Severe hepatitis B reactivation during direct-acting antiviral treatment in “the absence” of hepatitis B surface antigen

Abstract Hepatitis C virus (HCV) treatment with direct-acting antivirals (DAA) can be associated with reactivation of hepatitis B (HBV). We report a case of a kidney transplant recipient who had a fatal severe HBV reactivation during treatment for chronic hepatitis C with DAA. Diagnosis of HBV reactivation was delayed due to undetectable surface antigen (HBsAg) by standard assays. The latter was explained by the presence of HBsAg escape mutants. The case illustrates the relevance of HBV-DNA testing in transplant recipients with previous exposure to HBV, even in the absence of HBsAg, and particularly when liver test abnormalities are present.