Method and reagent for determining implantation ability of embryo into maternal body

Abstract

To provide a biomarker that can determine implantation ability of an embryo into a maternal body and quantify the implantation ability of the maternal body for more objective assessment in treatment of infertility or recurrent pregnancy loss, and to provide a method and assessment reagent using the same.SOLUTION: Leukocyte-associated immunoglobulin-like receptor 1 (LAIR1) is used as a biomarker for determining maternal implantation potential.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present invention relates to providing a biomarker capable of determining the ability of an embryo to implant into a mother, i.e., the maternal implantation ability, and a method for determining the maternal implantation ability.

Background Art

[0002] The number of infertile patients in Japan is said to be 300,000 to 500,000. In addition, the causes of infertility are due to both the mother and the fetus, and the diagnosis is difficult and the cause is often not identifiable. Infertility is defined as follows (Japan Obstetrics and Gynecology Society): "When there is a history of two or more miscarriages (before 22 weeks of gestation) or stillbirths (after 22 weeks of gestation), it is diagnosed as infertility." Infertility is caused by both the mother and the fetus. Representative infertility risk factors include uterine morphological abnormalities, chromosomal structural abnormalities, endocrine abnormalities, and positive antiphospholipid antibodies, and there are established test methods for these. Also, as an important test method for fetal chromosomal causes of miscarriage, there are preimplantation diagnosis, which reduces the miscarriage rate by examining the chromosomes of embryos in reproductive medicine before transplantation, and miscarriage chorionic villus staining examination, which examines the involvement of chromosomal abnormalities as a cause search after miscarriage, and these are performed in daily clinical practice.

[0003] Although there are multiple means for examining miscarriage and infertility risk factors on the maternal and fetal sides as described above, according to the AMED research group, risk factors cannot be identified in about 65% of infertility cases. The same is true for infertility, and it is thought that unexplained infertility, which cannot be identified by tests for known infertility causes, has been increasing in recent years. In cases of unexplained infertility or infertility where the cause cannot be identified by various tests, and recurrent implantation failure, which is infertility where morphological good embryos are transplanted by reproductive medicine but implantation and pregnancy do not occur, it is suspected that there is a problem with the maternal implantation ability. Regarding infertility targeting serum, methods for measuring autoantibodies against laminin-1 have been reported (Patent Document 1). Anti-Müllerian hormone (AMH), which is measured in reproductive medicine, is used as an indicator of ovarian reserve, but not as a marker for judging maternal implantation ability.

[0004] On the other hand, Leukocyte associated immunoglobulin like receptor 1 (also called CD305. Hereinafter, referred to as "LAIR1") is expressed in most human peripheral blood mononuclear cells and leukocytes, and its function as an immunosuppressive receptor has been reported (Non-Patent Document 1). There are research reports that inhibiting the function of this protein activates the immune response and leads to cancer treatment (Non-Patent Document 2). It has also been reported that the expression levels of collagen and LAIR1 are higher at the maternal-fetal interface in normal pregnancy than in miscarriage (Non-Patent Document 3). However, the relationship between LAIR1 and maternal implantation ability has not been reported so far.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Non-Patent Documents

[0006]

Non-Patent Document 1

Non-Patent Document 2

Non-Patent Document 3

Summary of the Invention

[0007] An object of the present invention is to provide a biomarker capable of determining the implantation ability of an embryo into a mother in the treatment of infertility or sterility, quantifying the implantation ability of the mother, and making a more objective determination, a method using the same, and a determination reagent. [Means for Solving the Problems]

[0008] As a result of intensive studies on the above problems, the present inventors have reached the present invention. That is, the present invention is as follows. [1] A biomarker for determining maternal implantation ability, consisting of LAIR1. [2] A method for measuring the concentration of LAIR1 in human (excluding patients with autoimmune diseases, asthma patients, hyperprolactinemia patients, cancer treatment patients, tacrolimus users, and patients whose male partners have AZFc gr / gr deletions or testicular tumors) body fluids, and determining maternal implantation ability from the measured value. [3] When the LAIR1 concentration is higher than the reference value, it is determined that the maternal implantation ability is high, and the reference value is a value predetermined based on the LAIR1 concentration in the body fluids of other humans in whom pregnancy did not occur despite transplantation of an embryo generated after fertilization from a human egg. The method according to [2]. [4] The method according to [2] or [3], wherein the body fluid is serum or plasma. [5] The method according to any one of [2] to [4], wherein the method for measuring the concentration of LAIR1 is an immunological measurement method. [6] The method according to [5], which is performed using an antibody that specifically recognizes LAIR1. [7] A determination reagent or determination kit for use in the method according to [6], characterized by containing an antibody that specifically recognizes LAIR1. [Advantages of the Invention]

