title: Protective role of IL-18 -137G/C polymorphism in a North Indian population with asthma: a pilot study.
abstract: BACKGROUND
  IL-18, a pleiotropic, pro-inflammatory cytokine that plays a major role in innate as well as acquired immunity, has been implicated in asthma etiology and this is the first study investigating the role of IL-18 -137G/C (rs 187238) promoter polymorphism in asthma pathogenesis in a North Indian population.
  
  
  METHODS
  A pilot study was conducted with a total of 824 subjects, out of which 410 were asthma patients including 323 patients suffering from allergic rhinitis and 414 healthy controls from regions of North India. Tetra-Primer Amplification Refractory Mutation System Polymerase Chain Reaction (Tetra-Primer ARMS PCR) was used for genotyping the IL-18 -137G/C polymorphism.
  
  
  RESULTS
  While the homozygous wild (GG) genotype was equally prevalent in asthma patients as well as control subjects (70.0%), the homozygous mutant (CC) genotype was more prevalent among the controls (8.0%) than in asthma patients (3.4%), which yielded a significant protection or decreased risk towards asthma. Statistical analysis revealed Odds Ratio (OR)=0.43 (95% CI=0.21-0.85), Chi2 (χ2)=6.93 and p-value=0.008 (p<0.005). Moreover, a few asthma phenotypic traits also revealed significant protective associations with the polymorphism.
  
  
  CONCLUSIONS
  The IL-18 -137G/C polymorphism confers a significant protection from asthma in the studied North Indian population. This is the first study to report the protective association of the polymorphism with the disease.
authors.affiliation: Department of Biotechnology, Panjab University, Chandigarh, India. nitibirbian@yahoo.com
authors.forename: Niti
authors.initials: N
authors.lastname: Birbian
authors.forename: Jagtar
authors.initials: J
authors.lastname: Singh
authors.forename: Surinder Kumar
authors.initials: SK
authors.lastname: Jindal
mesh_terms: D000328:Adult; D000483:Alleles; D001249:Asthma / Q000209:etiology / Q000235:genetics* / Q000276:immunology; D015992:Body Mass Index; D005260:Female; D005787:Gene Frequency; D056726:Genetic Association Studies; D020022:Genetic Predisposition to Disease; D005838:Genotype; D006801:Humans; D007194:India; D020382:Interleukin-18 / Q000235:genetics*; D008297:Male; D020641:Polymorphism, Single Nucleotide; D011401:Promoter Regions, Genetic; D065631:Rhinitis, Allergic; D012221:Rhinitis, Allergic, Perennial / Q000235:genetics; D012306:Risk
chemical_list: D020382:Interleukin-18