Aetiological Significance of Infectious Stimuli in Kawasaki Disease

Concurrent infections in children with Kawasaki disease: lessons learned over 26 years

Etiology of Kawasaki disease (KD) remains an enigma despite more than 50 years of extensive research. There is evidence that concurrent infections may play a role in the pathogenesis of KD. The present study reports various infections identified in a large cohort of patients with KD in Northwest India. We reviewed case records of patients with KD from January 1994 to February 2020. Patients with KD identified to have concurrent infection at presentation were analyzed in detail. Of 878 cases of KD during this period, 88 (60 boys, 28 girls; 64 incomplete KD, 24 complete KD) had evidence of concurrent infection. Infective manifestations included superficial and deep-seated abscesses (27.45%), pneumonia (28.4%), gastrointestinal manifestations (29.5%), urinary tract infection (4.5%), and septic arthritis (2.3%). Infectious agents were confirmed in 67/88 patients (76.13%) - these included bacteria (n = 51), viruses (n = 13), fungi (n = 2), and protozoa (n = 1). Among bacteria, infections with Staphylococcus sp. and Streptococcus sp. were the commonest (19/88 and 14/88 patients, respectively). Eighty-one children were treated with intravenous immunoglobulin (IVIg, 2 g/kg) and aspirin. Coronary artery abnormalities (CAAs) were seen in 11/88 patients (12.5%) during the acute phase - these normalized at 6 weeks of follow-up in all patients. To conclude, concurrent infections were seen in 10% of patients with KD at our center. If the clinical presentation suggests KD, one should not exclude the diagnosis even if there is evidence of an accompanying infection. Although 12.5% of patients with infection-associated KD had CAAs, none had persistent CAAs at 6 weeks of follow-up.

Associations of infection burden with Kawasaki disease in a population-based setting during 30 years

OBJECTIVES

The objective of this study was to investigate the role of infections in the pathogenesis of Kawasaki disease.

METHODS

The investigation was a nationwide epidemiological case-control study, comprising all cases of Kawasaki disease diagnosed in Sweden 1987-2018. Controls were randomly sampled from the general population, matched on sex, age, and area of residency. Data on infections were obtained from the Swedish National Patient Register, which prospectively collects data on all Swedish residents. Infections were classified by organ system, infectious agent and by temporal proximity to Kawasaki disease diagnosis date. Prescription of antibiotics and infections in family members were also considered in separate analyses.

RESULTS

The study comprised n=1774 (61% male) cases and n=17 731 controls. Overall, a history of infections was associated with Kawasaki disease with an OR of 2.3 (95% CI 2.0 to 2.5). Respiratory, skin, urogenital and gastrointestinal tract infections were all associated with Kawasaki disease. Temporal stratification revealed a prominent clustering of infections during the weeks before a Kawasaki diagnosis, but also higher frequencies of infections several months preceding Kawasaki disease with OR ranging from 5.1 (95% CI 3.6 to 7.1) 15-28 days to 1.3 (95% CI 1.1 to 1.6) 181-365 days prior Kawasaki disease. A dose-response relationship was observed, with repeated infections associating with higher ORs of Kawasaki.

CONCLUSIONS

The findings suggest that infections are closely linked with Kawasaki disease, and with a wider temporal association than previously known. Further, the data imply that many different agents may induce the disease.

Nomogram model based on serum chitotriosidase activity to predict coronary artery aneurysm in Kawasaki disease

OBJECTIVE

Kawasaki disease (KD) is a common children's disease with unknown etiology, which easily involves coronary artery and causes serious cardiovascular sequelae. The purpose was to investigate the relationship between chitotriosidase activity and coronary artery aneurysm (CAA) and develop and validate a nomogram to predict CAA in KD patients.

METHODS

A total of 338 KD patients were included in this study. Differences analysis compared baseline characteristics and multivariate logistic regression analysis to determine independent risk factors for CAA in KD patients. Based on this independent risk factor, the nomogram was constructed and validated.

RESULTS

Of 338 KD patients, 107 patients developed CAA. Multivariate logistic regression analysis identified that low-density lipoprotein (LDL) [odds ratio (OR):1.456, 95% confidence interval (CI): 1.062-1.996], age (OR: 0.986, 95% CI: 0.974-0.998), neutrophil-to-lymphocyte ratio (NLR) (OR: 1.098, 95% CI: 1.020-1.182), and chitotriosidase activity (OR: 1.115, 95% CI: 1.111-1.192) were independent predictors for CAA. The nomogram was established based on serum chitotriosidase activity and clinical characteristics, and this nomogram has demonstrated to be of potential value in clinical practice using the receiver operating characteristic curve, calibration curve, and decision curve analysis.

CONCLUSION

LDL, age, NLR, and chitotriosidase activity were independent risk factors for CAA. Based on this independent risk factor, the nomogram was constructed to guide clinicians to effectively predict CAA and adopt appropriate interventions such as more aggressive anti-inflammatory and more frequent follow-up.

Identification of key ferroptosis‑related biomarkers in Kawasaki disease by clinical and experimental validation

Kawasaki disease (KD) is an acute febrile rash that is primarily characterized by systemic vasculitis and is the leading cause of childhood-acquired heart disease. At present, a KD diagnosis is solely dependent on clinical symptoms and effective diagnostic markers are unavailable. Ferroptosis, a novel form of programmed cell death, contributes to the pathophysiology of infectious diseases. The present study aimed to identify key ferroptosis-related genes (FRGs) involved in the pathological process of KD and thus potential diagnostic biomarkers for this disease. For this purpose, differentially expressed-FRGs (DE-FRGs) between patients with KD and healthy controls were screened. The least absolute shrinkage and selection operator (LASSO) algorithm and a logistic regression model combined with receiver operating characteristic analysis were then used to identify and assess ferroptosis-related markers. Additionally, immune cell infiltration landscapes in the KD and control groups were evaluated using CIBERSORT. Moreover, the predictive value of the identified markers was validated in the clinical samples as well as vascular endothelial cells. A total of 10 DE-FRGs were screened from the KD and control samples. These 10 DE-FRGs were then applied to the LASSO model and 6 key ferroptosis-related markers were obtained. The subsequent Gene Set Variation Analysis results suggested that high expression levels of these markers were closely associated with innate immune activation and metabolism, while low expression was mainly linked to adaptive immune-related pathways. In addition to validating each gene in the training and validation sets, the diagnostic potential of these markers was assessed utilizing KD samples obtained from Shenzhen Baoan Women's and Children's Hospital. As a result, MAPK14, SLC2A3 and PGD were selected as potential diagnostic markers for KD. Additionally, changes in the expression of marker genes during inflammatory activation of vascular endothelial cells were measured by reverse transcription-quantitative PCR. The results of the present study will help to understand the role of FRGs in the pathogenesis of KD. Moreover, the identified FRGs may serve as diagnostic biomarkers, providing new strategies for KD prediction and treatment.