[0009] According to the present invention, it is possible to measure the LAIR1 concentration and determine the implantation ability of the mother body, narrow down the reasons for infertility and sterility for examination, and more strictly consider the necessity of pre-implantation diagnosis. As a result, since there is an expectation for the next pregnancy and childbirth, it is expected that a useful diagnostic criterion can be proposed in determining the treatment policy for infertility and sterility.

Brief Description of the Drawings

[0010]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Figure 11

Figure 12

Figure 13

Figure 14

Figure 15

Figure 16

Figure 17

Embodiments for Carrying Out the Invention

[0011] Hereinafter, the present invention will be described in more detail. The first aspect of the present invention is a biomarker for determining maternal implantation ability. The biomarker of the present invention consists of LAIR1 present in human body fluids.

[0012] As shown in the examples described below, the LAIR1 concentration (also referred to as level) in the serum of humans who have become pregnant and given birth is significantly higher than that in the serum of humans in whom pregnancy has not been established. Therefore, LAIR1 in human body fluids can be an indicator for determining maternal implantation ability.

[0013] Based on such findings, the second aspect of the present invention is a method for measuring the LAIR1 concentration in human body fluids and determining maternal implantation ability from the measured value. In this specification, "maternal implantation ability" refers to the degree of the maternal side's ability to achieve the process in which an embryo generated after fertilization from an egg implants in the endometrium of the mother and pregnancy is established. In other words, it may refer to the likelihood of whether a human from whom the body fluid is collected can implant an embryo. The measurement of the LAIR1 concentration in the method of the present invention is usually performed in vitro.

[0014] Note that the method of the present invention includes the steps up to determining the maternal implantation ability, but does not include the final judgment act of the diagnosis. A doctor refers to the determination result by the method of the present invention and diagnoses the maternal implantation ability or determines a treatment policy. Therefore, the method of the present invention can be rephrased as a method for providing a judgment material for diagnosing the maternal implantation ability. The said judgment material may be rephrased as information serving as a basis for judgment.

[0015] LAIR1 in a human specimen can be examined by measuring LAIR1 protein or its fragment in the specimen. Although LAIR1 is a type I transmembrane protein, a soluble form exists. Therefore, the full-length LAIR1 protein and its fragments include those that exist free, as well as those that exist in the specimen in a form bound or associated with other proteins or the like. Accordingly, the term "LAIR1" used as a biomarker in the present invention includes the full-length LAIR1 protein and its partial fragments that exist free in the specimen, as well as LAIR1 and its partial fragments that exist in the specimen in a form bound or associated with other proteins or protein fragments.

[0016] The specimen in the present invention is a human body fluid, and blood (whole blood, serum, plasma, etc.) can be used, but it is desirable to use serum or plasma. The specimen used in the method of the present invention refers to a specimen collected from, that is, isolated from, a subject. The human (subject) from whom the specimen is collected is a human having a uterus because the maternal implantation ability is to be determined. Usually, the diagnosis of infertility is a female patient, and more preferably, a female patient who is an indication for assisted reproductive medicine in infertility treatment. Also, the subject may be a female patient who has been diagnosed with infertility. However, in the present invention, the specimen excludes specimens derived from patients with autoimmune diseases, asthma patients, hyperprolactinemia patients, cancer treatment patients, tacrolimus-taking patients, and patients whose male partners have AZFc gr / gr deletions or testicular tumors. The reason is not clear, but it is because there is a risk that the determination of the maternal implantation ability cannot be correctly performed with specimens derived from these patients.

[0017] The timing of measuring the method of the present invention may be before starting infertility treatment or sterility treatment. By combining the determination result by the method of the present invention with the determination result of infertility or sterility by other methods, it can help in making a decision on treatment. Also, the timing of measuring the method of the present invention may be after additional treatment for infertility or sterility. For example, in the treatment of sterility, by referring to the determination result by the method of the present invention in the follow-up observation after administering low-dose aspirin, the course of sterility can be determined, which helps in making a decision on subsequent treatment.

