Application of S100A8 / A9 in evaluating severity of infectious diseases

Abstract

The invention discloses an application of S100A8 / A9 in evaluating the severity of infectious diseases. Specifically disclosed is the use of a biomarker (S100A8 / A9) and / or a substance for detecting the biomarker in the preparation of a product for evaluating the severity of infectious diseases. By detecting the level of S100A8 / A9 in serum or plasma, the severity of infectious diseases is rapidly and accurately evaluated, the evaluation process is simplified, the accuracy is improved, and the kit is suitable for various infectious diseases. The biomarker is high in sensitivity and good in specificity, decision support can be provided for clinicians by evaluating the severity of the illness state, a treatment scheme can be provided for patients more accurately, the treatment effect and the living quality of the patients can be improved, meanwhile, optimal disease management is achieved, the medical burden on families and the society of the patients is relieved, and the application prospect is wide. Good and wide clinical application values are realized.

Description

Technical Field

[0001] The present invention belongs to the technical field of biomedical diagnosis, and in particular relates to the application of S100A8 / A9 in assessing the severity of infectious diseases. Background Art

[0002] Infectious diseases, as a type of disease caused by pathogens invading the human body and causing pathological changes in the body, are of various types and have complex transmission routes, posing a serious threat to human health. Such diseases not only affect the quality of life of individuals, but may also cause epidemics and have a major impact on the social economy. The pathogens of infectious diseases are extensive, including but not limited to viruses, bacteria, Mycoplasma pneumoniae, Mycobacterium tuberculosis, fungi, parasites, etc. Viruses such as influenza virus, new coronavirus, adenovirus, respiratory syncytial virus, etc., spread rapidly through the air and can cause large-scale infections in the population; bacteria such as Mycobacterium tuberculosis, Mycoplasma pneumoniae, Streptococcus pneumoniae, etc., spread through the respiratory tract and other routes, causing infection and regional epidemics; fungal and parasitic infections are mostly related to personal hygiene, environmental hygiene and other factors. In the occurrence and development of infectious diseases, pathogens interact with the body's immune system, leading to a series of complex pathophysiological changes. These changes not only affect the site of infection, but may also involve multiple systems throughout the body, such as the respiratory system, digestive system, nervous system, etc. Therefore, the clinical manifestations of infectious diseases vary, ranging from mild fever and cough to severe respiratory failure and multiple organ failure.

[0003] In the diagnosis and treatment of infectious diseases, accurate assessment of the severity of the disease is the key to developing appropriate and effective treatment plans, predicting disease progression, and evaluating prognosis. Traditionally, doctors mainly rely on patients' clinical symptoms, signs, laboratory tests (such as blood routine, C-reactive protein, etc.) and imaging tests (such as X-rays, CT, etc.) to comprehensively judge the condition. However, these methods may have limitations in some cases, such as atypical early infection symptoms, differences in reactions caused by individual differences, etc., which affect the accuracy of the assessment.

[0004] In view of this, researching and developing biomarkers that can more sensitively and specifically reflect the body's immune response and pathophysiological changes during the infection process and accurately assess the severity of infectious diseases is one of the issues that need to be urgently addressed in clinical practice. It can provide strong support for the diagnosis and treatment of infectious diseases, and is of great significance for guiding the personalized and standardized treatment of infectious diseases and improving treatment outcomes. Summary of the invention

[0005] The purpose of the present invention is to provide an accurate, specific and sensitive biomarker for assessing the severity of infectious diseases. The technical problems to be solved are not limited to the described technical subjects, and those skilled in the art can clearly understand other technical subjects not mentioned in this article through the following description.

[0006] To achieve the above objectives, the present invention first provides the use of a biomarker and / or a substance for detecting the biomarker in preparing a product having any of the following functions:

[0007] A1) Used to assess the severity of infectious diseases;

[0008] A2) used to predict or assist in predicting the progression of infectious diseases;

[0009] The biomarker may be S100A8 / A9.

