IgM responses to hepatitis-A virus and hepatitis-B core antigen in acute and chronic liver disease in Malawi; possible role of non-A, non-B, hepatitis.

Of 33 patients with acute hepatitis in Malawi, 21 had infection by hepatitis-B virus (HBV), five by hepatitis-A virus (HAV) and seven, who had no markers of current HBV or HAV infections, were probably infected by the agent(s) of non-A, non-B, hepatitis. 87 of 88 sera from persons without liver disease contained antibody to HAV and 49 antibody to hepatitis-B surface antigen (anti-HBs) (six were positive for hepatitis-B surface antigen). The diagnosis of recent infection by HAV was made by detecting HAV-specific IGM in single serum samples and, although such tests showed that HAV caused acute hepatitis, its absence in patients with chronic liver disease suggests that, unlike HBV, infection by HAV does not play a role in chronic liver disease in Malawi. Anti-hepatis-B core antigen (anti-HBc)-specific IgM was detected in 19 of 21 patients with acute HBV infection, in three of five HbsAg-positive patients with cirrhosis, but in none of five HbsAg-positive patients with hepatoma.