Patients with gastrointestinal cancer were treated with 5-fluorouracil (5-FU) in combination with a streptococcal preparation, OK-432, or without OK-432 before operation, and lymphocyte response to PHA was examined. Oral administration of 5-FU with or without intramuscular injection of OK-432 did not affect the response. However, treatment with cytostatic drugs in combination with OK-432 markedly augmented the lymphocyte response to PHA, but the cytotoxic activity of lymphocytes was not elevated.

Lymphocyte activity of patients with gastric cancer and its relation to the stage of cancer were studied. PHA response of lymphocytes from patients with gastric cancer was decreased markedly even in early stage of cancer. The PHA-stimulated lympho-cytotoxicity was not impaired in all stages of the disease. Spontaneous lymphocyte-mediated cytotoxicity showed a tendency to decrease as the cancer stage advanced. The cytotoxic activity of the supernatants from lymphocytes cultured without PHA was significantly high in the advanced stage of gastric cancer.