The Role of CTLA-4 Exon-1 49 A/G Polymorphism and Soluble CTLA-4 Protein Level in Egyptian Patients with Behçet's Disease

This study analyzed the association of the A/G SNP at position +49 of exon-1 in the CTLA-4 gene to the susceptibility and clinical manifestations of Behcet's disease (BD). It was performed on 60 Egyptian BD patients and 95 age- and sex-matched healthy controls. The genotypes for the +49 A/G polymorphism of the CTLA-4 gene were determined by PCR-RFLP, while the serum level of CTLA-4 protein was measured by ELISA. CTLA-4 +49 A allele (P < 0.001, OR = 3.084, and CI (95%) = 1.90–4.99) and A/A genotype (P < 0.001, OR = 6.643, and CI (95%) = 2.58–17.10) frequency distribution was significantly more increased in patients than in the controls, with no significant differences between males and females with regard to the genotype or allele frequency distribution. A/A genotype was associated with a more reduced expression of sCTLA-4 protein in patients than in the controls (1.76 ± 0.19 versus 1.91 ± 0.30, resp; P < 0.0007). In addition, it is associated with the occurrence of ocular and vasculitic manifestations of BD in the patient group. The CTLA-4 gene could be considered as a susceptibility and a disease-modifying gene to BD in Egyptian population that needs further confirmatory studies on larger cohorts.