[0010] In the above application, the material for detecting the biomarker may include reagents and / or instruments for detecting the expression level of S100A8 / A9 by Western Blot, immunofluorescence, radioimmunoassay (RIA), immunoprecipitation, immunohistochemistry (IHC), enzyme-linked immunosorbent assay (ELISA), double antibody sandwich ELISA, fluorescence-linked immunosorbent assay (FLISA), enzyme immunoassay (EIA), flow cytometry (FACS), chromatography, mass spectrometry, polyacrylamide gel electrophoresis, capillary electrophoresis, near-infrared spectroscopy, immunochemiluminescence, colloidal gold immunoassay (GIC), colloidal gold immunochromatography (GICA), fluorescence immunochromatography, surface plasmon resonance, immuno-PCR or biotin-avidin technology.

[0011] In the above application, the substance for detecting the biomarker may include a reagent for detecting the expression level (or content) of S100A8 / A9.

[0012] In the above applications, the reagent may include an antibody, peptide, protein or nucleic acid molecule that specifically binds to S100A8 / A9.

[0013] Furthermore, the antibody can be a monoclonal antibody, a polyclonal antibody, a bispecific antibody, a multispecific antibody, a genetically engineered antibody, a humanized antibody (including a chimeric antibody, a CDR-grafted antibody and an SDR-grafted antibody) or a fully human antibody, and can also be an antigen-binding fragment that can specifically bind to a target antigen, such as Fab, Fab′, F(ab′)2, antibody variable region (Fv), disulfide bond-stabilized Fv (dsFv), single-chain antibody (ScFv), single-domain antibody (sdAb, i.e., nanoantibody), minibody or minimum recognition unit (MRU), etc., but not limited thereto.

[0014] In the above applications, the infectious diseases may include diseases caused by infections of viruses, bacteria, fungi, mycoplasmas, chlamydia, rickettsia, spirochetes and parasites.

[0015] Furthermore, the infectious diseases may include diseases caused by viral, bacterial, mycoplasma, and chlamydia infections.

[0016] In the above application, the infectious disease may be lower respiratory tract infection and / or pneumonia caused by various pathogens.

[0017] In the above applications, the products may include reagents, test kits, detection chips (such as protein chips), detection test strips (such as immunochromatographic diagnostic test strips), detection cards and immunosensors but are not limited thereto.

[0018] Furthermore, the application may include evaluating the severity of infectious diseases according to the expression level or content of S100A8 / A9 in the serum or plasma of patients with infectious diseases.

[0019] Furthermore, the application may include establishing and verifying a disease severity assessment model based on the expression level or content of S100A8 / A9 in the serum or plasma of patients with infectious diseases in combination with the patients' clinical information (including but not limited to symptoms, signs, laboratory tests, etc.), and performing a graded assessment of the disease condition of patients with infectious diseases.

[0020] Furthermore, the method for assessing the severity of an infectious disease may include the following steps:

[0021] (1) Detecting the expression level or content of S100A8 / A9 in the serum or plasma of patients with infectious diseases;

[0022] (2) comparing the S100A8 / A9 expression level with an evaluation threshold; when the S100A8 / A9 expression level in the serum or plasma of the infectious disease patient is greater than or equal to the evaluation threshold, it is predicted that the severity of the infectious disease is high; when the S100A8 / A9 expression level in the serum or plasma of the subject is less than the evaluation threshold, it is predicted that the severity of the infectious disease is low.

[0023] The evaluation threshold can be obtained through a receiver operating characteristic (ROC) curve.

[0024] The evaluation threshold can be modeled based on bioinformatics methods combined with clinical information. For example, the optimal cut-off value (Cut-off value) of serum or plasma S100A8 / A9 levels that can be used to evaluate the severity of infectious diseases can be determined based on the ROC curve. The optimal cut-off value can be the maximum slope point in the ROC curve or the value that maximizes sensitivity and specificity (i.e., the expression level of S100A8 / A9 in serum or plasma corresponding to the maximum sensitivity and specificity). Exceeding this threshold indicates that the severity of the patient's condition is high.

