Influence of in vivo diethylstilbosterol phosphate on some human blood lymphocyte sub-populations

The effects of in vivo diethylstilbosterol phosphate (DES-P) on lymphoid cells were studied in six patients with adenocarcinoma of the prostate. The administration of 500 mg DES-P intravenously caused increased numbers of circulating granulocytes, monocytes, and non-T lymphocytes lasting for 24-48 hours. The natural killer activity, as measured in a three-hours 51Cr-release assay with K562 cells as targets, was transiently depressed four hours after drug injection. Parallel variations were found in the fraction of lymphocytes bearing receptors for the Fc part of IgG. In mixed lymphocyte culture (MLC) the responding capacity of the T cells and the stimulatory capacity of the non-T cells were unaffected. In vitro preincubation with DES-P overnight was not toxic to the lymphocytes. To be suppressive in MLC DES-P had to be added in concentrations one thousand times higher than those of hydrocortisone. It is concluded that a single dose of DES-P in vivo modulates the kinetics of recirculating lymphoid cells.