Polymerized
human serum albumin (pHSA) binding activity due to
antibodies was evaluated by a sensitive and specific
enzyme-linked
immunosorbent assay (ELISA) in well characterized cases of acute (AVH) and chronic active (CAH) viral
hepatitis. Moreover, hepatitis B virus (HBV)
infection serum samples were tested for the presence of
HBsAg-associated pHSA receptors detected by radioimmunoassay. Specificity of ELISA in detecting pHSA binding activity due to
antibodies was assayed by testing
IgG fractions from positive serum samples and purified
HBsAg particles. A very high prevalence (mean = 87%) of antibody response to pHSA was detected in serum samples of patients with type B, A and post-transfusion non-A, non-B (NANB) AVH and CAH.
IgM antibodies were found in 75% of type B AVH, in 77% of type A AVH and in none of the NANB cases at the onset of illness. In CAH,
IgM antibodies were found in 37.5% of
HBsAg-positive cases and in 44% of NANB cases. In HBV-related AVH and CAH no correlation was found between anti-pHSA
antibodies and
HBsAg-associated pHSA receptors or the
HBeAg/anti-HBe status. The antibody response detected by ELISA showed a cross-reactivity with monomeric
human albumin and heterologous polymeric and monomeric
albumins. However, in HBV
infection the antibody binding was significantly higher for pHSA than for monomeric
human albumin or
albumins from other species, thus suggesting that the antigenic sites of pHSA evoking the antibody response may differ in relation to the etiology of viral
hepatitis.