Kawasaki disease: what is the epidemiology telling us about the etiology?

Chrysin improves endothelial inflammation via the NFAT pathway in Kawasaki disease

BACKGROUND

The purpose of this study was to evaluate the therapeutic effects of Chrysin on endothelial inflammation in a KD mouse model and to elucidate the molecular mechanisms underlying these effects, with a particular focus on the NFAT2 signaling pathway.

METHODS AND RESULTS

In vivo, a KD mouse model was used to assess the effects of Chrysin on coronary artery inflammation. Histological analysis, immunohistochemistry, and cytokine profiling were performed to evaluate inflammatory cell infiltration, structural changes in the arteries, and modulation of key inflammatory cytokines. In vitro, TNFα-stimulated HCAECs were used to examine the protective effects of Chrysin on endothelial injury, including cytokine secretion and adhesion molecule expression. Mechanistic studies were conducted to explore the role of the NFAT2 signaling pathway in mediating Chrysin's effects, utilizing molecular docking analysis and Western blotting. In vivo, Chrysin treatment significantly alleviated coronary artery inflammation in the KD mouse model. Histological analysis revealed reduced inflammatory cell infiltration and improved elastin fiber structure. Cytokine analysis showed that Chrysin attenuated the elevated levels of IL-6, IL-17, TNFα, and MCP-1 in KD mice. In vitro, Chrysin reduced TNFα-induced endothelial injury, as evidenced by decreased secretion of IL-6, IL-8, IL-23, ICAM-1 and VCAM-1 in HCAECs. Mechanistic investigations revealed that Chrysin's effects on endothelial inflammation were mediated through the NFAT2 signaling pathway, rather than the upstream PLCγ1 pathway, as confirmed by molecular docking and Western blotting. Inhibition of PLCγ1 did not alter the protective effects of Chrysin, suggesting that its action is primarily through NFAT2.

CONCLUSIONS

This study provides the first evidence that Chrysin significantly reduces endothelial inflammation and vascular injury in KD. The observed anti-inflammatory effects are mediated through the NFAT2 signaling pathway, highlighting the potential of Chrysin as a therapeutic agent for managing KD and its associated vascular complications.

Association between heat exposure and Kawasaki disease: A time-stratified case-crossover study

Nationwide studies investigating the association between daily mean temperature and Kawasaki disease are lacking. This study aimed to examine the association between ambient temperature and Kawasaki disease by utilizing daily data from nationwide administrative claims databases. The daily number of Kawasaki disease patients younger than 15 years old, who were hospitalized from 2011 to 2022, was extracted from the nationwide administrative claims database of hospitalizations in Japan. Daily mean temperature data and relative humidity data were obtained from the Japan Meteorological Agency. Since the exposure of interest includes heat, hospitalizations during the five warmest months (May through September) were used for analysis. A time-stratified case-crossover study with conditional quasi-Poisson regression analysis was used to estimate the relative risk (RR) of weather exposure for Kawasaki disease hospitalization with a lag of 0-5 days by prefecture. Relative humidity was included in the model simultaneously to control for its potential confounding effect. Random-effects meta-analysis was used to estimate pooled RRs. There was a total of 48,784 cases of Kawasaki disease hospitalization during the study period, of which 87.9% were under 5 years of age. Exposure to high daily mean temperatures was associated with an increased risk of hospitalization for Kawasaki disease. Specifically, exposure to extreme high daily mean temperatures (99th percentile high temperature) was associated with higher risk of hospitalization by 33% (RR 1.33, 95% confidence interval (CI):1.08, 1.65). Similar results were obtained from sensitivity analysis. Future research should elucidate the mechanisms by which high temperature is associated with hospitalization for Kawasaki disease.

The complex landscape of immune dysregulation in multisystem inflammatory syndrome in children with COVID-19

The immune responses following SARS-CoV-2 infection in children are still under investigation. While coronavirus disease 2019 (COVID-19) is usually mild in the paediatric population, some children develop severe clinical manifestations or multisystem inflammatory syndrome in children (MIS-C) after infection. MIS-C, typically emerging 2-6 weeks after SARS-CoV-2 exposure, is characterized by a hyperinflammatory response affecting multiple organs. This review aims to explore the complex landscape of immune dysregulation in MIS-C, focusing on innate, T cell-, and B cell-mediated immunity, and discusses the role of SARS-CoV-2 spike protein as a superantigen in MIS-C pathophysiology. Understanding these mechanisms is crucial for improving the management and outcomes for affected children.

Kawasaki Disease and Respiratory Viruses: Ecological Spatiotemporal Analysis

Background

Kawasaki disease is an uncommon vasculitis affecting young children. Its etiology is not completely understood, although infections have been frequently postulated as the triggers. Respiratory viruses, specifically, have often been implicated as causative agents for Kawasaki disease presentations.

Objective

We aimed to conduct an ecological spatiotemporal analysis to determine whether Kawasaki disease incidence was related to community respiratory virus circulation in a shared region and population, and to describe viral associations before and during the COVID-19 pandemic.

Methods

We obtained independent statewide data sets of hospital admissions of Kawasaki disease and respiratory multiplex polymerase chain reaction tests performed at two large hospital networks in Victoria, Australia, from July 2011 to November 2021. We studied spatiotemporal relationships by negative binomial regression analysis of the monthly incidence of Kawasaki disease and the rate of positive respiratory polymerase chain reaction tests in different regions of Victoria. Peak viral seasons (95th percentile incidence) were compared to median viral circulation (50th percentile incidence) to calculate peak season increased rate ratios.

Results

While no seasonal trend in Kawasaki disease incidence was identified throughout the study period, we found a 1.52 (99% CI 1.27-1.82) and a 1.43 (99% CI 1.17-1.73) increased rate ratio of Kawasaki disease presentations in association with human metapneumovirus and respiratory syncytial virus circulation, respectively, before the COVID-19 pandemic. No respiratory viral associations with Kawasaki disease were observed during the COVID-19 pandemic.

Conclusions

Our large ecological analysis demonstrates novel spatiotemporal relationships between human metapneumovirus and respiratory syncytial virus circulation with Kawasaki disease. The disappearance of these associations in the COVID-19 pandemic may reflect the reduced circulation of non-SARS-CoV-2 viruses during this period, supporting the prepandemic associations identified in this study. The roles of human metapneumovirus and respiratory syncytial virus in Kawasaki disease etiology warrant further investigation.

B-cell hub genes play a cardiovascular pathogenic role of in childhood obesity and Kawasaki disease as revealed by transcriptomics-based analyses

The study aims to explore the central genes that Kawasaki disease (KD) and Obesity (OB) may jointly contribute to coronary artery disease. Investigating single-cell datasets (GSE168732 and GSE163830) from a comprehensive gene expression database, we identified characteristic immune cell subpopulations in KD and OB. B cells emerged as the common immune cell characteristic subgroup in both conditions. Subsequently, we analyzed RNA sequencing datasets (GSE18606 and GSE87493) to identify genes associated with B-cell subpopulations in KD and OB. Lastly, a genome-wide association study and Mendelian randomization were conducted to substantiate the causal impact of these core genes on myocardial infarction. Quantitative real-time PCR (qRT-PCR) to validate the expression levels of hub genes in KD and OB. The overlapping characteristic genes of B cell clusters in both KD and OB yielded 70 shared characteristic genes. PPI analysis led to the discovery of eleven key genes that significantly contribute to the crosstalk. Employing receiver operating characteristic analysis, we evaluated the specificity and sensitivity of these core genes and scored them using Cytoscape software. The inverse variance weighting analysis suggested an association between TNFRSF17 and myocardial infarction risk, with an odds ratio of 0.9995 (95% CI = 0.9990-1.0000, p = 0.049). By employing a single-cell combined transcriptome data analysis, we successfully pinpointed central genes associated with both KD and OB. The implications of these findings extend to shedding light on the increased risk of coronary artery disease resulting from the co-occurrence of OB and KD.

