Study On The Correlation Between The Expression Of Anti-α-enolase Epitope Peptide P6 Antibody In Serum Of Pregnant Women With Autoimmune Thyroiditis And The Occurrence Of Miscarriage

Objective:AIT is an organ-specific autoimmune disease caused by the increased titer against TPOAb and Tg Ab.AIT is more common in pregnant women.As an autoimmune disease,AIT plays a vital role in pregnant women’s abortion,especially recurrent miscarriage that occurs twice or more consecutively.However,the specific mechanism of AIT causing maternal miscarriage is still unclear.ENO1 is widely present in human kidney,thyroid,placenta,uterus and various tissues and organs as well as on the surface of vascular endothelial cells.As an anti-trophoblast antibody,ENO1Ab can reduce the expression ofβ-human chorionic gonadotropin and progesterone,thereby serving as a RM autoimmune marker.Antigenic epitopes,also known as antigenic determinants,are special chemical groups with a certain composition and structure located on the surface of antigenic substances or other parts of the molecule.They are also the basic structural units for immunogens to cause immune responses and specific reactions with antibodies.In the early stage of our research group,the pathogenic epitope peptide was predicted through the IEDB website and the ABpred website,and the P6 peptide may be a pathogenic epitope peptide positively related to AIT abortion,but its specific biological function is still unclear.The purpose of this study is to determine whether anti-ENO1-P6antibodies can promote abortion in pregnant women with AIT by measuring the antibody titers of anti-ENO1-P6 specific total IgG antibodies and their IgG subtypes in the sera of pregnant women.And to clarify the correlation between anti-ENO1-P6 specific total IgG antibody and serum thyroid-related indicators and autoantibodies in AIT patients,so as to provide new targets for the cause of spontaneous abortion in pregnant women with AIT and provide new ideas for clinical diagnosis and treatment.Methods:The design method of this study is a nested case-control study,and the population is mainly derived from the mature SHEP project led by the Endocrinology Department of our hospital.Include pregnant women aged 21-43,adequate iodine,adequate ferritin nutrition,normal thyroid function,and exclude other thyroid-related diseases other than AIT,other autoimmune diseases,hypertension,diabetes,Epilepsy and other diseases related to abortion.The pregnant women who have placenta previa,abruption of placenta and premature birth,and pregnant women who take drugs that affect abortion and have a history of induced abortion are also excluded.The study grouped according to whether suffering from AIT and pregnancy with history of abortion and the SHEP project follow-up monitoring until a pregnancy outcomes occurred in spontaneous abortion,using the SPSS 22.0 PS Matching plug-in function to determine the number of AIT abortion samples according to the place of residence of pregnant women,1:3 preference matching based on educational background and family income.It was finally determined that the number of AIT non-abortion was 152,the number of non-AIT abortion was 107,and the number of non-AIT non-abortion was 344,and the total number of pregnant women included in this study was determined to be 661.The baseline data of the enrolled population was extracted for relevant statistical analysis,and the sera of the recruited patients were used for ELISA to detect the anti-ENO1-P6 specific total IgG antibody and the antibody titer of each IgG subtype.Results:1.The expression level of anti-ENO1-P6 specific total IgG antibody in serum of pregnant women with abortion was significantly higher than that of pregnant women without abortion（P<0.001）.The expression level of anti-ENO1-P6-specific total IgG antibody in serum of pregnant women with AIT abortion was significantly higher than that of pregnant women without AIT abortion（P<0.001）.Compared with non-AIT aborted women,the expression level of specific total IgG antibody ENO1-P6 in serum of pregnant women with AIT aborted women was also significantly increased（P<0.001）.2.There was no significant statistical difference in general factors related to abortion between AIT abortion group and AIT non-abortion group（P>0.05）except for anti-ENO1-P6 specific total IgG antibody（P<0.001）.The age of pregnancy and the serum TSH level of pregnant women were significantly different between the non-AIT abortion population and the non-AIT non-abortion population（P<0.05）.3.Serum anti-ENO1-P6 specific total IgG antibody is an independent risk factor for maternal abortion in pregnant women with AIT（P<0.01）.4.The serum anti-ENO1-P6 specific total IgG antibody titer level has a multiplicative interaction with TSH,FT4,TPOAb and Tg Ab（P<0.05）.5.In the ROC curve for predicting the risk of miscarriage in the population of anti-ENO1-P6 specific total IgG antibody,the area under the curve AUC=0.635±0.026,and the corresponding optimal cut-off value is OD_450nm=0.6372;In the ROC curve for predicting the risk of miscarriage in AIT population of anti-ENO1-P6 specific total IgG antibody,the area under the curve AUC=0.733±0.041,and the corresponding best cut point value is OD_450nm=0.5085.6.With the increase of the anti-ENO1-P6 antibody titer in the serum of pregnant women in the general population,the trend of the proportion of abortions showed an overall increase（P for trend=0.000）;As the titer of anti-ENO1-P6 antibody increased,the proportion of abortions rose significantly to the same degree（P for trend=0.000）.7.The population of pregnant women with spontaneous abortion has a significant dependence on the level of ENO1-P6 specific total IgG antibody titer and the occurrence of spontaneous abortion in pregnant women with AIT has a significant dependence on the level of ENO1-P6 specific total IgG antibody titer（P<0.01）.8.In the abortion population,the anti-ENO1-P6 specific total IgG antibody titer in the serum of pregnant women is positively correlated with TPOAb and Tg Ab（P<0.05）;in the AIT abortion population,the anti-ENO1-P6 specific total IgG antibody in the serum of pregnant women Titer level is positively correlated with TPOAb（P<0.05）.9.The expression levels of anti-ENO1-P6 antibody IgG1,IgG2,IgG3,IgG4 subtypes and IgG1/IgG2 in the serum of pregnant women with abortion were significantly higher than those of pregnant women without abortion（P<0.05）;The expression levels of anti-ENO1-P6 antibody IgG2,IgG3 and IgG4 subtypes in the serum of AIT pregnant women were significantly higher than those of non-AIT pregnant women（P<0.05）.10.The serum levels of anti-ENO1-P6 antibodies IgG1,IgG2,IgG3,IgG4 and the ratio of IgG1/IgG2 in the serum of pregnant women with AIT abortion were significantly higher than those of pregnant women without abortion（P<0.01）.The serum anti-ENO1-P6 antibody titers of pregnant women with AIT abortion IgG1,IgG2,IgG3,and IgG4 were also significantly higher than those of non-AIT aborted women.（P<0.05）.11.The contribution of the four anti-ENO1-P6 specific IgG antibody subtypes to the adverse outcome of AIT pregnant women in descending order is IgG2>IgG3>IgG4>IgG1,and the corresponding regression coefficients were 8.422,8.108,2.079 and 1.603（P<0.05）.Conclusions:The anti-ENO1-P6 specific total IgG antibody titer level is increased in the serum of pregnant women with AIT abortion,and the antibody titer level is positively correlated with TPOAb;The expression of anti-ENO1-P6 specific total IgG antibody may be a risk factor for maternal miscarriage in pregnant women with AIT.The four subtypes of anti-ENO1-P6 specific IgG antibodies have increased expression levels in the serum of pregnant women with abortion and AIT abortion,which may jointly promote the occurrence of spontaneous miscarriage in AIT pregnant women.,and the expression of IgG2 and IgG3 may play a major role in spontaneous miscarriage in AIT pregnant women,while the contribution of IgG1 and IgG4 is relatively small,while IgG1 and IgG4 play a relatively small role.