Darrah E, et al. - Researchers assessed baseline serum from 282 subjects to know whether the baseline presence of autoantibodies to peptidylarginine deiminase 4 (PAD4) predicted therapeutic response to biologic and conventional disease-modifying antirheumatic drugs (DMARDs) in rheumatoid arthritis (RA) cases [in whom methotrexate (MTX) monotherapy was unsuccessful]. An association of anti-PAD4 antibody positivity with male gender, a history of never smoking, and anti-citrullinated protein antibodies was reported. They noted subjects with anti-PAD4 antibodies with longer disease duration and significantly more radiographic joint damage as compared to anti-PAD4–negative patients at baseline, but no difference was recorded in disease activity according to the DAS28.