An Interesting Case of Refractory Kawasaki Disease With Co-infection

Kawasaki disease (KD), formerly called mucocutaneous lymph node syndrome, is one of the common vasculitides of childhood. KD most commonly occurs in children over six months up to five years of age, although it can occur in young infants, older children, and adults. Early diagnosis is critical to achieving optimal treatment. We present a case of a three-year-old female child who was admitted with a fever for five days and fulfilled the diagnostic clinical criteria for KD. She was given intravenous immunoglobulin (IVIG) and aspirin. However, the fever persisted, and a urine culture showed the growth of Klebsiella pneumoniae. We started an antibiotic based on her sensitivity. Since fever spikes were not subsiding, she was given a repeat dose of IVIG along with an oral corticosteroid for refractory KD, after which she showed clinical improvement. This case highlighted that refractory KD can coexist with infection.

Incomplete Kawasaki disease presenting with a cellulitis-like plaque: Lessons from an unusual presentation

Kawasaki disease (KD) is an acute small to medium-vessel vasculitis that primarily affects children under the age of 5 years. The cause of KD is unknown, but it is hypothesized to be a systemic inflammatory illness triggered by infections in genetically predisposed individuals. Diagnosis of incomplete KD is made in patients with prolonged fever without a source who do not meet diagnostic criteria but have some findings consistent with KD such as elevated inflammatory markers, transaminitis, and echocardiographic findings. We present a 7-year-old boy who developed 10 days of fevers and rash that began 3 days after his first dose of hepatitis A vaccination and had notable features of a peculiar cellulitis-like plaque and peripheral eosinophilia.

CD14 down-modulation as a real-time biomarker in Kawasaki disease

Objectives

The objectives of this study were to investigate the pathophysiology of Kawasaki disease (KD) from immunological and oxidative stress perspectives, and to identify real-time biomarkers linked to innate immunity and oxidative stress in KD.

Methods

We prospectively enrolled 85 patients with KD and 135 patients with diverse conditions including immune, infectious and non-infectious diseases for this investigation. Flow cytometry was used to analyse the surface expression of CD14, CD38 and CD62L on monocytes, along with a quantitative assessment of CD14 down-modulation. Additionally, oxidative stress levels were evaluated using derivatives of reactive oxygen metabolites (d-ROMs) and antioxidant capacity measured by a free radical elective evaluator system.

Results

During the acute phase of KD, we observed a prominent CD14 down-modulation on monocytes, reflecting the indirect detection of circulating innate immune molecular patterns. Moreover, patients with KD showed a significantly higher CD14 down-modulation compared with infectious and non-infectious disease controls. Notably, the surface expression of CD14 on monocytes was restored concurrently with responses to intravenous immunoglobulin and infliximab treatment in KD. Furthermore, d-ROM levels in patients with KD were significantly elevated compared with patients with infectious and non-infectious diseases. Following intravenous immunoglobulin treatment, oxidative stress levels decreased in patients with KD.

Conclusion

Monitoring CD14 down-modulation on monocytes in real-time is a valuable strategy for assessing treatment response, distinguishing KD relapse from concomitant infections and selecting second-line therapy after IVIG treatment in KD patients. The interplay between inflammation and oxidative stress likely plays a crucial role in the development of KD.

A Challenging Diagnosis of Kawasaki Disease Shock Syndrome Complicated by Bilateral Pleural Effusion: A Case Report and Literature Review

Kawasaki disease (KD) is an acute illness primarily affecting children under the age of five. It is characterized by fever and inflammation of small to medium-sized arteries. This case report presents the case of a nine-year-old boy with KD who developed Kawasaki disease shock syndrome (KDSS) complicated by bilateral pleural effusion, which is a rare occurrence. KDSS is defined as KD accompanied by low blood pressure or signs of inadequate blood flow, leading to increased cardiovascular complications. The patient exhibited typical KD symptoms, including conjunctivitis, mucosal changes, rash, extremity swelling, and lymphadenopathy. Additionally, he presented with shock symptoms, such as hypotension and tachycardia. Laboratory findings showed elevated inflammatory markers. Prompt diagnosis and treatment are crucial to prevent coronary artery lesions and other severe complications. The patient received intravenous immunoglobulin and showed significant improvement, with resolution of fever and respiratory distress. Follow-up echocardiography revealed normal results. While pulmonary involvement in KD is rare, the presence of bilateral pleural effusion underscores the challenges in diagnosing KDSS. Early recognition and management are essential for favorable outcomes in KD and its complications.

Diagnosis of childhood febrile illness using a multi-class blood RNA molecular signature

BACKGROUND

Appropriate treatment and management of children presenting with fever depend on accurate and timely diagnosis, but current diagnostic tests lack sensitivity and specificity and are frequently too slow to inform initial treatment. As an alternative to pathogen detection, host gene expression signatures in blood have shown promise in discriminating several infectious and inflammatory diseases in a dichotomous manner. However, differential diagnosis requires simultaneous consideration of multiple diseases. Here, we show that diverse infectious and inflammatory diseases can be discriminated by the expression levels of a single panel of genes in blood.

METHODS

A multi-class supervised machine-learning approach, incorporating clinical consequence of misdiagnosis as a "cost" weighting, was applied to a whole-blood transcriptomic microarray dataset, incorporating 12 publicly available datasets, including 1,212 children with 18 infectious or inflammatory diseases. The transcriptional panel identified was further validated in a new RNA sequencing dataset comprising 411 febrile children.

FINDINGS

We identified 161 transcripts that classified patients into 18 disease categories, reflecting individual causative pathogen and specific disease, as well as reliable prediction of broad classes comprising bacterial infection, viral infection, malaria, tuberculosis, or inflammatory disease. The transcriptional panel was validated in an independent cohort and benchmarked against existing dichotomous RNA signatures.

CONCLUSIONS

Our data suggest that classification of febrile illness can be achieved with a single blood sample and opens the way for a new approach for clinical diagnosis.

FUNDING

European Union's Seventh Framework no. 279185; Horizon2020 no. 668303 PERFORM; Wellcome Trust (206508/Z/17/Z); Medical Research Foundation (MRF-160-0008-ELP-KAFO-C0801); NIHR Imperial BRC.

A machine learning model for distinguishing Kawasaki disease from sepsis

KD is an acute systemic vasculitis that most commonly affects children under 5 years old. Sepsis is a systemic inflammatory response syndrome caused by infection. The main clinical manifestations of both are fever, and laboratory tests include elevated WBC count, C-reactive protein, and procalcitonin. However, the two treatments are very different. Therefore, it is necessary to establish a dynamic nomogram based on clinical data to help clinicians make timely diagnoses and decision-making. In this study, we analyzed 299 KD patients and 309 sepsis patients. We collected patients' age, sex, height, weight, BMI, and 33 biological parameters of a routine blood test. After dividing the patients into a training set and validation set, the least absolute shrinkage and selection operator method, support vector machine and receiver operating characteristic curve were used to select significant factors and construct the nomogram. The performance of the nomogram was evaluated by discrimination and calibration. The decision curve analysis was used to assess the clinical usefulness of the nomogram. This nomogram shows that height, WBC, monocyte, eosinophil, lymphocyte to monocyte count ratio (LMR), PA, GGT and platelet are independent predictors of the KD diagnostic model. The c-index of the nomogram in the training set and validation is 0.926 and 0.878, which describes good discrimination. The nomogram is well calibrated. The decision curve analysis showed that the nomogram has better clinical application value and decision-making assistance ability. The nomogram has good performance of distinguishing KD from sepsis and is helpful for clinical pediatricians to make early clinical decisions.

Alteration of the oral and gut microbiota in patients with Kawasaki disease

Background

Kawasaki disease (KD) is a multi-systemic vasculitis that primarily affects children and has an unknown cause. Although an increasing number of studies linking the gut microbiota with KD, the unchallengeable etiology of KD is not available.

Methods

Here, we obtained fecal and oral samples from KD patients and healthy controls, and then we use high-throughput sequencing to examine the diversity and composition of microbiota.

