To evaluate whether serum titers of second-generation anticyclic citrullinated peptide antibodies (anti-CCP2) are associated with the severity and extent of interstitial lung disease in rheumatoid arthritis (RA-ILD).
In across-sectional study, 39 RA-ILD patients confirmed by high-resolution computed tomography (HRCT) were compared with 42 RA without lung involvement (RA only). Characteristics related to RA-ILD were assessed in all of the patients and serum anti-CCP2 titers quantified.
Higher anti-CCP2 titers were found in RA-ILD compared with RA only (medians 77.9 versus 30.2 U/mL, P < 0.001). In the logistic regression analysis after adjustment for age, disease duration (DD), smoke exposure, disease activity, functioning, erythrocyte sedimentation rate, and methotrexate (MTX) treatment duration, the characteristics associated with RA-ILD were higher anti-CCP2 titers (P = 0.003) and + RF (P = 0.002). In multivariate linear regression, the variables associated with severity of ground-glass score were anti-CCP2 titers (P = 0.02) and with fibrosis score DD (P = 0.01), anti-CCP2 titers (P < 0.001), and MTX treatment duration (P < 0.001).
Anti-CCP2 antibodies are markers of severity and extent of RA-ILD in HRCT. Further longitudinal studies are required to identify if higher anti-CCP2 titers are associated with worst prognosis in RA-ILD.