[0025] Furthermore, the diagnostic criteria for evaluating the severity of an infectious disease may be: when the S100A8 / A9 expression level in the serum or plasma of an infectious disease patient is greater than or equal to 5.196 μmol / L, it is predicted that the severity of the infectious disease is high; when the S100A8 / A9 expression level in the serum or plasma of an infectious disease patient is less than 5.196 μmol / L, it is predicted that the severity of the infectious disease is low.

[0026] The present invention also provides a kit, which may include any of the substances for detecting the biomarkers described herein, and the kit may have at least one of the following uses:

[0027] B1) Used to assess the severity of infectious diseases;

[0028] B2) Used to predict or assist in predicting the progression of infectious diseases.

[0029] Furthermore, the test sample of the kit may be serum or plasma.

[0030] Specifically, the kit may include an antibody that specifically binds to S100A8 / A9 (anti-S100A8 / A9 antibody) or an antigen-binding fragment thereof.

[0031] The anti-S100A8 / A9 antibody or antigen-binding fragment thereof may also be labeled with a detectable marker. The detectable labels include enzymes (such as horseradish peroxidase or alkaline phosphatase), chemiluminescent agents (such as acridinium ester compounds, acridinium sulfonamide compounds, luminol and its derivatives, ruthenium derivatives), fluorescent dyes (such as AMCA, FITC, PE, PI, PerCP-Cy5.5, PE-Cy7, APC, APC-H7, BV421, V500, Alexa 700, BV605), near-infrared dyes (such as cyanine dyes, BODIPY dyes, rhodamine dyes, squaric acid dyes, porphyrin dyes), radionuclides (such as 124I, 18F, 11C, 99mTc, 123I), biotin, nanoparticles for magnetic resonance imaging, quantum dots for magnetic resonance imaging, magnetic substances (such as magnetic beads, nanoparticles containing gadolinium complexes, superparamagnetic iron oxide nanoparticles) and colloidal gold, but are not limited thereto.

[0032] The kit may be a chemiluminescent immunoassay kit, an enzyme-linked immunosorbent assay kit, an immunoprecipitation assay kit, an immunoblotting assay kit, an immunochromatography assay kit, a flow cytometry assay kit, an immunohistochemistry assay kit, a colloidal gold immunoassay kit or a fluorescent immunoassay kit, but is not limited thereto.

[0033] Furthermore, the kit may also include reagents required for immunoassay, such as labeled antibodies or antigens, magnetic particles, blocking solution, diluent, washing solution, color developing solution, stop solution, etc., but not limited thereto.

[0034] The various reagent components of the kit may be present in separate containers, or may be pre-combined in whole or in part into a reagent mixture.

[0035] The components of the kit may be provided in the form of a solution, such as an aqueous solution. In the case of being in the form of an aqueous solution, the concentration or content of these components can be easily determined by those skilled in the art according to different needs. For example, for storage purposes, the concentration of the components may be present in a higher form, and when in working state or use, the concentration may be reduced to the working concentration by diluting the above-mentioned higher concentration solution.

[0036] The kit may also contain, for example, a buffer, a preservative or a protein stabilizer. The kit may also contain components necessary for detecting the detectable marker, such as an enzyme or a substrate. The kit may also contain a control sample or a series of control samples that can be assayed and compared to the test sample. The kit may include a written product on or in the kit container. The written product describes how to use the reagents contained in the kit and instructs the user how to assess the severity of an infectious disease by testing serum S100A8 / A9 levels.

[0037] The present invention also provides a device for evaluating the severity of an infectious disease, which may include a data receiving module, a data processing module and an output module; the data receiving module is used to receive data on the expression level of S100A8 / A9 in the serum or plasma of patients with infectious diseases; the data processing module is used to evaluate the severity of the infectious disease based on the detection results of the S100A8 / A9 expression level; and the output module is used to display the evaluation results to indicate the severity of the infectious disease patient.

