Third generation anti-cyclic citrullinated peptide antibodies do not predict anti-TNF-α treatment response in rheumatoid arthritis

Objective of this study is to retrospectively compare the third generation anti-cyclic citrullinated peptide (anti-CCP3) test with the second generation (anti-CCP2) assay as markers of disease activity and predictors of clinical response in rheumatoid arthritis (RA) patients treated with TNF-α blocking agents. This study was performed in 42 RA patients treated either with infliximab (n = 11), etanercept (n = 7) or adalimumab (n = 24). Serum anti-CCP3 and anti-CCP2 levels were tested before and 6 months after starting a TNF-α blocking treatment using commercially available ELISA kits. Anti-CCP3 and anti-CCP2 antibody levels did not significantly change after 6 months of TNF-α blocking treatment. Furthermore, neither anti-CCP3 nor anti-CCP2 was useful to predict anti-TNF-α treatment response using receiving operating characteristic curve and logistic regression analyses. Both anti-CCP3 and anti-CCP2 are not differentially influenced by TNF-α blocking agents in RA patients and failed to predict anti-TNF-α treatment response.