Results

Results showed that both in the gut and oral microbiota, the diversity of KD patients was significantly lower than that of the healthy controls. In the gut microbiota, a higher abundance of Enterococcus (40.12% vs less than 0.1%), Bifidobacterium (20.71% vs 3.06%), Escherichia-Shigella (17.56% vs 0.61%), Streptococcus (5.97% vs 0.11%) and Blautia (4.69% vs 0.1%) was observed in the KD patients, and enrichment of Enterococcus in the patients was observed. In terms of oral microbiota, the prevalence of Streptococcus (21.99% vs 0.1%), Rothia (3.02% vs 0.1%), and Escherichia-Shigella (0.68% vs 0.0%) were significantly higher in the KD patients, with the enrichment of Streptococcus and Escherichia-Shigella. Additionally, significant differences in microbial community function between KD patients and healthy controls in the fecal samples were also observed, which will affect the colonization and reproduction of gut microbiota.

Conclusions

These results suggested that the dysbiosis of gut and oral microbiota are both related to KD pathogenesis, of which, the prevalence of Enterococcus in the gut and higher abundance of Streptococcus and Escherichia-Shigella in the oral cavity will be a potential biomarker of the KD. Overall, this study not only confirms that the disturbance of gut microbiota is a causative trigger of KD but also provides new insight into the oral microbiota involved in KD pathogenesis.

Autoptic Findings in Cases of Sudden Death Due to Kawasaki Disease

Kawasaki disease (KD) is the second-most-common childhood vasculitis, and its etiology is still unknown today. Even though the acute illness is usually self-limiting, sometimes, it can generate complications, such as coronary artery aneurysms (CAA), acute myocardial infarction (AMI), heart failure, or arrhythmias, and can rarely cause sudden or unexpected deaths. We present a review of the literature, which collects autoptic and histopathological data relating to many of the cases of these deaths. On the basis of the titles and abstracts, we selected 54 scientific publications for a total of 117 cases. Among them, as expected, the majority of the deaths were due to AMI (41.03%), arrhythmia (8.55%), acute coronary syndrome (8.55%), and CAA rupture (11.97%), involving mostly 20-year-olds or younger individuls (69.23%). This is not surprising since the CAs are the most involved arteries. Gross autoptic and histopathological findings are reported in the paper. Our work revealed that, when compared with the incidence of KD, only a few cases suffered from sudden death, underwent an autoptic examination, and were then described in the literature. We suggest that researchers should perform autopsies to gain a better understanding of the molecular pathways involved in KD so as to propose further innovative therapeutic protocols or implement more appropriate prevention schemes.

Cardiovascular outcomes in children with Kawasaki disease: a population-based cohort study

BACKGROUND

The risk of cardiovascular events after Kawasaki disease (KD) remains uncertain. Our objective was to determine the risk of cardiovascular events and mortality after KD.

METHODS

Population-based retrospective cohort study using Ontario health administrative databases (0-18 years; 1995-2018).

EXPOSURE

pediatric KD hospitalizations. Each case was matched to 100 non-exposed controls.

PRIMARY OUTCOME

major adverse cardiac events (MACE; cardiovascular death, myocardial infarction, or stroke composite).

SECONDARY OUTCOMES

composite cardiovascular events and mortality. We determined incidence rates and adjusted hazard ratios (aHR) using multivariable Cox models.

RESULTS

Among 4597 KD survivors, 79 (1.7%) experienced MACE, 632 (13.8%) composite cardiovascular events, and 9 (0.2%) died during 11-year median follow-up. The most frequent cardiovascular events among KD survivors were ischemic heart disease (4.6 events/1000 person-years) and arrhythmias (4.5/1000 person-years). KD survivors were at increased risk of MACE between 0-1 and 5-10 years, and composite cardiovascular events at all time periods post-discharge. KD survivors had a lower mortality risk throughout follow-up (aHR 0.36, 95% CI 0.19-0.70).

CONCLUSION

KD survivors are at increased risk of post-discharge cardiovascular events but have a lower risk of death, which justifies enhanced cardiovascular disease surveillance in these patients.

IMPACT

Among 4597 Kawasaki disease (KD) survivors, 79 (1.7%) experienced major adverse cardiac events (MACE) and 632 (13.8%) had composite cardiovascular events during 11-year median follow-up. KD survivors had significantly higher risks of post-discharge MACE and cardiovascular events versus non-exposed children. Only nine KD survivors (0.2%) died during follow-up, and the risk of mortality was significantly lower among KD survivors versus non-exposed children. Childhood KD survivors should receive preventative counseling and cardiovascular surveillance, aiming to mitigate adult cardiovascular disease.

Medication analysis and pharmaceutical care for a child with Kawasaki disease: A case report and review of the literature

OBJECTIVE

To explore the ideas and methods of clinical pharmacists regarding drug therapy for children with Kawasaki disease.

METHODS

By participating in a whole drug treatment process for a child with Kawasaki disease, the rationality of the drug treatment plan was analyzed, pharmaceutical care was provided for the child, and a pharmaceutical care model suited to this child was developed.

RESULTS

After treatment, the child was discharged from the hospital, and all signs and major inflammatory indicators returned to normal. The child's parents were instructed to bring medication, visit regularly, and adjust medication.

CONCLUSION

Through the entire process of pharmaceutical care, clinical pharmacists are able to identify and resolve drug treatment-related issues in a timely manner, and also make suggestions on rational drug use, which can improve the safety and compliance of drug use in children and the quality of clinical drug treatment.

Identifying differentially expressed genes and miRNAs in Kawasaki disease by bioinformatics analysis

Kawasaki disease (KD) is an acute systemic immune vasculitis caused by infection, and its etiology and underlying mechanisms are not completely clear. This study aimed to identify differentially expressed genes (DEGs) with diagnostic and treatment potential for KD using bioinformatics analysis. In this study, three KD datasets (GSE68004, GSE73461, GSE18606) were downloaded from the Gene Expression Omnibus (GEO) database. Identification of DEGs between normal and KD whole blood was performed using the GEO2R online tool. Gene ontology and Kyoto Encyclopedia of Genes and Genomes (KEGG) functional enrichment analysis of DEGs was undertaken with Metascape. Analysis and visualization of protein-protein interaction networks (PPI) were carried out with STRING and Cytoscape. Lastly, miRNA-genes regulatory networks were built by Cytoscape to predict the underlying microRNAs (miRNAs) associated with DEGs. Overall, 269 DEGs were identified, including 230 up-regulated and 39 down-regulated genes. The enrichment functions and pathways of DEGs involve regulation of defense response, inflammatory response, response to bacterium, and T cell differentiation. KEGG analysis indicates that the genes were significantly enriched in Neutrophil extracellular trap formation, TNF signaling pathway, Cytokine-cytokine receptor interaction, and Primary immunodeficiency. After combining the results of the protein-protein interaction (PPI) network and CytoHubba, 9 hub genes were selected, including TLR8, ITGAX, HCK, LILRB2, IL1B, FCGR2A, S100A12, SPI1, and CD8A. Based on the DEGs-miRNAs network construction, 3 miRNAs including mir-126-3p, mir-375 and mir-146a-5p were determined to be potential key miRNAs. To summarize, a total of 269 DEGs, 9 hub genes and 3 miRNAs were identified, which could be considered as KD biomarkers. However, further studies are needed to clarify the biological roles of these genes in KD.

Association of ITPKC gene polymorphisms rs28493229 and rs2290692 in North Indian children with Kawasaki disease

BACKGROUND

Single-nucleotide polymorphisms (SNPs) of several genes are linked to the etiopathogenesis of Kawasaki disease (KD). Association of SNPs of inositol 1,4,5-triphosphate-3-kinase C (ITPKC) gene with susceptibility to KD and coronary artery lesions (CALs) has been observed in children of certain ethnicities, but not from others. The present study was planned to explore this genetic association in the North Indian cohort.

METHODS

Fifty children with KD and 50 age- and sex-matched controls were studied for two SNPs (rs28493229 and rs2290692) of the ITPKC gene using polymerase chain reaction and restriction fragment length polymorphism. Findings were confirmed by Sanger sequencing. A meta-analysis was also carried out for GG and CC genotypes of the SNPs.

RESULTS

There was significant association between KD susceptibility and CG + GG genotype of rs2290692 (p = 0.015, odds ratio = 4.1, 95% confidence interval = 1.38-13.83). None of the single alleles or genotypes of the SNPs of ITPKC were, however, significantly associated with KD susceptibility. A meta-analysis also did not show any significant association of these SNPs to KD susceptibility.

