Assessment of lymphokine-activated killer activity and gamma-interferon production in patients with small hepatocellular carcinomas.

We have previously reported depressed gamma-interferon production and depressed lymphokine-activated killer and natural killer activity in patients with relatively large hepatocellular carcinomas. These parameters were normal in cirrhosis. Some evidence had suggested a gamma-interferon production defect as the main cause of depressed lymphokine-activated killer activity in hepatocellular carcinoma, (i.e., gamma-interferon enhances lymphokine-activated killer and natural killer activity and gamma-interferon antibody inhibits lymphokine-activated killer induction). However, we were unable to clinically define the precise mechanism operating here because gamma-interferon production and lymphokine-activated killer activity were both defective in advanced hepatocellular carcinoma. In recent years, it has become possible to detect even small hepatocellular carcinomas on ultrasonography and to confirm them by fine-needle biopsy. In this study, we assessed those immune parameters in 48 patients with hepatocellular carcinomas less than 2 cm in diameter to confirm depressed immune function and to clarify the mechanism of these defects. Lymphokine-activated killer activity was defective in 31 patients (64.6%), whereas gamma-interferon production was defective in only 1 of these patients (2.1%). This observation argues against the hypothesis that defective gamma-interferon production is the primary defect and provides new insight into the mechanism of progression of defective immune function in hepatocellular carcinoma. Thirty-one of the 48 hepatocellular carcinoma patients were treated surgically, and these immune parameters were followed for 6 mo. The recovery of lymphokine-activated killer activity in all hepatocellular carcinoma patients with low lymphokine-activated killer activity suggests the tumor burden as the cause of defective lymphokine-activated killer activity.