PRTN3 and rheumatoid arthritis: Since it has been reported that macrophages derived from the peripheral blood monocytes of RA patients produce inflammatory cytokines and chemokines after binding to the ACPA immune complex [22], abatacept-induced downregulation of CD64/FcγRI on monocytes may suppress ACPA immune complex-induced production of inflammatory cytokines/chemokines in patients with ACPA-positive RA.