CONCLUSIONS

Our findings suggest that ITPKC gene SNPs (rs28493229 and rs2290692) did not have a significant association with susceptibility to KD in children from North India. Larger multicentric studies incorporating different ethnicities are required to understand the genetic basis of KD.

IMPACT

While SNP rs28493229 of the ITPKC gene is not found to be associated with susceptibility to KD, the combined genotype of SNP rs2290692 is shown to be associated. Impact of ITPKC gene SNP on KD is different across different races and ethnicities. We could find an association of the combined genotype of rs2290692 with it in the Indian population. This study highlights that phenotype and genotypic association of KD varies with ethnicities. Larger multicentric studies are required to reach a conclusion regarding the genetic association of KD.

Hygienic behaviors during the COVID-19 pandemic may decrease immunoglobulin G levels: Implications for Kawasaki disease

Background

Due to the coronavirus disease 2019 (COVID-19) pandemic, hygienic behaviors became a new norm since January 2020. The hygiene hypothesis predicts that an excessively hygienic environment may adversely affect human health.

Objective

We quantified the effect of COVID-19 on immunological parameters linked to the hygiene hypothesis.

Methods

We examined age-specific levels of total nonspecific immunoglobulin G (IgG) and IgE in individuals who visited Fukuoka Tokushukai Hospital between 2010 and 2021. Pre-COVID (2010–2019) and COVID (2020–2021) periods were compared.

Results

IgG levels steadily decreased throughout Pre-COVID period. IgG levels fell abruptly from the pre-COVID period to the COVID period in all age groups (P = 0.0271, < 0.3 years; P = 0.0096, 0.3–5 years; P = 0.0074, ≥ 5 years). The declines in IgG in < 0.3 years and that in ≥ 5 years accelerated during the COVID period. IgE levels were seasonal, but did not change noticeably from the pre-COVID to COVID period. IgG levels recorded for patients with Kawasaki disease (KD) (mean 709 mg/dL) were significantly lower than for matched control subjects (826 mg/dL) (P<0.0001).

Discussion

Hygienic behaviors during the COVID-19 outbreak decreased the chance of infection, which may explain the decreases in IgG levels in children and adults. Neonatal IgG declined, possibly because of the decrease in maternal IgG.

Conclusion

Hygienic behaviors decreased the IgG levels in all age groups, from neonates to adults. This downturn in IgG may lead to vulnerability to infections as well as to KD.

Etiology, clinical presentation, and management of left main coronary artery aneurysms

BACKGROUND AND AIM OF THE STUDY

The widespread use of noninvasive/invasive coronary imaging increased the probability of recognition of coronary aneurysms. Left main coronary aneurysms (LMCA), though rare, are potentially life-threatening but in the absence of controlled studies, guidelines do not provide any specific recommendation for their management. We, therefore, aimed to investigate the epidemiology, clinical presentation, therapeutic strategies, and prognostic implication of LMCA.

METHODS

A systematic review of the literature was performed to retrieve all the reported cases of LMCA as of December 2021, which were summarized and classified according to their etiology, clinical presentation, and therapeutic management.

RESULTS

Out of 1997 works retrieved, 180 studies were analyzed, describing 209 LMCA cases (aged 51 ± 19 years, 68% males). Atherosclerosis was the most common etiology (40%), followed by inflammatory (12%), congenital (9%), or degenerative (6%) conditions. Stable angina (43%) and acute coronary syndromes (32%) were more often the first clinical manifestations, while 29 (14%) LMCA were incidental findings. Most cases were treated surgically (53%), while percutaneous intervention was rarely adopted (7%). Data about antithrombotic therapies were scarce and heterogeneous. Finally, when longitudinal data were reported (n = 81), LMCA resulted associated with a severe prognosis, with a 15% mortality over an 8-month median follow-up.

CONCLUSIONS

LMCA are most frequently, but not exclusively, caused by advanced atherosclerosis. Irrespective of their etiology and clinical presentation, LMCA may be associated with high short-term mortality. In absence of controlled studies, a careful evaluation of each case is warranted to optimize therapeutic strategies.

Kawasaki disease following immunization reported to the Canadian Immunization Monitoring Program ACTive (IMPACT) from 2013 to 2018

Kawasaki disease (KD) is an acute systemic vasculitis primarily affecting children younger than 5 y of age that has been reported as an adverse event following immunization (AEFI). The Canadian Immunization Monitoring Program ACTive (IMPACT) conducts active surveillance for KD following immunization across Canada. We characterized KD cases reported to IMPACT between 2013 and 2018. Cases admitted to an IMPACT hospital with a physician diagnosis of complete or incomplete KD with onset 0–42 d following vaccination were reviewed. Cases meeting the Brighton Collaboration case definition (BCCD) levels of diagnostic certainty levels 1 a/b, 2a/b or 3a-e were defined as KD cases. Demographic and vaccination characteristics were compared between KD cases and non-cases. Of 84 cases reviewed, 58 met the BCCD: 47 (81%) cases met level 1a (Complete KD), 8 (14%) met level 1b (Incomplete KD), 2 (3%) met level 2a, and 1 (2%) met level 2c (Probable KD). Median age at admission was 13 months (interquartile range 7–26 months). A median of 9.5 cases were reported per year (range 4–14). Thirty-one (53%) KD cases were temporally associated with diphtheria-tetanus acellular pertussis containing vaccinations, followed by 21 (36%) cases with pneumococcal conjugate vaccines. Symptom onset was 0–14 d after vaccination in 32 (55%) cases. Echocardiogram results were available for 43 (74%) cases with 22 reported as abnormal. Age, sex, interval to symptom onset, and vaccines received were similar between KD cases and non-cases. No safety signals were detected in these data.

Case of adult-onset Kawasaki disease and multisystem inflammatory syndrome following SARS-CoV-2 vaccination

Kawasaki disease (KD) and multisystem inflammatory syndrome (MIS) are rare conditions that occur predominately in children. Recent reports document KD and MIS in adult patients following infection with SARS-CoV-2. Rarely, MIS is observed following vaccination against SARS-CoV-2, mostly in patients with prior SARS-CoV-2 infection. We report a case of KD in a man after a second SARS-CoV-2 vaccine dose, in absence of concurrent or prior SARS-CoV-2 infection. This patient also met criteria for probable MIS associated with vaccination. He tested negative for SARS-CoV-2 RNA via reverse transcriptase PCR, negative for SARS-CoV-2 nucleocapsid antibodies and demonstrated high levels SARS-CoV-2 spike protein antibodies, commonly used to assess vaccine response. Symptom improvement followed treatment with intravenous immunoglobulin, including desquamation of the hands and feet. As widespread vaccination against SARS-CoV-2 continues, increased vigilance and prompt intervention is necessary to limit the effects of postvaccination inflammatory syndromes.

Association of SNP (rs1042579) in thrombomodulin gene and plasma thrombomodulin level in North Indian children with Kawasaki disease

BACKGROUND

Kawasaki disease (KD) is the commonest systemic vasculitis in children. It predisposes to development of coronary artery abnormalities (CAAs). Thrombomodulin (THBD) gene polymorphism rs1042579 is associated with high risk of cerebrovascular diseases. However, association of THBD polymorphism (rs1042579) and plasma thrombomodulin (TM) levels with susceptibility to KD and CAAs remains unclear.

METHODS AND RESULTS

Polymorphism in THBD gene (rs1042579) was analysed in 50 KD patients and 50 age, gender and ethnicity matched controls using Sanger sequencing. Plasma TM levels were measured by ELISA.

RESULTS

Mean plasma TM level (± SD) in KD patients was 2549.41 (± 853.18) pg/ml and in controls was 2298.03 (± 869.14) pg/ml; p = 0.042. Mean plasma TM levels in CC genotype was 2299.98 (± 834.88) pg/ml and in CT/TT genotype was 2837.96 (± 857.14) pg/ml; p = 0.005. Genotyping data did not reveal significant differences in patients with KD as compared to controls (p = 0.25), and in KD patients with and without CAAs (p = 0.407). Odds of finding T allele in cases were 2.07 times greater than in controls (p = 0.093).

