CRP and rheumatoid arthritis: Indices of RA disease activity and interstitial lung disease (Disease Activity Score in 28 joints using C-reactive Protein [DAS28-CRP], Simplified Disease Activity Index [SDAI], Clinical Disease Activity Index [CDAI], serum Krebs von den Lungen-6 levels, % forced vital capacity [%FVC], and semi-quantified chest high-resolution computed tomography scores) were evaluated before and 1 year after the start of abatacept administration.