Abstract
Objective. The aim of this study was to investigate if the inheritance of specific polymorphisms of interleukin 1 (IL‐1) A, IL‐1B and IL‐1 receptor antagonist (IL‐1RN) genes could affect the susceptibility to Behçet's disease (BD). Methods. A total of 132 BD patients and 105 healthy controls were genotyped for IL‐1A −889, IL‐1B −511, −35, +5810, +5887, and IL‐1RN +8006, +8061, +9589, +11100 single nucleotide polymorphisms, and IL‐1RN 86‐bp variable number of tandem repeat polymorphism. χ2‐analysis was used to compare the allele and genotype frequencies of the cases and controls. IL‐1A and IL‐1B haplotypes were reconstructed using the Phase program. Results. Inheritance of the C allele of the IL‐1A −889 polymorphism was associated with BD (OR=2.0, P=0.01) and inheritance of the IL‐1A −889C/IL‐1B +5887T haplotype was identified as an increased risk for BD. The IL‐1A −889 and IL‐1B +5887 CC/TT combined genotype was significantly more observed in BD cases than in controls (57.5 vs 38.1%, OR=2.2, P=0.003). No association with BD was found for other investigated polymorphisms in the IL‐1B and IL‐1RN genes. Conclusion. Susceptibility to BD is increased in individuals carrying both the IL‐1A −889C and IL‐1B +5887T haplotype. Individuals who are both homozygous CC at IL‐1A −889 and TT at IL‐1B +5887 appear to have twice the risk of developing BD as individuals having other IL‐1A −889/IL‐1B +5887 genotypes.