CONCLUSIONS

This is the first study from India, and second in the world, that investigates association of THBD gene polymorphism with KD. This is also the first study to assess plasma TM levels in KD patients. Our data show that plasma TM levels were significantly higher in KD patients with CT/TT genotypes. Further, the polymorphism rs1042579 at exon 1 of THBD gene was found to be more common in KD patients than in controls although the difference was not statistically significant.

Overview of infections as an etiologic factor and complication in patients with vasculitides

Vasculitides, a form of inflammatory autoimmune disease targeting the vessels, constitute an entity with significant morbidity and mortality. Infections have long been associated with vasculitides as a result of the incident immunosuppression following treatment induction and maintenance. Several microbial pathogens have been described as etiologic factors of infections in this patient population according to the type of vessels affected. Intense research has also been recently conducted in the interplay between vasculitides and certain viral infections, namely human immunodeficiency virus and severe acute respiratory syndrome coronavirus 2. Of note, a plethora of scientific evidence is available regarding the role of infections as triggering factors for vasculitides. Among the main mechanisms implicated in this direction are the activation of B and T cells, the direct endothelial insult, the immune complex-mediated vascular injury, and the cell-mediated, type IV hypersensitivity vessel damage. Therefore, this review aims to summarize all the available evidence concerning this bidirectional interplay between infections and vasculitides.

Epidemiology of Kawasaki disease in Australia using two nationally complete datasets

AIM

The incidence of Kawasaki disease (KD) is reported to be increasing in some populations. We sought to describe long-term trends in the incidence and epidemiology of KD in Australia over 25 years.

METHODS

Two nationally complete administrative datasets relevant to KD in Australia were analysed and compared. The Australian Red Cross Lifeblood Supply Tracking Analysis Reporting System (STARS) recorded all doses of immunoglobulin (IVIG) approved in Australia between January 2007 and June 2016. The Australian Institute of Health and Welfare National Hospital Morbidity Database (NHMD) records all episodes of care in hospitals across Australia. Data relevant to KD were extracted an analysed, with comparisons made for the period of data overlap.

RESULTS

During the period of data overlap (2007-2015) the IVIG treatment rate in the 0- to 4-year age group (calculated from STARS) was 14.31 per 100 000 person-years (95% confidence interval 13.67-14.97). The hospitalisation rate in the same age group (calculated from the NHMD) was 14.99 per 100 000 person-years (95% confidence interval 14.33-15.66). Hospitalisation rates rose at an average rate of 3.54% annually over the 25 years to 2017 in the 0- to 4-year age group, almost exclusively in the 1- to 4-year age group.

CONCLUSIONS

There is evidence of increasing KD diagnosis in Australia. Similar trends have also been reported in Asia but not in North America or Europe. Increasing diagnosis may reflect a true increase in disease incidence, increasing recognition or overdiagnosis. Further research is needed to determine the cause for these trends.

Prenatal and early life exposure to air pollution and the incidence of Kawasaki disease

Kawasaki disease (KD) is the most common form of acquired pediatric cardiac disease in the developed world. However, its etiology is still unclear. Epidemiological studies have shown that air pollution is a plausible risk factor in stimulating oxidative stress, inducing inflammation and causing autoimmune diseases. This study aims to assess the connections between prenatal and early life air pollution exposure to the incidence of KD. The main data source of this nationwide longitudinal study was the National Health Insurance Research Database (NHIRD) of Taiwan. NHIRD was linked with Taiwan Maternal and Child Health Database to establish the link between mothers and children. In total, 4192 KD cases involving children under 6 years of age were identified between January 2004 and December 2010. Children in the control group were randomly selected at a 1:4 ratio and matched using their age and index year. Integrated data for the air pollutants were obtained from 71 Environmental Protection Agency monitoring stations across Taiwan. Patients who had main admission diagnosis of KD and subsequently received intravenous immunoglobulin treatment were defined as incidence cases. Ambient exposure, including pollutant standards index (PSI), carbon monoxide (CO), nitric oxide (NO), nitric dioxide (NO₂), and nitrogen oxide (NOx) during pregnancy were all positively associated with KD incidence. Conversely, ozone (O₃) exposure had a negative correlation. Exposure to CO, NO, NO_2, and NOx after childbirth remained consistent with regards to having a positive association with KD incidence. Exposure to PSI and O₃ after delivery displayed no significant association with KD. Both prenatal and postnatal cumulative CO, NO, NO₂, and NOx exposure had a dose dependent effect towards increasing KD incidence. Certain prenatal and early life air pollutant exposure may increase the incidence of KD.

Number of Kawasaki Disease Admissions Is Associated with Number of Domestic COVID-19 and Severe Enterovirus Case Numbers in Taiwan

Background: Non-pharmaceutical interventions (NPIs) introduced in response to the COVID-19 pandemic, including mask-wearing and social distancing, have changed the prevalence of circulating viruses in the community. Since viral infections represent a potential triggering factor for the development of Kawasaki disease (KD), we examined the relationship between KD admission rates and the number of COVID-19, severe influenza, and severe enterovirus infections both before and after the COVID-19 pandemic. Methods: We conducted a retrospective study using data obtained from the Chang Gung Research Database (including seven Taiwanese hospitals and more than 10,000 beds) and the Centers for Disease Control in Taiwan from January 2018 to December 2020. We recorded the number of KD admissions, as well as COVID-19, severe influenza, and severe enterovirus infections. Results: The numbers of KD admissions, severe enterovirus infections, and severe influenza infections were significantly lower from April to September 2020. The number of KD hospitalizations was positively correlated with the number of domestic COVID-19 cases (p = 0.001). A decrease in KD admission numbers was positively correlated with a decrease in severe enterovirus case numbers (p = 0.007). Conclusion: Our findings provide further evidence that viral infections may be an important trigger factor in the development of KD. Therefore, NPIs may not only prevent transmissible viral infections in children, but also decrease the risk of KD.

Atypical Kawasaki Disease after COVID-19 Vaccination: A New Form of Adverse Event Following Immunization

Kawasaki disease (KD) is a medium-vessel vasculitis that is typically presented during childhood; fewer than 100 cases of KD have been reported worldwide in adult patients who met the criteria according to the American College of Rheumatology. This study presents the case of an 18-year-old patient with no previous history of any disease, who presented atypical KD with liver and kidney dysfunction, with a good response to intravenous immunoglobulin therapy. The symptoms began 22 days after the application of the COVID-19 vaccine (nonreplicating viral vector Vaxzevria), and other conditions were ruled out. The term Adverse Events Following Immunization (AEFI)encompasses all the reactions that follow the application of any vaccine with no necessary causal relationship and can be due to the vaccine product, quality of the vaccine, immunization errors, or anxiety or just happen to be coincident events. These reactions should be reported so that clinicians can identify compatible cases and consider that the presentation of this disease, despite being atypical, can be manifested in adult patients. Likewise, case reports are an important basis for the pharmacovigilance of vaccines.

The clinical implications of serum ferritin in Kawasaki disease: a helpful biomarker for evaluating therapeutic responsiveness, coronary artery involvement and the tendency of macrophage activation syndrome

INTRODUCTION

Serum ferritin (SF) is an acute-phase reactant in inflammatory diseases. Our aim was to analyze the clinical implications of SF in Kawasaki disease (KD).

METHODS

244 KD children were divided into 6 subgroups. SF, inflammatory mediators and blood cell counts were detected.

RESULTS

(1) SF dramatically increased in the acute phase of KD and maintained after IVIG therapy; (2) SF increased in IVIG-nonresponsive KD patients (AUC = 0.705; sensitivity: 57.10%; specificity: 82.90%); SF positively correlated with the internal diameter of the coronary artery (AUC = 0.603; sensitivity: 92.30%; specificity: 37.70%); (3) SF increased in 4 patients with the macrophage activation syndrome (MAS)/MAS tendency (979.03 ±474.19 μg/l).

CONCLUSIONS

SF is implied to be a helpful biomarker for forecasting IVIG-nonresponsive KD, coronary artery abnormalities (CAAs) and MAS tendency.

