Interleukin-1 Beta-Mediated Sex Differences in Kawasaki Disease Vasculitis Development and Response to Treatment.

OBJECTIVE: Kawasaki disease (KD) is the leading cause of acute vasculitis and acquired heart disease in children in developed countries. Notably, KD is more prevalent in males than females. We previously established a key role for IL (interleukin)-1 signaling in KD pathogenesis, but whether this pathway underlies the sex-based difference in susceptibility is unknown. Approach and Results: The role of IL-1 signaling was investigated in the Lactobacillus casei cell wall extract-induced experimental mouse model of KD vasculitis. Five-week-old male and female mice were injected intraperitoneally with PBS, Lactobacillus caseicell wall extract, or a combination of Lactobacillus caseicell wall extract and the IL-1 receptor antagonist Anakinra. Aortitis, coronary arteritis inflammation score and abdominal aorta dilatation, and aneurysm development were assessed. mRNA-seq (messenger RNA sequencing) analysis was performed on abdominal aorta tissue. Publicly available human transcriptomics data from patients with KD was analyzed to identify sex differences and disease-associated genes. Male mice displayed enhanced aortitis and coronary arteritis as well as increased incidence and severity of abdominal aorta dilatation and aneurysm, recapitulating the increased incidence in males that is observed in human KD. Gene expression data from patients with KD and abdominal aorta tissue of Lactobacillus caseicell wall extract-injected mice showed enhanced Il1b expression and IL-1 signaling genes in males. Although the more severe IL-1ß-mediated disease phenotype observed in male mice was ameliorated by Anakinra treatment, the milder disease phenotype in female mice failed to respond. CONCLUSIONS: IL-1ß may play a central role in mediating sex-based differences in KD, with important implications for the use of anti-IL-1ß therapies to treat male and female patients with KD.

Kawasaki disease fact check: Myths, misconceptions and mysteries.

Kawasaki disease (KD) is an important cause of childhood vasculitis and a common cause of acquired heart disease in children world-wide. The emergence of Paediatric Multisystem Inflammatory Syndrome-Temporally Associated with SARS-CoV-2, a KD-like hyperinflammatory syndrome and the recent death of Dr Tomisaku Kawasaki make this a timely review. Although KD was described by Dr Kawasaki over 50 years ago, there is still no specific diagnostic test and the aetiology remains elusive. This article summarises the latest evidence, highlights important myths and misconceptions and discusses some of the mysteries that surround this disease.

Kawasaki disease with tsutsugamushi disease: two case reports.

A number of microorganisms were hypothesised as an aetiology of the Kawasaki disease. Unfortunately, no specific agent that provides reproducible evidence has yet been reported. We report two cases of extremely rare Kawasaki disease with tsutsugamushi disease. These case reports suggest that Kawasaki disease can rarely occur concurrently or immediately after a rickettsial illness such as tsutsugamushi disease.

What's new with common, uncommon and rare rashes in childhood.

PURPOSE OF REVIEW: Children with rashes account for many of the outpatient visits to a general pediatrician. As such, pediatricians are often the first to identify and treat these rashes. Establishing an approach to common, uncommon and rare pediatric rashes assists in accurate assessment. This review highlights newly identified clinical patterns and disease severity. RECENT FINDINGS: Group A ß-hemolytic streptococci (GABHS) have been shown to be an important cause of intertrigo and to cause more widespread disease in some instances. Superficial skin infections with GABHS have been associated with strains secreting exfoliating toxins, whereas deeper infections have been associated with superantigen toxins. Hand-foot-and-mouth disease (HFMD) outbreaks have occurred with more virulent strains, causing more widespread disease that may be confused with eczema herpeticum or varicella. Mycoplasma pneumoniae has been shown to be an important cause of common disorders such as urticaria, and less common disorders such as Stevens-Johnson syndrome and Mycoplasma-associated mucositis. Recurrent toxin-mediated erythema is a recently described entity that must be differentiated from Kawasaki disease. SUMMARY: The number of rashes acquired in childhood is vast, requiring the pediatrician to be able to identify worrisome rashes from those with a more benign course. Key clinical signs may assist in clinical diagnosis and treatment.

