title: Associations between cytotoxic T lymphocyte-associated antigen-4 polymorphisms and serum tumor necrosis factor-α and interferon-γ levels in patients with chronic hepatitis B virus infection.
abstract: BACKGROUND
  Cytotoxic T lymphocyte-associated antigen 4 (CTLA-4) polymorphism, which may affect host immune response including cytokines production, is thought to be associated with hepatitis B virus (HBV) infection. This study investigated the associations between CTLA4 polymorphism and serum tumor necrosis factor (TNF)-α and interferon (IFN)-γ levels in patients with chronic HBV infection.
  
  
  METHODS
  CTLA4 promoter -318C/T and exon 1 +49A/G polymorphisms and serum TNF-α and IFN-γ levels were determined in 172 patients with chronic HBV infection and 145 healthy controls.
  
  
  RESULTS
  The genotype of CTLA4 -318C/T polymorphism had no association to TNF-α and IFN-γ levels. Serum levels of TNF-α and IFN-γ in chronic HBV patients with +49GG genotype were lower than those with +49AG genotype (p = 0.030 and p = 0.042, respectively), and haplotypes -318C + 49A and -318C + 49G seemed to have no significant effects on TNF-α and IFN-γ levels.
  
  
  CONCLUSIONS
  CTLA4 +49GG genotype was associated to lower TNF-α and IFN-γ levels in patients with chronic HBV infection but this association was diminished by haplotype formation with -318C/T alleles, indicating that the influence of CTLA4 -318C/T and +49A/G polymorphisms on the susceptibility and disease progress of chronic HBV infection may not be effectuated by affecting TNF-α and IFN-γ secretion.
authors.affiliation: Department of Infectious Diseases, First Affiliated Hospital, School of Medicine,  Xi'an Jiaotong University, Xi' an, 710061, Shaanxi, People's Republic of China.
authors.forename: Qunying
authors.initials: Q
authors.lastname: Han
authors.forename: Shaoqiong
authors.initials: S
authors.lastname: Duan
authors.forename: Guoyu
authors.initials: G
authors.lastname: Zhang
authors.forename: Zhu
authors.initials: Z
authors.lastname: Li
authors.forename: Na
authors.initials: N
authors.lastname: Li
authors.forename: Qianqian
authors.initials: Q
authors.lastname: Zhu
authors.forename: Yi
authors.initials: Y
authors.lastname: Lv
authors.forename: Jinghong
authors.initials: J
authors.lastname: Chen
authors.forename: Zhengwen
authors.initials: Z
authors.lastname: Liu
mesh_terms: D000328:Adult; D000483:Alleles; D060908:CTLA-4 Antigen / Q000097:blood / Q000235:genetics*; D005091:Exons; D005260:Female; D005838:Genotype; D006239:Haplotypes; D006515:Hepatitis B virus / Q000378:metabolism*; D019694:Hepatitis B, Chronic / Q000097:blood* / Q000821:virology*; D006801:Humans; D007371:Interferon-gamma / Q000097:blood*; D008297:Male; D008875:Middle Aged; D011110:Polymorphism, Genetic; D011401:Promoter Regions, Genetic; D014409:Tumor Necrosis Factor-alpha / Q000097:blood*
chemical_list: D060908:CTLA-4 Antigen; C556706:CTLA4 protein, human; D014409:Tumor Necrosis Factor-alpha; D007371:Interferon-gamma