Presence and meaning of anti-HBc IgM as determined by ELISA in patients with acute type B hepatitis and healthy HBsAg carriers

Abstract

To evaluate the clinical implication of IgM antibody against hepatitis B core antigen (anti‐HBc IgM), a consecutive series of 87 patients with acute type B hepatitis and 16 healthy carriers of hepatitis B surface antigen (HBsAg) were studied by a newly developed reverse ELISA technique. Anti‐HBc IgM was present for at least 2 months in 81 of the 82 patients with HBsAg at the time of admission. Seroconversion from HBsAg to anti‐HBs was observed in 38 patients during the time of observation, and in all patients, anti‐HBc IgM was present until clearance of HBsAg. Thirty‐three of the 38 patients remained anti‐HBc IgM positive, at least until the appearance of anti‐HBs. Quantitation of anti‐HBc IgM by ratio unit (RU) values revealed that 3 of 8 patients with RU values ≧5 for more than 6 months subsequently developed chronic liver disease, as compared to 1 of 72 patients with anti‐HBc IgM above this level for less than 6 months. Anti‐HBc IgM was demonstrated in 3 of 5 patients with total anti‐HBc titer above 1:100 despite the presence of anti‐HBs. In these patients, anti‐HBc IgM steadily decreased after the onset of illness indicating a recent acute hepatitis B infection. Anti‐HBc IgM was present in 12 of 16 healthy HBsAg carriers (75%). However, these 12 carriers had RU values between 2.5 to 5.5, compared with RU values above 5 (mean RU value 11.3) at the onset of illness in 80 of 82 HBsAg‐positive patients with acute hepatitis. Anti‐HBc IgM seems to be a specific serological marker for recent or ongoing hepatitis B infection which may be useful in differentiation between hepatitis B infection with or without HBsAg and acute non‐A, non‐B hepatitis.