Occult hepatitis B virus infection in hemodialysis patients with chronic HCV infection

Background: The aim of this study was to determine the prevalence of occult hepatitis B infection in hemodialysis patients with chronic HCV infection and to compare it with that of HCV-infected patients with normal renal function. Methods: Forty-nine patients on maintenance hemodialysis and 48 HCV-infected but otherwise normal patients, both groups HCV RNA-positive and HBsAg-negative and matched for age and sex, were evaluated for the presence of HBV DNA in serum by polymerase chain reaction (PCR). A proportion of patients (11/49 and 39/48, respectively) were also examined for HBV antigens in hepatocytes by immunohistochemistry. Results: HBV DNA was detected by PCR in 10/49 (20.4%) hemodialysis patients and in 3/48 (6.3%) patients with normal renal function (p=0.041). HBV DNA concentrations were low (< 10(3) copies/mL) in both groups. HBV DNA-positive hemodialysis; patients had a significantly lower prevalence of past HBV vaccination and lower anti-HBs titers in serum than HBV DNA-negative patients of the same group. No positive staining for HBsAg or HbcAg was observed in the liver biopsies of either group. Conclusions: Occult HBV infection is more frequent in HCV-infected hemodialysis patients than otherwise normal patients with chronic HCV infection, probably because of impaired immune function in uremic patients and high risk of parenteral exposure to HBV. The clinical significance of this finding is unknown, but HBV vaccination of hemodialysis patients and staff could be an effective way of limiting the risk of transmission of HBV infection within dialysis units.