RESUMO
Identification of hepatitis B virus (HBV) infection in the absence of surface antigen (HbsAg) became possible with the introduction of HBV DNA detection methods. Such occult HBV infection was diagnosed recently in about half of the Japanese HBsAg-negative haemophilia patients. The aim of our study was to assess the prevalence of occult HBV infection in Polish severe haemophilia population on the sample of 115 haemophilia A and B patients (mean age 34.9 +/- 10.9) treated with non-virus inactivated clotting factor preparations before 1995. HBV DNA was detected in nine HBsAg-positive patients (7.8%). The mean HBV DNA load was 72,800 IU mL(-1) (250-400,000 IU mL(-1)). Hepatitis C virus (HCV) RNA was found in six out of nine HBV-positive patients. In conclusion, HBV DNA was identified only in HBsAg-positive patients. Unlike in Japan, the frequency of occult HBV infection in Polish haemophilia population seems extremely rare or absent.