Natural negative seroconversion of HBs antigen in the carrier

An investigation on the risk of HB virus (HBV) related to liver diseases was made using a cohort of 32, 177 healthy male workers aged 40, 45 and 50 at the beginning of the study, during 7 years from 1973 through 1979. Of them, 495 (1.5%) were regarded as HBsAg carrier. These were followed up with HBV markers and liver function tests at least twice a year. The folow-up periods were 4 to 10 years with average 5.5 years. The determination of HBsAg was made by RPHA and anti-HBc by IAHA. During the follow-up period, HBsAg-natural-negative-seroconversion was detected in 19 of the 495 carriers (3.5%). The annual seroconversion rate was 0.69% (person-years). The rate increased with aging. There were highest rate (1.07%) at 50 to 54 age. Anti-HBc titers (2n) were compared between the 1st and the last tests in the 19 HBsAgnegatively-seroconverted cases (NCC) and the 476 remaining persistent HBsAg positive cases (PPC). The average titer levels of anti-HBc in NCC were 12.8±1.6 at the 1st test and 9.5±1.9 at the last test, and in PPC respectively 12.6±1.9 and 12.0±2.1. The NCC revealed a significant fall on anti-HBc titer at last test in comparison with the 1st test. It was also shown in the last test of the PCC. Of 19 cases, 14 showed normal liver function tests and 5 were abnormal. But these 5 cases showed only mild liver dysfunction. These results reveal that HBV naturaly have been cleared from body in Some cases of HBsAg carrier. Further Studies will be required to conclude whether the HBsAg-negativeseroconversion in HBsAg carrier has prognostic significance in the course of liver diseases.