Acute hepatitis B due to immune-escape mutations in a naturally immune patient

Incidence of hepatitis B virus infection (HBV) has been greatly reduced globally after the introduction of universal vaccination programs. However, another potential threat was noticed almost 2 decades ago, which is the selection of antibody escape HBV strains. Antibody or immune escape strains of HBV carry mutations in the S gene which encodes "a" determinant region located at amino acid positions 124 to 149. Certain mutations in this region, which promotes antibody response, might lead to an alteration in the antigenicity of hepatitis B surface antigen (HBsAg). Anti-HBs might fail to neutralize the mutant virus and transmission or reappearance of infection in previously immunized individuals can be possible. Herein, we report a patient with known HBV seropositivity (HBsAg negative, anti-HBs positive, anti-HBc IgG positive) for more than 10 years who developed a symptomatic acute hepatitis due to occurrence of immune escape mutants in the absence of any immunosuppression or cytotoxic chemotherapy. To the best of our knowledge, this is the first reported case of acute hepatitis B due to escape mutations in a naturally immune patient.