A Case of Refractory Kawasaki Disease With Yersinia pseudotuberculosis Infection Successfully Treated With Cefotaxime Following Immunosuppressive Therapy

Kawasaki disease (KD) is a vasculitis mainly affecting children under five, with symptoms such as persistent fever, rash, red lips, strawberry tongue, conjunctivitis, and swollen hands and feet. Diagnosis is based on a fever lasting over five days plus at least four of these symptoms. Treatment includes intravenous immunoglobulin (IVIG) and aspirin to reduce complications, especially coronary artery issues. Ye rsinia pseudotuberculosis (Y. ptsb.) infection is a gram-negative bacterium. In KD patients, the most prevalent gastrointestinal symptoms were vomiting (28.9%), abdominal pain (17.4%), and diarrhea (16.9%). By contrast, diarrhea is observed in over 50% of patients with Y. ptsb. infection. Y. pstb. is a gram-negative bacterium reported to infect a wide variety of animal hosts and contact with these animals can serve as a potential clue in diagnosis. Y. pstb. infection can mimic KD with similar fever and rash symptoms, posing a diagnostic challenge. In practice, however, differentiation remains challenging. Differentiating between KD and Y. ptsb. is essential, especially in cases resistant to typical KD treatment. Distinguishing KD from Y. pstb. infection in clinical practice is crucial to prevent misdiagnosis, avoid unnecessary immunosuppression, and minimize delays in effective treatment. Misinterpreting Y. pstb. infection as KD may lead to inappropriate treatment strategies that fail to address the underlying infection, potentially resulting in adverse patient outcomes. Accurate and timely diagnosis is therefore essential to initiate appropriate therapeutic interventions. A 16-month-old boy presented with fever and diarrhea and was initially treated for infectious gastroenteritis, with elevated inflammatory markers noted (C-reactive protein (CRP) 4.47 mg/dL, white blood cell (WBC) 8,200/μL). As his condition progressed, he developed symptoms consistent with KD, including a rash and mucous membrane changes, and was treated with IVIG and aspirin. However, the fever persisted, and elevated inflammatory markers continued (CRP 3.93 mg/dL, WBC 9,700/μL), prompting additional immunosuppressive therapies for refractory KD. Ultrasound revealed gastrointestinal and lymph node abnormalities suggestive of vasculitis. Eventually, Y. ptsb. infection was confirmed through serology, and antibiotic treatment was reintroduced, leading to defervescence. This case highlights the challenge of distinguishing KD from Y. ptsb. infection because they can coexist, complicating treatment decisions. Rapid diagnostic methods for Y. ptsb., specifically through loop-mediated isothermal amplification-polymerase chain reaction (LAMP-PCR) testing, are crucial to guide timely treatment, particularly given the risk of coronary artery complications associated with both conditions.

Secular trend of Kawasaki disease and its correlation with viral activity in Taiwan: a nationwide population-based study

BACKGROUND

Kawasaki disease (KD) is the most important acquired heart disease in children. This study investigated annual incidence, seasonality, secular trend and the correlation of KD incidence with viral activity in Taiwan.

METHODS

Through the national health insurance database, we identified KD during 2001-2020. The viral activity was obtained from nationwide surveillance database. We analyzed KD age-specific annual incidence, secular trends, seasonality and the correlation between KD incidence and common enteric or respiratory viral activity.

RESULTS

The KD incidence of subjects younger than 18 years significantly increased from 2001 to 2020 (11.78 and 22.40 per 100,000 person-years, respectively), and substantially decreased with age. Infants younger than 1 year presented the highest KD annual incidence at 105.82 to 164.34 per 100,000 person-years from 2001 to 2020. For all KD patients, the most frequently occurring season was summer followed by autumn. The KD incidence of infants younger than 1 year had significantly positive correlation with enteric (r = 0.14) and respiratory (r = 0.18) viral activity.

CONCLUSIONS

This study demonstrates the increasing trend of KD annual incidence and seasonality (more in summer and autumn) in Taiwan. The activity of common respiratory and enteric viruses was significantly correlated with KD incidence in infants.

Multisystem Inflammatory Syndrome in Children and Kawasaki Disease: A Spectrum of Postinfectious Hyperinflammatory Disease

Kawasaki disease and multisystem inflammatory syndrome in children are hyperinflammatory conditions that share similar emerging pathophysiology hypotheses, clinical features, treatment strategies, and outcomes. Although both conditions have key differences, growing evidence suggests that both conditions might be closely related on a larger spectrum of postinfectious autoimmune responses.

Concomitant Kawasaki Disease and Rotavirus Infection-More Than Just a Coincidence: A Case Report

The definitive role of viral infections, such as rotavirus, in causing Kawasaki disease (KD) remains uncertain. However, the intriguing observation of concomitant rotavirus infection and KD suggests a potential association. This study aimed to investigate this relationship. We reported a case of concomitant KD and rotavirus infection complicated by hyponatraemia and anasarca. For the systematic review, we used three large databases, namely PubMed, Ovid, and Scopus, to search articles with the terms "Kawasaki" and "rotavirus". We also used Google Scholar as our secondary source. We included articles that fulfilled the following criteria: (i) articles reporting on children aged 18 and below; (ii) articles reporting on patients infected with rotavirus prior to or concomitant with KD; and (iii) articles written in English only. Three articles were included and analysed in combination with our reported patient. All patients exhibited gastrointestinal symptoms, including diarrhoea and vomiting, in addition to non-resolving fevers, which eventually manifested more signs and symptoms to support the diagnosis of KD. Stool samples from all patients revealed positive rotavirus antigens. Two patients (n = 2) were noted to have hyponatraemia and hypoalbuminaemia. Three (n = 3) manifested coronary artery abnormalities (CAA). Even though the relationship is not fully understood yet, it is known that the combination of these two pathologies can cause catastrophic immune responses and complications.

Intravenous Immunoglobulin in Kawasaki Disease-Evolution and Pathogenic Mechanisms

Kawasaki disease (KD) is an acute vasculitis of childhood that affects the medium vessels with a special predilection to the involvement of coronary arteries. The major morbidity of this disease is due to coronary artery aneurysm, which occurs in about 25-30% of untreated cases. For decades now, intravenous immunoglobulin (IVIg) has consistently been shown to reduce the risk of CAAs to less than 5%. However, the mechanism of immunomodulation remains unclear. Several studies on the role of IVIg in the modulation of toll-like receptor pathways, autophagy, and apoptosis of the mononuclear phagocytic system, neutrophil extracellular trap, and dendritic cell modulation suggest a modulatory effect on the innate immune system. Similarly, certain studies have shown its effect on T-cell differentiation, cytokine release, and regulatory T-cell function. In this review, we discuss the potential mechanisms underlying the immunomodulatory actions of IVIg in patients with Kawasaki disease. Furthermore, we provide a summary of the evidence regarding various infusion protocols and dosages utilized in the treatment of KD patients.

Occurrence of Kawasaki disease and neoplasms in temporal proximity-single-center experience and systematic review of literature

Various factors (e.g., infections) have been postulated to trigger Kawasaki disease (KD) in genetically predisposed individuals. Whether neoplasms can trigger KD is largely unknown due to paucity of data. Herein, we provide a detailed account of KD occurring in temporal proximity (within 6 months) to neoplasms ('neoplasm-KD'). Patients with 'neoplasm-KD' diagnosed/treated at our center from January 1994 to May 2021 were included. Additionally, we performed a systematic literature review (as per PRISMA 2020 guidelines) utilizing PubMed, Web of Science and Scopus databases to retrieve details of all patients with 'neoplasm-KD' reported till June 2021. Patients with multisystem inflammatory syndrome in children were excluded. As all reports pertained to case description(s), risk of bias assessment was not performed. The details of patients with 'neoplasm-KD' were analyzed using SPSS software. Primary and secondary outcomes were occurrence of coronary artery abnormalities (CAAs) and clinical characteristics of 'neoplasm-KD', respectively. A total of 25 patients (data from 18 reports) were included in the 'neoplasm-KD' dataset. The most frequently diagnosed neoplasm was acute lymphoblastic leukemia followed by neuroblastoma and acute myeloblastic leukemia. Overall, CAAs were noted in 48% of patients. Interval between diagnoses of KD and neoplasm was shorter in patients with CAAs as compared to patients with normal coronary arteries (p-value = 0.03). Besides providing a comprehensive description of 'neoplasm-KD', this study raises a possibility that neoplasms might trigger KD. Also, 'neoplasm-KD' may be associated with a higher risk of development of CAAs. However, the small size of 'neoplasm-KD' dataset precludes definitive conclusions regarding this association. Funding: nil. Registration: PROSPERO (CRD42021270458).

