Interleukin‐2 gene polymorphism in T urkish patients with B ehçet's disease and its association with ocular involvement

Behçet's disease ( BD ) is a chronic immune‐mediated systemic disease, characterized by oral and genital lesions and ocular inflammation. Several cytokine genes may play crucial roles in host susceptibility to BD , because the cytokine production capacity varies among individuals and depends on the cytokine gene polymorphisms. The association of the interleukin ( IL )‐2 gene polymorphisms with the susceptibility to BD was investigated in this study. DNA samples were obtained from a Turkish population of 97 patients with BD and 76 healthy control subjects. Polymorphisms of IL ‐2 gene at position −330 and +166 were determined using the polymerase chain reaction with sequence‐specific primers. In the patients with BD , there was a significantly increased frequency of IL ‐2 −330 GT genotype. Interestingly, we demonstrated that the frequencies of IL ‐2 −330 GT and IL ‐2 + 166 GG genotypes were increased in BD patients with ocular involvement, whilst IL ‐2 −330 TT genotype was significantly decreased. Also, analysis of allele frequency demonstrated that the presence of G allele at position +166 of IL ‐2 seems to be a risk factor for ocular involvement. These results reveal that IL ‐2 −330 GT genotype may be a susceptibility factor for BD , whereas IL ‐2 −330 TT genotype seems to display a protective association with BD . Additionally, IL ‐2 gene polymorphisms might be associated with ocular involvement in BD .