Influence of interleukin 18 promoter polymorphisms in susceptibility to Kawasaki disease in Taiwan

Objective. Proinflammatory cytokines such as interferon-gamma (IFN-gamma) play an important role in the pathogenesis of Kawasaki disease (KD). Interleukin 18 (IL-18) plays a pivotal role in the T helper 1 (Th1)-type response, principally owing to its ability to induce IFN-gamma production. We assessed potential associations between functional IL-18 gene promoter polymorphisms and susceptibility to KD, in addition to clinical features of KD in individuals from Taiwan. Methods. One hundred forty-six patients with KD and 136 ethnically matched controls from the same geographic area were genotyped for IL-18 -656T/G, -607A/C, and -137C/G promoter polymorphisms. Results. No significant differences in allele and genotype frequencies were found between KD patients and controls for any of the IL-18 polymorphisms investigated. When we compared the overall distribution of haplotype frequencies between KD patients and controls, a significant difference was observed (p < 0.0001). In addition, the frequency of the GCG haplotype was significantly higher (p = 0.00001, p(c) = 0.00004; OR 20.8, 95% CI 3.05-142.3), whereas the frequency of the TAG haplotype was significantly lower in KD patients compared with controls (p = 0.0001, p(c) = 0.0004; OR 0.35, 95% CI 0.19-0.61). No significant associations were found for comparisons of KD patients to those with and without coronary artery lesions. Conclusion. Our results suggest a potential implication of IL-18 promoter polymorphisms in susceptibility to KD in Taiwan.