Environmental epidemiology of Kawasaki disease: Linking disease etiology, pathogenesis and global distribution

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.

Successful non-invasive imaging of the coronary artery IMT in pediatric patients with Kawasaki disease using high-resolution echocardiography

Kawasaki Disease (KD) is a multisystemic vasculitis of medium- and small-sized arteries. Abnormal intimal thickening may develop in the involved arterial area after regression of coronary artery aneurysm (CAA). Intimal dysfunction may induce local stenosis or arteriosclerosis in the future. In this case-control study, we investigated 29 consecutive KD patients [20 male, median current age, 7.9 years; median follow-up duration, 5.7 years] and a group of 29 healthy matched controls (CON) [19 male, median current age, 10.8 years]. They were assesed and compared for CAA, LVFS, GCS, GLS, coronary artery (CA) Z scores, carotid intima-media thickness (IMT) and coronary artery IMT by high-resolution transthoracic echocardiography (hrTTE). Coronary artery IMT (caIMT) was significantly higher in patients with a maximal CA Z score > 2.5 in acute KD than in CON: KD caIMT: 0.62 mm [IQR, 0.57-0.72 mm] vs. 0.53 mm [0.51-0.60 mm], p = 0.043. CAAs were found in 15 (51.7%) patients with acute KD. The maximal median LCA Z score in acute KD was 2.57z [IQR, 1.93-3.2z] and in follow-up -0.39z [IQR, -1.25 to -0.36z]. There was no significant difference in carotid IMT between KD patients and CON. Signs of CA intima-media thickening were detected by hrTTE in patients with a maximal CA Z score > 2.5 in acute KD. These data indicate that these patients may be at risk for cardiovascular sequale even in the absence of permanent CA luminal abnormalities. Therefore long-term follow-up of this group of KD patients may be required.

The mechanism underlying B-cell developmental dysfunction in Kawasaki disease based on single-cell transcriptomic sequencing

Background

Kawasaki disease (KD) is an acute systemic vasculitis that can lead to acquired heart disease in children mostly from in developed countries. The previous research showed that B cells in KD patients underwent a profound change in both the cell numbers and types after intravenous immunoglobulin (IVIG) therapy.

Methods

We performed the single-cell RNA-sequencing for the peripheral blood mononuclear cells (PBMCs) from three febrile patients and three KD patients to investigate the possible mechanism underlying B cell developmental dysfunction in KD. The pseudo-time analysis was employed to study the developmental trajectories of the PBMCs in febrile control and KD patients.

Results

Overall single-cell expression profiles show that the biological processes of immunity, B cell activation pathway and their related biological entities are repressed in KD patients before IVIG treatment compared to febrile patient and KD patients after IVIG treatment. The differentially expressed gene analyses further demonstrate that B cell signaling pathway is downregulated in B cells and plasma blast cells of KD patients before treatment while cell cycle genes and MYC gene are upregulated in dendritic cells (DCs) and hematopoietic stem and progenitor cells (HSPCs) of KD patients before treatment. The biological process of immune response is upregulated in the HSPCs of KD patients before treatment in our dataset while the biological process of inflammatory response is upregulated in the HSPCs of KD patients before treatment in GSE168732 dataset. Single-cell trajectory analyses demonstrate that KD patients before treatment have a shortened developmental path in which B cells and T cells are failed to differentiate into separate lineages. HSPD1 and HSPE1 genes show an elevated expression level in the early cell development stage of KD patients before treatment accompanied with the repression of MYC, SPI1, MT2A and UBE2C genes. Our analyses of all B cells from KD patients before treatment show most of B cells are arrested in a transitional state with an ill developmental path compared with febrile patients and KD patients after treatment.

Conclusion

Our results indicate that the immune premature HSPCs accompanied with the abnormal expression dynamics of cell cycle and SPI1 genes are the mechanism underlying B cell developmental dysfunction in KD patients.

Analysis and validation of clinical subgroups of Kawasaki disease in children in China: a retrospective study

OBJECTIVE

Although Kawasaki disease (KD) is commonly regarded as a single disease entity, clinical subgroups have recently been described. We aimed to validate previous research on clinical subgroups and establish a KD subgroup differentiation model specific to China.

