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Disease Markers
Volume 28 (2010), Issue 5, Pages 299-305

Potential Influence of Interleukin-1 Receptor Antagonist Gene Polymorphism on Knee Osteoarthritis Risk

Menha Swellam,1 Magda Sayed Mahmoud,1 Nervana Samy,1 and Ali Ahmed Gamal2

1Department of Biochemistry, Genetic Engineering and Biotechnology Research Division, National Research Center, Dokki, Giza, Egypt
2Department of Orthopedic and Rheumatology, Faculty of Medicine, Alazhar University, Naser City, Cairo, Egypt

Received 25 June 2010; Accepted 25 June 2010

Copyright © 2010 Hindawi Publishing Corporation. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


Objectives: 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.

Design and 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.

Conclusion: 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.