The significance of serum anti-peptidylarginine deiminase 4 antibodies in the diagnosis of rheumatoid arthritis

Abstract：To assess the value of serum anti-peptide arginine-deiminase enzyme 4 (PADI4) antibodies in the diagnosis of RA, we analyzed the serum anti- PADI4 antibody levels in rheumatoid arthritis (RA) group, other rheumatic group, and the healthy control group. Enzyme-linked immunosorbent assay (ELISA) was used to detect anti-PADI4 antibody levels, and illustrated that he prevalence of anti-PADI4 antibody in RA patients (47%) was significantly higher than in other rheumatic diseases and healthy controls(P<0.05). By analyzing the associations of the antibody with DAS28 score, anti-CCP antibodies, anti-keratin antibodies (AKA), and rheumatoid factor (RF), our group found that anti-PADI4 antibodies diagnostic sensitivity and specificity to RA were 43% and 92% respectively, and there was no association between anti-PADI4 antibodies and DAS28 score or anti-CCP antibodies (r = -0.025, P = 0.82;r =-0.058, P = 0.60). The positive rate for anti-PADI4 antibodies in RF-negative, AKA-negative, and anti-CCP antibodies-negative RA patients was 50%, 43%, and 60%, respectively. The results suggest that anti-PADI4 antibodies has high diagnostic value in RA,especially in RF-negative, AKA-negative, and anti-CCP antibodies-negative RA, due to PADI4 may be a pathogenic antigen for RA and play an important role in RA pathogenesis and pathological processes.