Lack of an association between E-selectin gene polymorphisms and risk of Kawasaki disease

Pro-inflammatory cytokine single nucleotide polymorphisms in Kawasaki disease

AIM

Kawasaki disease (KD) is a systemic vasculitis of children associated with cardiovascular sequelae. Proinflammatory cytokines play a major role in KD pathogenesis. However, their role is both influenced and modified by regulatory T-cells. IL-1 gene cluster, IL-6 and TNF-α polymorphisms have shown significant associations with some vasculitides. Herein we investigated their role in KD.

METHODS

Fifty-five patients with KD who were randomly selected from referrals to the main pediatric hospital were enrolled in this case-control study. Single nucleotide polymorphisms (SNPs) of the following genes were assessed in patients and 140 healthy subjects as control group: IL-1α at -889 (rs1800587), IL-1β at -511 (rs16944), IL-1β at +3962 (rs1143634), IL-1R at Pst-I 1970 (rs2234650), IL-1RN/A at Mspa-I 11100 (rs315952), TNF-α at -308 (rs1800629), TNF-α at -238, IL-6 at -174 (rs1800795) and IL-6 at +565.

RESULTS

Twenty-one percent of the control group had A allele at TNF-α -238 while only 8% of KD patients had A allele at this position (P = 0.003, OR [95%CI] = 0.32 [0.14-0.71]). Consistently, TNF-α genotype GG at -238 had significant association with KD (OR [95% CI] = 4.31 [1.79-10.73]). Most controls carried the CG genotype at IL-6 -174 (n = 93 [66.9%]) while GG genotype was the most common genotype (n = 27 [49%]) among patients. Carriers of the GG haplotype at TNF-α (-308, -238) were significantly more prevalent among the KD group. No association was found between IL-1 gene cluster, allelic or haplotypic variants and KD.

CONCLUSION

TNF-α GG genotype at -238 and GG haplotype at positions -308 and -238 were associated with KD in an Iranian population.

Genetic polymorphism of SMAD5 is associated with Kawasaki disease

Mothers against decapentaplegic homolog (SMAD) proteins are intracellular mediators of members of the transforming growth factor-β (TGF-β) superfamily, which are activated by bone morphogenetic proteins (BMPs). On activation, SMAD5 forms heterometric SMAD complexes, which are translated to the nucleus where they regulate gene transcription. TGF-β induces T cell activation and cardiovascular disease, two important features of Kawasaki disease (KD), whereas BMP is associated with coronary artery disease. In this study, we hypothesized that single nucleotide polymorphisms (SNPs) of SMAD5 may be associated with KD and coronary arterial lesions (CALs). Genotyping for 15 SNPs of the SMAD5 gene (rs3764941, rs10085013, rs6596284, rs7356756, rs13179769, rs13166063, rs1109158, rs4585442, rs4146185, rs12719481, rs6865297, rs3206634, rs6871224, rs1057898, and rs7031) was performed by direct sequencing of 105 KD patients and 303 healthy adult controls. We also compared the allele frequencies between a CAL group (n = 31) and a normal coronary group (n = 74). Results showed that among the 15 SNPs, rs3206634 was significantly associated with KD in a recessive model (odds ratio = 2.31, p = 0.019), whereas there was no association between any of the 15 SNPs and CALs. These findings may be used as a risk factors development of KD or for future generations of therapeutic treatments for KD.