[Activity of the natural killer cells in the peripheral blood of patients with brain tumors].

Activity of natural killer cells (NK-cells) was determined in a 4-hour 51Cr-release test using K-562 as target cells in patients with brain tumours and donors. This activity was significantly (P less than 0.05) reduced in preoperative patients with metastatic brain tumours (mean--5.7%), gliomas of III-IV malignancy grades (mean--16.4%) as compared with the control (mean--32.5%). The activity of NK-cells remained low after surgical treatment irrespective of the length of remission.