Multisystem inflammatory syndrome in children and Kawasaki disease: a critical comparison

Children and adolescents infected with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) are predominantly asymptomatic or have mild symptoms compared with the more severe coronavirus disease 2019 (COVID-19) described in adults. However, SARS-CoV-2 is also associated with a widely reported but poorly understood paediatric systemic vasculitis. This multisystem inflammatory syndrome in children (MIS-C) has features that overlap with myocarditis, toxic-shock syndrome and Kawasaki disease. Current evidence indicates that MIS-C is the result of an exaggerated innate and adaptive immune response, characterized by a cytokine storm, and that it is triggered by prior SARS-CoV-2 exposure. Epidemiological, clinical and immunological differences classify MIS-C as being distinct from Kawasaki disease. Differences include the age range, and the geographical and ethnic distribution of patients. MIS-C is associated with prominent gastrointestinal and cardiovascular system involvement, admission to intensive care unit, neutrophilia, lymphopenia, high levels of IFNγ and low counts of naive CD4⁺ T cells, with a high proportion of activated memory T cells. Further investigation of MIS-C will continue to enhance our understanding of similar conditions associated with a cytokine storm.

Paediatric Active Enhanced Disease Surveillance (PAEDS) 2019: Prospective hospital-based surveillance for serious paediatric conditions

Introduction

The Paediatric Active Enhanced Disease Surveillance (PAEDS) network is an Australian hospital-based active surveillance system employing prospective case ascertainment for selected serious childhood conditions, particularly vaccine preventable diseases and potential adverse events following immunisation (AEFI). This report presents surveillance data for 2019.

Methods

Specialist nurses screened hospital admissions, emergency department records, laboratory and other data on a daily basis in seven paediatric tertiary referral hospitals across Australia, to identify children with the conditions under surveillance. Standardised protocols and case definitions were used across all sites. In 2019, the conditions under surveillance comprised: acute flaccid paralysis (AFP; a syndrome associated with poliovirus infection), acute childhood encephalitis (ACE), influenza, intussusception (IS; a potential AEFI with rotavirus vaccines), pertussis, varicella-zoster virus infection (varicella and herpes zoster), invasive meningococcal and invasive Group A streptococcus diseases and two new conditions, Kawasaki disease and gram-negative bloodstream infections. An additional social research component continued to evaluate parental attitudes to influenza vaccination.

Results

PAEDS captured 2,701 cases for 2019 across all conditions under surveillance. Key outcomes of PAEDS included: contribution to national AFP surveillance to reach the World Health Organization reporting targets for detection of poliomyelitis cases; demonstration of high influenza activity in 2019 and influenza-associated deaths in ACE cases; identification of key barriers to influenza vaccination of children hospitalised for acute respiratory illness; reporting of all IS cases associated with vaccine receipt to relevant state health department; and showing a further reduction nationally in varicella cases. Enhanced pertussis surveillance continued to capture controls to support vaccine efficacy estimation. Invasive meningococcal disease surveillance showed predominance of serotype B and a reduction in cases nationally. Surveillance for invasive group A streptococcus captured severe cases in children. Monitoring of Kawasaki disease incidence and gram-negative bloodstream infections commenced.

Conclusions

PAEDS continues to provide unique policy-relevant data on serious paediatric conditions using sentinel hospital-based enhanced surveillance. Keywords: paediatric, surveillance, child, hospital, vaccine preventable diseases, adverse event following immunisation, acute flaccid paralysis, encephalitis, influenza, intussusception, pertussis, varicella zoster virus, meningococcal, group A streptococcus, Kawasaki, bloodstream infections.

Incidence and short-term outcomes of Kawasaki disease

OBJECTIVE

Kawasaki disease (KD) is a childhood vasculitis with conflicting reported North American trends in incidence and patient characteristics.

OBJECTIVES

(1) determine KD incidence between 1995 and 2017; (2) compare patient characteristics by era and age group; (3) determine complication and cardiovascular follow-up rates.

METHODS

We used population-based health administrative data to identify children (0-18 yr) hospitalized with KD in Ontario, Canada between 1995 and 2017. We excluded children with prior KD diagnosis or incomplete records. We determined the annualized incidence and follow-up trends.

RESULTS

KD was diagnosed in 4,346 children between 1995 and 2017. Annual KD incidence was 22.0 (<5 yr), 6.1 (5-9 yr), and 0.6 (10-18 yr) per 100,000 children. KD incidence increased significantly for all age groups, including from 18.4 to 25.0 cases per 100,000 children <5 yr. Ninety-day mortality occurred in ≤5 children (≤0.1%). Coronary artery aneurysm (CAA) occurred in 106 children (2.4%, 95% confidence interval 2.0-2.9) during admission and 151 (3.5%, 95% confidence interval 3.0-4.1) during 11-year median follow-up. Children 10-18 yr had longer hospitalizations (4.3 vs. 3.5 days, p = 0.003) and more CAA (7.4% vs. 3.4%, p = 0.007). By 1-year post-diagnosis, 3970 (91.3%) and 2576 (59.3%) children had echocardiography and cardiology follow-up, respectively.

CONCLUSIONS

KD incidence is increasing in Ontario, with greater healthcare utilization from hospitalizations and subsequent follow-up.

IMPACT

4346 children were hospitalized for Kawasaki disease over 22 years in Ontario, and Kawasaki disease incidence increased significantly for all age groups, males and females. Older children (10-18 years) had longer hospital length of stay, more PICU admissions and more frequent coronary artery aneurysms. Nearly all children with Kawasaki disease had follow-up echocardiography within 1 year.

The multisystem inflammatory syndrome in children and its association to SARS-CoV-2

PURPOSE OF REVIEW

Multisystem inflammatory syndrome in children (MIS-C)/pediatric inflammatory multisystem syndrome (PIMS) is a new and serious disease that occurs in temporal association with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. We describe the clinical presentation, diagnosis, and treatment recommendations.

RECENT FINDING

To date, no randomized prospective studies have been published; recommendations are based on some observational studies, case reports, and expert opinions. The article provides an overview of the most important publications, presents the current results of the German Registry for PIMS and expert recommendations for treatment.

SUMMARY

MIS-C PIMS is a new syndrome that is associated with a variety of virus infections, and also with SARS-CoV-2. The main characteristics are fever, multiple organ dysfunction due to a hyper-inflammatory state. In particular, cardiac dysfunction and severe shock. A high proportion of patients require intensive medical care, but the absolute number of children with SARS-CoV-2 MIS-C is low. Medical therapy is based on pathophysiologic considerations and is not evidence-based. Immunoglobulins, steroids and biologics are used and lead to effective treatment. Therefore, the mortality rate is very low. Patients usually recover within days, sequelae are reported only in a minority of cases.

Kawasaki Disease Shock Syndrome in the Eastern Region of Saudi Arabia: Case Series

Kawasaki disease (KD) is a treatable medium-sized vasculitis in the pediatric population consisting of a myriad of specific signs and symptoms. A new entity of the disease, Kawasaki disease shock syndrome (KDSS), is defined as a KD patient presenting with signs of hypoperfusion. Our aim is to describe the signs and symptoms of KDSS and how it is treated and its consequences. Out of 37 patients diagnosed with KD in the period between January 2018 and December 2019 in hospitalized patients younger than 14 years of age at Maternity and Children's Hospital in Al-Hassa, Eastern Province, Saudi Arabia, 3 (8.10%) patients fulfilled the diagnostic criteria for KDSS: 2 (66%) were male and 1 (33%) was female. The cardinal feature in all of them was peripheral cardiovascular collapse. Two patients (66%) were found to have aseptic meningitis. All patients were treated with immunomodulatory agents (intravenous immunoglobulin) and all responded well to anti-inflammatory doses of aspirin. KDSS is the shock state of KD presenting with hypoperfusion symptoms, mainly irritability and changes in the level of consciousness and peripheral cardiovascular collapse. Awareness of such presentation and management by immunomodulatory medications helps in recovery and prevention of tragic consequences of such disease.