METHODS

We analysed clinical data of 1682 patients diagnosed with KD at the Kunming Children's Hospital from December 2014 to December 2022. We performed principal component analysis and hierarchical clustering on 13 continuous variables. Then, we grouped the patients based on the optimal number of clusters and analysed the clinical characteristics of each subgroup.

RESULTS

We ultimately identified three subgroups. In cluster 1, younger patients predominantly exhibited the highest risk of coronary artery aneurysm and the lowest rate of intravenous immunoglobulin resistance. Cluster 2 was characterised by high inflammatory markers and a lowered risk of coronary artery aneurysm. Cluster 3 was characterised by liver involvement, with significant elevations in liver enzymes, gamma-glutamyl transferase and total bilirubin. We found a positive correlation between the ratio of the rising trend and intravenous immunoglobulin resistance. Cluster 1 and cluster 3 shared similarities with the previously identified younger age subgroup and liver subgroup, respectively, whereas cluster 2 was unique to our study.

CONCLUSIONS

Our study preliminarily validated a previous KD subgroup study and established a KD subgroup model in China.

The value of CT coronary angiography for a comprehensive assessment of left circumflex artery in Kawasaki disease: 9 years of experience from a tertiary center

Background

Transthoracic echocardiography (TTE) has traditionally been the primary method for coronary imaging in children with Kawasaki disease (KD). We aimed to evaluate coronary artery lesions (CALs) of the left circumflex artery (LCx) in KD on computed tomography coronary angiography (CTCA).

Methods

Over a 9-year period (November 2013-December 2022), 225 children with KD underwent radiation-optimized CTCA on a 128-slice dual-source platform. TTE was performed on the same day, or a day prior or after CTCA.

Findings

On CTCA, LCx CALs were seen in 41/225 (18.2%) patients. However, TTE detected CALs in only one third of these patients [15/41 (36.6%)]. CTCA showed 47 LCx CALs in 41 patients-aneurysms in 39 patients (40 fusiform, 2 saccular; 7 giant aneurysms), stenoses in 3, and thrombosis in 2. Thromboses and stenoses were both missed on TTE. Proximal LCx aneurysms were seen in 39 patients-of these, 12 had distal extension. Six patients had distal LCx aneurysms without proximal involvement and 2 non-contiguous multiple aneurysms. Four (9.75%) patients had isolated LCx involvement. Based on CTCA findings, treatment protocols had to be modified in 3/41 (7.3%) patients.

Interpretation

This study highlights anatomical findings of LCx involvement in KD. Isolated LCx CALs were noted in 4/41 (9.75%) patients. TTE alone proved inadequate for LCx assessment in children with KD. With abnormalities detected in 18.2% of cases, including those missed by TTE, CTCA emerges as an essential imaging modality. The findings have implications for treatment planning and follow-up strategies in children with KD.

Funding

None.

Incidence of Kawasaki disease among children in Chandigarh, India during 2015-2019: a trend analysis

Background

Only limited information exists regarding the epidemiology of Kawasaki disease (KD) in low-income and middle-income countries. The present study provides the incidence of KD during 2015-2019 in Chandigarh, north India. Our centre follows the largest KD cohort in India.

Methods

Children with KD at Chandigarh diagnosed during January 2015-December 2019 were enrolled in the study. Annual incidence rates were determined using decadal growth rates of the National Census 2011. We computed the incidence of KD in children aged <5, and <15 years. We also undertook linear trend analysis using our incidence data from 1994 to 2019.

Findings

During 2015-2019, 83 patients (66 males, 17 females) were diagnosed with KD in Chandigarh. Incidence rates during these 5 years were 5.64, 9.25, 9.11, 9.87, and 9.72/100,000 in children aged <5 years, and 2.65, 4.44, 3.86, 5.07, 4.74/100,000 in children aged <15 years. The median age at diagnosis was 48 months (range: 12 days to 15 years). Compared to previous data (2009-2014), there was a 53.1% increase in annual incidence of KD in children aged <5 years, and a 53.7% increase in children aged <15 years. Coronary artery abnormalities during acute phase were noted in 16.9%, and in 7.2% of patients at 6 weeks of follow-up. The trend analysis indicated a monthly rise of 0.002 cases per 100,000 children aged <5 years, and 0.0165 cases per 100,000 children aged <15 years.

