Interleukin-18 gene 105A/C genetic polymorphism is associated with the susceptibility of Kawasaki disease

The Central Role of Interleukin-1 Signalling in the Pathogenesis of Kawasaki Disease Vasculitis: Path to Translation

Kawasaki disease (KD) manifests as an acute febrile condition and systemic vasculitis, the etiology of which remains elusive. Primarily affecting children under 5 years of age, if untreated KD can lead to a significant risk of coronary artery aneurysms and subsequent long-term cardiovascular sequelae, including myocardial ischemia and myocardial infarction. Intravenous immunoglobulin therapy mitigates the risk of aneurysm formation, but a subset of patients exhibit resistance to this treatment, increasing the susceptibility of coronary artery lesions. Furthermore, the absence of a KD-specific diagnostic test or biomarkers complicates early detection and appropriate treatment. Experimental murine models of KD vasculitis have substantially improved our understanding of the disease pathophysiology, revealing the key roles of the NLRP3 inflammasome and interleukin-1 (IL-1) signalling pathway. This review aims to delineate the pathophysiologic findings of KD while summarising the findings for the emerging key role of IL-1β in its pathogenesis, derived from both human data and experimental murine models, and the translational potential of these findings for anti-IL-1 therapies for children with KD.

Amino acids analysis reveals serum methionine contributes to diagnosis of the Kawasaki disease in mice and children

BACKGROUND

Kawasaki disease (KD) patients often lack early and definitive diagnosis due to insufficient clinical criteria, whereas biomarkers might accelerate the diagnostic process and treatment.

METHODS

The KD mouse models were established and thirteen amino acids were determined. A total of 551 serum samples were collected including KD patients (n = 134), HCs (n = 223) and KD patients after intravascular immunoglobulin therapy (IVIG, n = 194). A paired analysis of pre- and post-IVIG was employed in 10 KD patients.

RESULTS

The pathological alterations of the aorta, myocardial interstitium and coronary artery vessel were observed in KD mice; the serum levels of methionine in KD mice (n = 40) were markedly altered and negatively correlated with the C-reactive protein levels. Consistent with the mouse model, serum methionine were significantly decreased in KD children, with the relative variation ratio of KD with HCs above 30% and AUROC value of 0.845. Serum methionine were correlated with Z-Score and significantly restored to the normal ranges after KD patient IVIG treatment. Another case-control study with 10 KD patients with IVIG sensitivity and 20 healthy controls validated serum methionine as a biomarker for KD patients with AUROC of 0.86. Elevation of serum DNMT1 activities, but no differences of DNMT3a and DNMT3b, were observed in KD patients when comparing with those in the HCs.

CONCLUSIONS

Our study validated that serum methionine was a potential biomarker for KD, the alteration of which is associated with the activation of DNMT1 in KD patients.

Kawasaki Disease-Associated Cytokine Storm Syndrome

Kawasaki disease (KD) is a hyperinflammatory syndrome manifesting as an acute systemic vasculitis characterized by fever, nonsuppurative conjunctival injection, rash, oral mucositis, extremity changes, and cervical lymphadenopathy. KD predominantly affects young children and shares clinical features and immunobiology with other hyperinflammation syndromes including systemic juvenile idiopathic arthritis (sJIA) and multisystem inflammatory syndrome in children (MIS-C). Cytokine storm syndrome (CSS) is an acute complication in ~2% of KD patients; however, the incidence is likely underestimated as many clinical and laboratory features of both diseases overlap. CSS should be entertained when a child with KD is unresponsive to IVIG therapy with recalcitrant fever. Early recognition and prompt institution of immunomodulatory treatment can substantially reduce the mortality and morbidity of CSS in KD. Given the known pathogenetic role of IL-1β in both syndromes, the early use of IL-1 blockers in refractory KD with CSS deserves consideration.

Whole-exome sequencing analysis identifies novel variants associated with Kawasaki disease susceptibility

BACKGROUND

Kawasaki disease (KD) is an acute pediatric vasculitis affecting genetically susceptible infants and children. Although the pathogenesis of KD remains unclear, growing evidence links genetic susceptibility to the disease.

