Thymosin-induced increase in E-rosette-forming capacity of lymphocytes in patients with malignant neoplasms

Thymosin, a thymic hormone, restores decreased cellular immunity under various experimental conditions. The purpose of this study was to evaluate the effect of thymosin on the E-rosette-forming capacity in cancer patients. Peripheral blood lymphocytes obtained from eight patients with various malignant neoplasms were examined. One of these patients received thymosin intramuscularly; his E-rosette formation was examined serially. Eight normal adults served as controls. Patients with advanced stages of malignant tumors showed decreased E-rosette-forming capacity, which increased significantly under the influence of thymosin. Patients with less-advanced tumors, as well as normal adults, demonstrated normal E-rosette formation without further effects by thymosin. The in vivo administration of thymosin to one patient was followed by a marked increase of the E-rosette-forming capacity. These results suggest that the administration of thymosin, both in vivo and in vitro, significantly increases the circulating T-lymphocyte levels and/or functions in patients with advanced malignant neoplasms.