[0018] The timing of specimen collection is not particularly limited and may be determined by a doctor's judgment. For example, it may be collection at the stage of making a treatment plan before a patient undergoing infertility treatment starts assisted reproductive medicine. Also, when a patient undergoing infertility treatment performs in vitro fertilization, specimen collection may be performed before embryo transfer, for example, at the time of determining egg collection or on the day of egg collection after controlled ovarian stimulation. Also, specimen collection may be performed on the day when the start of controlled ovarian stimulation is determined in the cycle of performing assisted reproductive medicine. Also, specimen collection may be performed after the start of menstruation in the cycle of performing assisted reproductive medicine, for example, between 1 to 7 days after the start of menstruation, between 2 to 5 days after the start of menstruation, or 3 days after the start of menstruation.

[0019] The method for measuring LAIR1 in a human specimen is not particularly limited as long as it is a quantitative measurement method such as an immunological measurement method (hereinafter also referred to as an immunoassay), liquid chromatography, electrophoresis, mass spectrometry, etc. However, since immunoassays do not require large-scale equipment and the measurement operation is simple, they can also be preferably used in the present invention.

[0020] Immunoassay itself is well-known in this field. When classifying immunoassay methods based on the reaction format, there are sandwich methods, competitive methods, agglutination methods, Western blot methods, etc. Also, when classifying based on labels, there are enzyme immunoassay, radioimmunoassay, fluorescence immunoassay, etc. In the present invention, any immunoassay method capable of quantitative detection may be used. Although not particularly limited, for example, a sandwich method such as sandwich ELISA can be preferably used.

[0021] The method for producing the antibody used in the present invention is not particularly limited, and typically, it is a non-human animal polyclonal or monoclonal antibody prepared in a non-human animal such as a mouse or a rabbit. Also, since the amino acid sequence of LAIR1 and the nucleotide sequence encoding the same are also known, an LAIR1 antibody that specifically recognizes a specific site of LAIR1 may be prepared and used by a conventional hybridoma method or the like.

[0022] The antibody used in the present invention may be a polyclonal antibody or a monoclonal antibody. An antiserum may be used as the polyclonal antibody. In the present invention, the term "polyclonal antibody" includes the antiserum before purification. Also, an antigen-binding fragment of the antibody can be used instead of the antibody. Hereinafter, in this specification, unless it is clear from the context that it is not the case, the term "antibody" includes the antigen-binding fragment of the antibody. Polyclonal antibodies, monoclonal antibodies, and antigen-binding fragments can all be prepared by well-known conventional methods.

[0023] Specifically, a polyclonal antibody that recognizes a specific site of LAIR1 can be obtained, for example, by mixing a plurality of types of monoclonal antibodies that specifically recognize the site. Or, a polypeptide containing the site of LAIR1 prepared by a well-known method such as chemical synthesis, or a polynucleotide encoding the same, etc. is used as an immunogen to immunize a non-human animal together with an adjuvant as appropriate, and an antiserum is obtained from the blood collected from the animal, and the polyclonal antibody (non-human animal anti-LAIR1 polyclonal antibody) in the antiserum is purified to obtain it. Immunization is usually performed multiple times over several weeks to increase the antibody titer in the immunized animal. Purification of the antibody in the antiserum can be performed, for example, by ammonium sulfate precipitation, fractionation by anion chromatography, affinity column purification, etc.

[0024] As an example of a well-known method for producing monoclonal antibodies, the hybridoma method can be cited. Specifically, for example, antibody-producing cells such as splenocytes and lymphocytes are collected from an immunized non-human animal as described above, and these are fused with myeloma cells to prepare hybridomas. Hybridomas that produce antibodies that bind to a specific site of LAIR1 are selected, and these are grown to obtain monoclonal antibodies that specifically recognize the non-human animal anti-LAIR1 specific site from the culture supernatant.

