Activation of suppressor function of human peripheral blood T cells by (+)cyanidanol-3: its application to chronic active liver diseases.

(+)Cyanidanol-3, a substance belonging to the flavonoids group, has been used in acute viral hepatitis (AVH) and chronic active liver disease (CALD). Studies were undertaken to determine if (+)cyanidanol-3 could affect a function of mitogen stimulated peripheral blood lymphocytes (PBL) in humans. First, (+)cyanidanol-3 was added directly to pokeweed mitogen (PWM) stimulated PBL or co-culture of B and T cells resulting in severe suppression of immunoglobulin (Ig) production. This suppression was mediated by radiosensitive T cells. Secondly, when normal T cells pre-incubated with 25 micrograms/ml of (+)cyanidanol-3 for 48 h were cultured with freshly prepared autologous or allogeneic normal PBL in the presence of PWM, Ig production was markedly suppressed. Similarly, there was a consistent suppression of blast transformation of concanavalin A (Con A) stimulated autologous or allogeneic responding PBL by (+)cyanidanol-3 pre-treated normal T cells. On the other hand, (+)cyanidanol-3-induced suppressor cell activity of T cells from patients with CALD was significantly decreased (P less than 0.001) when compared with that of normal individuals. These studies may explain the therapeutic effect of (+)cyanidanol-3 on certain types of liver disease.