Isradipine, a calcium-channel antagonist, has immunosuppressor activity on T lymphocytes from peripheral blood and synovial fluid from patients with autoimmune arthritis.

It has been shown that calcium-channel antagonists can have an immunomodulatory effect on the activation and function of lymphocytes and that autoimmune diseases are associated with alterations in the regulation of the immune system. This study investigated the effect of a calcium-channel antagonist, isradipine, on the activation and proliferation of mononuclear cells (MNC) from the peripheral blood (PB) and synovial fluid (SF) of 41 patients with chronic autoimmune arthritis and from the PB of 16 healthy controls. Isradipine inhibits the proliferative response of these cells to mitogenic stimulation from phytohemagglutinin (PHA) and anti-CD3 monoclonal antibodies in a time- and dose-dependent manner. This inhibitory effect of isradipine on the proliferative response in the different cell preparations was not overcome by the exogenous addition of interleukin-2 to the culture medium. Additionally, isradipine inhibited MNC expression of CD25, CD71, and class II molecules of the major histocompatibility system in patients and controls after mitogenic stimulation. These results demonstrate that isradipine suppresses the activation and proliferation of MNC in PB and SF from patients with autoimmune arthritis.