Human leukocyte antigen B polymorphism and association between HLA-B27 and endoplasmic reticulum aminopeptidase 1 rs30187 SNP in patients with ankylosing spondylitis in Bangladesh

Objectives:To determine the association of Human leukocyte antigen B(HLA‑B)alleles with ankylosing spondylitis and the allelic association of HLAB27 with endoplasmic reticulum aminopeptidase 1(ERAP1)single-nucleotide polymorphism(SNP)rs30187 in patients with ankylosing spondylitis(AS).Methods:We studied 48 consecutively enrolled well-defined AS patients and 48 healthy controls recruited from the outpatient clinic of the rheumatology department of Bangabandhu Sheikh Mujib Medical University(BSMMU),Dhaka,Bangladesh.To genotype HLA-B alleles from peripheral blood DNA,we designed sequence-specific primers for polymerase chain reaction.Sanger's sequencing method was used to detect the ERAP1 rs30187 SNP.The HLA-B allele distributions were compared between cases and controls.To infer an allelic association between HLA-B27 and ERAP1,allele distributions from both loci were compared using cross-tabulations.Chi-squared test or Fisher's exact test was used to quantify the association,and their strength of association was tested by odds ratio(OR)with 95%confidence interval(CI).Results:The frequency of HLA-B27 was found to be higher in AS patients(60.4%)than in healthy controls(8.3%).HLA-B27 allele had an OR of 16.8(95%CI=5.2–54.4)for the development of AS.Overall,4%of AS patients had both HLA-B27 and HLA-B40.No significant association was found between ERAP1 rs30187 SNP and HLA-B27 in patients with AS(OR=1.7,95%CI=0.5–5.6).Conclusions:HLA-B27 was significantly associated with AS in patients in Bangladesh.However,no association between ERAP1 rs30187 SNP and HLA-B27 was observed.