Exploring the diagnostic value of eosinophil-to-lymphocyte ratio to differentiate Kawasaki disease from other febrile diseases based on clinical prediction model

Kawasaki disease (KD) is a febrile disease that affects children under 5 years of age and leads to serious cardiovascular complications such as coronary artery disease. The development of markers that can predict early is important to reduce the under- and misdiagnosis of KD. The aim of this research was to develop a diagnostic predictive model to differentiate Kawasaki disease (KD) from other febrile diseases using eosinophil-to-lymphocyte ratio (ELR) and other biomarkers. We recruited a total of 190 children with KD and 1604 children with other febrile diseases. We retrospectively collected clinical information from the children, which included laboratory data on the day of admission, such as white blood cells (WBC), hemoglobin (HGB), calcitoninogen (PCT), hypersensitive c-reactive protein (CRP), snake prognostic nutritional index (PNI), peripheral blood neutrophil-lymphocyte ratio (NLR), platelet-lymphocyte ratio (PLR), and ELR. We performed analyses using univariate analysis, multivariate logistic regression, and column line plots, and evaluated the diagnostic parameters of the predictive models. ELR was significantly increased in patients with KD. After multivariate logistic regression, WBC, HGB, CRP, NLR, ELR and PNI were finally included as indicators for constructing the prediction model. The ROC curve analysis suggested that the C-index of the diagnostic prediction model was 0.921. The calibration curve showed good diagnostic performance of the columnar graph model. The cut-off value of ELR alone for KD was 0.04, the area under the ROC curve was 0.809. Kids with KD show highly expressive level of ELR compared to children with febrile disease, which can be used to diagnose KD, and column line graphs constructed together with other indicators can help pediatricians to identify KD more effectively from febrile children.

Kawasaki disease in Malaysia: Biochemical profile, characterization, diagnosis and treatment

Introduction

Kawasaki disease (KD) is an acute idiopathic systemic vasculitis with a self- limiting course that predominantly affects children under 5 years old, particularly in the East Asian countries. Nevertheless, to date, the data on KD in Malaysia are limited. This study aimed to evaluate the epidemiology, clinical features, treatment, and outcomes of KD among the pediatric patients admitted to Hospital Canselor Tunku Muhriz (HCTM), Kuala Lumpur, Malaysia.

Method

A retrospective cohort study of 66,500 pediatric patients presented at HCTM from the year 2004 to 2021 was conducted.

Results

62 KD cases out of 66,500 pediatric admissions were reported, with a male-to-female ratio of 1.58 to 1. Majority of KD patients (95.0%) were younger than 5 years old. Prior infection was reported in 5 KD patients (8.1%). Apart from the classical features, manifestations of various organ systems including cardiovascular (16.1%), gastrointestinal (43.5%), neurological (1.61%), musculoskeletal (1.61%), and genitourinary (17.7%) systems were observed. There was a significant association between sterile pyuria and coronary artery aneurysm (CAA) (p < 0.05). Interestingly, abnormal liver parameters (p < 0.05) and incomplete KD (p < 0.05) were significantly related to IVIG resistance.

Discussion

The presence of family history, immunological disorder, and previous infection in our KD patients suggested that there is a possibility of genetic, immunological, and infectious roles in the pathophysiology of KD. IVIG resistance is more likely to occur in KD patients with hepatic dysfunction or incomplete KD presentation. These findings highlighted the significant contribution of laboratory parameters to the prognosis of KD, prompting more in-depth research on the KD scoring systems and their relevance in this country.

Research trends on causes of Kawasaki disease in the COVID-19 era: focus on viral infections

Despite studies on the etiology of Kawasaki disease (KD) ongoing for half a century since its discovery, its cause has not yet been clearly identified. Although the clinical, epidemiological, and pathophysiological characteristics of KD are presumed to be closely related to infectious diseases, studies of various pathogens to identify its etiology have been actively conducted. To date, bacteria, fungi, and viruses have been investigated to determine the relationship between KD and infection, among which viruses have attracted the most attention. In particular, during the coronavirus disease 2019 pandemic, there were many reports in Europe of a sharp increase in cases of Kawasaki-like disease (KLD), while conflicting reports that the prevalence of KD decreased due to thorough "social distancing" or "wearing mask" in Asian countries drew more attention regarding the association between KD and viral infection. Therefore, the differential diagnosis of KD from KLD with these similar spectra has become a very important issue; simultaneously, research to solve questions about the association between KD and viral infections, including sudden acute respiratory syndrome coronavirus 2, is drawing attention again. Moreover, a new concept has emerged that immune responses occurring in patients with KD can be caused by the pathogen itself as well as host cells damaged by infection. This paper summarizes the research trends into KD etiology and related pathophysiology, especially its association with viral infections, and present future research tasks to increase our understanding of KD.

Virus Infection and Systemic Inflammation: Lessons Learnt from COVID-19 and Beyond

Respiratory infections with newly emerging zoonotic viruses such as SARS-CoV-2, the etiological agent of COVID-19, often lead to the perturbation of the human innate and adaptive immune responses causing severe disease with high mortality. The responsible mechanisms are commonly virus-specific and often include either over-activated or delayed local interferon responses, which facilitate efficient viral replication in the primary target organ, systemic viral spread, and rapid onset of organ-specific and harmful inflammatory responses. Despite the distinct replication strategies, human infections with SARS-CoV-2 and highly pathogenic avian influenza viruses demonstrate remarkable similarities and differences regarding the mechanisms of immune induction, disease dynamics, as well as the long-term sequelae, which will be discussed in this review. In addition, we will highlight some important lessons about the effectiveness of antiviral and immunomodulatory therapeutic strategies that this pandemic has taught us.

Gut Microbiota Dysbiosis in Childhood Vasculitis: A Perspective Comparative Pilot Study

Kawasaki disease (KD) and Henoch-Schönlein purpura (HSP) are the most frequent vasculitis in childhood. For both, a multifactorial mechanism has been hypothesised, with an abnormal immune response in genetically predisposed children. Gut microbiota (GM) alterations might trigger the hyperimmune reaction. Our aim was to explore the GM in KD and compare it with the GM of HSP and febrile children. Children diagnosed with KD, HSP and non-KD febrile illness (F) were enrolled. GM was profiled by 16S rRNA gene sequencing and compared with the profiles of healthy children from previous studies. We enrolled 13 KD, 10 HSP and 12 F children. Their GM significantly differed from controls, with an overall reduction in the relative abundance of beneficial taxa belonging to the Ruminococcaceae and Lachnospiraceae families. Potential KD and HSP signatures were identified, including smaller amounts of Dialister in the former, and Clostridium and Akkermansia in the latter. Notably, the GM structures of KD, HSP and F patients stratified by abdominal involvement, with more severe dysbiosis in those suffering from intestinal symptoms. This is the first study analysing GM in a mostly Caucasian cohort of KD and HSP children. Our data could open up new opportunities for childhood vasculitis treatment.

