title: T helper-2 cytokine/regulatory T-cell gene polymorphisms and their relation with risk of psoriasis in a South Indian Tamil cohort.
abstract: BACKGROUND
  Psoriasis is known to be associated with an up-regulation of T-helper (Th)-1 & Th-17 cytokines and a relative down-regulation of Th-2 and T-regulatory (T-reg) cytokines. Certain allelic variants of these cytokine genes may alter Th1/Th17 and Th2/T-reg balance and may be associated with the risk of psoriasis. Hence we aimed to determine the association of IL-4 (rs2243250), IL-10 (rs1800871 and rs1800896) and FOXP3 (rs3761548) gene polymorphisms with risk of psoriasis in South Indian Tamils.
  
  
  METHODS
  A total of 360 cases of psoriasis and 360 healthy controls were recruited. The polymorphism in IL-4 (rs2243250) & IL-10 (rs1800871) were typed by ARMS-PCR and IL-10 (rs1800896) & FOXP3 (rs3761548) were typed by TaqMan 5'allele discrimination assay.
  
  
  RESULTS
  We observed that IL-4 (rs2243250) had a reduced risk of psoriasis, while the IL-10 (rs1800871) conferred an increased susceptibility to psoriasis, as compared with controls. However, IL-10 (rs1800896) and FOXP3 (rs3761548) gene polymorphisms were not associated with psoriasis risk. The plasma IL-4 levels was not different between the cases and controls, however the heterozygous CT genotype demonstrated significant high IL-4 levels. Plasma IL-10 levels were significantly increased in cases compared to controls, however none of the genotypes were associated with the plasma IL-10 levels.
  
  
  CONCLUSIONS
  Our results suggest that IL-4 (rs2243250) polymorphism is protective against psoriasis, while IL-10 (rs1800871) polymorphism confers increased risk of psoriasis in South Indian Tamils. Detection of these genetic variants as predictive risk factors may lead to the selection of patient-tailored therapy to maximize the effectiveness of therapy.
authors.affiliation: Department of Biochemistry, Jawaharlal Institute of Postgraduate Medical Education and Research, Puducherry, India.
authors.forename: Sundar
authors.initials: S
authors.lastname: Indhumathi
authors.affiliation: Department of Biochemistry, Jawaharlal Institute of Postgraduate Medical Education and Research, Puducherry, India. Electronic address: linkmedha@gmail.com.
authors.forename: Medha
authors.initials: M
authors.lastname: Rajappa
authors.affiliation: Department of Dermatology, Jawaharlal Institute of Postgraduate Medical Education and Research, Puducherry, India.
authors.forename: Laxmisha
authors.initials: L
authors.lastname: Chandrashekar
authors.affiliation: Department of Biochemistry, Jawaharlal Institute of Postgraduate Medical Education and Research, Puducherry, India.
authors.forename: Palghat Hariharan
authors.initials: PH
authors.lastname: Ananthanarayanan
authors.affiliation: Department of Dermatology, Jawaharlal Institute of Postgraduate Medical Education and Research, Puducherry, India.
authors.forename: Devinder Mohan
authors.initials: DM
authors.lastname: Thappa
authors.affiliation: Department of Clinical Immunology, Jawaharlal Institute of Postgraduate Medical Education and Research, Puducherry, India.
authors.forename: Vir Singh
authors.initials: VS
authors.lastname: Negi
mesh_terms: D000328:Adult; D015331:Cohort Studies; D005260:Female; D051858:Forkhead Transcription Factors / Q000235:genetics*; D005787:Gene Frequency; D020022:Genetic Predisposition to Disease; D005838:Genotype; D006801:Humans; D007194:India; D016753:Interleukin-10 / Q000235:genetics*; D015847:Interleukin-4 / Q000235:genetics*; D008297:Male; D008875:Middle Aged; D020641:Polymorphism, Single Nucleotide; D011565:Psoriasis / Q000235:genetics*; D012306:Risk; D050378:T-Lymphocytes, Regulatory / Q000502:physiology*; D018418:Th2 Cells / Q000502:physiology*
chemical_list: C418974:FOXP3 protein, human; D051858:Forkhead Transcription Factors; D016753:Interleukin-10; D015847:Interleukin-4
keywords: FOXP3; IL-10; IL-4; Psoriasis; T-reg cytokines; Th-2 cytokines