Failure of preexisting antibody against hepatitis B surface antigen to prevent subsequent hepatitis B infection.

We studied a patient who developed acute hepatitis B virus (HBV) infection despite the presence of preexisting antibody to the surface antigen of HBV (anti-HBs). Anti-HBs has been reported to consist primarily of antibody against the common a determinant of HBV. Antibody directed against this major determinant appears to confer protection against HBV, regardless of the subtype. Our patient was shown to have had preexisting anti-HBs of anti-d but not anti-a specificity. She subsequently developed non-A, non-B viral hepatitis followed by an episode of acute hepatitis B after exposure to HBV of the ayw subtype.