IgM antibody to hepatitis B core antigen in Korean patients with hepatocellular carcinoma

Primary hepatocellular carcinoma (PHC) has been linked etiologically to persistent hepatitis B virus (HBV) infections by epidemiologic, serologic and molecular lines of evidence. To evaluate the frequency of IgM antibody to the viral core antigen (IgM anti-HBc) detected by a highly sensitive radioimmunoassay, we compared 110 Korean patients with PHC to a group of 63 age- and sex-matched control patients with other tumors. Results were correlated with those of commercially available HBV assays. IgM anti-HBc was found in 74 of 110 PHC patients (67%), but only 1 of 63 (1.6%) control patients. Although HBsAg was found in a larger percentage of PHC patients (81%), it was also present in more control patients (14%). Thus, IgM anti-HBc was more specifically associated with PHC than was the presence of HBsAg. IgM anti-HBc was found in 91% of PHC patients with detectable HBeAg and 74% of PHC patients with positive anti-HBe tests (p less than 0.04). The frequency of IgM anti-HBc was similar among HBsAg-positive PHC patients with and without anti-HBs, or those with low or high levels of serum alpha-fetoprotein. In 18 patients with PHC, IgM anti-HBc was further characterized by rate-zonal centrifugation of sera, all were found to have 19S IgM anti-HBc although 6 also had greater or equal IgM anti-HBc reactivity in the low molecular weight region. The presence of IgM anti-HBc in adult Korean HBsAg carriers may indicate an especially high risk for the development of PHC, and this should be evaluated in prospective studies.