Association of fine specificity and repertoire expansion of anticitrullinated peptide antibodies with rheumatoid arthritis associated interstitial lung disease

Background Interstitial lung disease (ILD) is associated with high morbidity and mortality in rheumatoid arthritis (RA). Citrullinated proteins are observed in RA lung tissues; however, the association of specific anticitrullinated peptide antibodies (ACPA) with ILD in RA is unknown. Methods RA patients underwent multidetector CT (MDCT) of the chest, from which ILD features and a semiquantitative ILD Score (ILDS; range 0–32) were assessed. Anti-CCP (CCP2) and levels of a panel of antibodies against 17 citrullinated and four non-citrullinated peptides were assessed from concurrent serum samples using a custom Bio-Plex bead array. High level ACPA was defined as ≥the group 75th percentile. Results Among the 177 RA patients studied, median levels of CCP2 and all specific ACPAs were 46–273% higher among RA patients with versus those without ILD (all p values