title: Association of IL1R polymorphism with HLA-B27 positive in Iranian patients with ankylosing spondylitis.
abstract: 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. 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: The IL1α rs1800587, IL1β rs16944 and IL1β rs1143634 were not significantly associated with AS. Genotype frequencies at IL1R rs2234650 differed between cases and controls (χ(2)=8.85; p=0.01); the IL1R rs2234650 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 HLA-B2702 patients rather than HLA-B2705 but was not associated with HLA-B27 negative patients (OR=0.33; p=0.01). 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.
authors.affiliation: Molecular Immunology Research Center, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran; Department of Immunology, School of Medicine, Tehran University of Medical Sciences.
authors.forename: M
authors.initials: M
authors.lastname: Mahmoudi
authors.forename: A A
authors.initials: AA
authors.lastname: Amirzargar
authors.forename: A R
authors.initials: AR
authors.lastname: Jamshidi
authors.forename: E
authors.initials: E
authors.lastname: Farhadi
authors.forename: S
authors.initials: S
authors.lastname: Noori
authors.forename: M
authors.initials: M
authors.lastname: Avraee
authors.forename: B
authors.initials: B
authors.lastname: Nazari
authors.forename: M H
authors.initials: MH
authors.lastname: Nicknam
mesh_terms: D000483:Alleles; D016022:Case-Control Studies; D005260:Female; D005787:Gene Frequency; D020022:Genetic Predisposition to Disease; D005838:Genotype; D015796:HLA-B27 Antigen / Q000096:biosynthesis / Q000235:genetics*; D006801:Humans; D007492:Iran; D008297:Male; D020641:Polymorphism, Single Nucleotide; D017472:Receptors, Interleukin-1 / Q000235:genetics*; D013167:Spondylitis, Ankylosing / Q000235:genetics* / Q000378:metabolism / Q000473:pathology
chemical_list: D015796:HLA-B27 Antigen; D017472:Receptors, Interleukin-1