B-cell depletion induced immunologic responses in relation to clinical outcome in patients with HCV-MC vasculitis. (A) The percentage of CD4⁺CD25⁺FoxP3⁺ regulatory T cells increased significantly in HCV-MC patients with complete clinical response (CR; n = 14; circles) following rituximab compared with patients with partial response and nonresponse (PR/NR; n = 7; squares; *P < .05, **P < .01). (B) Flow cytometry figures showing the increase in CD4⁺CD25⁺FoxP3⁺ regulatory T cells following rituximab (at month + 12) in a patient with complete response (CR) of HCV-MC compared with nonresponse (NR). (C) The percentage of CD8⁺HLA-DR⁺ activated T cells normalized in HCV-MC patients with complete clinical response (CR; circles) following rituximab compared with those with partial response and nonresponse (PR/NR; n = 7; squares; **P < .01). Data are expressed as mean plus or minus SEM.