title: Tumor necrosis factor genetic polymorphisms and response to antiviral therapy in patients with chronic hepatitis C.
abstract: OBJECTIVE
  Hepatitis C virus (HCV) is the major causal agent of non-A, non-B hepatitis and the leading indication for liver transplantation worldwide. The emerging field of immunogenetics has confirmed the significant role of heritability in host immune responses to infectious pathogens. Both the major and non-major histocompatibility complex genes are increasingly identified as candidate genes hypothesized to influence the susceptibility to, or the course of, a particular disease. We hypothesized that polymorphisms within the major histocompatibility complex class III region that encode for tumor necrosis factors (TNF)-alpha and TNF-beta might be predictive of response to antiviral therapy in patients with chronic hepatitis C.
  
  
  METHODS
  A total of 155 subjects, including 110 HCV-seropositive individuals undergoing antiviral therapy and 45 ethnically similar HCV-negative controls, were studied. The HCV-positive patients had undergone antiviral treatment with either interferon monotherapy (n = 73) or in combination with ribavirin (n = 37) and were categorized as either nonresponders, sustained responders, or relapsers. Sixty (55%) patients had genotype 1 (1a or 1b). Genomic DNA was extracted, followed by polymerase chain reaction amplification and sequencing for two promoter TNF-alpha variants (at positions -238 and -308), as well as restriction fragment length analysis for four polymorphic loci within the TNF-beta gene (NcoI, TNFc, aa13, aa26).
  
  
  RESULTS
  Although there was a trend toward higher frequency of the A allele in the TNF 238 promoter among HCV-infected patients (12% vs 4%), there were no significant differences in the distribution of the genotypic polymorphisms between patients and controls. Patients with the TNF 238 A allele had higher pretreatment viral loads as compared with patients homozygous for the wild type allele (7.2 x 10(6) +/- 4.2 x 10(6) copies/ml vs 3.8 x 10(6) +/- 0.34 x 10(6) copies/ml, p = 0.03). However, there was no association between TNF genetic markers, including multiple haplotypic combinations, and response to therapy. In addition, there was no correlation with these polymorphic loci and histological severity of liver disease.
  
  
  CONCLUSIONS
  Although previous work has suggested potential roles for TNF in the pathogenesis of HCV infection, we were unable to identify any link between TNF genetic polymorphisms and histological severity or response to antiviral therapy.
authors.affiliation: Division of Gastroenterology, Portland VAMC and Oregon Health Sciences University, 97207, USA.
authors.forename: Hugo R
authors.initials: HR
authors.lastname: Rosen
authors.forename: John G
authors.initials: JG
authors.lastname: McHutchison
authors.forename: Andrew J
authors.initials: AJ
authors.lastname: Conrad
authors.forename: Jennifer J
authors.initials: JJ
authors.lastname: Lentz
authors.forename: Gail
authors.initials: G
authors.lastname: Marousek
authors.forename: Steven L
authors.initials: SL
authors.lastname: Rose
authors.forename: Atif
authors.initials: A
authors.lastname: Zaman
authors.forename: Kent
authors.initials: K
authors.lastname: Taylor
authors.forename: Sunwen
authors.initials: S
authors.lastname: Chou
mesh_terms: D000328:Adult; D000368:Aged; D000998:Antiviral Agents / Q000494:pharmacology* / Q000627:therapeutic use; D005260:Female; D019698:Hepatitis C, Chronic / Q000188:drug therapy / Q000235:genetics* / Q000473:pathology; D006801:Humans; D007372:Interferons / Q000494:pharmacology* / Q000627:therapeutic use; D008233:Lymphotoxin-alpha / Q000235:genetics*; D008297:Male; D008875:Middle Aged; D011110:Polymorphism, Genetic / Q000187:drug effects* / Q000235:genetics*; D011237:Predictive Value of Tests; D012254:Ribavirin / Q000494:pharmacology* / Q000627:therapeutic use; D012720:Severity of Illness Index; D016896:Treatment Outcome; D014409:Tumor Necrosis Factor-alpha / Q000187:drug effects* / Q000235:genetics*
chemical_list: D000998:Antiviral Agents; D008233:Lymphotoxin-alpha; D014409:Tumor Necrosis Factor-alpha; D012254:Ribavirin; D007372:Interferons