CTLA4 and rheumatoid arthritis: Currently, abatacept, a fusion protein of the extracellular domain of cytotoxic T lymphocyte-associated protein 4 (CTLA4) and the Fc region of human IgG1, is considered to be the most reasonable option for treating RA patients with ILD (7); however, recent reports suggest that the efficacy and safety of JAKi may be comparable to those of abatacept in terms of their impact on the disease behavior of RA-ILD (8, 9).