A prospective study on clinical response and cell-mediated immunity of pemphigus patients treated with rituximab.

Rituximab has recently been reported in retrospective studies to be effective in pemphigus at the dosing schedule used for treating rheumatoid arthritis (RA) of two 1,000 mg infusions 2 weeks apart. While the effect of rituximab on B cells has been well described, its effect on global T cell function has not been assessed. Ten patients who received RA dosage rituximab were prospectively assessed for clinical response. Immunological response including autoantibody titers, CD20+ B cell, and CD4+ T cell counts was assessed pre- and post-treatment. The CD4+ T cell function was determined by a novel assay measuring intracellular ATP levels in response to mitogenic stimulus. At 6 months, 90 % of patients achieved remission. Disease control and remission were achieved at median times of 1 and 3.7 months, respectively. There was a 67 % relapse rate during an average follow-up of 22 months. Global CD4+ T cell numbers and function were preserved 3 months after rituximab. A single cycle of RA dosage rituximab with concomitant immunosuppression is effective in pemphigus. We did not find an effect on total CD4+ T cell numbers or function 3 months after treatment.