler / Nitschmann Precipitate of Supernatant B (KN B+1), and combinations thereof.

17. The method of any one of claims 1 to 16, wherein the plasma sample or fraction thereof is a human blood plasma sample or fraction thereof from one or more subjects.- 3 - 18. The method of any one of paragraphs 1 to 17, wherein the method further comprises administering the plasma sample or fraction thereof to a subject if the anti-FcεRI Ig is not present in a detectable amount.

19. The method of any one of paragraphs 1 to 18, wherein the method further comprises including the plasma sample or fraction thereof into a pooled blood plasma sample if the anti-FcεRI Ig is not present in a detectable amount.

20. The method of any one of paragraphs 1 to 19, wherein the method further comprises excluding the plasma sample or fraction thereof from a pooled blood plasma sample if the anti-FcεRI Ig is present in a detectable amount.

21. A method of preparing an anti-Fc epsilon Receptor I (FcεRI) immunoglobulin (Ig) reduced preparation from a plasma sample or a fraction thereof, the method comprising: (i) loading the plasma sample or fraction thereof onto an affinity chromatography resin comprising a ligand which binds to the anti-FcεRI Ig in the plasma sample or fraction thereof immobilized to a matrix of the affinity chromatography resin; and (ii) collecting an anti-FcεRI Ig reduced preparation.

22. The method of claim 21, the method further comprising detecting the level of anti-FcεRI Ig in the plasma sample or fraction thereof by performing the method of any one of claims 1 to 24.

23. The method of claim 21 or claim 22, wherein the anti-FcεRI Ig reduced preparation induces reduced activation of a FcεRI mediated signalling pathway relative to a preparation wherein the anti-FcεRI Ig is not reduced.

24. The method of any one of claims 21 to 23, wherein the anti-FcεRI Ig reduced preparation induces reduced basophil and / or mast cell activation relative to a preparation wherein the anti-FcεRI Ig is not reduced.

25. The method of claim 24, wherein the proportion of basophils expressing CD63 following exposure to the anti-FcεRI Ig reduced preparation is less than 5 % of the total population of basophils exposed to the anti-FcεRI Ig reduced preparation, and / or the proportion of basophils expressing CD203c following exposure to the anti-FcεRI Ig reduced preparation is less than 5 % of the total population of basophils exposed to the anti-FcεRI- 4 - Ig reduced preparation, and / or the proportion of mast cells expressing CD107a following exposure to the anti-FcεRI Ig reduced preparation is less than 5 % of the total population of mast cells exposed to the anti-FcεRI Ig reduced preparation.

26. The method of any one of claims 21 to 25, wherein the anti-FcεRI Ig reduced preparation comprises less than 40 μg / mL of an anti-FcεRI IgG and / or less than 0.1 kU / L of an anti- FcεRI IgE.

27. The method of any one of claims 21 to 26, wherein the affinity chromatography is continuous affinity chromatography comprising: (i) a first affinity chromatography resin comprising a ligand which binds to the anti- FcεRI Ig in the plasma sample or fraction thereof immobilized to a matrix of the first affinity chromatography resin; and (ii) a second affinity chromatography resin comprising a blood group A antigen and / or a blood group B antigen immobilized to a matrix of the second affinity chromatography resin.

28. A pharmaceutical composition comprising the anti-Fc epsilon Receptor I (FcεRI) immunoglobulin (Ig) reduced preparation produced by a method of any one of claims 21 to 27.

29. An anti-Fc epsilon Receptor I (FcεRI) immunoglobulin (Ig) reduced IgG preparation, comprising polyclonal IgG.

30. The anti-FcεRI Ig reduced IgG preparation of claim 29, comprising less than 40 μg / mL of anti-FcεRI IgG and / or less than 0.1 kU / L of anti-FcεRI IgE.

31. The anti-FcεRI Ig reduced IgG preparation of any one of claims 29 to 30, wherein the proportion of basophils expressing CD63 following exposure to the anti-FcεRI Ig reduced IgG preparation is less than 5 % of the total population of basophils exposed to the anti- FcεRI Ig reduced IgG preparation, and / or the proportion of basophils expressing CD203c following exposure to the anti-FcεRI Ig reduced IgG preparation is less than 5 % of the total population of basophils exposed to the anti-FcεRI Ig reduced IgG preparation and / or the proportion of mast cells expressing CD107a following exposure to the anti-FcεRI Ig reduced IgG preparation is less than 5 % of the total population of mast cells exposed to the anti-FcεRI Ig reduced IgG preparation.- 5 - 32. A pooled IgG preparation, wherein the pooled IgG preparation comprises a detectable amount of an anti-Fc epsilon Receptor I (FcεRI) immunoglobulin (Ig).

33. The pooled IgG preparation of claim 32, wherein the proportion of basophils expressing CD63 following exposure to the pooled IgG preparation is less than 5 % of the total population of basophils exposed to the pooled IgG preparation, and / or the proportion of basophils expressing CD203c following exposure to the pooled IgG preparation is less than 5 % of the total population of basophils exposed to the pooled IgG preparation and / or the proportion of mast cells expressing CD107a following exposure to the pooled IgG preparation is less than 5 % of the total population of mast cells exposed to the pooled IgG preparation.

34. A method of treating, preventing and / or delaying progression of a condition relating to an immune deficiency, an inflammatory disease, an autoimmune disease or an acute infection in a subject, the method comprising administering the pharmaceutical composition of claim 28 or the anti-FcεRI Ig reduced IgG preparation of any one of claims 29 to 31.

35. The pharmaceutical composition of claim 28 or the anti-FcεRI Ig reduced IgG preparation of any one of claims 29 to 31 for use in treating, preventing and / or delaying progression of a condition relating to an immune deficiency, an inflammatory disease, an autoimmune disease or an acute infection in a subject.

36. Use of the pharmaceutical composition of claim 28 or the anti-FcεRI Ig reduced IgG preparation of any one of claims 29 to 31 for treating, preventing and / or delaying progression of a condition relating to an immune deficiency, an inflammatory disease, an autoimmune disease or an acute infection in a subject.

37. Use of the pharmaceutical composition of claim 28 or the anti-FcεRI Ig reduced IgG preparation of any one of claims 29 to 31 in the manufacture of a medicament for treating, preventing and / or delaying progression of a condition relating to an immune deficiency, an inflammatory disease, an autoimmune disease or an acute infection in a subject.

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