Reexamination of hepatitis B virus subtypes and e-antigen expression by radioimmunoassays.

Radioimmunoassay methods were used to determine both the hepatitis B virus (HBV) subtype and hepatitis B e antigen (HBeAg) and antibody (anti-HBe) status of a group of hepatitis B surface antigen (HBsAg)-positive blood donors. The study involved sera containing HBV of the three major occidental subtypes, adw2, ayw3, and ayw2. The previously reported association of the y-type virus with HBeAg and the d types with anti-HBe was again observed. However, when the two y subgroups, ayw2 and ayw3, were considered individually, it was evident that the ayw3 specimens alone accounted for the association with HBeAg while the ayw2 sera were strongly associated with anti-HBe. The study also indicated that the prevalence of HBeAg declined and that of anti-HBe increased progressively with advancing age. On the average, ayw2 donors were significantly older than the adw2 donors, and donors from both of these groups were older than the ayw3 donors. It is postulated that the observed age differences account, at least in part, for the differing prevalence of e markers in the three HBV subtype groups, and that these age differences, in turn, may reflect a tendency for infections with the ayw2 viral strain to persist longer than adw2 infections, and both of these longer than ayw3 infections. Alternately, the three subtypes may represent epidemiologic shifts from remote ayw2 and adw2 infections to more recent ayw3 infections.