Lynestrenol: a progesteronelike agent with immunostimulatory properties.

Lynestrenol, a synthetic progesteronelike drug, was assessed for its influence upon human leukocyte tests in vitro and in vivo. Lynestrenol markedly enhanced the lymphocyte response to phytohemagglutinin, the mixed lymphocyte culture, the active T-rosette test, the autologous red cell rosettes, and the number of nonadherent cells in the leukocyte adherence inhibition test. All these results indicate a stimulatory effect upon human T-cell function. Lynestrenol also increased monocyte phagocytosis. Lynestrenol delayed the appearance of malignant tumors in hamsters. Finally, lynestrenol, given to lung cancer patients, increased their T-cell functions as evaluated by skin tests. T-cell rosettes, and phytohemagglutinin response. Lynestrenol does possess immunostimulatory properties.