Objective: Genetic susceptibility to Behçet's disease (BD) is well documented for HLA-B51; however, contribution of other genetic polymorphisms is estimated to be substantial. Interleukin 8 (IL-8), a potent chemoattractant for neutrophils, has been found to be elevated in BD serum, and the serum concentrations correlate with disease activity. Novel polymorphisms in IL-8 (CXCL8) and in one of its receptors, CXCR2 gene, may have a role in enhanced IL-8 activity in BD.
Methods: Three single nucleotide polymorphisms (SNP; -353 A/G, +1530 T/C, +3331 A/G) of the IL-8 gene and 2 SNP (+785 C/T and +1208 T/C) of the CXCR2 gene were screened in 100 patients with BD (61 men, 39 women, mean age 42.1 yrs) and 100 healthy controls (50 men, 50 women, mean age 36.8 yrs) by genotyping with PCR-RFLP and PCR-SSP methods.
Results: No differences were observed between BD patients and controls for the allele and genotype frequencies of the screened IL-8 and CXCR2 gene polymorphisms. Distribution of these polymorphisms revealed no significant differences between clinical subgroups of BD patients. Each pair of the SNP -353/+1530, -353/+3331, and +1530/+3331 of IL-8 and +785/+1208 of CXCR2 showed strong linkage disequilibrium in both patients and controls (p < 0.001 for all). The distribution of the estimated IL-8 and CXCR2 haplotypes revealed no association with BD or any of its clinical subsets.
Conclusion: These results suggest that the IL-8 gene -353 A/G, +1530 T/C, and +3331 A/G and the CXCR2 gene +785 C/T and +1208 T/C polymorphisms have no role in the increased expression of IL-8 in BD.