Spontaneous loss of HBeAg and development of anti-HBe during long-term follow-up of blood donors found to be HBsAg-positive.

Since 1980, at North London Blood Transfusion Centre 61 (14%) of a total of 442 hepatitis B surface antigen (HBsAg) positive carriers have been hepatitis B e antigen (HBeAg) positive by radioimmunoassay at the time of detection, with 353 (80%) anti-HBe positive. We have undertaken long-term follow-up of infectivity markers in 285 of these 442 HBsAg carriers detected by routine screening. Donors undergoing acute HBV infection were excluded from the analysis. The donor follow-up times ranged from 1.2 to 13.5 years. Regular follow-up samples were obtained and examined for HBsAg, HBeAg, anti-HBe, serum alanine aminotransferase (ALT) and aspartate aminotransferase (AST). Thirty-five (12.3%) of the 285 carriers were HBeAg-positive when first detected. Eight of these 35 developed anti-HBe during follow-up. At no time did any carrier revert from anti-HBe to HBeAg. When these data were subjected to a Kaplan--Meier analysis an estimated lower quartile time to seroconversion of 3.83 years, and a median seroconversion time of 8.25 years were predicted. This corresponds to a mean rate of 6.5% per annum for the first 25% to seroconvert, and 5.7 for the next 25%.