An Artificial Intelligence-guided signature reveals the shared host immune response in MIS-C and Kawasaki disease

Multisystem inflammatory syndrome in children (MIS-C) is an illness that emerged amidst the COVID-19 pandemic but shares many clinical features with the pre-pandemic syndrome of Kawasaki disease (KD). Here we compare the two syndromes using a computational toolbox of two gene signatures that were developed in the context of SARS-CoV-2 infection, i.e., the viral pandemic (ViP) and severe-ViP signatures and a 13-transcript signature previously demonstrated to be diagnostic for KD, and validated our findings in whole blood RNA sequences, serum cytokines, and formalin fixed heart tissues. Results show that KD and MIS-C are on the same continuum of the host immune response as COVID-19. Both the pediatric syndromes converge upon an IL15/IL15RA-centric cytokine storm, suggestive of shared proximal pathways of immunopathogenesis; however, they diverge in other laboratory parameters and cardiac phenotypes. The ViP signatures reveal unique targetable cytokine pathways in MIS-C, place MIS-C farther along in the spectrum in severity compared to KD and pinpoint key clinical (reduced cardiac function) and laboratory (thrombocytopenia and eosinopenia) parameters that can be useful to monitor severity.

Exploration of Potential Biomarker Genes and Pathways in Kawasaki Disease: An Integrated in-Silico Approach

Kawasaki disease (KD) is a common childhood systemic vasculitis with a special predilection for coronary arteries. Even after more than five decades of the initial description of the disease, the etiology of KD remains an enigma. This transcriptome data re-analysis study aimed to elucidate the underlying pathogenesis of KD using a bioinformatic approach to identify differentially expressed genes (DEGs) to delineate common pathways involved in KD. Array datasets from the Gene Expression Omnibus database were extracted and subjected to comparative meta-analysis for the identification of prominent DEGs. Fifteen hub genes with high connectivity were selected from these DEGs (IL1B, ITGAM, TLR2, CXCL8, SPI1, S100A12, MMP9, PRF1, TLR8, TREM1, CD44, UBB, FCER1G, IL7R, and FCGR1A). Of these 15 genes, five genes (CXCL8, FCGR1A, IL1B, TLR2, and TLR8) were found to be involved in neutrophil degranulation. To gain further insight into the molecular mechanism, a protein–protein network was established. Significantly enriched pathways based on the above-mentioned genes were mainly centered on biological regulation and signaling events. In addition, the pathway analysis also indicated that the majority of the DEGs in KD were enriched in systemic lupus erythematosus, suggesting a strong interplay between immunological and genetic factors in the pathogenesis of KD. These findings could significantly aid in identifying therapeutic targets and understanding KD biosignatures to design a biomarker panel for early diagnosis and severity of the disease.

Temporal Correlation Between Kawasaki Disease and Infectious Diseases in South Korea

IMPORTANCE

Infections are proposed to be triggering factors for Kawasaki disease (KD), although its etiological factors remain unknown. Recent reports have indicated a 4- to 6-week lag between SARS-CoV-2 infection and multisystem inflammatory syndrome in children with a similar presentation to that of KD.

OBJECTIVE

To investigate the temporal correlation between KD and viral infections, focusing on respiratory viruses.

DESIGN, SETTING, AND PARTICIPANTS

This cohort study was conducted among individuals aged 0 to 19 years diagnosed with KD between January 2010 and September 2020 from the Korean National Health Insurance Service. Data on infectious disease outbreaks from 2016 to 2019 were collected from the Korea Disease Control and Prevention Agency, Korean Influenza and Respiratory Virus Monitoring System, Korea Enteroviruses Surveillance System, and the Enteric Pathogens Active Surveillance Network in South Korea. Data were analyzed from December 2020 to October 2021.

MAIN OUTCOMES AND MEASURES

National databases for infectious diseases were used for a time-series analysis of the correlation between viral infections and KD. The temporal correlation between infectious disease outbreaks and KD outbreaks was evaluated using the Granger causality test (G-test), which is a useful tool to estimate correlations between 2 time series of diseases based on time lags.

RESULTS

Overall, 53 424 individuals with KD were identified, including 22 510 (42.1%) females and 30 914 (57.9%) males and 44 276 individuals (82.9%) younger than 5 years. Intravenous immunoglobulin-resistant KD was identified in 9042 individuals (16.9%), and coronary artery abnormalities were identified in 384 individuals (0.7%). Of 14 infectious diseases included in the analyses, rhinovirus infection outbreaks were identified as significantly correlated at 1 to 3 months before KD outbreaks in South Korea (r = 0.3; 1 month: P < .001; 2 months: P < .001; 3 months: P < .001). Outbreaks of respiratory syncytial virus infection were identified as significantly correlated with KD outbreaks by 2 months (r = 0.5; 2 months: P < .001). Additionally, varicella outbreaks were identified as significantly correlated at 2 and 3 months before KD outbreaks (r = 0.7; 2 months: P < .001; 3 months: P < .001).

CONCLUSIONS AND RELEVANCE

In this cohort study with a time series analysis of children and youth in South Korea with KD, respiratory infections caused by rhinovirus and respiratory syncytial virus and varicella outbreaks were significantly correlated with KD at 1 to 3 months before KD outbreaks.

Spatiotemporal clusters of Kawasaki disease in South Korea from 2008 to 2017: A municipal-level ecological study

INTRODUCTION

As the etiology of Kawasaki disease (KD) remains unknown, identifying spatiotemporal clusters with proper stratification of KD could provide further evidence for investigating the triggers of KD. However, spatiotemporal distributions of KD with sex stratification have never been reported. Therefore, we aimed to analyze the spatiotemporal patterns of KD by sex in South Korea.

METHODS

We extracted epidemiologic week (Epiweek)-based KD cases in patients <5 years of age (ICD-10-CM code: M303) from 2008 to 2017 national health insurance service data at the 250 municipal level. To determine whether spatial autocorrelation and persistent municipal-level clusters exist, year- and sex-stratified global Moran's I statistics, Getis-Ord Gi* statistics, and emerging hotspot analysis on KD incidence were conducted.

RESULTS

A total of 72,510 KD cases were reported between 2008 and 2017 (male-to-female ratio = 1.40:1). Incidence has increased since 2008, with the highest incidence in 2016 (396.8 per 100,000 population). KD had seasonality of winter and summer but different by sex. Positive spatial autocorrelation was consistently reported in every stratum, with the 2011-2014 period having the strongest index value (total sex I = 0.286, p < 0.001; male I = 0.242, p < 0.001; female I = 0.213, p < 0.001). Hot spots were consistently detected in the northern parts, and cold spots were in the southern part for 9 years in both sexes. The emerging hot spot analysis showed new, consecutive, and sporadic hot spots on the northwestern and eastern coasts and new and sporadic cold spots in the southwestern part. However, the distribution and proportion of hot or cold spot types differed according to sex.

DISCUSSION

The spatiotemporal features of KD had limits to concluding that only infectious triggers result in KD occurrence. Therefore, our findings support the notion that KD is a syndrome with multiple factors, including infectious, genetic, and environmental factors, that are associated with sex differences.

The triumvirate of NF-κB, inflammation and cytokine storm in COVID-19

The coronavirus disease (COVID-19) has once again reminded us of the significance of host immune response and consequential havocs of the immune dysregulation. The severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) inflicts severe complications to the infected host, including cough, dyspnoea, fever, septic shock, acute respiratory distress syndrome (ARDs), and multiple organ failure. These manifestations are the consequence of the dysregulated immune system, which gives rise to excessive and unattended production of pro-inflammatory mediators. Elevated circulatory cytokine and chemokine levels are accompanied by spontaneous haemorrhage, thrombocytopenia and systemic inflammation, which are the cardinal features of life-threatening cytokine storm syndrome in advanced COVID-19 diseases. Coronavirus hijacked NF-kappa B (NF-κB) is responsible for upregulating the expressions of inflammatory cytokine, chemokine, alarmins and inducible enzymes, which paves the pathway for cytokine storm. Given the scenario, the systemic approach of simultaneous inhibition of NF-κB offers an attractive therapeutic intervention. Targeted therapies with proteasome inhibitor (VL-01, bortezomib, carfilzomib and ixazomib), bruton tyrosine kinase inhibitor (acalabrutinib), nucleotide analogue (remdesivir), TNF-α monoclonal antibodies (infliximab and adalimumab), N-acetylcysteine and corticosteroids (dexamethasone), focusing the NF-κB inhibition have demonstrated effectiveness in terms of the significant decrease in morbidity and mortality in severe COVID-19 patients. Hence, this review highlights the activation, signal transduction and cross-talk of NF-κB with regard to cytokine storm in COVID-19. Moreover, the development of therapeutic strategies based on NF-κB inhibition are also discussed herein.