Kawasaki disease for the paediatric dermatologist: skin manifestations and new insights into the pathophysiology

Early diagnosis of Kawasaki disease (KD) is critical to allow prompt initiation of treatment and avoid cardiac complications. All children with KD have fever accompanied by clinical signs, with four of the five classic criteria for complete KD being mucocutaneous, thus creating an important role for dermatologists. Moreover, dermatologists must be familiar with other dermatological findings that are not included in the American Heart Association classification criteria but can support the diagnosis, particularly in incomplete forms of the disease. We review the skin manifestations described for KD and perform an overview of pathophysiological advances and new treatments.

Characteristics of Children With Kawasaki Disease-Like Signs in COVID-19 Pandemic: A Systematic Review

Recent studies have shown that several children diagnosed with COVID-19 have developed Kawasaki Disease (KD)-like symptoms. This systematic review aims to assess the demographic, laboratory, and clinical characteristics of children with KD-like syndrome during the COVID-19 pandemic and evaluate efficacy of treatments and patients' outcome. A comprehensive search was carried out systematically through PubMed, Scopus, and Web of Science (WoS), medRxiv, and bioRxiv by two reviewers independently for all studies or preprints data on the demographic, laboratory, and clinical characteristics of children with K.D-like signs during the COVID-19 outbreak. Overall, 378 studies were identified by the systematic search, of which 25 studies were included in the study. The included studies involved 599 patients in total. Thirteen studies (52%) were case reports or case series, and the rest (48%) were cohort studies. In 19 studies, patients were diagnosed with Multisystem inflammatory syndrome in children (MIS-C). In 16 studies COVID-19 was diagnosed in all patients based on their polymerase chain reaction result, serological findings, and computed tomography results. Higher C-reactive protein and erythrocyte sedimentation rate level were the most prevalent laboratory findings. In most studies, patients had leucopenia with marked lymphopenia, hypoalbuminemia, and increased ferritin, as well as hyponatremia. Abnormal echocardiography and respiratory outcomes were the most common clinical outcomes. In 11 studies, all patients required intensive care unit admission. Findings of the present systematic review show that the incidence of KD-like syndrome in the COVID-19 pandemic increased significantly. Moreover, this study offers new insights in the KD-like syndrome pathogenesis and clinical spectrum during COVID-19 pandemic.

Multisystem Inflammatory Syndrome in Children: An International Survey

OBJECTIVES

To describe presentation, hospital course, and predictors of bad outcome in multisystem inflammatory syndrome in children (MIS-C).

METHODS

Retrospective data review of a case series of children meeting the published definition for MIS-C who were discharged or died between March 1, 2020, and June 15, 2020, from 33 participating European, Asian, and American hospitals. Data were collected through a Web-based survey and included clinical, laboratory, electrocardiographic, and echocardiographic findings and treatment management.

RESULTS

We included 183 patients with MIS-C: male sex, 109 (59.6%); mean age 7.0 ± 4.7 years; Black race, 56 (30.6%); obesity, 48 (26.2%). Overall, 114 of 183 (62.3%) had evidence of severe acute respiratory syndrome coronavirus 2 infection. All presented with fever, 117 of 183 (63.9%) with gastrointestinal symptoms, and 79 of 183 (43.2%) with shock, which was associated with Black race, higher inflammation, and imaging abnormalities. Twenty-seven patients (14.7%) fulfilled criteria for Kawasaki disease. These patients were younger and had no shock and fewer gastrointestinal, cardiorespiratory, and neurologic symptoms. The remaining 77 patients (49.3%) had mainly fever and inflammation. Inotropic support, mechanical ventilation, and extracorporeal membrane oxygenation were indicated in 72 (39.3%), 43 (23.5%), and 4 (2.2%) patients, respectively. A shorter duration of symptoms before admission was found to be associated with poor patient outcome and for extracorporeal membrane oxygenation and/or death, with 72.3% (95% confidence interval: 0.56-0.90; P = .006) increased risk per day reduction and 63.3% (95% confidence interval: 0.47-0.82; P < .0001) increased risk per day reduction respectively.

CONCLUSIONS

In this case series, children with MIS-C presented with a wide clinical spectrum, including Kawasaki disease-like, life-threatening shock and milder forms with mainly fever and inflammation. A shorter duration of symptoms before admission was associated with a worse outcome.

Long-term Incidence of Kawasaki Disease in a North American Community: A Population-Based Study

To assess the longitudinal incidence of Kawasaki disease (KD) within the well-defined predominantly White population of Olmsted County, MN. This retrospective cohort study used a population-based medical record linkage system and manual chart reviews to identify children with KD in Olmsted County, MN between January 1, 1979-December 31, 2016. Age- and gender-adjusted incidence rates were calculated using the 2010 U.S. White population. 124 children with KD were confirmed during the study period (median age 3.5, 61% male, 85% White, 9% Asian). The overall age- and gender-adjusted incidence rates for all ages and < 5 years old were 9.8 and 21.4 per 100,000 person-years, respectively. There was an overall increase in incidence up to 1994 followed by plateau, except among children between the ages of 1-5 years. There was also an overall increase in incidence among females compared to males. 24% of children had cardiac complications. While the overall incidence of KD in Olmsted County appears to be stable since 1994, the incidence of KD in subgroups of children 1-5 years old and females seems to have increased. Given the rising trends and one-quarter of children developing cardiac complications, further studies identifying factors driving these trends are warranted.

Kawasaki disease with a concomitant primary Epstein - Barr virus infection

BACKGROUND

Kwasaki disease (KD) is the leading cause of acquired heart disease in children in most developed countries. The cause of KD remains unknown. The presumed theory is that KD occurs due to one or more infectious agents who evoke an abnormal immunological response in susceptible individuals. Epstein - Barr virus (EBV) infection has been considered as a suspected causative agent because of the potential effect on the immune system.

CASE PRESENTATION

A previously healthy 19 month old boy presented with a 6 day history of fever accompanied by a diffuse macular erythematous rash that appeared 1 day after. The physical examination on admission revealed bilateral non-suppurative conjunctivitis, dry fissured and injected lips without "strawberry" tongue, diffuse macular rash on the trunk, face and limbs, swelling of the hands and feet, and right cervical lymphadenopathy (2 cm in diameter). Following fulfillment of all the clinical criteria, the diagnosis of KD was made and treatment with IVIG 2 g/Kg was administered along with oral aspirin (80 mg/ kg/day). However, despite the treatment, he remained febrile for an additional 2 days with persistent clinical manifestations. Therefore, he received a second 2 g/kg IVIG course with a favorable response. On the 14th day of illness the patient became febrile again and was readmitted. Blood examinations revealed remarkable leukocytosis up to 35.7 X 10⁹/L with 87.3% lymphocytes and the blood smear revealed atypical lymphocytes and monocytes. The liver enzymes were elevated. The serology for infectious mononucleosis from his first admission revealed: IgM CMV (+), IgG CMV (-); IgM VCA EBV (+) IgG VCA EBV (-), IgG EBNA (-). To confirm infectious mononucleosis following the administration of 2 doses of IVIG, serum EBV PCR was performed and was positive (1.6X 10³ cp/ml).

CONCLUSIONS

We describe here a case of KD with a concomitant primary EBV infection. To the best of our knowledge, this is the first case in western country that describes KD with acute EBV infection as confirmed by PCR. The case we described stands as a contribution in favor of the possible role of EBV in the development of KD.

Update on the COVID-19-associated inflammatory syndrome in children and adolescents; paediatric inflammatory multisystem syndrome-temporally associated with SARS-CoV-2

We provide an update on the state of play with regards a newly described inflammatory condition which has arisen during the current SARS-CoV-2 pandemic. The condition has been named paediatric inflammatory multisystem syndrome temporally associated with SARS-CoV-2 or multisystem inflammatory syndrome in children. This condition has shown significant similarities to Kawasaki disease and toxic shock syndrome.

