Association of interleukin-2, interleukin-4 and transforming growth factor-beta gene polymorphisms with Behcet's disease.

Behçet's disease (BD) is a chronic immune-mediated disease, characterised by oral and genital lesions and ocular inflammation. As cytokines seem to have important roles in the pathogenesis of BD and production of cytokines could be affected by genetic polymorphisms, this study was performed to investigate gene polymorphisms of a number of cytokines in the patients with BD in comparison with control subjects. One hundred and fifty patients with BD were enrolled in this study. Interleukin (IL)-2 (-330, +166), IL-4 (-1098, -590, -33), IL-10 (-1082, -819, -592), IL-12 (-1188), IFN-γ (5644), transforming growth factor (TGF)-β (codon 10, 25), and IL-4RA (+1902) typing were performed by polymerase chain reaction with sequence-specific primers. In the patients with BD, there were significantly increased frequency of IL-2 (-330) GG genotype (p<0.001), IL-4 (-33) CC genotype (p<0.001), and TGF-β (codon 10) CC genotype (p=0.004). Meanwhile a significant decrease in the frequency of IL-4 (-33) TC genotype (p<0.001) was detected in the patient group in comparison with normal controls. The genotype CC of TGF-β at codon 10 was also significantly overrepresented in the patient group (p=0.004). Haplotype frequencies of IL-4 (-1098, -590, -33) showed that the frequency of TTC haplotype was significantly increased in the patients (p<0.001), whereas TTT haplotype was significantly decreased in this group of patients (p<0.001). There was not any significant difference in allele and genotype frequencies of IL-10, IL-12, IFN-γ, and IL-4RA between patient and control groups. Cytokine single nucleotide polymorphisms could play a role in the pathophysiology of BD. The results of this study could suggest a tendency towards higher production of IL-2 and lower production of IL-4 in the patients with BD.