LAG3 and rheumatoid arthritis: In summary, the data presented herein propose LAG-3 as a faceted inhibitory receptor in the pathogenesis of RA with several key points to highlight (1) the increased level of LAG-3, particularly in the inflamed joint; (2) the positive correlation to autoantibody seropositivity and radiographic progression; and (3) the biologically active role by decreasing inflammatory cytokine production.