Etiopathogenetic aspects of hepatitis A. II. Specific and nonspecific humoral immune response during the course of infection

Abstract
The anti‐HAV humoral immune response in the IgM, IgA, and IgG classes was analyzed weekly in 35 patients with clinically overt hepatitis A during the time of their hospitalization and 2–3 years afterward. In parallel, the dynamics of total immunoglobulins and complement C3 component (C3) levels were determined. The results suggest that the appearance of class‐specific anti‐HAV is compatible with the course of primary humoral immune response, with IgM and IgA anti‐HAV, providing immunity in the early and intermediate phases of the infection, and IgG anti‐HAV, providing immunity in the later phase. The overall appearance of anti‐HAV, total immunoglobulins, and C3, do not support the view that liver injury is mediated by the humoral immune mechanisms. Instead, the hepatocyte damage is probably caused by direct viral cytotoxicity. This hypothesis is supported by a case of hepatitis A in a patient under immunosuppressive treatment.