Background Increasing evidence suggest that single nucleotide polymorphism (SNP) rs6822844, within KIAA1109-TENR-IL2-IL21 gene cluster, is strongly associated with autoimmune diseases in Caucasian population, including rheumatoid arthritis (RA) [1, 2, 3].
Objectives The aim of this study was to investigate possible association between this polymorphism, susceptibility to RA, auto-antibody profile and RA severity in Algerian population.
Methods We investigated 289 Algerian patients with RA and 266 healthy subjects, for rs6822844 polymorphism, using Taqman allelic discrimination assays (Applied biosystems 7500). We recorded demographics, clinical, and laboratory data, including evidence of inflammatory activity and presence of autoantibodies (rheumatoid factor (RF) and cyclic citrullinated peptide antibodies (anti-CCP)).
Results The allele G of IL-21 gene polymorphism (rs6822844) was associated significantly with susceptibility to RA (odds ratio (OR) =1.33 [95% CI 1.21 to 1.46], p=0.000). No significant association was observed between rs6822844 and ACPA+ or ACPA- RA groups. However, the major G allele frequency was significantly increased in the RF- RA group compared with RF+ RA group (96% vs 92%, OR=0.95 [95% CI 0.91 to 0.99], p =0.039). Concerning RA severity, the minor T allele was associated with (1) disease activity, assessed by HAQ score and DAS-28-CRP, and (2) ACPA serum levels (p =0.027, p =0.031 and p =0.005 respectively).
Conclusions Our results indicate that there is a strong relationship between rs6822844, susceptibility and severity of RA in Algerian population.
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Hollis-Moffatt JE, Chen-Xu M, Topless R, Dalbeth N, Gow PJ, Harrison AA, Highton J, Jones PB, Nissen M, Smith MD, van Rij A, Jones GT, Stamp LK, Merriman TR. Only one independent genetic association with rheumatoid arthritis within the KIAA1109-TENR-IL2-IL21 locus in Caucasian sample sets: confirmation of association of rs6822844 with rheumatoid arthritis at a genome-wide level of significance. Arthritis Research & Therapy 2010; 12: R116.
Nina A. Daha, Fina A. S. Kurreeman, Rute B. Marques, Gerrie Stoeken-Rijsbergen, Willem Verduijn, Tom W. J. Huizinga, René E. M. Toes. Confirmation of STAT4, IL2/IL21, and CTLA4 Polymorphisms in Rheumatoid Arthritis. Arthritis & rheumatism 2009; 60: 1255–1260.
Disclosure of Interest None declared
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