The Influence of B and T Lymphocyte Attenuator Genetic Variants on Susceptibility to Chronic Hepatitis B Virus Infection.

BACKGROUND/AIMS: B and T lymphocyte attenuator (BTLA) is an immune inhibitory receptor involved in the pathogenesis of chronic viral infections. Little is known about the effects of BTLA gene polymorphisms on chronic hepatitis B virus (HBV) infections. In this study, we investigated whether the polymorphisms of BTLA are associated with the progression of chronic HBV infection.

METHODS

A total of 382 chronic HBV carriers and 170 healthy individuals in the same region were recruited for this study. The chronic HBV carriers were divided into three groups: asymptomatic HBV carriers (ASC), moderate chronic hepatitis B group (MCHB), and severe chronic hepatitis B group (SCHB). Two BTLA functional single nucleotide polymorphisms (SNPs; rs76844316 and rs9288952) were genotyped by polymerase chain reaction and sequenced directly.

RESULTS

The results showed that the frequency of the G allele of rs76844316 was significantly lower in the SCHB group than in the other three groups. Subjects bearing at least one G allele (TG or GG genotype) at rs76844316 had decreased susceptibility to severe chronic hepatitis B compared with those bearing the TT genotype. Haplotype analysis of the two SNPs revealed that the frequency of the G-G haplotype was significantly lower in SCHB patients than in controls. Moreover, in the SCHB group, patients carrying the G allele of rs76844316 tended to have lower ALT levels than those without it.

CONCLUSION

Our findings suggest that the genetic variants of rs76844316 in BTLA influence the susceptibility to severe chronic hepatitis B and might play a protective role against the progression of chronic hepatitis B.