Delineating phenotypes of Kawasaki disease and SARS-CoV-2-related inflammatory multisystem syndrome: a French study and literature review

Objective

To better define the clinical distinctions between the new severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2)-related paediatric inflammatory multisystem syndrome (PIMS) and Kawasaki disease (KD).

Methods

We compared three groups of patients: group 1, cases from our national historic KD database (KD-HIS), before the SARS-CoV-2 pandemic; group 2, patients with KD admitted to an intensive care unit (KD-ICU) from both our original cohort and the literature, before the SARS-CoV-2 pandemic; and group 3, patients with PIMS from the literature.

Results

KD-HIS included 425 patients [male:female ratio 1.3, mean age 2.8 years (s.d. 2.4)], KD-ICU 176 patients [male:female ratio 1.3, mean age 3.5 years (s.d. 3.1)] and PIMS 404 patients [male:female ratio 1.4, mean age 8.8 years (s.d. 3.7)]. As compared with KD-HIS patients, KD-ICU and PIMS patients had a higher proportion of cardiac failure, digestive and neurological signs. KD-ICU and PIMS patients also had a lower frequency of typical KD-mucocutaneous signs, lower platelet count, higher CRP and lower sodium level. As compared with KD-HIS and KD-ICU patients, PIMS patients were older and more frequently had myocarditis; they also had fewer coronary abnormalities and lower sodium levels. Unresponsiveness to IVIG was more frequent in KD-ICU than KD-HIS and PIMS patients.

Conclusion

On clinical grounds, KD-HIS, KD-ICU and PIMS might belong to a common spectrum of non-specific pathogen-triggered hyperinflammatory states. The causes of increasing inflammation severity within the three entities and the different effects on the heart remain to be determined.

Association of TNF-α rs1800629, CASP3 rs72689236 and FCGR2A rs1801274 Polymorphisms with Susceptibility to Kawasaki Disease: A Comprehensive Meta-Analysis

Kawasaki Disease (KD) is a multifactorial condition at the junction of infectious diseases, immunology, rheumatology, and cardiology. The aim of this study is to derive a more precise estimation of the association of TNF-α rs1800629, CASP3 rs72689236 and FCGR2A rs1801274 polymorphisms with risk of KD. Methods: PubMed, EMBASE, CNKI databases were searched to identify all relevant studies. Pooled odds ratios (OR) with 95% confidence intervals (CI) were calculated using CMA 2.2 software. Results: A total of 25 studies including eleven studies on TNF-α rs1800629, five studies on CASP3 rs72689236 and nine studies on FCGR2A rs1801274 were selected. Overall, pooled data revealed that CASP3 rs72689236 and FCGR2A rs1801274 polymorphisms were significantly associated with an increased risk of KD. However, there was no significant association between TNF-α rs1800629 and KD. Conclusions: This meta-analysis suggested that CASPS rs72689236 and FCGR2A rs1801274 polymorphisms may modulate individual susceptibility to KD.

Atypically Protracted Course of Liver Involvement in Kawasaki Disease. Case Report and Literature Review

Hypertransaminasemia in patients with Kawasaki disease (KD) is reported to be transient. Here, we describe a child with an atypically protracted course of liver tests abnormalities and review the inherent literature. The patient was hospitalized at age 7-months for isolated hypertransaminasemia detected during a classical KD diagnosed 3 months before, and persistent since then. KD clinical evolution had been favorable, with rapid response to acetylsalicylic acid and intravenous immunoglobulins. Liver enzymes however remained persistently elevated with a fluctuating pattern (ALT > AST levels; peak of AST 186 IU/L and ALT 240 IU/L). During follow-up, the main causes of liver dysfunction had to be excluded through appropriate and extensive laboratory investigations. Transaminases values become steadily normal only 7 months after the acute presentation of KD. Conclusions: Our report shows that an atypically protracted courses of KD-related hypertransaminasemia above the previously reported temporal limits should be taken into account during the stepwise diagnostic approach to the patient's liver dysfunction. Insidious acetylsalycilic acid-hepatotoxicity warrants consideration in the differential diagnosis.

Kawasaki disease and influenza-new lessons from old associations

Kawasaki disease (KD), an enigmatic medium vessel vasculitis, presents as an acute febrile illness predominantly affecting young children. KD appears to be a hyper-inflammatory response elicited by environmental or infectious agents (including respiratory viruses) in genetically predisposed individuals. Numerous reports from the current era of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic have described the occurrence of KD/KD-like illness in close temporal proximity to SARS-CoV-2 infection or exposure. Notably, KD has been reported in association with H1N1-pdm09 virus that caused the previous pandemic a decade ago. Non-H1N1 influenza infections as well as influenza vaccination have also been reported to trigger KD. Herein, we report a case of H1N1-pdm09 influenza who developed KD. We review the published literature on influenza infection or vaccination triggering KD. This may help in a better understanding of the KD/KD-like illness associated with SARS-CoV-2. Besides, we also evaluate the safety of aspirin in influenza-triggered KD as aspirin administration in children with influenza is associated with the risk of development of Reye syndrome.

Kawasaki Disease Patient Stratification and Pathway Analysis Based on Host Transcriptomic and Proteomic Profiles

The aetiology of Kawasaki disease (KD), an acute inflammatory disorder of childhood, remains unknown despite various triggers of KD having been proposed. Host 'omic profiles offer insights into the host response to infection and inflammation, with the interrogation of multiple 'omic levels in parallel providing a more comprehensive picture. We used differential abundance analysis, pathway analysis, clustering, and classification techniques to explore whether the host response in KD is more similar to the response to bacterial or viral infections at the transcriptomic and proteomic levels through comparison of 'omic profiles from children with KD to those with bacterial and viral infections. Pathways activated in patients with KD included those involved in anti-viral and anti-bacterial responses. Unsupervised clustering showed that the majority of KD patients clustered with bacterial patients on both 'omic levels, whilst application of diagnostic signatures specific for bacterial and viral infections revealed that many transcriptomic KD samples had low probabilities of having bacterial or viral infections, suggesting that KD may be triggered by a different process not typical of either common bacterial or viral infections. Clustering based on the transcriptomic and proteomic responses during KD revealed three clusters of KD patients on both 'omic levels, suggesting heterogeneity within the inflammatory response during KD. The observed heterogeneity may reflect differences in the host response to a common trigger, or variation dependent on different triggers of the condition.

