Background
Apoptosis of peripheral blood T lymphocytes from patients with Crohn's disease has been described after in vitro activation followed by incubation with infliximab. These ex vivo data raised the question of whether in vivo treatment of rheumatoid arthritis (RA) with the chimeric tumor necrosis factor alpha antibody, infliximab, causes apoptosis in peripheral blood mononuclear cells. This study was designed to detect the early effects of infliximab treatment on apoptosis in the peripheral blood of patients with RA.