[0038] Furthermore, the data processing module can establish a disease severity assessment model based on the test results of serum or plasma S100A8 / A9 expression levels in combination with the patient's clinical information (including but not limited to symptoms, signs, laboratory tests, etc.), and perform a graded assessment of the condition of patients with infectious diseases, which can then be used to predict or assist in predicting the progression of infectious diseases.

[0039] Furthermore, the data processing module may use bioinformatics methods, such as using receiver operating characteristic curve (ROC curve) analysis to determine the optimal critical value (Cut-off value) of serum or plasma S100A8 / A9 levels, which is then used to distinguish patients with infectious diseases of different severity.

[0040] Furthermore, the device may also include a computer-readable storage medium, which can be used to store and update serum or plasma S100A8 / A9 level detection data and corresponding clinical information of patients with infectious diseases to support continuous optimization and verification of the evaluation model.

[0041] The S100A8 / A9 described herein is a heterodimeric complex formed by S100A8 protein (GenBank accession number: P05109) and S100A9 protein (GenBank accession number: P06702).

[0042] The expression levels of S100A8 / A9 described herein are significantly different between patients with infectious diseases (such as pneumonia patients) and healthy controls, and between patients with mild and severe infectious diseases. Furthermore, the expression level of S100A8 / A9 is significantly upregulated in patients with infectious diseases (such as pneumonia patients), and the expression level of S100A8 / A9 is significantly correlated with the severity of the infectious disease.

[0043] The biomarkers described herein can be applied to conventional protein detection experiments using ELISA. Although the embodiments provided herein exemplarily use ELISA methods to detect the biomarker S100A8 / A9 in serum or plasma samples, the present invention is not limited to this specific detection method. Those skilled in the art may use any other suitable method known to those skilled in the art (such as protein immunoblotting, immunofluorescence, radioimmunoassay, immunoprecipitation, immunohistochemistry, double antibody sandwich ELISA, fluorescence-linked immunosorbent assay, enzyme immunoassay, flow cytometry, chromatography, mass spectrometry, polyacrylamide gel electrophoresis, capillary electrophoresis, near infrared spectroscopy, immunochemiluminescence, colloidal gold immunoassay, colloidal gold immunochromatography, fluorescent immunochromatography, surface plasmon resonance, immuno-PCR or biotin-avidin technology, etc.) to detect the expression level of S100A8 / A9 in serum or plasma samples. These alternative methods do not depart from the scope of the present invention, and the present invention should include these alternative methods.

[0044] The infectious disease described herein may be lower respiratory tract infection and / or pneumonia (eg, community-acquired pneumonia) caused by various pathogens.

[0045] Furthermore, the infectious disease described herein may be pneumonia caused by infection with Mycoplasma pneumoniae, bacteria and / or viruses.

[0046] The present invention also provides a method for evaluating the severity of an infectious disease, the method comprising evaluating the severity of the infectious disease according to the expression level or content of S100A8 / A9 in the serum or plasma of a patient with the infectious disease.

[0047] Furthermore, the method may include the following steps:

[0048] (1) Detecting the expression level or content of S100A8 / A9 in the serum or plasma of patients with infectious diseases;

[0049] (2) comparing the S100A8 / A9 expression level with an evaluation threshold; when the S100A8 / A9 expression level in the serum or plasma of the infectious disease patient is greater than or equal to the evaluation threshold, it is predicted that the severity of the infectious disease is high; when the S100A8 / A9 expression level in the serum or plasma of the subject is less than the evaluation threshold, it is predicted that the severity of the infectious disease is low.

[0050] The present invention also provides a method for predicting or assisting in predicting the progression of an infectious disease, the method comprising predicting or assisting in predicting the progression of the infectious disease based on the expression level or content of S100A8 / A9 in the serum or plasma of a patient with the infectious disease.