COVID-19 in Immunosuppressed Children

Following the spread of the SARS-CoV-2 infection and coronavirus disease 2019 (COVID-19) to a global pandemic, concerns have arisen for the disease impact in at-risk populations, especially in immunocompromised hosts. On the other hand, clinical studies have clarified that the COVID-19 clinical burden is mostly due to over-inflammation and immune-mediated multiorgan injury. This has led to downsizing the role of immunosuppression as a determinant of outcome, and early reports confirm the hypothesis that patients undergoing immunosuppressive treatments do not have an increased risk of severe COVID-19 with respect to the general population. Intriguingly, SARS-CoV-2 natural reservoirs, such as bats and mice, have evolved mechanisms of tolerance involving selection of genes optimizing viral clearance through interferon type I and III responses and also dampening inflammasome response and cytokine expression. Children exhibit resistance to COVID-19 severe manifestations, and age-related features in innate and adaptive response possibly explaining this difference are discussed. A competent recognition by the innate immune system and controlled pro-inflammatory signaling seem to be the pillars of an effective response and the premise for pathogen clearance in SARS-CoV-2 infection. Immunosuppression-if not associated with other elements of fragility-do not represent per se an obstacle to this competent/tolerant phenotype in children. Several reports confirm that children receiving immunosuppressive medications have similar clinical involvement and outcomes as the pediatric general population, indicating that maintenance treatments should not be interrupted in suspect or confirmed SARS-CoV-2 infection.

Kawasaki disease recurrence in the COVID-19 era: a systematic review of the literature

Kawasaki disease (KD) is a vasculitis of unknown origin of small and medium caliber blood vessels, especially involving coronary arteries and is the leading cause of acquired heart disease in childhood in developed countries. Although rarely, it can recur: most recurrences occur within 2 years of the initial episode. No data are available on incidence of recurrent KD in Europe and multiple recurrences are rarely seen. We reviewed the medical literature on Kawasaki disease recurrence and reported a new case of Kawasaki disease recurrence in a child with SARS-CoV-2 infection. We believe that in our case SARS Cov2 acted as a trigger capable to determine, in a genetically susceptible individual, a second recurrence of the disease. In the Covid-19 era we affirm the importance for Kawasaki disease to be tested for SARS Cov2 infection.

Application of intravenous immunoglobulin (IVIG) to modulate inflammation in critical COVID-19 - A theoretical perspective

COVID-19 is an airway disease that has affected ~125 million people worldwide, caused by a novel coronavirus termed severe acute respiratory syndrome coronavirus 2 (SARS-CoV2), spread through respiratory droplets, direct contact, and aerosol transmission. Although most patients presenting with absent or mild symptoms recover completely, the highest morbidity and mortality rates are seen in the elderly, and patients with comorbidities such as cardiovascular diseases, cancer, immunosuppressive diseases, diabetes, and pre-existing respiratory illnesses. Several therapeutic strategies have been examined, but a wide-ranging therapeutic option for particularly severe cases of COVID-19 remains to be elucidated. Considering the indications presented by COVID-19 patients who present similarly with inflammatory conditions, intravenous immunoglobulin (IVIG) administration has been examined as a possible route to reduce proinflammatory markers such as ESR, CRP and ferritin by reducing inflammation, based on its anti-inflammatory effects as indicated by utilisation of IVIG for numerous other inflammatory conditions. Herein, summarising the recent key clinical evaluations of IVIG administration, we present our hypothesis that administration of IVIG within a specific dosage would be extremely beneficial towards reducing mortality and perhaps even the length of hospitalisation of patients exhibiting severe COVID-19 symptoms.

Assessment of Pediatric Admissions for Kawasaki Disease or Infectious Disease During the COVID-19 State of Emergency in Japan

IMPORTANCE

The development of Kawasaki disease (KD) has been suggested to be associated with droplet- or contact-transmitted infection; however, its triggers and transmission modes remain to be determined. Under an epidemic of SARS-CoV-2, the COVID-19 state of emergency in Japan served as a nationwide social experiment to investigate the impact of quarantine or isolation on the incidence of KD.

OBJECTIVE

To assess the role of droplet or contact transmission in the etiopathogenesis of KD.

DESIGN, SETTING, AND PARTICIPANTS

This multicenter, longitudinal, cross-sectional study was conducted from 2015 to 2020 at Fukuoka Children's Hospital and 5 adjacent general hospitals. The number of admissions for KD and infectious diseases were analyzed. Participants were pediatric patients admitted to the participating hospitals for KD or infectious diseases.

EXPOSURES

Quarantine and isolation owing to the COVID-19 state of emergency.

MAIN OUTCOMES AND MEASURES

The primary end points were the ratios of patients with KD to patients with respiratory tract or gastrointestinal infections admitted from April to May in 2015 to 2019 and 2020. A Poisson regression model was used to analyze them.

RESULTS

The study participants included 1649 patients with KD (median [interquartile range] age, 25 [13-43] months; 901 boys [54.6%]) and 15 586 patients with infectious disease (data on age and sex were not available for these patients). The number of admissions for KD showed no significant change between April and May in 2015 to 2019 vs the same months in 2020 (mean [SD], 24.8 [5.6] vs 18.0 [4.0] admissions per month; 27.4% decrease; adjusted incidence rate ratio [aIRR], 0.73; 95% CI, 0.48-1.10; P = .12). However, the number of admissions for droplet-transmitted or contact-transmitted respiratory tract infections (mean [SD], 157.6 [14.4] vs 39.0 [15.0] admissions per month; 75.3% decrease; aIRR, 0.25; 95% CI, 0.17-0.35; P < .001) and gastrointestinal infections (mean [SD], 43.8 [12.9] vs 6.0 [2.0] admissions per month; 86.3% decrease; aIRR, 0.14; 95% CI, 0.04-0.43; P < .001) showed significant decreases between April and May in 2015 to 2019 vs the same months in 2020 (total, 12 254 infections). Thus, the ratio of KD to droplet- or contact-transmitted respiratory tract and gastrointestinal infections incidence in April and May 2020 was significantly increased (ratio, 0.40 vs 0.12; χ21 = 22.76; P < .001).

CONCLUSIONS AND RELEVANCE

In this study, the significantly increased incidence of KD compared with respiratory tract and gastrointestinal infections during the COVID-19 state of emergency suggests that contact or droplet transmission is not a major route for KD development and that KD may be associated with airborne infections in most cases.

Potential New Treatments for Kawasaki Disease, Its Variations, and Multisystem Inflammatory Syndrome

The causation of Kawasaki disease has been a medical mystery for over 54 years. However, the causations of Kawasaki disease, its variations, and COVID-19-associated Multisystem Inflammatory Syndrome have been recently explained to involve high replication rate viral infections. In a subset of patients, the extensive antigen-antibody immune complexes that are not quickly cleared by phagocytosis will create a type III hypersensitivity immune reaction. The subsequent release of proteases and other enzymes and the expression or exposure of new immunogenic antigens due to protease attacks on basement membranes of epithelial cells or endothelial cells in blood vessels will induce new autoantibodies and cause Kawasaki disease, its variations, and COVID-19-related Multisystem Inflammatory Syndrome. There is now increasing evidence that a viral infection of a large surface area of tissue, such as the respiratory tract, gastrointestinal tract or blood vessels, and a resultant type III hypersensitivity immune reaction is the most plausible explanation for the causations of Kawasaki disease, its variations, and COVID-19-related Multisystem Inflammatory Syndrome. Furthermore, an improved understanding of these causations also suggests several potential new treatments which can be more effective.

Clinical characteristics of Kawasaki disease and concurrent pathogens during isolation in COVID-19 pandemic

BACKGROUND

The aim of this study is to explore the characteristics of Kawasaki disease (KD) and concurrent pathogens due to a stay-at-home isolation policy during coronavirus disease 2019 (COVID-19) epidemic.

METHODS

All patients with KD admitted between February and April in 2015-2020, were classified into before (group 1, in 2015-2019) and after (group 2, in 2020) isolation groups. A total of 4742 patients [with KD (n = 98) and non-KD (n = 4644)] referred to Mycoplasma pneumoniae (MP) and virus detection were analyzed in 2020. Clinical characteristics, laboratory data, and 13 pathogens were analyzed retrospectively.