Metagenomic analysis demonstrates distinct changes in the gut microbiome of Kawasaki diseases children.

Background: Kawasaki disease (KD) has been considered as the most common required pediatric cardiovascular diseases among the world. However, the molecular mechanisms of KD were not fully underlined, leading to a confused situation in disease management and providing precious prognosis prediction. The disorders of gut microbiome had been identified among several cardiovascular diseases and inflammation conditions. Therefore, it is urgent to elucidate the characteristics of gut microbiome in KD and demonstrate its potential role in regulating intravenous immunoglobulin (IVIG) resistance and coronary artery injuries. Methods: A total of 96 KD children and 62 controls were enrolled in the study. One hundred forty fecal samples had been harvested from KD patients, including individuals before or after IVIG treatment, with or without early coronary artery lesions and IVIG resistance. Fecal samples had been collected before and after IVIG administration and stored at -80°C. Then, metagenomic analysis had been done using Illumina NovaSeq 6000 platform. After that, the different strains and functional differences among comparisons were identified. Results: First, significant changes had been observed between KD and their controls. We found that the decrease of Akkermansia muciniphila, Faecalibacterium prausnitzii, Bacteroides uniformis, and Bacteroides ovatus and the increase of pathogenic bacteria Finegoldia magna, Abiotrophia defectiva, and Anaerococcus prevotii perhaps closely related to the incidence of KD. Then, metagenomic and responding functional analysis demonstrated that short-chain fatty acid pathways and related strains were associated with different outcomes of therapeutic efficacies. Among them, the reduction of Bacteroides thetaiotaomicron, the enrichment of Enterococcus faecalis and antibiotic resistance genes had been found to be involved in IVIG resistance of KD. Moreover, our data also revealed several potential pathogenetic microbiome of that KD patients with coronary artery lesions. Conclusion: These results strongly proved that distinct changes in the gut microbiome of KD and the dysfunction of gut microbiomes should be responsible for the pathogenesis of KD and significantly impact the prognosis of KD.

Bacille Calmette Guérin (BCG) can induce Kawasaki disease-like features in programmed death-1 (PD-1) gene knockout mice.

OBJECTIVES: Various genetic variants of inhibitory immune signals have been suspected as feasible causes of Kawasaki disease (KD). We investigated the associative role of programmed death-1 (PD-1) gene in the pathogenesis of KD by injecting bacilli Calmette Guérin (BCG) to PD-1 gene knockout (PD-1KO) mice. METHODS: In order to induce KD-like clinical manifestations in young PD-1KO mice, intradermal injection of the bacilli Calmette Guérin (BCG) was performed twice on the abdominal skin with a 4-week interval. For defining the role of BCG, heat shock protein (HSP) 65 was challenged. In addition, Staphylococcus aureus was adopted as a microorganism that does not contain HSP65 structure. One month after the second injection, heart, liver, and kidneys were removed and examined. RESULTS: PD-1KO mice showed KD-like features including prolonged fever for more than 5 days, erythematous swelling on soles, tail skin desquamation, and gallbladder (GB) hydrops. Inflammatory cell aggregation and intimal proliferation in at least more than one coronary artery was found in all PD-1KO mice whereas scanty coronary lesion was found in wild type (WT) mice. When the PD-1KO mice were injected twice with HSP65, coronary arterial lesions similar to those seen after BCG injection were observed. Inflammatory reactions in other organs including hepatic arteries, renal arteries, and biliary arteries were also observed in PD-1KO mice. CONCLUSIONS: Our data suggest that PD-1 gene may be one of the genetic predispositions of KD and antigens containing HSP65 structure could be a triggering factor of KD by our animal model of KD.

Correlation of gut microbial compositions to the development of Kawasaki disease vasculitis in children.

