Importance of Isolated Anti‐HBc in Detection of Occult Hepatitis B Virus Infection in Hemodialysis Patients

Abstract

Dear Editor, We greatly enjoyed reading the article by Nagakawa et al. on occult hepatitis B virus (HBV) infection in Japanese chronic hemodialysis (HD) patients, which was recently published in your journal. They showed that the prevalence of occult HBV infection (OBI) in HD patients from eastern Japan was 0.3% and all of them were only hepatitis B core antibody (anti-HBc) positive (1). Occult HBV infection is defined by the presence of HBV-DNA in the liver or serum with undetectable hepatitis B surface antigen (HBsAg) (2).OBI patients may be seronegative (both anti-HBc and hepatitis B surface antibody [anti-HBs] are negative) or seropositive (anti-HBc is positive with or without anti-HBs positivity) (3). OBI is predominantly detected in patients with isolated anti-HBc (HBsAg negative, anti-HBs negative and anti-HBc positive) (4,5). We previously conducted a study in Iranian HD patients with isolated anti-HBc, and HBV-DNA was detected in 50% of these patients (6). In another recent study of ours, conducted in 100 HBsAg negative HD patients, isolated anti-HBc was found in 2% of subjects and HBV-DNA was detected in 1% of HBsAg negative HD cases (unpubl. data), so a lower rate of isolated anti-HBc in our HD patients had resulted in lower frequency of OBI in HD subjects. The national vaccination program in Iran and improvement of the people’s knowledge about the HBV transmission routes has decreased HBV incidence in the general population of Iran and also in HD patients (7). These surveys showed that isolated anti-HBc can be considered as a sentinel marker for OBI in high risk cases such as HD subjects and screening of these patients is useful in prediction of OBI. Therefore, it seems that there is no need for screening large numbers of HD cases for determination of OBI and only screening of cases with isolated anti-HBc could be evidence of OBI in HD patients.