Genetic Polymorphisms in Transforming Growth Factor-beta, Interferon-gamma and Interleukin-6 Genes and Susceptibility to Behcet's Disease in Saudi Population

Background: Behcet's disease (BD) is a complex, inflammatory, immune-mediated multi-systemic disease of unknown etiology. Cytokines play major roles in the pathophysiology of BD, and its production may be affected by polymorphism in cytokine genes. Hence, the present study was planned to investigate any possible association between the polymorphism in TGF-beta, IFN-gamma, and IL-6 genes and BD in the Saudi population. Materials and Methods: The present study includes 79 BD cases and 117 age-matched controls. Polymerase chain reaction with restriction fragment length polymorphism (PCR-RFLP) and amplification refractory mutation systems (ARMS) PCR methods were used for polymorphic analysis. Results: The heterozygous (CT) and (CT+TT) combined genotypes of TGF-beta (509-C/T), heterozygous (AT), variant (TT), and (AT+TT) combined genotypes of IFN-gamma (874-A/T) were significantly (P<0.05) associated with BD in the Saudi population. No significant differences were observed for IL-6 (174-G/C) genotypes and alleles between BD cases and controls. Gender does not reflect any significant genotypic and allelic association with males and females. Conclusion: CT genotype of TGF-beta, and AT and TT genotypes of IFN-gamma could be associative genetic risk factors for BD in Saudis. Regulatory region polymorphism in cytokines gene can increase inflammation and deregulated immune response, which could be risk factor for BD.