[0051] Furthermore, the method may include the following steps:

[0052] (1) Detecting the expression level or content of S100A8 / A9 in the serum or plasma of patients with infectious diseases;

[0053] (2) comparing the S100A8 / A9 expression level with an evaluation threshold; when the S100A8 / A9 expression level in the serum or plasma of the infectious disease patient is greater than or equal to the evaluation threshold, it is predicted that the infectious disease will progress to severe pneumonia; when the S100A8 / A9 expression level in the serum or plasma of the subject is less than the evaluation threshold, it is predicted that the infectious disease will progress to mild pneumonia.

[0054] Beneficial effects of the present invention:

[0055] (1) Rapid and accurate: By detecting the level of S100A8 / A9 in serum or plasma, the severity of infectious diseases can be quickly and accurately assessed, avoiding the complexity and subjectivity of traditional assessment methods.

[0056] (2) Wide clinical application: The biomarkers developed by the present invention can be applied to the disease assessment and prognosis prediction of various infectious diseases and have broad application prospects.

[0057] (3) Guiding treatment: By assessing the severity of the disease, providing decision support for clinicians, providing patients with more accurate treatment plans, and guiding the selection and adjustment of treatment plans, it helps to improve treatment outcomes and the quality of life of patients, while achieving optimal disease management and reducing the medical burden on patients’ families and society. It has great clinical application value.

[0058] In summary, the present invention proposes for the first time a new method for evaluating the severity of infectious diseases using serum or plasma S100A8 / A9 levels. The S100A8 / A9 concentration in serum or plasma is detected by ELISA, and an evaluation model is established in combination with clinical information to achieve rapid and accurate classification of the severity of the disease. This method simplifies the evaluation process, improves accuracy, is applicable to a variety of infectious diseases, and provides strong support for clinical treatment decisions. At the same time, a matching kit and system (device) are provided to support detection and evaluation, and its accuracy and reliability are verified by the ROC curve. It has broad application prospects and is of great significance to precision medicine and personalized medicine for infectious diseases. BRIEF DESCRIPTION OF THE DRAWINGS

[0059] Figure 1 The standard curve is made according to the concentration and absorbance of the standard in the S100A8 / A9 ELISA kit.

[0060] Figure 2 Box plots comparing all pneumonia groups with the normal control group, mild pneumonia group, and severe pneumonia group.

[0061] Figure 3 ROC curve plotted for the value of S100A8 / A9 in predicting pneumonia disease severity. DETAILED DESCRIPTION

[0062] The present invention is further described in detail below in conjunction with specific embodiments, and the examples provided are only for illustrating the present invention, rather than for limiting the scope of the present invention. The examples provided below can be used as a guide for further improvements by those of ordinary skill in the art, and do not constitute a limitation of the present invention in any way.

[0063] The experimental methods in the following examples, unless otherwise specified, are all conventional methods, and are performed according to the techniques or conditions described in the literature in the field or according to the product instructions. The materials, reagents, etc. used in the following examples, unless otherwise specified, can all be obtained from commercial channels.

[0064] The S100A8 / A9 ELISA kit in the following examples was purchased from Abcam (Cat. No.: ab267628), including standard products, antibodies, enzyme-labeled secondary antibodies, substrate solutions, and the like.

[0065] Example 1: Obtaining S100A8 / A9 as a biomarker for assessing the severity of infectious diseases

[0066] 1. Sample information

[0067] Clinical information of 534 patients diagnosed with pneumonia who visited the Beijing Children's Hospital Baoding Hospital affiliated to Capital Medical University from 2021 to 2023 was collected (see Table 1), including clinical diagnosis, symptoms, signs, laboratory test results, and imaging test results. According to the Diagnosis and Treatment Guidelines for Community-Acquired Pneumonia in Children (2019 Edition), pneumonia patients were divided into a mild pneumonia group of 390 cases and a severe pneumonia group of 144 cases. At the same time, healthy people who underwent health examinations in the hospital during the same period were selected as the control group, with a total of 93 cases included.

