PreS1 deleted variants of hepatitis B virus in patients with chronic hepatitis

Defective hepatitis B virus lacking 183 bases of the 3'-terminus part of the preS1 region was found in the sera of two patients with chronic hepatitis B virus infection. Results of sequencing analysis of samples with or without polymerase chain reaction yielded the same result, proving that this deletion was not due to an artifact obtained during polymerase chain reaction. One of the deletion ends lay in TCAGG that appeared five times in the genome of subtype adr and the other end was identified as TCAGG in direct repeats of the genome. The mutated hepatitis B virus became predominant in one patient's serum only after consecutive interferon therapy, suggesting that the deleted part might play a role in viral elimination from the circulation.