IgM Antibody to Hepatitis B Core Antigen in Korean Patients with Hepatocellular Carcinoma

Primary hepatocellular carc1inoma (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 < 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 a‐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.