Investigating The Association Of HLA-B27,IL-23R And ERAP1 Polymorphisms In Patients With Ankylosing Spondylitis In China

Background: Although HLA-B27 is recognized to be the major gene associated with AS, a role for genes outside the HLA region (non-MHC) is increasingly being recognized, among which interlukin23R and ERAP1 are recently been suggested to be associated with AS by studied performed on a gene-targeted association study of 14500 ncSNP in 1000 AS cases and 1500 controls by (WTCCC-TASC) in 2007. We here aim to see the relationship between HLA-B27, IL23R and ERAP1 polymorphism in Chinese AS patients.Methods: A total of 248 Patients attending orthopedics, rheumatology, and physiotherapy clinic of union Hospital and Tongji medical College were selected. Among these 248, 84(74 Male/ 10 Female) patients satisfied the modified New York criteria of AS.360 ethnically related healthy controls that did not have any previous autoimmune diseases were also included for our study. The AS populations included of 84 patients (35±8.79) years (mean±standard deviation). The mean BASDAI Score (Bath AS Disease Activity Index) and BASFAI (Bath AS Function al Index) was 3.7 Years (SD 2.0) and 2.3 (SD 2.2) respectively.Results: The mean BASDAI, BASFI, and ESR and CRP for as patients were 5.4(SD 1.7), 4.7(SD 2.5), 56.97 mm/h (SD 11.45) and 38.33 mg/L (SD 27.03) respectively. The 6 types of HLA-B27 found were (B*2702, 03,04,05,06 and B* 2713).Four alleles were detected both in AS patients and in controls (B*2702, 03, 04 and B*2705).B*2704 and B*2705 were predominant alleles in the AS group and controls. In total 5 SNP within the IL23R were genotyped. The result showed no association of IL23R polymorphism with AS. The four genotypes selected for ERAP1 (rs30187, rs10050860, rs27044, rs30187) for genotyping were in Hardy Weinberg equilibrium .Significant positive association of AS with ERAP1 SNPS rs27044 (p=9.36X10-7) and rs30187 (p=7.32X10-6) was seen. The four SNPrs17482087.rs10050860, rs27044 and rs30187 formed a LD Block with D ranging from 95 to 100, indicating strong or complete association .two haplotype showed association with AS(GCCT:P=4.71x10-7 , CCCC:P=8.56x10-6) . Conclusion: Our result confirms IL23R polymorphism is not associated in Chinese AS patients while ERAP1 is associated with AS Chinese as Caucasians.