IgM antibody to hepatitis B core antigen in children with chronic type B hepatitis

IgM antibody to hepatitis B core antigen (anti-HBc IgM) was investigated by an antibody-capture radioimmunoassay (serum dilution 1∶4000) in serum samples from 31 untreated children with chronic hepatitis B who were followed prospectively for 1–7 years. At the start, all patients were positive for hepatitis B e antigen (HBeAg), and anti-HBc IgM was detected in 23 cases, including 15 out of 16 with chronic active hepatitis and 7 out of 14 with chronic persistent hepatitis. A significant positive correlation was found between anti-HBc IgM levels and severity of liver damage (P<0.05), while an inverse relationship was found between anti-HBc IgM levels and distribution of hepatitis B core (HBcAg) antigen in the liver as detected by immunofluorescence. In fact 75% of anti-HBc IgM positive patients showed a focal HBcAg pattern (less than 40% positive nuclei), whereas 87% of antibody negative cases exhibited a diffuse HBcAg expression (more than 60% stained nuclei). During follow-up, seroconversion from HBeAg to anti-HBe with subsequent remission of liver disease occurred in 82% of patients presenting with detectable levels of anti-HBc, including three out of seven cases with chronic persistent hepatitis, but in none of the cases that were initially negative (P<0.01). These results indicate that during the natural course of chronic hepatitis B in children, anti-HBc IgM levels in serum reflect the degree of host immune response to infected hepatocytes. The close correlation between anti-HBc IgM seropositivity and seroconversion from HBeAg to anti-HBe suggests that anti HBc IgM may have a prognostic value during the follow-up of children with chronic HBeAg positive hepatitis B.