METHODS

To explore the genes associated with susceptibility in KD, we applied whole-exome sequencing to KD and control subjects from Yunnan province, China. We conducted association study analysis on the two groups.

RESULTS

In this study, we successfully identified 11 significant rare variants in two genes (MYH14 and RBP3) through the genotype/allele frequency analysis. A heterozygous variant (c.2650G > A, p.V884M) of the RBP3 gene was identified in 12 KD cases, while eight heterozygous variants (c.566G > A, p.R189H; c.1109 C > T, p.S370L; c.3917T > G, p.L1306R; c.4301G > A, p.R1434Q; c.5026 C > T, p.R1676W; c.5329 C > T, p.R1777C; c.5393 C > A, p.A1798D and c.5476 C > T, p.R1826C) of the MYH14 gene were identified in 8 KD cases respectively.

CONCLUSION

This study suggested that nine variants in MYH14 and RBP3 gene may be associated with KD susceptibility in the population from Yunnan province.

Inositol-Triphosphate 3-Kinase C and DNA Methylation Involvement in NLRP3 Inflammasome Activation in Kawasaki Disease

OBJECTIVE

To evaluate ITPKC and NLRP3 expression in children with Kawasaki disease (KD) and investigate the relationship between serum pro-inflammatory cytokines triggered by NLRP3 and inflammatory indices. Simultaneously, the methylation level in the ITPKC promoter was evaluated in children with KD.

METHODS

Children who satisfied the American Heart Association diagnostic criteria for KD were enrolled in the study from August 2018 to January 2019. The levels of ITPKC, NLRP3, IL-1β, and IL-18 were measured. The effect of DNA methylation on the activity of the ITPKC promoter was observed. Methylation-specific PCR was used to verify methylation modification of the ITPKC promoter region in children with KD.

RESULTS

ITPKC expression was downregulated in patients with KD, whereas NLRP3 was upregulated. Expression of the downstream cytokine, IL-18, was significantly upregulated in children with KD and correlated positively with inflammatory indices. Modifying DNA methylation significantly decreased the luciferase activity of the plasmid containing the ITPKC promoter region and thus, may inhibit ITPKC gene promoter activity. Furthermore, methylation modification was observed in the ITPKC promoter region of children with KD.

CONCLUSION

Modification of DNA methylation inhibits ITPKC promoter activity and is involved in NLRP3 inflammasome activation in children with KD.

Associations between interleukin 18 gene polymorphisms and susceptibility to vasculitis: A meta-analysis

Interleukin 18 (IL18), a pro-inflammatory cytokine, affects the development and progress of vasculitis. The production, expression, and function of this cytokine are affected by polymorphisms of promoter region of the IL18 gene. In this study, a meta-analysis of the associations between several IL18 polymorphisms and susceptibility to vasculitis was performed. Published literature from PubMed and Embase were retrieved. In total, nine studies comprising 1006 patients with vasculitis and 1499 controls combined, and the investigating the rs187238, rs194618, and rs360719 polymorphisms of the promoter region of the IL18 gene, were included in the meta-analysis. Pooled odds ratios (OR) and 95% confidence intervals (CI) were estimated with fixed-effects model or random-effects model. The recessive model of the rs194618 polymorphism was found to be significantly associated with a high susceptibility to vasculitis (OR = 1.54, 95% CI = 1.02–2.33, P = 0.04), especially in the Mongoloid race, where the A allele of rs194618 was associated with a low risk of the disease (OR = 0.77, 95% CI = 0.62–0.95, P = 0.01). By contrast, the rs187238 and rs360719 polymorphisms were not associated with this inflammatory condition. This meta-analysis showed that some IL18 polymorphisms are associated with susceptibility to vasculitis. (Sarcoidosis Vasc Diffuse Lung Dis 2020; 37 (2): 203-211)

