Serum interleukin-6 and interferon-gamma levels in patients with hepatitisB-associated chronic liver disease

Hepatitis B virus (HBV) infection can elicit a variety of clinical sequelae ranging from acute self-limited hepatitis to hepatocellular carcinoma, whi ch are not attributable to a direct cytopathic effect of the virus but rath er to the individual host's immune response. Cytokines, low-molecular-weigh t proteins with a broad range of activity, have been shown to be involved i n the regulation of hepatocyte functions, as well as in the pathogenesis le ading to liver damage. In the present study, we investigated the correlatio n between serum interleukin 6 (IL-6) and interferon gamma (IFN-gamma) in al together 75 patients chronically infected with HBV. They comprised 15 asymp tomatic carriers, 15 chronic persistent hepatitis (CPH) and 15 chronic acti ve hepatitis (CAH) patients, 15 cases of cirrhosis and 15 patients with hep atocellular carcinoma (HCC) previously diagnosed by serology and histology, respectively. IL-6 and IFN-gamma levels in their sera were determined usin g a commercially available kit. Our results showed various concentrations o f serum IL-6 detectable in 6.7% of asymptomatic carriers, 13.3% of patients with CPH, 20% of patients with CAH, 33.3% in cirrhotic patients and 66.7% in HCC. in contrast, serum IFN-gamma was only found in 13.3% of asymptomati c carriers and CAH, but could not be detected in the other groups. Our data demonstrated a positive correlation between serum IL-6 and clinical severi ty of chronic HBV infection, whereas the IFN-gamma levels appeared not to b e correlated. From this we conclude that among chronic hepatitis patients I FN-gamma is mostly not expressed at a level detectable by serology, whereas according to other authors it is involved in the immediate immune response triggered by acute hepatitis. IL-6 on the other hand, might rather be resp onsible for liver inflammation and regeneration in chronic liver disease.