In vivo effect of Rituximab on regulatory T cells and apoptosis in patients with rheumatoid arthritis

The aim of this study was to assess the in vivo effect of anti-CD20 therapy with Rituximab on regulatory T lymphocytes, and apoptosis of immune cells in patients with rheumatoid arthritis (RA). In an open and pilot clinical trial, Rituximab was administered (1.0 g at days 1 and 30) to seven patients with RA that were refractory to conventional therapy. Peripheral blood samples were obtained at days 0, 15, and 180 of Rituximab therapy, and the number and function of regulatory T lymphocytes, as well as the presence of apoptotic cells were analyzed. Five out of seven patients showed significant clinical improvement upon Rituximab therapy (ACR response 50-70), and a significant increase in the number and function of regulatory T cells. In addition, an increased percent of apoptotic cells was detected in the peripheral blood after the onset of Rituximab therapy. These data suggest that Rituximab seems to exert an interesting effect on regulatory T cells in patients with RA; this phenomenon may contribute to the therapeutic effect of this anti-CD20 agent in RA.

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