OBJECTIVEKawasaki disease (KD) is an acute febrile vasculitic syndrome of unknown etiology that preferentially affects coronary artery. It has been suggested that proinflammatory cytokines like tumor necrosis factor alpha (TNF-alpha) and interleukin-10 (IL-10) are key players during acute KD. Recently, the polymorphisms relative to major transcriptional start site of TNF-alpha and IL-10 gene were shown to influence the level of TNF-alpha and IL-10 production in vitro. This study was aimed to investigate the genetic association of TNF-alpha and IL-10 promoter polymorphisms in juvenile patients of Han nationality with KD, and to investigate the possible associations with clinical manifestations of the disease.

METHODSFour polymorphism sites of TNF-alpha and IL-10 gene promoter regions from 96 children with KD were determined by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP). One hundred and sixty age-matched normal children of the Han nationality were used as control. All patients accepted Doppler echocardiography examination in order to differentiate coronary artery lesions.

RESULTSThere was significant difference in allele frequencies of -308 (A/G) site of the TNF-alpha gene between children of the Han nationality and those of Japanese and Caucasian in America. There were significant differences in the allele frequencies of -1082 (G/A), -819 (C/T) and -592 (A/C) of IL-10 gene between children of the Han nationality and their British Counterparts (P < 0.01). There was no significant difference in allele frequencies of -308 (A/G) site of TNF-alpha gene between children with KD and normal controls. There was no significant difference in the haplotypes and the allele frequencies of the above three sites of IL-10 between the two groups. However, when clinical features were examined, the genotype frequency of TNF-alpha-308A was significantly higher in IVIG-resistant KD patients than that of TNF-alpha-308G genotype (67% vs 5%, chi(c)(2) = 90.48, P < 0.01). The genotype of TNF-alpha-308A was closely associated with IVIG-resistant KD (P < 0.01, relative risk 42.25, 95% confidence interval 15.81-112.88). The haplotype frequency of IL-10 -1082A/-819T/-592A was also higher in patients with coronary artery lesion (CAL) caused by KD than those of Non-ATA haplotype (52% vs 20%, chi(2) = 18.36, P < 0.01). The haplotypes of IL-10 -1082A/-819T/-592A was significantly associated with CAL caused by KD (P < 0.01, relative risk 4.26, 95% confidence interval 2.20-8.25).

CONCLUSIONThe genotype of TNF-alpha-308A is one of the important factors that probably influence the therapeutic effect of KD. The haplotypes (-1082/-819/-592) of IL-10 gene promoter might be related to the pathogenesis of coronary artery complication of KD and -1082A/-819T/-592A haplotypes might be regarded as a genetic marker of risk factor for coronary artery lesion in KD.