Prospective study of natural cytotoxicity in peripheral blood of patients with nonlymphoid solid malignancies.

Natural killer (NK) cells have been implicated as an initial immunosurveillance mechanism for carcinogenesis in humans. Work in the murine system as well as the findings of depressed NK activity in patients with advanced malignancies and the discovery of increased incidences of cancer in humans congenitally deficient in NK ability have supported this. Few prospective studies have demonstrated a prognostic change in NK activity with respect to malignant disease course. In 32 healthy donors, NK activity against K562 was determined. No race or sex difference existed with respect to NK cell function. Esophageal (5), bronchogenic (3), breast (3), cervical (3), and endometrial (1) cancer patients who had received no prior chemotherapy were compared to controls. All patients subsequently received radiotherapy. Prior to such treatment NK activity could not be associated with stage of malignancy. Of the 15 patients studied, 11 were sequentially followed. Five of eight patients with stable or improving clinical courses as assessed by weight and Karnofsky scores were found to have increasing NK activity. Two of three patients with poor clinical courses presented with subnormal killing which never rose to normal while the third declined to subnormal before expiring. Esophageal, cervical, and endometrial carcinoma patients all presented with low or subnormal NK activity. Of these, only cervical and endometrial cancer patients exhibited an increase to normal levels.