Our Evolving Understanding of Kawasaki Disease Pathogenesis: Role of the Gut Microbiota

Kawasaki disease (KD) was first described by Dr. Tomisaku Kawasaki in 1967. The etiology of KD has been studied comprehensively but remains largely unknown. The disease seems to result from the interplay of genetic and environmental susceptibility factors with infectious triggers, followed by a subsequent abnormal immune response characterized by increased levels of inflammatory cytokines and chemokines during the acute phase. Evidence has mounted to suggest that an imbalance between T helper 17 cells (Th17s) and regulatory T cells (Tregs) is associated with aberrant immune responses in KD. Recent advances in culture-independent techniques for detection and identification of intestinal commensal bacteria enabled the discovery that Th17 and Treg differentiation are regulated by short chain fatty acids (SCFAs), in particular butyrate, produced by the gut microbiota. This finding provided a mechanistic link between dysbiosis, defined as changes in the composition of the gut microbiota, and various inflammatory diseases. On this basis, we propose that dysbiosis, with reduced production of SCFAs leading to imbalances of Th17s/Tregs, could be involved in the etiology of KD. A pilot study supported this hypothesis, as only fecal concentrations of butyrate were significantly reduced in KD patients among SCFAs. This evolving perspective prompted us to undertake metagenomic analyses of bacterial DNA from the feces of KD patients who were antibiotic-naïve at diagnosis. Simultaneous measurements of Th17s/Tregs in peripheral blood and SCFA concentrations in feces would provide valuable information regarding the association between dysbiosis and dysregulated immune responses in KD.

Australian hospitalisations for Kawasaki disease, 1993-1994 to 2017-2018

AIM

To estimate and describe trends in hospitalisations for Kawasaki disease in Australia.

METHODS

Analysis of the National Hospital Morbidity Database for separations with a principal diagnosis of Kawasaki disease, 1993-1994 to 2017-2018. Limited to persons aged 0-19 years.

RESULTS

Over the period 1993-1994 to 2017-2018, there were 6368 hospitalisations for Kawasaki disease among people aged 0-19 years; 433 same-day (6.8%) and 5935 overnight (93.2%). Among overnight separations, 15.8% were for children under the age of 1 year and 58.7% for those aged 1-4 years; 60.3% were for males. The hospitalisations rate has increased from 5.2 per 100 000 population in 1993-1994 to 12.4 per 100 000 in 2017-2018. The ratio of male to female hospitalisations was 1.5:1.

CONCLUSIONS

Kawasaki disease is uncommon among Australia children, but its incidence is increasing. As there are no known preventable risk factors for the disease, prompt identification and treatment remain crucial to minimising the risk of cardiovascular sequelae.

Unleashing the mysterious link between COVID-19 and a famous childhood vasculitis: Kawasaki disease

Background

Coronavirus disease 2019 (COVID-19) emerged as a small outbreak in Wuhan rapidly progressing into the deadliest pandemic since the Spanish flu of 1918. The disease was deemed trivial in children, until the reporting, few days ago, of an emerging pediatric multi-inflammatory syndrome mimicking Kawasaki disease (KD).

Main body

This report reveals that coronaviridae were implicated in induction of several post-infectious vasculitides, namely, KD, AHEI, and HSP. This occurs in genetically susceptible individuals to vascular inflammation. Shared genetic susceptibilities between KD and CoV include genes encoding for CD 40, HLAB-15:03, and ACE. This leads to augmented inflammation with hypersecretion of cytokines especially IL-6.

Conclusion

The revealed relationships between KD and CoV can help to predict the risk of KD in COVID-19 patients through screening levels of upregulated cytokines. It might also signify that classic treatment of KD with IVIG might need to be replaced with anti-cytokine therapy in COVID-19 patients.

Antibodies and Immunity During Kawasaki Disease

The cause of Kawasaki disease (KD), the leading cause of acquired heart disease in children, is currently unknown. Epidemiology studies support that an infectious disease is involved in at least starting the inflammatory cascade set off during KD. Clues from epidemiology support that humoral immunity can have a protective effect. However, the role of the immune system, particularly of B cells and antibodies, in pathogenesis of KD is still unclear. Intravenous immunoglobulin (IVIG) and other therapies targeted at modulating inflammation can prevent development of coronary aneurysms. A number of autoantibody responses have been reported in children with KD and antibodies have been generated from aneurysmal plasma cell infiltrates. Recent reports show that children with KD have similar plasmablast responses as other children with infectious diseases, further supporting an infectious starting point. As ongoing studies are attempting to identify the etiology of KD through study of antibody responses, we sought to review the role of humoral immunity in KD pathogenesis, treatment, and recovery.

Alves N, Selleski N, Zandonadi RP, Nakano EY, Pratesi CB. Clinical Manifestations of Kawasaki Disease at Different Age Spectrum: A Ten-Year Study

Background and objectives: The present study is the first known in Latin America to enroll a substantial number of Kawasaki disease (KD) patients with an extended follow-up. This study aimed to: (1) to expose the difficulties and delays in the diagnosis of KD in a developing country, (2) to describe and correlate the clinical features of this disorder with the children’s age at the time of disease onset, (3) to correlate the frequent lack of early diagnosis with a delayed application of appropriate treatment, and (4) to describe the outcome and eventual recurrences of KD in our region. Materials and Methods: Three hundred and one participants (183 males and 118 females) included in the study were diagnosed and, subsequently, clinically followed for ten years (January 2007 to December 2016) at the Pediatric Rheumatology Walk-in Clinic of the Children’s Hospital of Brasilia. Results: Episodes ranged from four months to two years. This rate of recurrence was well-above that disclosed by previous reports. Delay in diagnosis, in all age groups, caused an undesirable delay between the disease onset, the final diagnosis, and the administration of intravenous immunoglobulin (IVIG). KD recurred in 25 (8.3%) of the children during the first three years of follow-up. In seven patients, KD recurred twice, with an interval between episodes ranging from four months to two years. Conclusions: This rate of recurrence was well-above that disclosed by previous reports. In Latin America, aside from a handful of physicians and researchers, KD is being ignored. There is a pressing need to educate primary health care physicians and bring awareness to the fact that KD is not an exotic condition that affects only the Asian populations but a disorder that already exists among us and that frequently results in severe consequences.

Increased QT Interval Dispersion is Associated with Coronary Artery Involvement in Children with Kawasaki Disease

Objectives

Coronary artery (CA) involvement is the most well known complication of Kawasaki disease (KD). Previous studies have suggested that QT dispersion has a predictive value in diagnosing cardiac ischemia, ventricular arrhythmia, and sudden cardiac death. However, limited data exits regarding the application of QT dispersion in KD. Therefore, we sought to determine whether there is a relationship between QT dispersion and CA involvement in patients with KD.

Methods

We performed a cross-sectional study of all consecutive patients with KD who were followed-up at the Pediatric Rheumatology Department (Pediatrics Center of Excellence affiliated to Tehran University of Medical Sciences, Tehran, Iran) from September 2013 to November 2015. Patients who met the criteria for KD, based on the American Heart Association guideline, were enrolled in the study. We collected data regarding patients' demographics, clinical manifestations, laboratory, and echocardiographic findings.

Results

A total of 70 KD patients were identified, including 43 males (61.4%) and 27 females (38.6%). The median age of patients was 21.0 (11.0-48.0) months. We found statistically significant differences between age, gender, and platelet count among patients with and without CA involvement (p < 0.050). Median corrected QT dispersion in patients with CA involvement calculated from 12 leads in the acute phase was significantly higher compared to the non-CA involvement group (108.0 (89.5-138.5) ms vs. 63.0 (54.0-74.5) ms, respectively (p < 0.001)).

Conclusions

Prolonged QT dispersion (corrected or non-corrected) during the acute and convalescence phases in patients with KD is associated with coronary involvement.

Kawasaki Disease: Global Burden and Genetic Background

Kawasaki disease (KD) is a childhood vasculitides associated with serious coronary artery lesions. It is the most common cause of pediatric acquired heart disease in developed countries, and is increasingly reported from many rapidly industrializing developing countries. The incidence varies widely among different nations and is highest in North-East Asian countries, where almost 1 in 100 children in Japan having the disease by age of 5, where the lowest incidence reported in sub-Saharan Africa. The etiology of KD is still uncertain; interaction between a genetic predisposition and several environmental and immunological factors has been hypothesized. Several susceptibility genes were identified to be associated with the development of KD and increased risk of coronary artery lesions. Gene-gene associations and alteration of deoxyribonucleic acid (DNA) methylation are also found to play key roles in the pathogenesis and prognosis of KD. This article will focus on the global epidemiological patterns of KD, and the currently known genetic predisposition.