Interleukin 12 (IL-12) production and its relations to other cytokines in patients with chronic hepatitis C

Recent reports emphasize the importance of the T helper (Th)1/Th3 immunolog ical balance in viral infections. We investigated this immune response in p atients infected with hepatitis C virus (HCV). Using enzyme-linked immunoso rbent assays (ELISA), we measured the Staphylococcus aureus-stimulated inte rleukin (IL)-12, IL-120, and IL-6 production by peripheral blood mononuclea r cells (PBMC), and plasma levels of transforming growth factor (TGF)-beta 1. Ninety HCV-seropositive patients [43 with chronic hepatitis (CH), 27 wit h liver cirrhosis (LC), and 20 with hepatocellular carcinoma (HCC)], were e nrolled in this study. IL-12 levels produced by PBMC were significantly low er in patients infected with HCV than in normal controls. Moreover, IL-12 p roduction decreased with the progression of liver disease in patients with chronic hepatitis C. There was no relationship between IL-12 and IL-6 produ ction. Decrease in IL-12 production was accompanied by decrease in IL-10 pr oduction and increase in plasma TGF-beta 1 levels. When IL-12 production wa s compared with blood chemistry and laboratory parameters, there were no co rrelations with blood HCV RNA levels and serum immunoglobulin concentration s, but a correlation existed between serum transaminase (ALT) level and IL- 12 production. These results suggest that HCV infection may suppress IL-12 production and stimulate TGF-beta 1 production, and these changes may be re lated to the progression of liver disease in patients with chronic hepatiti s C. (C) 1999 Elsevier Science Ireland Ltd. All rights reserved.