**3.7 IL-33**

IL-33 is a member of the IL-1 cytokine family that expressed by various types of immune cells such as mast cells, macrophages and dendritic cells, that drives production of Th2-associated cytokines [69, 70]. The rs7044343 and rs11792633 variants of IL-33 gene were associated with the decreased risk of BD in Turkish patients [71]. Talei et al. showed that a significantly higher prevalence of the IL-33 SNP rs1342326T/G in BD patients. They showed also this genotype was also associated with increased IL-33 expression in patients with BD compared to healthy controls [72].