Interpretation

The incidence of KD has continued to show an upward trend in Chandigarh over the period 2015-2019. This may indicate a true rise in the occurrence of KD or may reflect better disease ascertainment as a result of greater awareness about KD amongst healthcare professionals.

Funding

None.

Research perspective in the clinical management of Kawasaki disease

This study examines research perspective in the clinical diagnosis, treatment, and prevention of cardiovascular complications in Kawasaki Disease (KD). Starting with an overview of the disease, it introduces KD's clinical manifestations, etiology, epidemiological features, and its impact on the cardiovascular system. Subsequently, the study discusses in detail the diagnostic methods, pathological mechanisms, and treatment strategies for KD, including foundational and emerging approaches such as high-dose intravenous immunoglobulin and aspirin therapy, biologic therapy, and corticosteroid pulse therapy. Additionally, it outlines strategies for preventing cardiovascular complications, including early risk assessment and long-term management. The study also explores the intersection of the COVID-19 pandemic with an increase in KD-like symptoms, emphasizing the need for further studies on the association between SARS-CoV-2 and KD. Lastly, it explores future research directions to enhance understanding of KD and improve patient outcomes and quality of life. This study provides valuable insights into the comprehensive treatment and management of KD and highlights avenues for future research.

Environmental Exposures and Pediatric Cardiology: A Scientific Statement From the American Heart Association

Environmental toxicants and pollutants are causes of adverse health consequences, including well-established associations between environmental exposures and cardiovascular diseases. Environmental degradation is widely prevalent and has a long latency period between exposure and health outcome, potentially placing a large number of individuals at risk of these health consequences. Emerging evidence suggests that environmental exposures in early life may be key risk factors for cardiovascular conditions across the life span. Children are a particularly sensitive population for the detrimental effects of environmental toxicants and pollutants given the long-term cumulative effects of early-life exposures on health outcomes, including congenital heart disease, acquired cardiac diseases, and accumulation of cardiovascular disease risk factors. This scientific statement highlights representative examples for each of these cardiovascular disease subtypes and their determinants, focusing specifically on the associations between climate change and congenital heart disease, airborne particulate matter and Kawasaki disease, blood lead levels and blood pressure, and endocrine-disrupting chemicals with cardiometabolic risk factors. Because children are particularly dependent on their caregivers to address their health concerns, this scientific statement highlights the need for clinicians, research scientists, and policymakers to focus more on the linkages of environmental exposures with cardiovascular conditions in children and adolescents.

Incidence and seasonality of Kawasaki disease in children in the Philippines, and its association with ambient air temperature

Background

Despite an unknown cause, Kawasaki disease (KD) is currently the primary leading cause of acquired heart disease in developed countries in children and has been increasing in recent years. Research efforts have explored environmental factors related to KD, but they are still unclear especially in the tropics. We aimed to describe the incidence of KD in children, assess its seasonality, and determine its association with ambient air temperature in the National Capital Region (NCR), Philippines from January 2009 to December 2019.

Methods

Monthly number of KD cases from the Philippine Pediatric Society (PPS) disease registry was collected to determine the incidence of KD. A generalized linear model (GLM) with quasi-Poisson regression was utilized to assess the seasonality of KD and determine its association with ambient air temperature after adjusting for the relevant confounders.

Results

The majority of KD cases (68.52%) occurred in children less than five years old, with incidence rates ranging from 14.98 to 23.20 cases per 100,000 population, and a male-to-female ratio of 1.43:1. Seasonal variation followed a unimodal shape with a rate ratio of 1.13 from the average, peaking in March and reaching the lowest in September. After adjusting for seasonality and long-term trend, every one-degree Celsius increase in the monthly mean temperature significantly increased the risk of developing KD by 8.28% (95% CI: 2.12%, 14.80%). Season-specific analysis revealed a positive association during the dry season (RR: 1.06, 95% CI: 1.01, 1.11), whereas no evidence of association was found during the wet season (RR: 1.10, 95% CI: 0.95, 1.27).

Conclusion

We have presented the incidence of KD in the Philippines which is relatively varied from its neighboring countries. The unimodal seasonality of KD and its linear association with temperature, independent of season and secular trend, especially during dry season, may provide insights into its etiology and may support enhanced KD detection efforts in the country.