[0068] Inclusion criteria for pneumonia patients: meeting the diagnostic criteria for community-acquired pneumonia, with clear respiratory symptoms such as fever, cough, and sputum, and chest X-ray or CT examination indicating lung inflammatory changes.

[0069] Exclusion criteria for pneumonia patients: those who do not meet the inclusion criteria or have incomplete clinical data; those with immune deficiency or diseases that may affect immune function.

[0070] Table 1 Information of 534 samples

[0071]

[0072]

[0073] 2. Diagnostic criteria for severity of infectious diseases

[0074] According to the Diagnosis and Treatment Guidelines for Community-Acquired Pneumonia in Children (2019 Edition), pneumonia patients are divided into mild and severe cases. The diagnostic criteria are as follows: patients who meet any one of the following criteria can be diagnosed with severe pneumonia: (1) poor general condition; (2) impaired consciousness; (3) hypoxemia: cyanosis; tachypnea, RR ≥ 70 times / min (infants), RR ≥ 50 times / min (> 1 year old); assisted breathing (groaning, nasal fanning, three-point sign); intermittent apnea; oxygen saturation < 92%; (4) hyperpyrexia, continuous high fever for > 5 days; (5) dehydration signs / refusal to eat; (6) ≥ 2 / 3 of the lung infiltration, multi-lobar infiltration, pleural effusion, pneumothorax, atelectasis, lung necrosis, lung abscess; (7) severe extrapulmonary complications (heart failure, myocarditis, gastrointestinal bleeding, central nervous system infection, severe electrolyte imbalance, etc.). Patients who meet any one of the above criteria are diagnosed as severe pneumonia, and those who do not meet them are diagnosed as mild pneumonia. The collected pneumonia patients were divided into mild and severe groups according to the above diagnostic criteria, including 390 cases in the mild group and 144 cases in the severe group.

[0075] 3. S100A8 / A9 concentration detection and calculation

[0076] All children with pneumonia had 2-3 mL of fasting venous blood collected in the morning within 24-48 hours (acute phase) after admission. The blood was centrifuged at 3000 r / min for 10 min, and the serum or plasma was kept in a -80°C refrigerator for testing. The serum or plasma S100A8 / A9 levels were detected by enzyme-linked immunosorbent assay (ELISA).

[0077] According to the instructions of the S100A8 / A9 ELISA kit, thaw the standards, antibodies, enzyme-labeled secondary antibodies and other reagents in advance and dilute them to the working concentration.

[0078] Standard wells, sample wells and blank control wells were set in a 96-well plate. Standard solutions of different concentrations were added to the standard wells, serum samples to be tested were added to the sample wells, and buffer was added to the blank control wells.

[0079] An appropriate amount of capture antibody was added to each well, and the plate was sealed and incubated on a shaker at room temperature for 2.5 hours.

[0080] After the incubation, the unbound antibody was washed away, and the detection antibody (specific antibody against S100A8 / A9) was added, followed by another incubation and washing.

[0081] Add enzyme-labeled secondary antibody, incubate and wash, then add substrate solution and incubate in the dark for a period of time until color develops.

[0082] The reaction was terminated by adding the stop solution, and the absorbance of each well was measured at a wavelength of 450 nm using an enzyme reader.

[0083] Calculate the average absorbance of each set of replicates of standards, controls, and samples. Subtract the average zero standard optical density. Plot a standard curve on a log-log scale with standard concentration on the x-axis and absorbance on the y-axis. Draw a best fit straight line through the standard points and calculate the concentration of S100A8 / A9 in the sample using the equation.

