Increased natural killer cell activity in uterine cervix cancer patients undergoing radiation therapy

Natural killer (NK) cell activity in peripheral blood mononuclear cells (PBMCs) from women with carcinoma of the uterine cervix was studied using a 4-hour 51Cr release assay and K562 cells as the sensitive target. PBMCs were obtained from 21 previously untreated patients at different stages of disease according to the International Federation of Gynecology and Obstetrics classification. PBMCs were also obtained from 36 patients treated with radiation therapy at different disease stages. Seventeen healthy age-matched volunteer women were used as controls. Mean cytotoxicity for the normal donors was 25.1 +/- 6.56% at a 100:1 effector-target cell ratio, 33.8 +/- 7.96% for the previously untreated cancer patients and 52 +/- 18.4% for the treated cancer patients. Most of the treated patients (86%) showed a complete response to radiation therapy and the mean cytotoxicity of the whole group (36 treated patients) was significantly increased compared to controls (p < 0.05). It is suggested that radiation therapy may produce cell alterations leading to an increase in NK cell activity in patients treated for uterine cervical cancer. The significance of this increase is discussed.