To study the etiology of acute
hepatitis superimposed upon previously unrecognized asymptomatic
HBsAg carriers, paired sera were collected in acute and
convalescence phases for measurement of
HBeAg, anti-HBe, hepatitis B virus
DNA and anti-delta from 76 adult patients with acute
hepatitis who were
HBsAg positive but
IgM anti-HBc negative or positive only at low titer. None of them were
IgM anti-hepatitis A virus positive on admission. Of the 34 patients who were
HBeAg positive initially, two (5.9%) were diagnosed as having
delta superinfection, and another two (5.9%) were suspected to have non-A, non-B virus
superinfection because of a transient decrease of serum hepatitis B virus
DNA. The remaining 30 (88.2%) cases were hepatitis B virus
DNA negative with or without anti-HBe seroconversion on follow-up. The episodes of acute
hepatitis in these cases may represent "immune clearance of
HBeAg" or "immune clearance of hepatitis B virus with delayed anti-HBe seroconversion," respectively, in the natural course of
chronic hepatitis B virus infection. Of the patients who were anti-HBe positive initially, 23 (54.8%) were diagnosed as having
delta superinfection, including eight with de novo seroconversion of anti-delta and 15 with a rising titer of anti-delta; 10 (23.8%) were positive for hepatitis B virus
DNA and were considered as reactivation of hepatitis B virus, and the other nine (21.4%) were suspected as having non-A, non-B virus
superinfection.(ABSTRACT TRUNCATED AT 250 WORDS)