[0084] 4. Results Analysis

[0085] Figure 1 The standard curve based on the concentration and absorbance of the standard in the S100A8 / A9 ELISA kit is shown. The horizontal axis (X-axis) represents the concentration of the standard, ranging from 0 to 3500 pg / ml, showing the range of concentration changes. The vertical axis (Y-axis) represents the absorbance, ranging from 0 to 1.6, in units of Abs, reflecting the degree of change in absorbance. The equation of the straight line in the chart is y=0.0004x+0.0269, which describes the mathematical relationship between the standard concentration (x) and the absorbance (y). By comparing the absorbance of the actual sample with the value on the standard curve, the concentration of S100A8 / A9 in the actual sample can be inferred for subsequent research and analysis.

[0086] Figure 2 The box plots are compared between all pneumonia groups and the normal control group, as well as the mild pneumonia group and the severe pneumonia group. The results show that the S100A8 / A9 level in the pneumonia group was significantly higher than that in the healthy control group (P<0.001); the S100A8 / A9 level in the severe pneumonia group was significantly higher than that in the mild pneumonia group (P<0.001).

[0087] Statistical methods were used to analyze the correlation between serum S100A8 / A9 levels and disease severity, and the receiver operating characteristic curve (ROC curve) was used for analysis. Serum S100A8 / A9 levels were used as test variables (TestVariable), and the actual disease severity of the patient (based on the diagnosis and treatment standards for community-acquired pneumonia in children) was used as the state variable (State Variable).

[0088] The ROC curve was drawn using statistical software SPSS27.0 and GraphPad Prism10.0. During the drawing process, the software automatically calculates the sensitivity and specificity at different S100A8 / A9 level thresholds and generates a ROC curve. Observe the shape and position of the ROC curve, especially the area under the curve (AUC). The closer the AUC value is to 1, the higher the accuracy of the S100A8 / A9 level in predicting or assessing the severity of pneumonia. Find the point closest to the upper left corner on the ROC curve, and the S100A8 / A9 level threshold corresponding to this point is the Cut-off value (critical value). This critical value can balance sensitivity and specificity, minimizing the risk of misdiagnosis and missed diagnosis.

[0089] Figure 3 ROC curve drawn for the value of S100A8 / A9 in predicting the severity of pneumonia. The AUC value is 0.8311, which indicates that S100A8 / A9 has good specificity and is suitable for relevant clinical or research applications. The critical value is 5.196pg / ml. When the concentration of S100A8 / A9 exceeds 5.196pg / ml, the model predicts that the patient's pneumonia may be more serious. This indicates that when the serum concentration of S100A8 / A9 exceeds 5.196pg / ml, the patient's pneumonia may be severe pneumonia and should be treated accordingly. Below this critical value, the predicted severity of the disease may be lower. The selection of this critical value is intended to balance the sensitivity and specificity of the model to achieve the best prediction effect.

[0090] The above screening and analysis results show that S100A8 / A9 can be used as a biomarker to assess the severity of infectious diseases. Among them, S100A8 / A9 is a heterodimer complex formed by S100A8 protein (GenBank accession number: P05109) and S100A9 protein (GenBank accession number: P06702).

[0091] Example 2: Verification of the value of S100A8 / A9 in assessing the severity of infectious diseases

[0092] 1. Sample information

[0093] Clinical information of 177 patients diagnosed with pneumonia who visited the Baoding Hospital of Beijing Children's Hospital Affiliated to Capital Medical University from 2021 to 2023 (not repeated with the samples in Example 1, see Table 2), including diagnosis, symptoms, signs, laboratory test results, etc. The inclusion and exclusion criteria are the same as those in Example 1 above. The 177 patients with pneumonia included were used as a validation group to test the value of the evaluation model of S100A8 / A9 for the severity of infectious diseases in Example 1.

[0094] Table 2 Information of 177 samples

[0095]

[0096]

[0097] 2. The S100A8 / A9 concentration detection and calculation methods are carried out according to the steps of Example 1 above.

