Open Access

ARTICLE

Association of IL1R polymorphism with HLA-B27 positive in Iranian patients with ankylosing spondylitis

M. Mahmoudi^1,2, A. A. Amirzargar^1,2, A. R. Jamshidi³, E. Farhadi¹, S. Noori⁴, M. Avraee², B. Nazari², M. H. Nicknam^1,2

1 Molecular Immunology Research Center, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran
2 Department of Immunology, School of Medicine, Tehran University of Medical Sciences
3 Rheumatology Research Centre, Shariati Hospital, Tehran University of Medical Sciences
4 Department of Epidemiology and Biostatistics, School of Public Health, Tehran University of Medical Sciences, Tehran

* Corresponding Author: M.H. Nicknam,

European Cytokine Network 2011, 22(4), 175-180. https://doi.org/10.1684/ecn.2011.0293

Accepted 02 November 2011;

Abstract

Objective. Ankylosing spondylitis (AS) is one of the most common causes of inflammatory arthritis, with an estimated prevalence of 0.1-0.9%. Genetic factors have been strongly implicated in its aetiology, and heritability as assessed by twin studies has been estimated to be >90%. HLA- B27 is almost essential for inheritance of AS; it is not merely sufficient for explaining the pattern of familial recurrence of the disease. This study’s purpose is to investigate the association of ankylosing spondylitis with single-nucleotide polymorphisms (SNPs) in the IL-1 family: IL-1a (-889C/T) rs1800587, IL-1b (-511C/T) rs16944, IL-1b (+3962C/T) rs1143634, IL-1R (Pst-1 1970C/T) rs2234650 and IL-1RA (Mspa-1 11100C/T) rs315952. Methods. 99 unrelated Iranian AS patients and 217 healthy control subjects were selected. Cytokine typing was performed by the polymerase chain reaction with sequence-specific primers assay. The allele and genotype frequencies of the polymorphisms were determined: Results. The IL1α rs1800587, IL1β rs16944 and IL1β rs1143634 were not significantly associated with AS. Genotype frequencies atIL1Rrs2234650 differed between cases and controls (x²=8.85; p=0.01); the IL1Rrs2234650 C/T and T/T genotypes were less common in AS patients than controls. The IL1R rs2234650 C/T genotype was inversely associated with AS comparing with the IL1R rs2234650 C/C genotype (OR=0.48; p=0.005). IL1R rs2234650 C/T genotype was less common in patients than controls (OR=0.37; p=0.02).Furthermore IL1R rs2234650 T allele was strongly associated with HLAB2702 patients rather than HLA-B2705 but was not associated with HLA-B27 negative patients (OR=0.33; p=0.01). Conclusion. Polymorphisms of IL1α rs1800587, IL1β rs16944 and IL1β rs1143634 were not significantly associated with ankylosing spondylitis but inversely in this study IL1R rs2234650 was significantly associated and carriage of T allele in IL1R rs2234650 seems to be protective, while carriage of C allele result in two fold higher risk of developing AS.

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Keywords

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