[0025] The "antigen-binding fragment" means an antibody fragment that maintains the binding property (antigen-antibody reactivity) to the corresponding antigen of the antibody, such as the Fab fragment or F(ab')2 fragment of an immunoglobulin. It is well known that such antigen-binding fragments can also be used in immunoassays and are as useful as the original antibody. As is well known, Fab fragments and F(ab')2 fragments can be obtained by treating the antibody with proteolytic enzymes such as papain or pepsin. Note that the antigen-binding fragment is not limited to Fab fragments and F(ab')2 fragments, and can be any fragment that maintains the binding property to the corresponding antigen, and can also be prepared by genetic engineering techniques. Also, for example, an antibody in which a single-chain variable region (scFv: single chain fragment of variable region) is expressed in Escherichia coli can be used by genetic engineering techniques. The method for producing scFv is also well known. The mRNA of the hybridoma prepared as described above is extracted, single-stranded cDNA is prepared, PCR is performed using primers specific for the immunoglobulin H chain and L chain to amplify the immunoglobulin H chain gene and L chain gene, these are ligated with a linker, appropriate restriction enzyme sites are added and introduced into a plasmid vector, then Escherichia coli is transformed, and scFv can be prepared by recovering scFv from Escherichia coli. Such scFv is also included in the "antigen-binding fragment".

[0026] Although immunoassay itself is a well-known technique, briefly described, for example, in the sandwich method, an antibody that binds to LAIR1 is immobilized on a solid phase (immobilized antibody), reacted with a sample, washed if necessary, and then reacted with a labeled antibody labeled with a label at the same or different site as the immobilized antibody that binds to LAIR1. After washing, the labeled antibody bound to the solid phase is measured.

[0027] The measurement of the labeled antibody can be performed by measuring the signal from the labeling substance. The signal measurement method is appropriately selected according to the type of labeling substance. For example, in the case of an enzyme label, a substrate such as a chromogenic substrate, a fluorescent substrate, or a luminescent substrate corresponding to the enzyme is reacted with the enzyme, and the resulting signal such as color development or luminescence is measured with a suitable instrument such as a spectrophotometer or a luminometer to determine the enzyme activity and measure the analyte. For example, when alkaline phosphatase is used as the labeling substance, a luminescent substrate such as 3-(4-methoxyspiro(1,2-dioxetane-3,2'-tricyclo[3.3.1.13,7]decane)-4-yl)phenyl phosphate disodium (e.g., trade name AMPPD) can be used. The labeled antibody may have the labeling substance directly bound to the antibody, or a specific binding molecule such as biotin or hapten may be bound to the antibody, and the partner of the specific binding molecule bound to the labeling substance (such as streptavidin or hapten antibody) may be reacted so that the labeling substance is indirectly bound. For standard samples of known concentration containing LAIR1 at various concentrations, immunoassay is performed using an anti-LAIR1 antibody or its antigen-binding fragment, and the correlation between the amount of signal from the label and the concentration of LAIR1 in the standard sample is plotted to create a calibration curve. The same operation is performed on a sample with unknown LAIR1 to measure the amount of signal from the label, and the measured value is applied to this calibration curve to quantify LAIR1 in the sample.

[0028] Whether the LAIR1 concentration in human body fluids is high or not is determined by statistically appropriately calculating a reference value defined from the LAIR1 concentration in the body fluids of other humans in whom pregnancy was not achieved despite the transfer of an embryo developed after fertilization from a human egg, and using this reference value as a threshold value, and can be determined by comparison with this threshold value. When the measured value of the LAIR1 concentration is higher than this reference value (threshold value), it can be determined that the maternal implantation ability is high. This reference value (threshold value) may be set for each age group (for example, under 30 years old, 30s, 40s, 50s, etc.) and for each race. Also, the number of body fluids for measuring the LAIR1 concentration for determining the reference value (threshold value) or other humans from whom it is collected may be any number that allows the reference value to be statistically appropriately determined. For example, it may be 5 or more, 10 or more, 20 or more, or 50 or more, and may be 10,000 or less, 1,000 or less, or 100 or less, or a combination thereof. The reference value (threshold value) may be set so that, for example, in 70% or more, 80% or more, 90% or more, 95% or more, 97% or more, or 100% of the body fluid groups of other humans in whom pregnancy was not achieved despite the transfer of an embryo developed after fertilization from a human egg, the maternal implantation ability is determined to be low.

[0029] Based on the result of the determination of the maternal implantation ability based on the LAIR1 concentration in human body fluids, a doctor finally diagnoses the maternal implantation ability or determines a treatment policy with reference to it. The method for determining the maternal implantation ability of the present invention can assist in the policy of infertility treatment.

