Significance Of Combined Detection Of Five Auto-antibodies In The Diagnosis Of Seronegative Rheumatoid Arthritis

Objective: To evaluate significance of anti type II collagen(CII)antibody,anti-RA33 antibody,anti-mutated citrullinated vimentin(MCV)antibody,anti-Sa antibody,anti-carbamylated protein(Car P)antibody in the diagnosis of seronegative rheumatoid arthritis(SNRA),and to compare the significance of combined detection of multiple indicators in SNRA diagnosis.Methods: We collected 35 patients with SNRA and 15 patients with other Other rheumatic diseases,include dermatomyositis,systemic lupus erythematosus,mixed connective tissue disease etc,who were treated in Department of Rheumatology and Immunology of the Affiliated Rocky Mountain Hospital of Wannan Medical College from January,2018 to September,2018 for the study,and also selected 10 healthy people who were in our hospital during the same period as controls.Among them,SNRA patients were set to case group,other rheumatic diseases patients were the case control group,and healthy people were the healthy control group.ELISA method was used to detect anti-CII antibody,anti-RA33 antibody,anti-MCV antibody,anti-Sa antibody and anti-Car P antibody.The test results were compared with clinical parameters.Results: 1.Comparison of antibody levels among the three groups: the levels of anti-CII antibody,anti-RA33 antibody,anti-MCV antibody,anti-Sa antibody and anti-Car P antibody were 38.38± 33.42 ug /L,28.98(10.96,124.85)U/L,9.54(4.32,14.83)ug/L,3.20(2.77,14.00)ng/L and 7.94(6.61,16.62)U/m L in the 35 case groups.The antibody levels of the 15 cases in the control group were 24.87± 13.91 ug /L,21.8(9.63,38.92)U/L,13.33(1.99,19.04)ug/L,2.66(2.01,9.14)ng/L and 7.33(5.08,9.58)U/m L respectively.The average antibody levels of the 10 healthy controls were 13.75± 6.96 ug /L,9.84(3.66,17.08)U/L,9.83(6.51,16.02)ug/L,2.31(2.04,2.77)ng/L and 6.44(5.03,8.57)U/m L,respectively.The value of anti-CII antibody in the case group was higher than that in the case control group and the healthy control group(F=3.669,P=0.032),the value of anti-RA33 antibody in the case group and the case control group was higher than that in the healthy control group(H=7.521,P=0.023),and the value of anti-Sa antibody in the case group was higher than that in the control group(H=8.687,P=0.013),the difference was statistically significant.2.Comparison of positive rates between different groups: The positive rate of anti-CII antibody in the case group was higher than that in the case control group and healthy control group(P=0.039),and the positive rate of anti-Car P antibody was higher than that in the case control group and healthy control group(P=0.039),with statistically significant differences.3.Comparison of antibody levels and disease activity parameters in the case group: The ESR and DAS28 levels of anti-CII antibody,anti-MCV antibody and anti-Car P antibody positive patients in the case group were all higher than those in the negative antibody groups respectively,and the mean CRP level of anti-CII antibody positive SNRA patients was significantly higher than that of the negative patients,with statistically significant differences(P<0.05).4.Comparison of antibody levels and X-ray staging in the case group: Serum anti-MCV antibody and anti-Car P antibody levels in patients with different X-ray staging were different(P<0.05).The higher the X-ray staging was,the higher the content of anti-carp antibody might be.5.Correlation between antibody level and disease activity parameters and X-ray: Correlation analysis of 5 antibodies and clinical parameters in patients showed that CRP,ESR,DAS28,and X-ray staging were significantly correlated with anti-carp antibody levels(P<0.05).DAS28 joint activity score and bone damage X-ray staging were strongly correlated with anti-MCV antibodies and anti-Car P antibodies(r> 0.40,P<0.05).6.ROC curve analysis: Single antibody detection: The area under the ROC curve was used to study the diagnostic value of single antibodies to SNRA.The area under the curve of anti-CII antibody,anti-RA33 antibody,anti-MCV antibody,anti-Sa antibody and anti-Car P antibody were 0.715,0.658,0.490,0.707 and 0.644,respectively.Multiple antibody combination tests: The area under the curve of anti-RA33 antibody + anti-Car P antibody,anti-MCV antibody + anti-Car P antibody,anti-CII antibody + anti-RA33 antibody + anti-MCV antibody,anti-CII antibody + anti-RA33 antibody + anti-Sa antibody and anti-CII antibody + anti-RA33 antibody + anti-Car P antibody were 0.794,0.782,0.771,0.751 and 0.771 respectively.Conclusion: 1.The anti-CII antibody content of SNRA patients is higher than that of other groups,which can be used as an auxiliary identification indicator of SNRA;2.Anti-MCV antibody is a good indicator of disease activity and can be used to monitor SNRA disease activity;3.Anti-Carp antibody can better reflect the degree of imaging disease progression in SNRA patients;4.anti-CII antibody,anti-Sa antibody are of high diagnostic value for SNRA of which anti-Sa antibody has higher sensitivity,while anti-CII antibody has better specificity;5.The combined detection of anti-RA33+anti-Car P and anti-MCV+anti-Car P are of high diagnostic value for SNRA,and both have higher sensitivity and specificity.