title: Association of genetic polymorphisms in interferon-γ, interleukin-6 and transforming growth factor-β1 gene with oral lichen planus susceptibility.
abstract: BACKGROUND
  Oral lichen planus (OLP) is a premalignant mucocutaneous disease in which genetic factors and immune responses play a major role. Cytokines play an important role in the pathogenesis and disease progression of OLP. The aim of this study was to investigate the impact of gene polymorphisms of T helper cell subtype Th1 and Th2 cytokines, interferon-gamma (IFN-γ), interleukin-6 (IL-6) and transforming growth factor (TGF)-β1 on OLP susceptibility in a Saudi cohort.
  
  
  METHODS
  Forty two unrelated patients with OLP and 195 healthy controls were genotyped for IFN-γ (874A/T), IL-6 (174G/C) and TGF-β1 (509C/T) polymorphisms.
  
  
  RESULTS
  The frequency of genotype AT of IFN-γ (874A/T) was significantly higher while genotype AA was lower in OLP patients as compared to controls (P < 0.05). The frequency of T containing genotypes (AT + TT) was also higher in OLP patients as compared to that in controls (P = 0.003). The frequencies of allele T was higher while that of allele A lower in patients than the controls however the difference was not statistically significant (P = 0.07). There was no significant difference in the frequencies of alleles and genotypes of IL-6 (174G/C) and TGF-β1 (509C/T) polymorphisms between patient and control groups. These results indicated that genotype AT of IFN-γ (874A/T) polymorphism is associated with OLP risk and genotype AA is protective to OLP. On the other hand the polymorphisms IL-6 (174G/C) and TGF-β1 (509C/T) may not be associated with OLP risk in our population.
  
  
  CONCLUSIONS
  It is concluded that IFN-γ (874A/T) polymorphism is associated with the susceptibility of OLP, however further studies with large sample size involving different ethnic populations should be conducted to strengthen our results.
authors.affiliation: Department of Dentistry, Prince Sultan Military Medical City, Riyadh, Saudi Arabia.
authors.forename: Maha Ali M
authors.initials: MA
authors.lastname: Al-Mohaya
authors.affiliation: Department of Dentistry, Prince Sultan Military Medical City, Riyadh, Saudi Arabia.
authors.forename: Lubna
authors.initials: L
authors.lastname: Al-Otaibi
authors.affiliation: Department of Dermatology, Prince Sultan Military Medical City, Riyadh, Saudi Arabia.
authors.forename: Fahad
authors.initials: F
authors.lastname: Al-Harthi
authors.affiliation: Department of Dentistry, Prince Sultan Military Medical City, Riyadh, Saudi Arabia.
authors.forename: Ebtissam
authors.initials: E
authors.lastname: Al Bakr
authors.affiliation: Research Center, Prince Sultan Military Medical City, P. O. Box 7897, Riyadh, 11159, Saudi Arabia.
authors.forename: Misbahul
authors.initials: M
authors.lastname: Arfin
authors.affiliation: Research Center, Prince Sultan Military Medical City, P. O. Box 7897, Riyadh, 11159, Saudi Arabia. abdulrahman.alasmari@gmail.com.
authors.forename: Abdulrahman
authors.initials: A
authors.lastname: Al-Asmari
mesh_terms: D016022:Case-Control Studies; D005787:Gene Frequency; D020022:Genetic Predisposition to Disease; D005838:Genotype; D006801:Humans; D007371:Interferon-gamma / Q000235:genetics; D015850:Interleukin-6 / Q000235:genetics; D017676:Lichen Planus, Oral / Q000235:genetics*; D011110:Polymorphism, Genetic; D015291:Transforming Growth Factors; D014409:Tumor Necrosis Factor-alpha
chemical_list: D015850:Interleukin-6; D014409:Tumor Necrosis Factor-alpha; D015291:Transforming Growth Factors; D007371:Interferon-gamma
keywords: Interferon-γ; Interleukin -6; Oral lichen planus; Polymorphism; Saudis; Transforming growth factor -β1