[Defective short variants of S region in chronic HBV carriers].

We analyzed the pre-S and S region of hepatitis B virus by polymerase chain reaction in 60 chronic carriers. In 10 hepatitis B e antigen-positive chronic carriers, a single DNA band was detected at the expected size, whereas additional shorter DNA bands were observed in some cases with chronic hepatitis, liver cirrhosis, and hepatocellular carcinoma. The smaller-sized DNA bands from chronic hepatitis patients had the deletion of 183 bp in the pre-S gene, and the deletion of 492 bp in S gene. The reasons of the appearance of these mutants are unknown, but it may be interesting to study in relationship to the mechanism of host immune response.