[Hepatitis A, B, and non-A, non-B. Epidemiologic, clinical and differential immunologic aspects]

The results of a clinical and epidemiological investigation on the differential characters of hepatitis A, hepatitis B and hepatitis non-A, non-B (NANB) are reported. A more accurate nosological definition of NANB hepatitis has showed the following characters: on incubation period intermediate between hepatitis A and hepatitis B; transmission similar to hepatitis B; onset of the disease and clinical features similar to hepatitis A; jaundice of lower intensity than hepatitis A; lower IgM levels than hepatitis A; a remarkable tendency to evolve towards chronic liver disease, higher than hepatitis A and hepatitis B.