The diagnostic role of AIM2 in Kawasaki disease

Kawasaki disease (KD), a systemic vasculitis in children, may bring serious complications. However, the etiology of KD remains unclear. AIM2, an intracellular receptor, plays a vital role during the infection caused by a variety of pathogens. However, its role in KD remains unclear. The principal aim of the present research is to concentrate on the relation between AIM2 and KD. We detected the levels of AIM2, IL-18 and IL-1β in all subjects by ELISA. The conventional inflammatory indices were detected in all subjects, such as WBC, HB, CRP and so on. The serum concentrations of AIM2, IL-18 and IL-1β were notably upregulated in the KD group compared to the febrile group and healthy group, respectively. And the three indicators in the KD patients were greatly reduced after interpreted with IVIG. Furthermore, the expressions of IL-18 and IL-1β were positively correlated with AIM2. Meanwhile, the cutoff value of serum AIM2 level for the diagnosis of KD was 541.90 ng/L with the specificity of 60% and sensitivity of 92.5%, compared to the febrile controls. And the area under curve (AUC) of AIM2 was 0.771. And no difference was observed in patients with CALs when compared with patients without CALs. The serum AIM2, IL-18 and IL-1β might play a critical role during the progress of KD. AIM2 can be considered as a candidate indicator for Kawasaki disease diagnosis.

Serum IP-10 and IL-17 from Kawasaki disease patients induce calcification-related genes and proteins in human coronary artery smooth muscle cells in vitro

Background

Kawasaki disease (KD) is one of the major causes of heart disease and vasculitis in children under 5 years old in the world. Clinical evidence has shown that coronary artery calcification may develop in KD patients, however the mechanism has not been elucidated. Previous studies have found that interferon-γ-inducible protein (IP)-10 and interleukin (IL)-17 can be elevated and may play a role in KD development and coronary artery lesion formation. The purpose of this in vitro study was to investigate the possible role of plasma circulating IP-10 and IL-17 of KD patients in vascular calcification development and its underlying mechanism.

Result

Human coronary artery smooth muscle cells (HCASMCs) were used in this study. We found that HCASMCs treated with IP-10/IL-17-containing KD serum and co-treated with IP-10/IL-17 recombinant proteins could induce a phenotype that may promote vascular calcification by the bone morphogenetic protein (BMP) 6 autocrine effect. Moreover, the BMP6 autocrine stimulation in IP-10/IL-17 co-treated HCASMCs could upregulate the smad1/5-runx2 signaling activation, thus increasing the expression of bone matrix-related proteins, i.e., osteopontin, osteocalcin, and alkaline phosphatase.

Conclusions

The presented in vitro results provided new insights into the comprehension of the pathogenesis of vascular calcification in SMCs in KD progression. Although additional in vivo experimental models should be completed to confirm the in vivo relevance of these in vitro findings, the results related to the autocrine role of BMP6 may provide a new direction for theranostic drug development to treat KD.

Analysis of biomarker serum levels in IVIG and infliximab refractory Kawasaki disease patients

Infliximab (IFX) is effective for treatment of refractory Kawasaki disease (KD). However, the precise mechanisms and biomarkers for IFX efficacy are unknown. We tried to evaluate the effect and response to IFX therapy by measuring serum cytokine levels. Twenty-nine children with KD who had been resistant to two courses of high-dose intravenous immunoglobulin were enrolled and treated with IFX. Plasma samples were analyzed for cytokines before and after IFX administration. Serum levels of interleukin-6, granulocyte colony-stimulating factor (G-CSF), interferon-gamma-induced monokine, interferon-gamma inducible protein 10 (IP-10), monocyte chemotactic protein 1, and soluble tumor necrosis factor-alpha receptor (sTNFR) 1 and 2 were significantly elevated before IFX treatment, but promptly decreased after the administration. The pre-treatment G-CSF and sTNFR1 levels in non-responders to IFX were significantly higher than in responders, who were defined as patients who defervesce (< 37.5 °C). After IFX administration, elevated cytokines declined to normal ranges in responders, but in non-responsive group, G-CSF and sTNFR1 remained elevated without failing to normal levels. IFX treatment significantly reduced the levels of serum cytokines, chemokines, and sTNFRs in refractory KD. G-CSF and sTNFR1 may be indicators predictive of poor response to IFX.

