title: Potential influence of interleukin-1 receptor antagonist gene polymorphism on knee osteoarthritis risk.
abstract: OBJECTIVE
  Genes encoding for cytokines have been associated with susceptibility for joint osteoarthritis (OA) and interleukin (IL)-1 gene is supposed to be involved in the cartilage destruction process. In this regard, interleukin-1 receptor antagonist (IL-1RA) competing with IL-1 for binding to its receptor may act as an inhibitor of cartilage breakdown. We assessed the association of primary knee OA with IL-1RA region as a putative factor of susceptibility to knee OA in Egyptian patients.
  
  
  METHODS
  Eighty patients with primary knee OA and 40 aged-matched healthy controls were included into the study. DNA samples were used to study genotypes of IL-1RN gene by polymerase chain reaction (PCR) in both groups.
  
  
  RESULTS
  An increased frequency of the IL-1RN*1 and IL-1RN*2 alleles was found in OA patients relative to controls (60.5% vs. 39.5%, P=0.039, 85.4% vs. 14.6%, P=0.002, respectively) however, only the carriage rate of IL-1RN*2 allele was found to be significant when OA patients were compared to the controls. Significant higher frequencies of IL-1RN*1/*2 and IL-1RN*2/*2 genotypes in OA patients were observed as compared with controls. Both visual analogue scale (VAS) {and radiographic score revealed} significant correlation with both the allelic frequency and the carriage rate of IL-1RN*2 allele. Moreover, absolute frequency of IL-1RN*1/*2 genotype OA patients revealed severe VAS and high radiographic score.
  
  
  CONCLUSIONS
  These results suggest that IL-1RN*2 allele represent a significant factor influencing the severity and course of knee OA; thereby supporting the potential role of IL-1 in the pathogenesis of this disease.
authors.affiliation: Department of Biochemistry, National Research Center, Dokki, Giza, Egypt. swellam@hotmail.com <swellam@hotmail.com>
authors.forename: Menha
authors.initials: M
authors.lastname: Swellam
authors.forename: Magda Sayed
authors.initials: MS
authors.lastname: Mahmoud
authors.forename: Nervana
authors.initials: N
authors.lastname: Samy
authors.forename: Ali Ahmed
authors.initials: AA
authors.lastname: Gamal
mesh_terms: D018501:Antirheumatic Agents / Q000378:metabolism; D016022:Case-Control Studies; D004534:Egypt; D005260:Female; D005787:Gene Frequency; D020022:Genetic Predisposition to Disease; D005838:Genotype; D006801:Humans; D053590:Interleukin 1 Receptor Antagonist Protein / Q000235:genetics*; D007375:Interleukin-1 / Q000235:genetics; D007438:Introns / Q000235:genetics*; D008297:Male; D008875:Middle Aged; D020370:Osteoarthritis, Knee / Q000235:genetics* / Q000473:pathology; D016133:Polymerase Chain Reaction; D011110:Polymorphism, Genetic / Q000235:genetics*; D012307:Risk Factors
chemical_list: D018501:Antirheumatic Agents; D053590:Interleukin 1 Receptor Antagonist Protein; D007375:Interleukin-1