Aim: Here, we hypothesize that dysbiotic gut microbiota might contribute to the development of Kawasaki disease (KD), a pediatric disease with unknown etiology. This is the second report on gut microbiota composition in KD patients. Materials & results: 16S amplicon sequencing was performed on fecal DNA samples and revealed predominance of bacterial pathogens, such as Fusobacterium, Neisseria, Shigella and Streptococcus, in the gut of KD patients, but absent or suppressed after immunoglobulin/antibiotics therapy. In addition, beneficial bacteria propagated after the therapy. Conclusion: We conclude that prevalence of Fusobacteria, Shigella and Streptococcus might contribute to KD pathogenesis.

Altered gut microbiota correlated with systemic inflammation in children with Kawasaki disease.

Kawasaki disease (KD) is a multi-systemic vasculitis of unknown etiology that occurs mainly in children, and the disturbance of gut microbiota is generally believed to cause a hyperimmune reaction triggering KD. The aim of the study was to investigate the alterations in the fecal microbiota and assess its relationship with systemic inflammation. Totally 30 KD children were enrolled and followed up for 6 months, with another group of 30 age- and sex-matched healthy children as controls. Phylotype profiles of fecal microbial communities were analyzed using 16S rRNA gene sequencing. Serum inflammatory markers were detected by flow cytometer. We showed that KD children exhibited a significant reduction in fecal microbial diversity in the acute phase compared with the healthy controls. Enterococcus, Acinetobacter, Helicobacter, Lactococcus, Staphylococcus and Butyricimonas in acute KD children were significantly higher than the healthy children. Levels of systemic inflammation biomarkers, including IL-2, IL-4, IL-6, IL-10, TNF-α, and INF-γ, were significantly elevated in the acute KD children. Altered microbiota genera Enterococcus and Helicobacter abundances were shown to be correlated positively with IL-6, which were never previously reported in KD. This study suggested that gut microbiota alteration is closely associated with systemic inflammation, which provides a new perspective on the etiology and pathogenesis of KD.

Heat shock proteins and superantigenic properties of bacteria from the gastrointestinal tract of patients with Kawasaki disease.

We previously suggested that gut bacteria may be involved in the onset of Kawasaki disease (KD). In this study, we evaluated the production of heat shock proteins (hsps) and superantigens (sAgs) by microorganisms isolated from the jejunal mucosa of 19 children with KD in the acute phase and from 15 age-matched control children. We identified 13 strains of Gram-negative microbes from patients with KD; these microbes produced large amounts of hsp60 and induced pro-inflammatory cytokine production by peripheral blood mononuclear cells. The Gram-negative microbes also elicited endogenous hsp60 production, leading to the secretion of anti-inflammatory intereukin-10 (IL-10). We also identified 18 strains of Gram-positive cocci that had superantigenic properties and which induced the expansion of Vbeta2 T cells in vitro. All bacteria identified in this study were antibiotic resistant. These data suggest that sAg and hsps produced by gut bacteria might be involved in KD.

[Previous or coincident infections with suspected Kawasaki disease. Should we change our approach?] / Infecciones previas o coincidentes con la sospecha de enfermedad de Kawasaki ¿debemos cambiar nuestra actitud?

INTRODUCTION: Kawasaki disease (KD) is a multisystem vasculitis associated with coronary artery abnormalities. Infections could be a trigger of the inflammation. The main aim of this study was to describe the presence of infections in children with KD, and to analyse the clinical characteristics and the presence of coronary abnormalities in these cases. PATIENTS AND METHODS: A retrospective study was performed within the Kawasaki Diseases Network (KAWA-RACE (2011-2016). An analysis was performed that included patients with positive microbiological findings (PMF) during the acute phase, as well as those with a previous recent infection (PRI) during the 4 weeks preceding KD diagnosis. RESULTS: The study included total of 621 children with KD, with PMF being found in 101 (16.3%) patients, and a PRI in 107 (17.2%). Significantly less echocardiographic abnormalities were found in the in the group with a PRI, when compared to those without a PRI (23 vs. 35%, P=.01) and also a lower proportion of overall coronary artery lesions (16 vs. 25%, P=.054). No significant differences were found in the proportion of aneurysms in either of these groups (PRI or PMF) when compared to those without infection. CONCLUSIONS: In the present study, no differences were found in the incidence of coronary aneurysms in either of the groups, with or without PRI or PMF. Therefore, if KD is suspected, appropriate treatment should be started despite having a confirmed infection.

