Association of Interleukin-1 Receptor Antagonist Gene 86bp VNTR Polymorphism with Systemic Lupus Erythematosus in South East of Iran

Article history: Received: 20 July 2013 Accepted: 24 Aug 2013 Available online: 15 Oct 2013 ZJRMS 2014; 16(12): 51-54 Background: Systemic lupus erythematosus (SLE) is an autoimmune disease with unknown etiology. Interleukin-1 receptor antagonist (IL-1Ra) is naturally occurring cytokine that inhibits interleukin-1 (IL-1) activity by binding to the IL-1 receptors without signal transduction. The aim of this study was to investigate the association between IL1Ra gene 86bp VNTR polymorphism and systemic lupus erythematosus in the SouthEast of Iran. Materials and Methods: In this case control study, genetic polymorphism was analyzed in 163 SLE patients and 183 healthy controls. Genotyping of IL-1Ra VNTR polymorphism was determined by gel electrophoresis after PCR amplification. Results: IL-1Ra VNTR alleles have different copies of 86bp tandem repeats: allele 1 (four repeats), allele 2 (two repeats), allele 3 (five repeats), allele 4 (three repeats) and allele 5 (six repeats). We found an increased frequency of IL-1Ra allele 4 and 1/4 genotype in SLE patients compared to healthy controls (p=0.001 and p=0.002 respectively). Whereas, the frequency of IL-1Ra allele 3 was higher in controls than SLE patients (p=0.01). There was no any association between the IL-1Ra allele 2 and SLE. We did not observe any association between IL-1Ra polymorphism and SLE manifestations. Conclusion: We concluded that IL-1Ra allele 4 was involved in the pathogenesis of SLE. However, there was no association between the IL-1Ra allele 2 and SLE in South East of Iran. Copyright © 2014 Zahedan University of Medical Sciences. All rights reserved.