Natural killer cells in patients with renal cell cancer

Cytotoxic activity of natural killer (NK) cells in peripheral blood was studied in 60 patients with renal cell carcinoma (RCC) by means of a 51Cr release assay against K 562 cells, homologous and autologous RCC. All patients were tested prior to surgery and thereafter followed up for 1 year. Immunostimulating agents as interferon, levamisole, OMPI, and various bacterial extracts were tested for their boosting capacity on NK cells. Patients with localized tumor showed increased activity in comparison to age-matched controls, whereas NK cell activity and interferon-boosted activity in patients with advanced disease and tumor spread was decreased. Augmentation of NK activity could only be achieved by interferon, while application of levamisole, OMPI, and bacterial extracts resulted rather in suppression of cytotoxic activity.