Effectiveness of two same-manufacturer intravenous immunoglobulin for Kawasaki disease

BACKGROUND

To investigate whether two brands of intravenous immunoglobulin (IVIG) from the same manufacturer lead to varied effects when administered to patients with Kawasaki disease.

(KD) METHODS

Clinical characteristics, laboratory data, IVIG response, and coronary arteries change were analyzed between two groups.

RESULTS

We included 158 KD cases. The mean age at KD diagnosis was 23 ± 1.39 (range, 2-95) months. In the first IVIG course, 18 (11.4 %) patients were unresponsive. TBSF (brand T) and Privigen (brand P) were administered to 94 and 64 patients, respectively. The brand P group had a significantly longer fever (P < 0.001) and hospitalization (P = 0.007) durations after the therapy and a higher number of IVIG unresponsiveness (P = 0.016) than the brand T group. In the multivariate logistic regression analysis, a high Formosa score (≥3, Odds ratio [OR], 4.939; 95 % confidence interval [CI], 1.199-20.337; P = 0.027), high levels of CRP (≥12 mg/L, OR: 4.257,95 % CI,1.265-14.322; P = 0.019), and treatment with brand P (OR, 3.621; 95 % CI, 1.029-12.677; P = 0.045) were independent risk factors for IVIG unresponsiveness.

CONCLUSIONS

Compared with brand T, brand P prolonged the fever and hospitalization durations after IVIG treatment and increased the proportion of IVIG treatment unresponsiveness, but it did not infer the coronary arteries sequelae.

The etiologies of Kawasaki disease

Kawasaki disease (KD) is a systemic vasculitis that affects young children and can result in coronary artery aneurysms. The etiology is currently unknown, but new clues from the epidemiology of KD in Japan, the country of highest incidence, are beginning to shed light on what may trigger this acute inflammatory condition. Additional clues from the global changes in KD incidence during the COVID-19 pandemic, coupled with a new birth cohort study from Japan, point to the potential role of person-to-person transmission of an infectious agent. However, the rising incidence of KD in Japan, with coherent waves across the entire country, points to an increasing intensity of exposure that cannot be explained by person-to-person spread. This Review discusses new and historical observations that guide us toward a better understanding of KD etiology and explores hypotheses and interpretations that can provide direction for future investigations. Once the etiology of KD is determined, accurate diagnostic tests will become available, and new, less expensive, and more effective targeted therapies will likely be possible. Clearly, solving the mystery of the etiologies of KD remains a priority for pediatric research.

Association of Kawasaki disease with urbanization level and family characteristics in Taiwan: A nested case-control study using national-level data

Kawasaki disease (KD) is an inflammatory vasculitis disorder of unknown etiology. It is a rare but fatal disease and the leading cause of acquired coronary heart disease in children under the age of 5 years. We examined the association of KD with the demographics of family members, parents' characteristics, and perinatal factors in Taiwanese children. This nested case-control study used data from Taiwan's Health and Welfare Data Science Center and initially included children born in Taiwan between January 1, 2006, and December 31, 2015 (n = 1,939,449); the children were observed for KD development before the age of 5 years (n = 7870). The control group consisted of children without KD who were matched with each KD case by sex and birth date at a ratio of 8:1. The odds ratio (ORs) of the aforementioned associations were estimated using conditional logistic regression. The risk of KD decreased in children with younger parents [<25 years; younger maternal age, OR = 0.72, 95% confidence interval (CI), 0.66-0.79; younger paternal age, OR = 0.68, 95% CI, 0.59-0.78], lower socioeconomic status, more than 2 siblings (OR = 0.80, 95% CI, 0.73-0.89), and siblings with a history of KD (OR = 4.39, 95% CI, 3.29-5.86). Children living in suburban (OR = 0.95, 95% CI, 0.90-1.00) and rural (OR = 0.81, 95%CI, 0.74-0.90) areas exhibited a lower risk of KD than children living in urban areas. In conclusion, a higher incidence rate of KD was observed in children aged <5 years who had an urban lifestyle, had siblings with KD, were born to older mothers, and belonged to high-income and smaller families. Parental allergic or autoimmune diseases were not associated with the risk of KD.