Endothelial cell pyroptosis plays an important role in Kawasaki disease via HMGB1/RAGE/cathespin B signaling pathway and NLRP3 inflammasome activation.

Kawasaki disease (KD) is the most common cause of pediatric cardiac disease in developed countries, and can lead to permanent coronary artery damage and long term sequelae such as coronary artery aneurysms. Given the prevalence and severity of KD, further research is warranted on its pathophysiology. It is known that endothelial cell damage and inflammation are two essential processes resulting in the coronary endothelial dysfunction in KD. However, detailed mechanisms are largely unknown. In this study, we investigated the role of pyroptosis in the setting of KD, and hypothesized that pyroptosis may play a central role in its pathophysiology. In vivo experiments of patients with KD demonstrated that serum levels of pyroptosis-related proteins, including ASC, caspase-1, IL-1ß, IL-18, GSDMD and lactic dehydrogenase (LDH), were significantly increased in KD compared with healthy controls (HCs). Moreover, western blot analysis showed that the expression of GSDMD and mature IL-1ß was notably elevated in KD sera. In vitro, exposure of human umbilical vein endothelial cells (HUVECs) to KD sera-treated THP1 cells resulted in the activation of NLRP3 inflammasome and subsequent pyroptosis induction, as evidenced by elevated expression of caspase-1, GSDMD, cleaved p30 form of GSDMD, IL-1ß and IL-18, and increased LDH release and TUNEL and propidium iodide (PI)-positive cells. Furthermore, our results showed that NLRP3-dependent endothelial cell pyroptosis was activated by HMGB1/RAGE/cathepsin B signaling. These findings were also recapitulated in a mouse model of KD induced by Candida albicans cell wall extracts (CAWS). Together, our findings suggest that endothelial cell pyroptosis may play a significant role in coronary endothelial damage in KD, providing novel evidence that further elucidates its pathophysiology.

[Etiologic agent of Kawasaki disease].

Clinical and epidemiologic features suggest infectious agent or agents as a possible cause of Kawasaki disease; however, the etiology of Kawasaki disease still remains unknown. A number of microorganisms including bacteria, viruses, rickettsiae etc. were hypothesized as an etiology of the illness. Unfortunately, no specific agent that provides reproducible evidence has yet reported. The differences of histology between vasculitic disorders indicate the differences of etiology and pathogenesis. The histological characteristics that abnormal activation of monocytes/macrophages is caused in the vascular lesions of Kawasaki disease can be of help when considering the etiology of Kawasaki disease.

[Kawasaki disease and infection].

Kawasaki disease (KD) is an acute multisystemic vasculitis. Although some infectious agents are highly suspected the etiology of KD remains unknown. Various bacteria such as, Streptococcus pyogenes, Staphylococcus aureus, and Yersinia pseudotuberculosis have been implicated in etiology of KD. However, modern molecular techniques failed to identify the positive relation between these agents and etiology of KD. Recently, one hypothesis suggests that superantigens (TSS-1, SEB, SEC, SPEB, SPEC), which are produced by streptococci and staphylococci, play an important role in the cause of KD. Although several studies show that superantigens, mainly bacterial toxins and viral antigens, are involved in causing some diseases, there is no obvious evidence that superantigens are able to induce KD. Host-derived factor as well as infectious agents should be investigated to understand the immunopathogenesis of KD.

Profile of resistance to IVIG treatment in patients with Kawasaki disease and concomitant infection.

