Effects of retinoids on human thymus-dependent and thymus-independent mitogenesis.

The effects of all-trans-retinoic acid (RA), 13-cis-retinoic acid, and N-(4-hydroxyphenyl)retinamide on the mitogenic responses of various populations of human lymphocytes have been evaluated. Superoptimal concentrations of mitogens allowed the greatest RA-induced potentiation of lymphocyte proliferation. All three retinoids at concentrations as low as 5 x 10(-14)M significantly potentiated the proliferation of adenoidal and tonsillar lymphocytes stimulated by pokeweed mitogen (PWM).