Immunological effects of retinoids

Vitamin A treatment (100,000 U daily) of systemic lupus erythematosus, non-Hodgkin's lymphoma and chronic lymphocytic leukemia patients, children suffering from recurrent respiratory tract infections and healthy controls resulted in an enhancement of antibody-dependent cell-mediated cytotoxicity, natural killer activity and blastogenic response to mitogens. In vitro, retinoids, depending on the concentration, stimulated mitogen- and interleukin-2-induced blastogenesis and lectin-dependent T cell cytotoxicity. Retinoids caused an early plasma membrane hyperpolarization of cells of various origin. This effect was similar to that seen by interferon alpha. Retinoids also slightly inhibited intracellular calcium accumulation.