INTRODUCTION: Kawasaki disease (KD) can be associated with concomitant viral or bacterial infections. Children with persistent or recurrent fever 36 hours after the end of intravenous immunoglobulin (IVIG) are considered to be resistant to treatment and are at increased risk for coronary complications. Although concomitant infection does not affect coronary outcome, it is unknown how it influences the response to IVIG treatment. METHODOLOGY: Retrospective cohort study between 2008 and 2016 in a tertiary pediatric university hospital, including 154 children, of which 59 (38%) had concomitant infection. RESULTS: Children with concomitant infection were more likely to have fever 48 hours after initial IVIG treatment (36% vs 20%, p = 0.05) and to be treated with a second dose (33% vs 18%, p = 0.04). Children with infection had higher C-reactive protein at the time of diagnosis (148 vs 112 mg/L, p = 0.04), and 48 hours after IVIG administration (111 vs 59 mg/L, p = 0.003). Nevertheless, there was no statistically significant difference in the prevalence of coronary complications (Z-score > 2.5) between children with and without concomitant infection (36% vs 39%, p = 0.68). CONCLUSION: Children with KD and concomitant infection are more likely to have persistent fever and elevated inflammatory markers after treatment. This association increases the likelihood of receiving a second dose of IVIG but not the risk of coronary complication. Accordingly, prospective studies to distinguish true IVIG resistance from infection induced persistent fever is warranted.

Similarities of Kawasaki disease and Yersinia pseudotuberculosis infection epidemiology.

Although an infectious etiology is strongly suspected in Kawasaki disease (KD), an etiologic agent has not yet been identified. By reviewing epidemiologic data published in past decades, this work highlights a higher incidence of KD when populations were exposed to the risk of Yersinia pseudotuberculosis infection. This hitherto unnoticed element reinforces the hypothesis whereby this bacterium might contribute to the development of KD in some cases.

Clostridium baratii bacteremia associated with Kawasaki syndrome. First case report.

We experienced a case of a 3-year-old boy who presented signs and symptoms of Kawasaki syndrome. Two blood culture sets were processed by the hospital microbiology laboratory using a standard blood culturing system. The anaerobic bottles gave a positive result at day 3 after inoculation. The biochemical profiles produced by the RapID ANA II System showed that the organism was Clostridium baratii with a probability of 99%. Our case highlights the importance of C. baratii as a potential human pathogen and reports the associations with manifestations, which, to our knowledge, have not been previously described concomitantly with a clostridial infection.

Clarithromycin Plus Intravenous Immunoglobulin Therapy Can Reduce the Relapse Rate of Kawasaki Disease: A Phase 2, Open-Label, Randomized Control Study.

BACKGROUND: We previously reported that biofilms and innate immunity contribute to the pathogenesis of Kawasaki disease. Therefore, we aimed to assess the efficacy of clarithromycin, an antibiofilm agent, in patients with Kawasaki disease. METHODS AND RESULTS: We conducted an open-label, multicenter, randomized, phase 2 trial at 8 hospitals in Japan. Eligible patients included children aged between 4 months and 5 years who were enrolled between days 4 and 8 of illness. Participants were randomly allocated to receive either intravenous immunoglobulin (IVIG) or IVIG plus clarithromycin. The primary end point was the duration of fever after the initiation of IVIG treatment. Eighty-one eligible patients were randomized. The duration of the fever did not differ between the 2 groups (mean±SD, 34.3±32.4 and 31.1±31.1 hours in the IVIG plus clarithromycin group and the IVIG group, respectively [P=0.66]). The relapse rate of patients in the IVIG plus clarithromycin group was significantly lower than that in the IVIG group (12.5% versus 30.8%, P=0.046). No serious adverse events occurred during the study period. In a post hoc analysis, the patients in the IVIG plus clarithromycin group required significantly shorter mean lengths of hospital stays than those in the IVIG group (8.9 days versus 10.3 days, P=0.049). CONCLUSIONS: Although IVIG plus clarithromycin therapy failed to shorten the duration of fever, it reduced the relapse rate and shortened the duration of hospitalization in patients with Kawasaki disease. CLINICAL TRIAL REGISTRATION: URL: http://www.umin.ac.jp/ctr/index.htm. Unique identifier: UMIN000015437.