Polymerized albumin binding to serum in various liver diseases: its significance and relation to hepatitis B virus infection.

Sensitive and specific enzyme-linked immunosorbent assays (ELISA) were developed to detect separately the binding of polymerized human serum albumin (PHSA) to its antibody (A-PHSA) and to the hepatitis B surface antigen (HBsAg). A-PHSA was not detected in normal serum, whereas more than one-third to about half of sera from patients with acute liver cell injury showed this antibody. Frequency of A-PHSA positivity was low in chronic liver diseases, being relatively higher in those with continuing liver injury. A-PHSA detection was not related to seropositivity for HBsAg. PHSA binding of HBsAg positive sera showed a higher frequency of positivity in chronic carriers than acute hepatitis B. Of 172 asymptomatic HBsAg carriers, PHSA binding was demonstrated in 25 (15%), the frequency being significantly high if HBeAg was also present (84%). Binding was infrequent in sera having anti-HBe (2.9%) and in those negative for both HBeAg and anti-HBe (2.7%). Binding of HBsAg to PHSA was significantly higher than to human serum albumin (HSA). Immunoblotting of separated HBsAg components showed PHSA binding specifically to the high molecular weight peptide. PHSA binding in HBsAg positive serum may indicate the latter's infectivity as detected in a study of maternal-fetal transmission, where it demonstrates 100% infectivity in HBsAg and HBeAg positive mothers. PHSA possibly mediates the attachment of the HBV to the hepatocyte and a competitive binding between A-PHSA with HBsAg for PHSA may modulate the course of HBV infection.