RESULTS

Group 2 had a significantly increased incidence of KD (0.11%) with 107 patients compared to that of group 1 (0.03%) with 493 patients. The comparisons of oral mucosal change, strawberry tongue, desquamation of the fingertips, cervical lymphadenopathy and neutrophil percentage decreased in group 2 compared to group 1. The infection rate of MP increased significantly in group 2 (34.7%) compared to group 1 (19.3%), while the positive rate of viruses decreased significantly in group 2 (5.3%) compared to group 1 (14.3%). In 2020, the positive rate of MP infection increased significantly in patients with KD compared to the increase in patients with non-KD. The infection rate of MP for younger children aged less than 3 years old was higher in group 2 than in group 1.

CONCLUSION

Compared with the characteristics of KD from 2015 to 2019 years, the incidence of KD was increased in 2020 and was accompanied by a high incidence of MP infection, especially in younger children (less than 3 years old) during the isolation due to COVID-19 pandemic.

A meta-analysis on association between viral infections and Kawasaki disease in children

Aim: To investigate the association between different viral infections and the development of Kawasaki disease (KD) in children. Materials & methods: Electronic databases were searched for relevant studies published from inception to May 2020. The pooled odds ratios (ORs) of the association of different viral pathogens with KD were estimated using a random-effects model weighted by the inverse variance method. Results: The strongest associations were found between KD and human parvovirus B19 viremia (OR = 41.05; 95% CI: 5.13–328.28; I-square = 0%), EBV IgM seropositivity (OR = 7.18; 95% CI: 3.65–14.12, I-square = 0%) and human herpesvirus-6 IgG seropositivity (OR = 5.83; 95% CI: 1.06–32.01). Conclusion: Human parvovirus B19, EBV and human herpesvirus-6 are highly suspected to be key contributors to the development of KD.

Patterns of Presentation of SARS-CoV-2 Infection in Children. Experience at the Italian Epicentre of the Pandemic

Background: COVID-19, a disease caused by the new coronavirus SARS-CoV-2, spread worldwide, and Bergamo was one of the most affected areas in Europe. Following the first outbreak, more than half of the population of the Bergamo province had been infected. We aimed to describe the patients admitted to our unit shortly after the first outbreak. Methods: we retrospectively reviewed the notes of all pediatric patients diagnosed with COVID-19. We enrolled patients with positive swabs or serology and classified them based on the pattern and the timing of presentation after the first outbreak. This setting was considered a reliable reflection of the consequences of unmitigated SARS-CoV-2 circulation. Results: We diagnosed 35 patients over a 3-month period and we identified six patterns presenting in two temporal phases: Early phase, Group 1 (median of 20 days from epidemic start, IQR: 15-27): neonatal sepsis (n.7), pneumonia (n.5), flu-like symptoms (n.2). Late phase, Group 2 (59:51-66 days, p < 0.001): MIS-C (n.18), neurological manifestations (n.3). Group 1 differed from Group 2 for younger age (1 vs. 8 years, p = 0.02), lower C-reactive protein (0.9 vs. 16.6 mg/dl, p = 0.008), procalcitonin (0.16 vs. 7.9 ng/ml, p = 0.008) and neutrophil count (3,765 vs. 6,780/μl, p = 0.006), higher rate of positive swabs (14/14 vs. 9/21, p < 0.001), higher lymphocyte count (3,000 vs. 930/μl, p = 0.006) and platelet count (323,000 vs. 210,000/μl, p = 0.009). Conclusions: Following an outbreak of unmitigated SARS-CoV-2 diffusion, infected children may present with clinical patterns suggesting two temporal clusters, the first characterized by markers of direct viral injury, the second suggesting an immune-mediated disease.

Kawasaki disease seasonality in Venezuela supports an arbovirus infection trigger

Kawasaki disease (KD) is an inflammatory disease primarily affecting infants and young children, whose etiology remains uncertain. Observational studies of the overlap between KD outbreaks and seasonal peaks of arboviral infections, suggest the possible role of these pathogens as triggers of KD. In Venezuela, regions with the highest reported arboviral infections simultaneously have the highest incidence of KD. One proposed explanation for this association involves the role of proinflammatory mediators, interleukin-1 (IL-1), IL-6, tumor necrosis factor, and vascular endothelial growth factor as mediators of coronary endothelial damage. The promotion of inflammation and tissue destruction by these cytokines is thought to contribute to the coronary endothelial damage experienced in KD. The utilization of overlapping KD and arboviral infection trends contribute to the comprehension of KD etiology, with improvements in diagnosis, prognosis and treatment.

Comprehensive pathogen detection in sera of Kawasaki disease patients by high-throughput sequencing: a retrospective exploratory study

Background

Kawasaki disease (KD) is an idiopathic systemic vasculitis that predominantly damages coronary arteries in children. Various pathogens have been investigated as triggers for KD, but no definitive causative pathogen has been determined. As KD is diagnosed by symptoms, several days are needed for diagnosis. Therefore, at the time of diagnosis of KD, the pathogen of the trigger may already be diminished. The aim of this study was to explore comprehensive pathogens in the sera at the acute stage of KD using high-throughput sequencing (HTS).

Methods

Sera of 12 patients at an extremely early stage of KD and 12 controls were investigated. DNA and RNA sequences were read separately using HTS. Sequence data were imported into the home-brew meta-genomic analysis pipeline, PATHDET, to identify the pathogen sequences.

Results

No RNA virus reads were detected in any KD case except for that of equine infectious anemia, which is known as a contaminant of commercial reverse transcriptase. Concerning DNA viruses, human herpesvirus 6B (HHV-6B, two cases) and Anelloviridae (eight cases) were detected among KD cases as well as controls. Multiple bacterial reads were obtained from KD and controls. Bacteria of the genera Acinetobacter, Pseudomonas, Delfita, Roseomonas, and Rhodocyclaceae appeared to be more common in KD sera than in the controls.

Conclusion

No single pathogen was identified in serum samples of patients at the acute phase of KD. With multiple bacteria detected in the serum samples, it is difficult to exclude the possibility of contamination; however, it is possible that these bacteria might stimulate the immune system and induce KD.

Kawasaki Disease and Multisystem Inflammatory Syndrome in Children with COVID-19

Since December 2019, the world has been exposed to a novel virus from the coronaviruses family, named coronavirus disease 2019 (COVID-19), which has affected the life of millions people around the world. This global pandemic causes a wide spectrum of clinical manifestation in children, adults, and elderly. One side of the spectrum in children is being asymptomatic and the other side is severe inflammatory symptoms. In this article, we describe the clinical manifestations, genetic background, and immune response of children with COVID-19, who are presented with severe multisystem inflammatory syndrome (MIS).

An Outbreak of Kawasaki-like Disease in children during SARS-CoV- 2 Epidemic: No Surprise?

Background and aim:

Kawasaki disease is an acute systemic febrile illness of unknown aetiology, which usually affects children under 5 years of age. It is well known that Kawasaki disease is one of the most common causes of acquired heart diseases in children in the developed countries. Many studies, have suggested that heterogeneous infectious agents, such as common viruses, may trigger Kawasaki disease in young children with genetic background. Nowadays we are facing a pandemic caused by a Novel Coronavirus named SARS-CoV-2. Consequently, it could be possible that once exposed to this new coronavirus, some children, genetically predisposed, may mount an exaggerated inflammatory response which clinically manifests as Kawasaki Disease.

Methods:

from January to May 2020 a systematic search was performed on Pubmed for the following search terms: “COVID-19”, “children”, “SARS-CoV-2”, “complications”, “Kawasaki disease”, “cytokine storm”.

