Previously reported mechanisms of anti-CD20 mAb: (A) depletion of B cells and subsequent decrease in plasma B-cell population and antibody production; (B) downregulation of Th1 and upregulation of Treg populations for unclear reasons. Work by Guo et al revealed a novel mechanism: (C) inhibition of CD8⁺ T-cell proliferation and amelioration of CD8⁺ T-cell–mediated pathogenesis. Professional illustration by Patrick Lane, ScEYEnce Studios.