HBsAg subtypes among HBsAg carriers in Okinawa, Japan. Evidence of an important relationship in seroconversion from HBeAg to anti-HBe.

In Okinawa, Japan 1261 hepatitis B surface antigen (HBsAg) carriers were investigated for clinical differences among HBsAg subtypes. Among the 854 for whom they could be determined, subtype adw was found in 604 (70.7%), adr in 232 (27.2%) and others in 18 (2.1%). The overall prevalence of hepatitis B e antigen (HBeAg) was significantly lower in subtype adw (11.9%) than in adr (17.7%) (P < 0.01). The mean age of HBeAg-positive carriers was significantly lower in adw (20.4 years) than in adr (26.9 years) (P < 0.05). Seroconversion from HBeAg to antibody to HBeAg (anti-HBe) occurred in 43 carriers. The seroconversion rate was higher in adw (43.1%) than in adr (29.3%) and the seroconversion age was younger in adw (22.7 years) than in adr (27.9 years). These results suggest that carriers with subtype adw tend to seroconvert from HBeAg to anti-HBe at a higher rate and a younger age than do those with adr. HBsAg subtypes may be closely associated with the HBeAg/anti-HBe status.