Background A “window of opportunity” exists in early RA. Autoantibodies against citrullinated proteins catalyzed by PADs are often detected in patients with RA. They are produced early & are more specific than rheumatoid factor (RF).Anti-PAD 4 antibodies are specific markers of RA, independently associated with more severe disease. Autoantibodies to PAD-4 are present during the preclinical phase of RA in a subset of patients (pts).
Objectives to study the presence of anti PAD-4 in early RA pts (<2 years) & first degree relatives and its relation to disease activity & extra-articular involvement
Methods BMI,CBC,kidney functions, ESR, CRP, RF, Anti-CCP, Anti-PAD4 were assessed in 40 RA pts, 20 first degree relatives & 20 matched controls. DAS 28 calculated in RA pts, pts with history of renal, cardiac or liver dysfunction were excluded
Results It was observed that: highly significant increase in anti-PAD4 in RA group (gp)than controls, & in female relatives than control females, significant increase anti-CCP in RA pts & in relatives gp than the control gp. The sensitivity of anti-CCP alone was 87.5%, anti-PAD4 alone 60%, combining the two markers the sensitivity rose to 97.5%. The specificity of anti-CCP was 95%, of anti-PAD4 was 90%, on combining the two it reached 100% in controls. No significant difference between positive and negative anti-PAD4 RA pts regarding DAS28. RF and anti-CCP show a significant increase in positive anti-PAD4 pts than the negative ones. ESR & CRP show no significant difference in both positive and negative anti-PAD4 pts. The number of tender joints (TJC) and swollen joints, morning stiffness was higher in anti-PAD 4 pts but not to the level of significance, disease duration show no significant difference between the positive and negative anti-PAD4 pts. A positive significant correlation between: anti-PAD4 and DAS 28 score (r= +0.43, P=0.006), between anti-PAD4 and anti-CCP (r=0.819, p=0.0001). between anti-PAD4 and RF (r=0.6, p=0.0001), and between Anti-PAD4 and TJC (r=0.50, p<0.001) in RA pts was observed. As most of ' pts had early RA no significant extra-articular manifestations
Conclusions Significant increase in anti-PAD4 in RA & their relatives -female ones- than controls. Sensitivity & specificity of anti-CCP increased in the presence of anti-PAD4. Anti-PAD4 was correlated with RF, anti-CCP & disease activity reflected by DAS 28 & TJC
Roth EB, et al. Antibodies against transglutaminases, peptidylargininedeiminase and citrulline in RA – new pathways to epitope spreading. Clin Exp Rheumatol 2006; 24:12-8
Disclosure of Interest None declared