Genetic Association of HLA-A*26, -A*31, and -B*51 with Behcet's Disease in Saudi Patients.

BACKGROUND: HLA-B*51 has been universally associated with Behcet's disease (BD) susceptibility, while different alleles of HLA-A have also been identified as independent BD susceptibility loci in various ethnic populations. The objective of this study was to investigate associations of HLA-A and -B alleles with BD in Saudi patients. MATERIALS AND METHODS: Genotyping for HLA-A and HLA-B was performed using HLA genotyping kit (Lab type((R)) SSO) in 120 Saudi subjects, including 60 BD patients and 60 matched healthy controls. RESULTS: Our results revealed that frequencies of HLA-A*26, -A*31, and -B*51 were significantly higher in BD patients than in controls, suggesting that HLA-A*26, -A*31, and -B*51 are associated with BD. The frequency of HLA-B*15 was significantly lower in BD patients than in controls. Stratification of genotyping results into active and nonactive forms of BD revealed that the frequency of HLA-A*31 was significantly higher in the nonactive form than in the active form of BD, while there was no significant difference in the distribution of other alleles between the two forms of BD. CONCLUSION: This study suggests that HLA-A*26, -A*31, and -B*51 are associated with susceptibility risk to BD, while HLA-B*15 may be protective in Saudi patients. However, larger scale studies are needed to confirm these findings.

Inflammation-related cytokine gene polymorphisms in Behçet's disease.

Behçet's disease (BD) is a complex, multisystemic inflammatory disorder of unclear etiology. Single nucleotide polymorphisms in tumor necrosis factor (TNF) and interleukin (IL)-10 genes have been implicated in susceptibility to BD with inconsistent results in several ethnic populations. The aim of this case-control study was to evaluate the association of TNF-α (-308G/A), TNF-ß (+252A/G), and IL-10 (-1082G/A, -819C/T, and -592 C/A) polymorphisms with susceptibility of BD in Saudi patients. Molecular genotyping of TNF-α, TNF-ß, and IL-10 gene polymorphisms was performed to analyze the alleles and genotypes distribution in 272 Saudi subjects, including BD patients (61) and healthy controls (211). The frequencies of allele A and genotype GA of TNF-α (-308G/A) were significantly higher, whereas those of allele G and genotypes GG were significantly lower in BD patients than controls, indicating that A allele and GA genotype are susceptible, while G allele and GG genotype may be refractory to BD. The distribution of frequencies of alleles and genotype of TNF-ß (+252A/G) promoter polymorphism was not significantly different between BD patients and healthy controls. Genotypes 1082GG, -819TT, and 592AA of IL-10 polymorphisms are significantly associated with susceptibility risk of BD, while genotypes 1082AA, 1082GA, 819CC, 819CT, 592CC, and 592CA are resistant to BD. This study indicates that TNF-α (-308G/A) and IL-10 (-1082G/A, -819C/T, and -592C/A) polymorphisms are associated with risk of BD susceptibility in Saudi patients. However, larger scale studies in Saudi population as well as in other ethnicities are needed to confirm this association.