Interleukin-18, interleukin-12B and interferon-γ gene polymorphisms in Brazilian patients with rheumatoid arthritis: a pilot study

Polymorphisms in interleukin (IL)-18, IL-12 and interferon (IFN)-γ genes are associated with different levels of cytokines expression and have been associated with rheumatoid arthritis (RA). IL-18 +105 A/C, IL-12B +1188 A/C and IFN-γ +874 T/A polymorphisms were analyzed by restriction fragment length polymorphism-polymerase chain reaction (PCR) and amplification refractory mutation system PCR from 90 RA patients and 186 healthy individuals. There were significant differences to IL-18 +105 A/C polymorphism between the RA and control groups (odds ratio = 3.77; P < 0.0001). Individual carriers of the variant allele C had a 3.77-fold increased risk of for RA (P = 0.0032). No association was observed for IL-12B and IFN-γ polymorphisms. Our finds suggest a possible role for IL-18 polymorphism in the RA susceptibility in studied population.

CXCL10/IP-10 is a biomarker and mediator for Kawasaki disease

RATIONALE

Kawasaki disease (KD), an acute febrile vasculitis, is the most common cause of acquired heart disease in childhood; however, diagnosing KD can be difficult.

OBJECTIVE

To identify unique proteomic biomarkers that can be used to facilitate earlier diagnosis of KD.

METHODS AND RESULTS

We enrolled 214 children with fever and clinical features suggestive of KD. Of those, only 100 were diagnosed with KD. Their plasma samples were globally analyzed for cytokines, chemokines, and cell adhesion molecules using an unbiased, large-scale, quantitative protein array. This study was conducted in 3 stages: discovery, replication, and blinded validation. During the discovery phase (n [KD]=37; n [control]=20), the expression of interleukin-17F, sCD40L, E-selectin, CCL23 (myeloid progenitor inhibitory factor 1), and CXCL10 (IFN-γ-inducible protein 10 [IP-10]) were upregulated during the acute phase in patients with KD when compared with that in the controls. A notable increase was observed in the IP-10 levels (KD, 3037 ± 226.7 pg/mL; control, 672 ± 130.4 pg/mL; P=4.1 × 10(-11)). Receiver-operating characteristic analysis of the combined discovery and replication data (n [KD]=77; n [control]=77) showed that the IP-10 level had high area under the curve values (0.94 [95% confidence interval, 0.9055-0.9778]; sensitivity, 100%; and specificity, 77%). With 1318 pg/mL as the optimal cutoff, the blinded validation study confirmed that the IP-10 levels were a good predictor of KD. With intravenous immunoglobulin treatment, the IP-10 levels returned to normal. The downstream receptor of IP-10, CXCR3, was activated in the T cells of patients with acute KD.

CONCLUSIONS

IP-10 may be used as a biomarker to facilitate KD diagnosis, and it may provide clues about the pathogenesis of KD.

Association of interleukin-18 gene polymorphisms with the outcomes of hepatitis C virus infection in high-risk Chinese Han population

Interleukin 18 (IL-18) gene polymorphisms have been reported to be associated with the outcomes of hepatitis C virus (HCV) infection in Americans, Indians and Europeans. We aimed to investigate whether the association can be replicated in Chinese Han population. Three IL-18 variants, -656G>T, -137G>C and +105A>C, were genotyped in three independent Han cohorts consisting of 552 cases and 784 controls. By using logistic regression analysis and multiple testing, haplotype GCC were associated with a protection from susceptibility to HCV. After stratified analysis, both the carriage of -137C allele in the older or hemodialysis subgroup and the carriage of +105C allele in the younger subgroup were found to be significantly associated with a decreased risk of HCV susceptibility. By using logistic regression analysis and multiple testing for the resolution of HCV infection, our study showed that +105C allele and haplotype GGC displayed a negative effect on HCV persistence. After stratified analysis, a significantly decreased risk for HCV persistence was found in +105C allele in the subgroups of young, male or female, drug user or hemodialysis and HCV-1 or HCV mixed genotype. No significant association was observed between -656G>T and the outcomes of HCV infection. Our results demonstrated that the carriage of -137C allele, +105C allele, haplotype -656G/-137C/+105C and haplotype -656G/-137G/+105C of IL-18 gene may contribute to better outcomes of HCV infection in high-risk Chinese Han population.

