Association of the HLA ‐B27 antigen and the CTLA 4 gene CT 60/rs3087243 polymorphism with ankylosing spondylitis in Algerian population: A case–control study

Summary Ankylosing spondylitis ( AS ) is a complex inflammatory disease that represents a major health problem both in Algeria and worldwide. Several lines of evidence support that genetic risk factors play a role in AS etiology and the CTLA 4 gene has attracted a considerable attention. In this study, we were interested in evaluating the HLA ‐B27 frequency and in exploring the CTLA 4 gene in a sample of the North African population. The dataset of the current study is composed of 81 patients with AS and 123 healthy controls. All samples were genotyped by TaqMan ® allelic discrimination assay. The genetic risk of the HLA ‐B27 specificity and the CTLA 4/ CT 60 polymorphism were assessed by odds ratios ( OR ) with 95% confidence intervals ( CI ). High spondylitis risk was detected for HLA ‐B27 allele ( OR = 14.62, p  =   10 −6 ) in addition to a significant association of the CT 60 *G allele ( OR = 1.89, p  =   .002). After gender and age stratifications, the association of the CT 60 *G allele was still significant in females sample ( OR = 2.10, p  =   .001) and when age up to 30 years ( OR = 2.21, p  =   .008). Interestingly, the CT 60 *G allele revealed an increased spondylitis risk in the B27 negative group ( OR = 2.81, p  =   .006). The present work showed in West Algerian population that the HLA ‐B27 antigen and the variation in the CTLA 4 3′ UTR region played an important role in the ankylosing spondylitis susceptibility. The heterogeneity of this disease is deduced by genetic difference found between B27+ and B27− groups.