Enhancement of lymphocyte-mediated cytotoxicity after tumor resection in patients with colorectal cancer.

Lymphocyte numbers and function in 37 patients with colorectal cancer were compared with those in 23 healthy controls of the same age range. No significant difference in lymphocyte count, numbers of cells forming erythrocyte rosettes or bearing surface immunoglobulin, cell-mediated cytotoxicity, or mitotic response to phytohemagglutinin (PHA) was found. Six to 12 months after tumor resection, patients showed a rise in spontaneous, antibody-induced, and PHA-induced cytotoxicities to levels significantly higher than those found in age-matched controls. This rise occurred irrespective of whether patients had received adjuvant immunotherapy with Corynebacterium parvum.