Natural killer and activated killer activities in chronic liver disease and hepatocellular carcinoma: evidence for a decreased lymphokine-induced activity of effector cells.

Natural killer (NK) and activated killer (AK) cells appear to be important in immunoregulation, elimination of virus-infected cells and resistance to tumours. NK activity against K 562 and AK activity against FL target cells of peripheral blood mononuclear cells (PBMC) from patients with chronic persistent hepatitis (CPH), chronic active hepatitis (CAH), liver cirrhosis (LC) and hepatocellular carcinoma (HCC) were investigated using 51Cr release assay. Spontaneous NK activity of patients with LC (P less than 0.05) and HCC (P less than 0.001) was decreased when compared to that of controls. The sera and PBMC from patients with low NK activity had no inhibitory effect on the NK activity of normal subjects. Indomethacin treatment significantly enhanced the NK activity of controls (P less than 0.05), whereas the drug did not affect that of patients with low NK activity. The percentages of PBMC that reacted with monoclonal antibodies anti-Leu-7 and anti-Leu-11a were similar in controls and patients. However, a Leu-11a+/Leu-7+ ratio, and NK activity of Leu-11+ and Leu-7+ cell-rich populations were significantly decreased in cirrhotic and HCC patients when compared to controls. Interleukin 2 boosted both NK and AK activities of patients, but to a lesser degree in comparison with those of controls when similarly stimulated. gamma-Interferon also significantly augmented NK and AK activities of patients, but the levels of cytotoxicity were lower in HCC patients (P less than 0.05) than those of controls. These findings suggest that the decreased NK and AK activities in chronic liver disease and HCC are due to an altered subpopulation ratio of NK cells and a functional defect of effector cells.