Understanding the pathogenesis of Kawasaki disease by network and pathway analysis

Kawasaki disease (KD) is a complex disease, leading to the damage of multisystems. The pathogen that triggers this sophisticated disease is still unknown since it was first reported in 1967. To increase our knowledge on the effects of genes in KD, we extracted statistically significant genes so far associated with this mysterious illness from candidate gene studies and genome-wide association studies. These genes contributed to susceptibility to KD, coronary artery lesions, resistance to initial IVIG treatment, incomplete KD, and so on. Gene ontology category and pathways were analyzed for relationships among these statistically significant genes. These genes were represented in a variety of functional categories, including immune response, inflammatory response, and cellular calcium ion homeostasis. They were mainly enriched in the pathway of immune response. We further highlighted the compelling immune pathway of NF-AT signal and leukocyte interactions combined with another transcription factor NF- κ B in the pathogenesis of KD. STRING analysis, a network analysis focusing on protein interactions, validated close contact between these genes and implied the importance of this pathway. This data will contribute to understanding pathogenesis of KD.

Polymorphisms of transforming growth factor-β signaling pathway and Kawasaki disease in the Taiwanese population

Kawasaki disease (KD) is a systemic vasculitis associated with cardiovascular symptom. A previous study in the European descent has indicated that genetic variants of the transforming growth factor-β (TGF-β) pathway are involved in the KD susceptibility and clinical status. This study was conducted to investigate if polymorphisms in TGF-β signaling pathway are associated with KD susceptibility, and the coronary artery lesion formation. A total of 950 subjects (381 KD patients and 569 controls) were investigated to identify 12 single-nucleotide polymorphisms in the TGF-β signaling pathway (rs2796817, rs10482751, rs2027567, rs12029576, rs11466480, rs4776338, rs12901071, rs7162912, rs1438386, rs6494633, rs12910698 and rs4776339) by using TaqMan Allelic Discrimination assay. Our results indicated that rs1438386 in the SMAD3 is significantly associated with the susceptibility of KD. Additionally, both haplotypes of TGFβ2 and SMAD3 were also associated with the risk of KD. This study showed that genetic polymorphisms in TGF-β signaling pathway are associated with KD susceptibility, but not coronary artery lesions formation, or intravenous immunoglobulin treatment response in the Taiwanese population.

Genetic polymorphisms in Kawasaki disease

Kawasaki disease (KD) is an acute febrile systemic vasculitis, and the cause of KD is not well understood. It is likely due to multiple interactions between genes and environmental factors. The development of genetic association and genome-wide association studies (GWAS) has opened an avenue to better understanding the molecular mechanisms underlying KD. A novel ITPKC signaling pathway was recently found to be responsible for the susceptibility to KD. Furthermore, the GWAS demonstrated the functionally related susceptibility loci for KD in the Caucasian population. In the last decade, the identification of several genomic regions linked to the pathogenesis of KD has made a major breakthrough in understanding the genetics of KD. This review will focus on genetic polymorphisms associated with KD and describe some of the possible clinical implications and molecular mechanisms that can be used to explain how genetic variants regulate the pathogenesis in KD.

Involvement of tryptophan hydroxylase 2 (TPH2) gene polymorphisms in susceptibility to coronary artery lesions in Korean children with Kawasaki disease

Kawasaki disease (KD) is an acute vasculitis of childhood that predominantly affects the coronary arteries. We investigated single nucleotide polymorphisms (SNPs) of the tryptophan hydroxylase 2 (TPH2) gene as risk factors for KD with coronary artery lesions (CALs) in Korean children. We genotyped two SNPs [rs7305115 (exon 7) and rs4290270 (exon 9)] using direct sequencing in 101 KD and 256 control subjects. To analyze the genetic data, SNPStats, SNPAnalyzer, and Helixtree programs were used. The genotype analysis of rs7305115 and rs4290270 showed no significant differences between KD and control groups. However, we found a statistically significant association between the two SNPs and the development of CALs in KD (p < 0.05). The minor homozygous genotype (rs7305115, AA genotype and rs42901270, AA genotype) of each SNP showed increased susceptibility to risk of CALs in KD patients. These results suggest that TPH2 may be associated with the development of KD with CALs in Korean children.