title: The association of IL-18 gene promoter polymorphisms and the levels of serum IL-18 on the risk of multiple sclerosis.
abstract: OBJECTIVE
  Multiple sclerosis is an inflammatory condition of the central nervous system whose etiology is influenced by immunologic, genetic, and environmental factors. Aim of the present study was to determine if any relation exists between IL-18 -137C/G and -607C/A gene promoter polymorphisms on the individual susceptibility of multiple sclerosis and also to investigate the possible effect of IL-18 activity regarding this kind of polymorphism and MS.
  
  
  METHODS
  113 patients with clinically definite MS and 135 ethnically-matched controls were participated in this study. IL-18 -137C/G and -607C/A gene promoter polymorphisms were analyzed by Sequence Specific Polymerase Chain Reaction (SS-PCR), while levels of serum IL-18 were measured by Enzyme Linked Immunoassay Assay (ELISA) in patients with MS and healthy controls.
  
  
  RESULTS
  Our results showed that the IL-18 -607AA genotype indicated 6 times higher risk in the development of MS (OR=6.883; 3.17-14.96; p<0.001). According to our findings, smoking seems to be an important confounding factor in MS patients with carrying IL-18 -607 AA and CA+AA genotypes. However, no meaningful association was found with IL-18 -137C/G gene promoter polymorphism.
  
  
  CONCLUSIONS
  In conclusion, we suggest that IL-18 -607C/A gene promoter polymorphism is a major genetic factor for determining individual susceptibility to MS, where smoking status also increases the risk of MS.
authors.affiliation: Ankara Numune Hospital, Clinics of Neurology, Ankara, Turkey.
authors.forename: Gürdal
authors.initials: G
authors.lastname: Orhan
authors.affiliation: Ankara Numune Hospital, Clinics of Neurology, Ankara, Turkey.
authors.forename: Esra
authors.initials: E
authors.lastname: Eruyar
authors.affiliation: Ankara Numune Hospital, Clinics of Neurology, Ankara, Turkey.
authors.forename: Semra Öztürk
authors.initials: SÖ
authors.lastname: Mungan
authors.affiliation: Ankara Numune Hospital, Clinics of Neurology, Ankara, Turkey.
authors.forename: Fikri
authors.initials: F
authors.lastname: Ak
authors.affiliation: Gazi University, Faculty of Pharmacy, Department of Toxicology, 06330 Ankara, Turkey. Electronic address: bensuka@gmail.com.
authors.forename: Bensu
authors.initials: B
authors.lastname: Karahalil
mesh_terms: D000328:Adult; D005260:Female; D005838:Genotype; D006801:Humans; D020382:Interleukin-18 / Q000097:blood* / Q000235:genetics*; D008297:Male; D008875:Middle Aged; D009103:Multiple Sclerosis / Q000097:blood* / Q000235:genetics*; D011110:Polymorphism, Genetic; D011401:Promoter Regions, Genetic; D012306:Risk; D012907:Smoking / Q000009:adverse effects / Q000235:genetics
chemical_list: D020382:Interleukin-18
keywords: IL-18 activity; IL-18 gene polymorphism; Multiple sclerosis; PCR