Binding and receptors for human albumin polymers and IgM/HBs circulating complex in HBsAg chronic carriers.

Binding activity for polymerized human serum albumin (pHSA-binding), studied in passive haemoagglutination, receptors for polymerized human serum albumin (pHSA-receptors), studied in ELISA, as well as the circulating IgM/HBs complex were tested in 71 chronic carriers of HBsAg with and without liver pathology. We found that 73.2% of the sera were reactive for pHSA-binding while 45% were reactive for pHSA-receptors and 42.2% for the circulating IgM/HBs complex. The distribution and mode of association of these 3 markers showed a close correlation with the e-antigen in circulation (HBeAg) and with liver disease (p less than 0.05). We further observed that pHSA-binding can be present in the absence of pHSA-receptors, suggesting the possible existence of further reactants in the serum-pHSA reaction. We did not observe any correlations between the circulating IgM/HBs complexes, pHSA-binding and pHSA-receptors. Blocking experiments, in fact, confirmed the non-involvement of polymerized human serum albumin in the formation of the circulating IgM/HBs complex. Elution experiments showed that, in addition to HBsAg, class-G immunoglobulins are also directly involved in the serum-pHSA reaction.