[0030] The method for determining the maternal implantation ability of the present invention can be applied to a treatment method for infertility or sterility. That is, according to the present invention, a method for treating infertility or sterility in a patient or a method for increasing the establishment of pregnancy by assisted reproductive medicine, (i) a step of measuring the LAIR1 concentration in the body fluid collected from the patient, (ii) a step of identifying that the patient has a high maternal implantation ability when the measured value exceeds a preset reference value, and identifying that the patient has a low maternal implantation ability when the measured value is below the reference value, and (iii) A step of transplanting an embryo obtained by assisted reproductive medicine into a patient identified as having high maternal implantation ability, or a step of treating a patient identified as having low maternal implantation ability. The treatment is not particularly limited as long as it is appropriate for infertility, and examples include administration of aspirin and heparin.

[0031] The third aspect of the present invention also relates to a reagent for use in a method for determining maternal implantation ability, which contains an antibody that specifically recognizes LAIR1. This determination reagent may consist only of an antibody or an antigen-binding fragment that specifically recognizes LAIR1, or may further contain other components useful for stabilizing these antibodies or their antigen-binding fragments. Further, these antibodies or their antigen-binding fragments may be in a form bound to a labeling substance or a specific binding molecule such as biotin, or in a form immobilized on a solid phase such as a plate or particles.

[0032] An aspect of the present invention may also be a kit for determining maternal implantation ability, which contains the above-described determination reagent of the present invention. The kit is an immunoassay kit and may also contain other reagents necessary for immunoassay. Other reagents necessary for immunoassay are well known. For example, in addition to the above-described detection reagent, the kit may further contain a sample diluent, a washing solution, and, when the labeling substance used for the labeled antibody is an enzyme, a substrate solution for the enzyme. Further, the kit usually contains an instruction manual.

[0033] Another aspect of this aspect is the use of an antibody that specifically recognizes LAIR1 in the manufacture of a reagent for determining maternal implantation ability. Also, another aspect is the use of an antibody that specifically recognizes LAIR1 in the determination of maternal implantation ability. Another aspect is an antibody that specifically recognizes LAIR1 and is used for determining maternal implantation ability.

Examples

[0034] The present invention will be described in detail based on the following examples. However, the present invention is not limited to these examples. The concentration of LAIR1 was measured using a commercially available LAIR1 measurement reagent (product name Human LAIR1 ELISA kit, manufactured by Raybaiotech). The infertile patients in the following examples are patients who underwent reproductive assisted medical treatment and embryo transfer.

[0035] [Example 1] Using serum specimens of infertile patients who achieved pregnancy and gave birth (27 specimens) and serum specimens of infertile patients who did not achieve pregnancy (40 specimens), the concentration of LAIR1 was measured (when the outcome was childbirth). The serum specimens used were specimens obtained by performing controlled ovarian stimulation, which is reproductive assisted medical treatment, on infertile patients and collecting blood simultaneously on the day of oocyte retrieval decision or oocyte retrieval. The results are shown in Table 1 and Figure 1. P = 0.012 in the Mann Whitney test.

[0036]

Table 1

[0037] On the other hand, from these data, excluding the specimens with low values at Birth(+) in Figure 1 that gave birth (7 specimens enclosed by a frame: corresponding to patients with autoimmune diseases, asthma, or hyperprolactinemia) and the specimens with high values at Birth(-) that did not achieve pregnancy and give birth (12 specimens enclosed by a frame: corresponding to cancer treatment patients, tacrolimus users, or patients whose male partners have AZFc gr / gr deletions or testicular tumors), 20 specimens that achieved pregnancy and gave birth and 28 specimens that did not achieve pregnancy were analyzed. The results are shown in Table 2 and Figure 2. A significant difference (p<0.0001) was observed by the Mann Whitney test. From this, it can be seen that when determining maternal implantation ability using LAIR1 as an indicator, patients with autoimmune diseases, asthma, hyperprolactinemia, cancer treatment patients, tacrolimus users, and patients whose male partners have AZFc gr / gr deletions or testicular tumors are exclusion factors for the determination target.

