Clinical significance of concurrent hepatitis B surface antigen and antibody positivity.

Over a period of 30 months, 64 patients with concurrently positive hepatitis B surface antigen (HBsAg) and antibody (anti-HBs) were identified at two institutions. When all assays were considered, 23.9% of HBsAg-positive individuals exhibited anti-HBs. Both persistent HBsAg/anti-HBs positivity and variable changes in antigen or antibody status were observed among the 36 patients with follow-up beyond six months. When compared to a control group, these patients did not exhibit differences in risk factors for acquiring hepatitis B or in clinical and histological diagnoses. Concurrent HBsAg and anti-HBs was present at detection in 25 patients, while antibody appeared in the remaining 11 subjects. Subsequently, it was undetectable in seven of these 36 patients; no clinical changes occurred at the time of acquisition or loss of the antibody. The titer of the antibody was below 10 mIU/ml in 75% of these individuals. In 10 patients, the subtype of HBsAg was ad, while the anti-HBs was anti-y. Concurrent HBsAg and anti-HBs is a pattern frequently observed throughout the spectrum of hepatitis B-related events. The heterotypic antibody in these patients is of a low titer, and its appearance or disappearance is not associated with changes in the clinical course; simultaneous HBsAg/anti-HBs positivity does not appear to reflect a distinct clinical entity.