Effect of estrogen on the mixed lymphocyte reaction in normal individuals and prostatic cancer patients

Lack of initial response or relapse to hormones in advanced prostatic cancer may be due to an adverse effect of estrogen on host immune function. This study investigated the effect of diethylstilbestrol diphosphate (DES-P) on the normal mixed lymphocyte reaction (MLR) and on the MLR in prostatic cancer patients before and during treatment with DES-P. These data showed that the normal MLR was suppressed by high concentrations of estrogen in vitro, but physiologic levels of DES-P were not suppressive. Therapeutic doses of DES-P did not suppress the spontaneous MLR of prostatic cancer patients compared with previous treatment. Estrogens did not significantly impair the immunologic responsiveness of normal individuals or prostatic cancer patients.