Subgroups of children with Kawasaki disease: a data-driven cluster analysis

BACKGROUND

Although Kawasaki disease is commonly regarded as a single disease entity, variability in clinical manifestations and disease outcome has been recognised. We aimed to use a data-driven approach to identify clinical subgroups.

METHODS

We analysed clinical data from patients with Kawasaki disease diagnosed at Rady Children's Hospital (San Diego, CA, USA) between Jan 1, 2002, and June 30, 2022. Patients were grouped by hierarchical clustering on principal components with k-means parcellation based on 14 variables, including age at onset, ten laboratory test results, day of illness at the first intravenous immunoglobulin infusion, and normalised echocardiographic measures of coronary artery diameters at diagnosis. We also analysed the seasonality and Kawasaki disease incidence from 2002 to 2019 by subgroup. To explore the biological underpinnings of identified subgroups, we did differential abundance analysis on proteomic data of 6481 proteins from 32 patients with Kawasaki disease and 24 healthy children, using linear regression models that controlled for age and sex.

FINDINGS

Among 1016 patients with complete data in the final analysis, four subgroups were identified with distinct clinical features: (1) hepatobiliary involvement with elevated alanine transaminase, gamma-glutamyl transferase, and total bilirubin levels, lowest coronary artery aneurysm but highest intravenous immunoglobulin resistance rates (n=157); (2) highest band neutrophil count and Kawasaki disease shock rate (n=231); (3) cervical lymphadenopathy with high markers of inflammation (erythrocyte sedimentation rate, C-reactive protein, white blood cell, and platelet counts) and lowest age-adjusted haemoglobin Z scores (n=315); and (4) young age at onset with highest coronary artery aneurysm but lowest intravenous immunoglobulin resistance rates (n=313). The subgroups had distinct seasonal and incidence trajectories. In addition, the subgroups shared 211 differential abundance proteins while many proteins were unique to a subgroup.

INTERPRETATION

Our data-driven analysis provides insight into the heterogeneity of Kawasaki disease, and supports the existence of distinct subgroups with important implications for clinical management and research design and interpretation.

FUNDING

US National Institutes of Health and the Irving and Francine Suknow Foundation.

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.

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.

Socioeconomic Status and Kawasaki Disease Outcomes in a Single-Payer Health Care System

Background

For patients with Kawasaki disease (KD), lower socioeconomic status (SES) may adversely affect the timeliness of presentation and initiation of intravenous immune globulin, and coronary artery outcomes. Multipayer systems have been shown to affect health care equity and access to health care negatively. We sought to determine the association of SES with KD outcomes in a single-payer health care system.

Methods

Patients with KD presenting from 2007 to 2017 at a single institution were included. SES data were obtained by matching patient postal code district with data from the 2016 Census Canada.

Results

SES data were linked for 1018 patients. The proportion of households living below the after-tax low-income cutoff in the patient's postal code district was 13% for not treated, 13% for delayed intravenous immune globulin treatment, and 12% for prompt treatment (P = 0.58). Likewise, the average median annual household income was unrelated to delayed or no treatment. The percentage >15 years of age with advanced education differed between groups at 33%, 29%, and 31% for delayed treatment, prompt treatment, and missed groups, respectively (P = 0.004). SES variables were not significantly different for those with vs without coronary artery aneurysms (max Z-score: >2.5), including the proportion of households living below low-income cutoff (12% vs 13%; P = 0.37), average median annual household income (CAD$81,220 vs $82,055; P = 0.78), and proportion with a university degree (33% vs 31%; P = 0.49), even after adjusting for sex, age, year, and KD type.

Conclusions

Timeliness of treatment for KD and coronary artery outcomes were not associated with SES variables within a single-payer health care system.

Epidemiological and Clinical Features of Kawasaki Disease During the COVID-19 Pandemic in the United States

IMPORTANCE

Public health measures implemented during the COVID-19 pandemic had widespread effects on population behaviors, transmission of infectious diseases, and exposures to environmental pollutants. This provided an opportunity to study how these factors potentially influenced the incidence of Kawasaki disease (KD), a self-limited pediatric vasculitis of unknown etiology.

OBJECTIVES

To examine the change in KD incidence across the United States and evaluate whether public health measures affected the prevalence of KD.