[0038] [Table 2]

[0039] [Comparative Example 1] Using the measurement specimens used in Example 1 (serum specimens of infertile treatment patients who became pregnant and gave birth (27 specimens) and serum specimens of infertile patients who did not become pregnant (40 specimens)), the concentration of the existing marker AMH measured in infertility treatment was measured. The measured values of AMH were referred to clinical information. The results are shown in Table 3 and Figure 3. As is clear from Figure 3, no clear tendency to diagnose implantation ability like LAIR1 was confirmed for AMH.

[0040] [Table 3]

[0041] [Example 2] Among the specimens used in Example 1, serum specimens of patients (20 specimens) excluding patients with autoimmune diseases, asthma, and hyperprolactinemia from the patients who gave birth, and serum specimens of patients (7 specimens) excluding cancer treatment patients, tacrolimus users, and patients whose male partners have AZFc gr / gr deletions or testicular tumors from the abortion patients were used to measure the LAIR1 concentration. The results are shown in Table 4 and Figure 4. As is clear from Table 4 and Figure 4, the measured values of the abortion patients were low, and a significant difference (p = 0.035) was observed (when the outcome was birth and the target was abortion).

[0042]

Table 4

[0043] [Example 3] Using serum specimens from infertile patients who achieved pregnancy (38 specimens) and serum specimens from infertile patients who did not achieve pregnancy (29 specimens), the LAIR1 concentration was measured. The serum specimens used were specimens obtained by performing controlled ovarian stimulation, which is assisted reproductive medicine, on infertile patients and collecting blood simultaneously on the day of oocyte retrieval decision or oocyte retrieval. The results are shown in Table 5 and Figure 5. No significant difference was observed with P = 0.162 in the Mann Whitney test.

[0044]

Table 5

[0045] On the other hand, excluding specimens with low values that achieved pregnancy (11 specimens enclosed in a frame in Pregnancy(+) in Figure 5: corresponding to patients with autoimmune diseases, asthma, or hyperprolactinemia) and specimens with high values that did not achieve pregnancy (8 specimens enclosed in a frame in Pregnancy(-) in Figure 5: corresponding to cancer treatment patients, tacrolimus users, or male partners with AZFc gr / gr deletion or testicular tumor), 27 specimens that achieved pregnancy and 21 specimens that did not achieve pregnancy were analyzed. The results are shown in Table 6 and Figure 6. As is clear from Table 6 and Figure 6, a significant difference was observed with P = 0.0003 in the Mann Whitney test. Even when pregnancy was used as the outcome, since all specimens showing high values reached delivery (when the outcome was pregnancy; results in Figure 6), the diagnosis of maternal implantation ability can be expected as a new diagnostic criterion for infertility and sterility.

[0046]

Table 6

[0047] [Comparative Example 2] Using the measurement specimens used in Example 3 (serum specimens of 38 infertile treatment patients who became pregnant and 29 serum specimens of infertile patients who did not become pregnant), the concentration of the existing marker AMH measured in infertility treatment was measured. The same commercially available AMH measurement reagent as in Comparative Example 1 was used for the measurement of AMH. The results are shown in Table 7 and Figure 7. As is clear from Figure 7, no tendency to diagnose implantation ability such as LAIR1 was confirmed with AMH.

[0048]

Table 7

[0049] [Comparative Example 3] Measurement was performed using the specimens used in Example 1, and a correlation test between AMH and LAIR1, which are existing markers measured in infertility treatment, was conducted. The measurement of the existing markers was carried out with reference to clinical information. The results are shown in Figure 8. As is clear from Figure 8, no correlation was found between AMH and LAIR1.

[0050] [Comparative Example 4] Measurement was performed using the specimens used in Example 1, and a correlation test between LH and LAIR1, which are existing markers measured in infertility treatment, was conducted. The measurement of the existing markers was carried out with reference to clinical information. The results are shown in Figure 9. As is clear from Figure 9, no correlation was found between LH and LAIR1.

[0051] [Comparative Example 5] Measurement was performed using the specimens used in Example 1, and a correlation test between FSH and LAIR1, which are existing markers measured in infertility treatment, was conducted. The measurement of the existing markers was carried out with reference to clinical information. The results are shown in Figure 10. As is clear from Figure 10, no correlation was found between FSH and LAIR1.