Results:

Usually, infants and children present milder symptoms of SARS-CoV-2 disease with a better outcome than adults. At variance, some children may be genetically disposed to a more robust inflammatory response to SARS-CoV-2, similar to Kawasaki disease. In fact, Kawasaki disease is the result of an abnormal immune response, in susceptible children, to an external trigger such as an infection. Thus, according to the pathogenesis of Kawasaki disease, paediatricians may expect an increase in cases of Kawasaki disease during the COVID-19 pandemic. (www.actabiomedica.it)

Tenascin-C in cardiac disease: a sophisticated controller of inflammation, repair, and fibrosis

Tenascin-C (TNC) is a large extracellular matrix glycoprotein classified as a matricellular protein that is generally upregulated at high levels during physiological and pathological tissue remodeling and is involved in important biological signaling pathways. In the heart, TNC is transiently expressed at several important steps during embryonic development and is sparsely detected in normal adult heart but is re-expressed in a spatiotemporally restricted manner under pathological conditions associated with inflammation, such as myocardial infarction, hypertensive cardiac fibrosis, myocarditis, dilated cardiomyopathy, and Kawasaki disease. Despite its characteristic and spatiotemporally restricted expression, TNC knockout mice develop a grossly normal phenotype. However, various disease models using TNC null mice combined with in vitro experiments have revealed many important functions for TNC and multiple molecular cascades that control cellular responses in inflammation, tissue repair, and even myocardial regeneration. TNC has context-dependent diverse functions and, thus, may exert both harmful and beneficial effects in damaged hearts. However, TNC appears to deteriorate adverse ventricular remodeling by proinflammatory and profibrotic effects in most cases. Its specific expression also makes TNC a feasible diagnostic biomarker and target for molecular imaging to assess inflammation in the heart. Several preclinical studies have shown the utility of TNC as a biomarker for assessing the prognosis of patients and selecting appropriate therapy, particularly for inflammatory heart diseases.

Kawasaki disease in siblings in close temporal proximity to each other-what are the implications?

Kawasaki disease (KD) is the commonest medium vessel vasculitis in children. The etiology of KD remains an enigma despite extensive research. Infections are considered to be one of the triggers for KD, especially in genetically susceptible hosts. KD occurring within a short time interval among siblings is an important clinical observation supporting this hypothesis. In addition, siblings of children with KD are at a higher risk of developing the disease as compared with other children. Screening for KD in febrile siblings, therefore, seems prudent. This would help initiate timely therapy and prevent complications. We briefly review 16 English language reports of KD in siblings diagnosed within 1 month of each other to highlight its etiological and therapeutic implications.

Key Points • KD should be suspected in febrile children who have a sibling recently diagnosed with KD. • Etiological studies should also focus on siblings who develop KD in close temporal proximity.

Hypertension and related diseases in the era of COVID-19: a report from the Japanese Society of Hypertension Task Force on COVID-19

Coronavirus disease-2019 (COVID-19), caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), has affected more than seven million people worldwide, contributing to 0.4 million deaths as of June 2020. The fact that the virus uses angiotensin-converting enzyme (ACE)-2 as the cell entry receptor and that hypertension as well as cardiovascular disorders frequently coexist with COVID-19 have generated considerable discussion on the management of patients with hypertension. In addition, the COVID-19 pandemic necessitates the development of and adaptation to a “New Normal” lifestyle, which will have a profound impact not only on communicable diseases but also on noncommunicable diseases, including hypertension. Summarizing what is known and what requires further investigation in this field may help to address the challenges we face. In the present review, we critically evaluate the existing evidence for the epidemiological association between COVID-19 and hypertension. We also summarize the current knowledge regarding the pathophysiology of SARS-CoV-2 infection with an emphasis on ACE2, the cardiovascular system, and the kidney. Finally, we review evidence on the use of antihypertensive medication, namely, ACE inhibitors and angiotensin receptor blockers, in patients with COVID-19.

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.

SARS-CoV-2 Inflammatory Syndrome. Clinical Features and Rationale for Immunological Treatment

The current pandemic coronavirus, SARS-CoV-2, is a global health emergency because of its highly contagious nature, the great number of patients requiring intensive care therapy, and the high fatality rate. In the absence of specific antiviral drugs, passive prophylaxis, or a vaccine, the treatment aim in these patients is to prevent the potent virus-induced inflammatory stimuli from leading to the acute respiratory distress syndrome (ARDS), which has a severe prognosis. Here, the mechanism of action and the rationale for employing immunological strategies, which range from traditional chemically synthesized drugs, anti-cytokine antibodies, human immunoglobulin for intravenous use, to vaccines, are reviewed.

SARS-CoV-2 Inflammatory Syndrome. Clinical Features and Rationale for Immunological Treatment

The current pandemic coronavirus, SARS-CoV-2, is a global health emergency because of its highly contagious nature, the great number of patients requiring intensive care therapy, and the high fatality rate. In the absence of specific antiviral drugs, passive prophylaxis, or a vaccine, the treatment aim in these patients is to prevent the potent virus-induced inflammatory stimuli from leading to the acute respiratory distress syndrome (ARDS), which has a severe prognosis. Here, the mechanism of action and the rationale for employing immunological strategies, which range from traditional chemically synthesized drugs, anti-cytokine antibodies, human immunoglobulin for intravenous use, to vaccines, are reviewed.

A framework for understanding Kawasaki disease pathogenesis

Kawasaki disease (KD) is a common vasculitis of childhood, typically affecting children under the age of five. Despite many aspects of its presentation that bear resemblence to acute infection, no causative infectious agent has been identified despite years of intense scrutiny. Unlike most infections, however, there are significant differences in racial predilection that suggest a strong genetic influence. The inflammatory response in KD specifically targets the coronary arteries, also unusual for an infectious condition. In this review, we discuss recent hypotheses on KD pathogenesis as well as new insights into the innate immune response and mechanisms behind vascular damage. The pathogenesis is complex, however, and remains inadequately understood.

Gastrointestinal hemorrhage before anticoagulant therapy in Kawasaki disease: a case report

Background

Kawasaki disease (KD) is an acute febrile multisystem vasculitis and has been recognized to be the most common cause of acquired heart disease in children. Owing to its propensity to involve vessels throughout the entire body, KD often mimics other disease processes. The diagnosis might be delayed if other prominent symptoms appear before the characteristic clinical features of KD. Although gastrointestinal symptoms including vomiting, diarrhea, and abdominal pain are not uncommon in KD patients, KD with gastrointestinal bleeding is quite rare.

Case presentation

A previously healthy 4-year-old boy initially presented with abdominal pain, followed by fever, rash, and gastrointestinal hemorrhage, eventually diagnosed as complete KD. The patient recovered smoothly after appropriate management and no subsequent complications occurred in the following months.

Conclusion

The diagnosis of KD should be considered in children presenting with abdominal symptoms and fever without definable cause. Pediatricians should be aware of the risk of gastrointestinal bleeding in patients with KD, especially in those with prominent abdominal symptoms.

Kawasaki Disease Following Severe Sunburn Injury

Background: Although an etiology of Kawasaki disease (KD) is unknown, an aberrant innate immune system in predisposed individuals has been proposed to play a key role in the development of KD vasculitis. Various etiological pathogens have been proposed as the trigger of KD and a scaled injury preceding symptom onset has been reported as one of them. Here, we report a 17-month-old Japanese female who was hospitalized due to high fever lasting for 4 days with infection ruled out as a cause. On admission, she displayed severe sunburn all over her body following a prolonged period of outdoor play 5 days ago. On the 5 day of illness, she developed complete KD. Serum levels of high mobility group box 1, a representative for damage-associated molecular patterns (DAMPs), were elevated during acute phase and continued to decrease during subacute phase. This unique course suggested the inflammatory process of KD involving innate immunity via DAMPs.