Acute delta superinfection in a previously unrecognised HBsAg carrier with transient loss of HBsAg simulating acute non-A, non-B hepatitis

An 18 yr old previously well male Taiwanese was admitted with malaise, anorexia, and jaundice for two weeks. Results of liver tests were compatible with acute hepatitis. On day 1, he was seronegative for HBsAg, IgM anti-HAV, IgM anti-HBc, IgM anti-CMV, and IgM EBV capsid Ab, but positive for anti-delta in association with anti-HBc and anti-HBs. At follow up on day 5 HBsAg converted to positive with decreasing titre of anti-HBs. On day 19, the titre of HBsAg increased concomitantly with loss of anti-HBs. The results of these serological profiles indicated that this patient was a previously unrecognised HBsAg carrier, who developed acute hepatitis delta virus superinfection with transient loss of HBsAg. This phenomenon should be kept in mind in the serodiagnosis of acute viral hepatitis, especially in areas of high HBV prevalence.