[0052] [Comparative Example 6] Measurement was performed using the specimen used in Example 1, and a correlation test between E2 and LAIR1, which are existing markers measured in infertility treatment, was conducted. The measurement of the existing markers was carried out with reference to clinical information. The results are shown in Fig. 11. As is clear from Fig. 11, no correlation was found between E2 and LAIR1.

[0053] [Example 4] LAIR1 was evaluated using serum specimens collected on the day when the start of controlled ovarian stimulation for infertility patients before the implementation of assisted reproductive medicine was determined, excluding patients with autoimmune diseases, asthma patients, hyperprolactinemia patients, cancer treatment patients, tacrolimus-taking patients, and patients whose male partners have AZFc gr / gr deletions or testicular tumors. The concentration of LAIR1 was measured using serum specimens from infertility patients who achieved pregnancy and gave birth (11 specimens) and serum specimens from infertility patients who did not achieve pregnancy (21 specimens) (when the outcome was defined as giving birth). The results are shown in Table 8 and Fig. 12. With a P value of 0.008 in the Mann Whitney test, a significant difference was observed.

[0054]

Table 8

[0055] [Example 5] LAIR1 was evaluated using serum specimens collected on the day when the start of controlled ovarian stimulation for infertility patients before the implementation of assisted reproductive medicine was determined, excluding patients with autoimmune diseases, asthma patients, hyperprolactinemia patients, cancer treatment patients, tacrolimus-taking patients, and patients whose male partners have AZFc gr / gr deletions or testicular tumors. The concentration of LAIR1 was measured using serum specimens from infertility patients who achieved pregnancy (17 specimens) and serum specimens from infertility patients who did not achieve pregnancy (15 specimens) (when the outcome was defined as pregnancy). The results are shown in Table 9 and Fig. 13. With a P value of 0.005 in the Mann Whitney test, a significant difference was observed.

[0056]

Table 9

[0057] [Comparative Example 7] Measurement was performed using the sample used in Example 4, and a correlation test was conducted between AMH and LAIR1, which are existing markers measured in infertility treatment. The measurement of the existing markers was carried out with reference to clinical information. The results are shown in Fig. 14. As is clear from Fig. 14, no correlation was found between AMH and LAIR1.

[0058] [Comparative Example 8] Measurement was performed using the sample used in Example 4, and a correlation test was conducted between LH and LAIR1, which are existing markers measured in infertility treatment. The measurement of the existing markers was carried out with reference to clinical information. The results are shown in Fig. 15. As is clear from Fig. 15, no correlation was found between LH and LAIR1.

[0059] [Comparative Example 9] Measurement was performed using the sample used in Example 4, and a correlation test was conducted between FSH and LAIR1, which are existing markers measured in infertility treatment. The measurement of the existing markers was carried out with reference to clinical information. The results are shown in Fig. 16. As is clear from Fig. 16, no correlation was found between FSH and LAIR1.

[0060] [Comparative Example 10] Measurement was performed using the sample used in Example 4, and a correlation test was conducted between E2 and LAIR1, which are existing markers measured in infertility treatment. The measurement of the existing markers was carried out with reference to clinical information. The results are shown in Fig. 17. As is clear from Fig. 17, no correlation was found between E2 and LAIR1.

Claims

1. A biomarker for determining maternal implantation ability, comprising leukocyte associated immunoglobulin-like receptor 1 (LAIR1).

2. A method for measuring the concentration of LAIR1 in human body fluids (excluding patients with autoimmune diseases, asthma, hyperprolactinemia, cancer treatment, patients taking tacrolimus, and patients whose male partners have AZFc gr / gr deletion or testicular tumors) and determining the mother's implantation ability from the measured value.

3. If the LAIR1 concentration is higher than the reference value, it is determined that the maternal implantation ability is high, The method according to claim 2, wherein the reference value is a value predetermined based on the LAIR1 concentration in the body fluids of other humans in whom pregnancy was not established despite the transplantation of an embryo developed after fertilization of a human egg.

4. The method of claim 2 or 3, wherein the body fluid is serum or plasma.

5. The method according to claim 2 or 3, wherein the method for measuring the concentration of LAIR1 is an immunological assay.

6. The method according to claim 5 , which is carried out using an antibody that specifically recognizes LAIR1.

7. 7. An assessment reagent or kit for use in the method according to claim 6, comprising an antibody that specifically recognizes LAIR1.

Images