[0098] 3. According to the critical value of 5.196pg / ml in the ROC curve evaluation model in Example 1, the S100A8 / A9 concentration data in all validation group serum samples were divided into 115 cases in a mild group and 62 cases in a severe group. The actual severity of the disease was observed in the two groups of patients after evaluation according to the Diagnosis and Treatment Guidelines for Community-Acquired Pneumonia in Children (2019 Edition). 107 cases in the mild pneumonia group were true negative results, and 8 cases were false negative results; 39 cases in the severe group were true positive results, and 23 cases were false positive results. As shown in Table 3, the ROC curve evaluation model for judging the severity of pneumonia in Example 1 has a specificity of 82%, a sensitivity of 83%, and an accuracy of 82%.

[0099] Table 3. Validation of the specificity, sensitivity and accuracy of S100A8 / A9 levels in assessing the severity of pneumonia

[0100]

[0101] The above results show that S100A8 / A9 has good accuracy, high sensitivity and specificity when used to assess the severity of infectious diseases, and has high clinical diagnostic application value.

[0102] The present invention has been described in detail above. For those skilled in the art, without departing from the purpose and scope of the present invention, and without the need to carry out unnecessary experimental conditions, the present invention can be implemented in a wide range under equivalent parameters, concentrations and conditions. Although the present invention provides specific embodiments, it should be understood that the present invention can be further improved. In a word, according to the principles of the present invention, the application is intended to include any changes, uses or improvements to the present invention, including departure from the disclosed scope in the application, and changes made with conventional techniques known in the art.

Claims

1. Use of biomarkers and / or substances for detecting said biomarkers in the preparation of products having any of the following functions: A1) Used to assess the severity of infectious diseases; A2) used to predict or assist in predicting the progression of infectious diseases; The biomarker is S100A8 / A9.

2. The use according to claim 1, characterized in that: The substances for detecting the biomarkers include reagents and / or instruments for detecting the expression level of S100A8 / A9 by protein immunoblotting, immunofluorescence, radioimmunoassay, immunocoprecipitation, immunohistochemistry, enzyme-linked immunosorbent assay, double antibody sandwich ELISA, fluorescence-linked immunosorbent assay, enzyme immunoassay, flow cytometry, chromatography, mass spectrometry, polyacrylamide gel electrophoresis, capillary electrophoresis, near-infrared spectroscopy, immunochemiluminescence, colloidal gold immunoassay, colloidal gold immunochromatography, fluorescent immunochromatography, surface plasmon resonance, immuno-PCR or biotin-avidin technology.

3. The use according to claim 1 or 2, characterized in that: The substance for detecting the biomarker includes a reagent for detecting the expression level of S100A8 / A9.

4. The use according to claim 3, characterized in that: The reagents include antibodies, peptides, proteins or nucleic acid molecules that specifically bind to S100A8 / A9.

5. The use according to any one of claims 1 to 4, characterized in that: The infectious diseases include diseases caused by viral, bacterial, fungal, mycoplasma, chlamydia, rickettsia, spirochetal and parasitic infections.

6. The use according to any one of claims 1 to 5, characterized in that: The infectious diseases are lower respiratory tract infections and / or pneumonia caused by various pathogens.

7. The use according to any one of claims 1 to 6, characterized in that: The products include reagents, test kits, detection chips, detection test strips, detection cards and immunosensors.

8. A kit, characterized in that The kit comprises the substance for detecting the biomarker according to any one of claims 1 to 4, and the kit has at least one of the following uses: B1) Used to assess the severity of infectious diseases; B2) Used to predict or assist in predicting the progression of infectious diseases.

9. The kit according to claim 8, characterized in that The test sample of the kit is serum or plasma.

10. A device for assessing the severity of an infectious disease, characterized in that: The device comprises a data receiving module, a data processing module and an output module; the data receiving module is used to receive data on the expression level of S100A8 / A9 in the serum or plasma of patients with infectious diseases; the data processing module is used to evaluate the severity of the infectious disease according to the detection results of the S100A8 / A9 expression level; and the output module is used to display the evaluation results.

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