Serologic response in human hepatitis A: detection of antibody by radioimmunoassay and immune adherence hemagglutination.

An indirect solid-phase radioimmunoassay (RIA) for detection of antibody to the hepatitis A antigen (anti-HAV) was developed using polystyrene pearls as the solid phase and hepatitis A antigen (HAAg) extracted from marmoset livers. This RIA was compared to an immune adherence hemagglutination assay (IAHA) which employed HAAg derived from the stools of chimpanzees collected during acute hepatitis A. Anti-HAV was detected in the sera of 15 humans with naturally acquired hepatitis A infection. Sensitivity and specificity were greater using the RIA, permitting the detection of anti-HAV as early as the time of onset of jaundice. Either seroconversion or a significant increase in the titer of anti-HAV was demonstrated following hepatitis A exposure in paired sera from six patients by both techniques. No significant difference in anti-HAV responses was noted between patients with icteric compared to anicteric hepatitis A or between children and adults with hepatitis A.