Quantitative analysis of hepatitis B virus precore mutant in hepatitis type B

Active liver disease has been detected in chronic hepatitis B after seroconversion from positive KBe antigen to positive anti-HBe antibody. Active replication of HE virus (HBV) containing a precore stop-codon mutation has been implicated in this condition. The usual methods, such as direct sequencing, to characterize the responsible mutant of HBV are not suitable for routine clinical use. Here pre employed the competitive mutation site specific assay (CMSSA) to detect precore mutant HBV-DNA in patients with positive HE surface antigen. In patients with HBe antigen, precore mutant HBV-DNA was significantly higher than in patients with HBe antibody. The level of precore mutant HBV-DNA in patients with elevated serum ALT was significantly higher than in patients with normal serum ALT. Sex, age and the level of serum HBV-associated DNA polymerase levels were not correlated with levels of precore mutant HBV-DNA. Ten of 11 negative patients for the precore mutant by polymerase chain reaction followed by restriction fragment length polymorphism assay (PCR-RFLP) mere positive for the precore mutant by CMSSA. These results suggest that the precore mutant has already emerged in the HBeAg-positive phase as determined by CMSSA, which is more sensitive than PCR-RFLP and is useful for evaluating the clinical course of patients with chronic hepatitis B. (C) 1998 Tohobu University Medical Press.