[Clinical study of immunosuppressives in cancer patients]

Induction of suppressor cell activities in normal lymphocytes by the sera from cancer patients was investigates. The sera were collected and assayed from the patient with colo-rectal, liver, gall bladder, pancreas, esophageal, breast and gastric cancer. They induced suppressor cell activities and depressed significantly the proliferative response of autologous responder lymphocytes, while the sera from the patients with benign + diseases did not. Sera induced suppressor cells were found to reside in T cells. Monocytes increased the induction of suppressor cell activities but complement did not. Sera induced suppressor cell activities apparently correlated with spontaneous suppressor cell activities in cancer donors, and these activities declined after the treatment of plasma exchange. In patients with gastric cancer, clinical prognostic factors such as staging of the disease, tumor size, liver metastasis, histological pattern of tumor and invasion of vein, affected on the suppressor cell activities, which significantly decreased after curative resection. From these results it might be postulated that the sera from cancer patients contain factors which induced suppressor cell activities and that serum factor activates the suppressor precursors to be matured suppressor cells in-vivo in a manner similar to that seen in-vitro.