Interleukin-33 gene expression and rs1342326 polymorphism in Behçet's disease

Behçet's disease (BD) is a chronic multi-factorial inflammatory disease with the important role of genetic in activation of its inflammatory response. Interleukin (IL)-33 is a member of the IL-1 family of cytokines that affects innate and adaptive immune systems to promote inflammatory responses. In the current study, we investigated the association of IL-33 gene rs1342326 polymorphism and expression levels of this gene in peripheral blood mononuclear cells (PBMCs) with the susceptibility to BD in Azari population of Iran.

We recruited 44 patients with BD and 61 age and sex-matched healthy controls in this cross-sectional study. The existence of rs1342326 T/G IL-33 gene single nucleotide polymorphism was investigated using Tetra-Amplification Refractory Mutation System (Tetra-ARMS)-PCR. Allele and genotype distributions were evaluated among groups using chi-square or Fisher's test. Moreover, the mRNA levels of IL-33 in PBMCs were assessed through the Real-time PCR.

Patients with BD exhibited a significantly higher prevalence of the T/G genotype of rs1342326 polymorphism compared with the control group. Moreover, the expression level of IL-33 in PBMCs was significantly higher in the BD group compared to the healthy controls. Interestingly, the rs1342326 T/G polymorphism was associated with higher IL-33 expression in patients with BD. There was no association between the clinical manifestation of BD and disease activity with rs1342326 polymorphism and IL-33 expression.

Our study implies that rs1342326 T/G polymorphism of the IL-33 gene may contribute to the genetic susceptibility to BD in part through regulation of the IL-33 expression.