Diagnostic Value of Immunoglobulin A and M antibodies as a disease Marker for hepatitis A Infection

This study was conducted to assess the effect of anti-immunoglobulin antibodies onthe measurement of the humoral immune response in hepatitis A virus (HAV) infectedpatients. Serum samples from 47 patients with acute hepatitis A and from 47 age/sexmatched healthy adult subjects were tested for IgA, IgG and IgM by ELISA. Antiimmunoglobulinantibodies were defined using goat immunoglobulins as a target tocharacterize distinct changes in levels of interacting immunoglobulins. Initial resultsobtained before removal of antibodies that interacted with goat immunoglobulinssuggested that HAV patients had increased levels of IgA and IgM in their sera. It wasfound that normal individuals had mean IgA, IgG and IgM levels of 2.52 ± 0.22 mg/ml,9.86 ± 0.94 mg/ml and 1.75 ± 0.13 mg/ml, respectively while HAV patients had meanlevels of 2.89 ± 0.20 mg/ml, 10.03 ± 1.05 mg/ml and 1.97 ± 0.13 mg/ml (p <0.0002, p<0.41 and p <0.0001). However, the mean levels of IgA and IgM in HAV infected sera,after purification from antibodies that interacted with goat immunoglobulins, were 2.49± 0.21 mg/ml and 1.73 ± 0.14 mg/ml. Therefore, there was no significant difference inHAV patients compared to normal individuals (p <0.55 and p <0.56). The presence ofcirculating immune complex in serum during the early phase of infection may contributeto immunopathological effects in the infected host and provide some new insights intoantibody response to HAV