Low natural killer cell activity in patients with malignant lymphoma.

Natural killer (NK) cell activity was found decreased (mean value: 27.5%) in peripheral blood lymphocytes from 59 untreated patients with malignant lymphoma, when compared to 112 healthy subjects (46.3%) and to 75 cancer patients with nonlymphoid tumors (43.7%) (P less than 0.001). NK cell values were similar in patients with Hodgkin's disease (25.5%) and with non-Hodgkin's lymphoma (28.2%). Decreased NK cell activity was not correlated with age, lymphoma extension or leukocyte counts. A physiological role for NK cells in the immune surveillance against lymphoid neoplasias is discussed.