DESIGN, SETTING, AND PARTICIPANTS

This multicenter cohort study included consecutive, unselected patients with KD who were diagnosed between January 1, 2018, and December 31, 2020 (multicenter cohort with 28 pediatric centers), and a detailed analysis of patients with KD who were diagnosed between January 1, 2002, and November 15, 2021 (Rady Children's Hospital San Diego [RCHSD]).

MAIN OUTCOMES AND MEASURES

For the multicenter cohort, the date of fever onset for each patient with KD was collected. For RCHSD, detailed demographic and clinical data as well as publicly available, anonymized mobile phone data and median household income by census block group were collected. The study hypothesis was that public health measures undertaken during the pandemic would reduce exposure to the airborne trigger(s) of KD and that communities with high shelter-in-place compliance would experience the greatest decrease in KD incidence.

RESULTS

A total of 2461 KD cases were included in the multicenter study (2018: 894; 2019: 905; 2020: 646), and 1461 cases (median [IQR] age, 2.8 years [1.4-4.9 years]; 900 [61.6%] males; 220 [15.1%] Asian, 512 [35.0%] Hispanic, and 338 [23.1%] White children) from RCHSD between 2002 and 2021 were also included. The 28.2% decline in KD cases nationally during 2020 (646 cases) compared with 2018 (894 cases) and 2019 (905 cases) was uneven across the United States. For RCHSD, there was a disproportionate decline in KD cases in 2020 to 2021 compared with the mean (SD) number of cases in earlier years for children aged 1 to 5 years (22 vs 44.9 [9.9]; P = .02), male children (21 vs 47.6 [10.0]; P = .01), and Asian children (4 vs 11.8 [4.4]; P = .046). Mobility data did not suggest that shelter-in-place measures were associated with the number of KD cases. Clinical features including strawberry tongue, enlarged cervical lymph node, and subacute periungual desquamation were decreased during 2020 compared with the baseline period (strawberry tongue: 39% vs 63%; P = .04; enlarged lymph node: 21% vs 32%; P = .09; periungual desquamation: 47% vs 58%; P = .16). School closures, masking mandates, decreased ambient pollution, and decreased circulation of respiratory viruses all overlapped to different extents with the period of decreased KD cases. KD in San Diego rebounded in the spring of 2021, coincident with lifting of mask mandates.

CONCLUSIONS AND RELEVANCE

In this study of epidemiological and clinical features of KD during the COVID-19 pandemic in the United States, KD cases fell and remained low during the period of masking and school closure. Mobility data indicated that differential intensity of sheltering in place was not associated with KD incidence. These findings suggest that social behavior is associated with exposure to the agent(s) that trigger KD and are consistent with a respiratory portal of entry for the agent(s).

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.

The Long-term Cardiac and Noncardiac Prognosis of Kawasaki Disease: A Systematic Review

CONTEXT

It is uncertain if children with Kawasaki Disease (KD) are at risk for non-cardiac diseases and if children with KD but without coronary artery aneurysms (CAA) are at risk for long-term cardiac complications.

OBJECTIVE

To determine the long-term mortality and prognosis of children after KD.

DATA SOURCES

Medline, Embase, and the Cochrane Central Register.

STUDY SELECTION

Controlled trials and observational studies were included if they included children with KD and reported mortality, major adverse cardiovascular events (MACE), chronic cardiac or other disease over an average follow-up of ≥1 year.

DATA EXTRACTION

Data extracted included sample size, age at diagnosis, the proportion with coronary artery aneurysms (CAA), follow-up duration, and outcome(s).

RESULTS

Seventy-four studies were included. Thirty-six studies reported mortality, 55 reported a cardiac outcome, and 12 reported a noncardiac outcome. Survival ranged from 92% to 99% at 10 years, 85% to 99% at 20 years, and 88% to 94% at 30 years. MACE-free survival, mostly studied in those with CAA, varied from 66% to 91% at 10 years, 29% to 74% at 20 years, and 36% to 96% at 30 years. Seven of 10 studies reported an increased risk in early atherosclerosis. All 6 included studies demonstrated an increased risk in allergic diseases.

LIMITATIONS

Our study may have missed associated chronic comorbidities because short-term studies were excluded. The majority of outcomes were evaluated in East-Asian patients, which may limit generalizability. Studies frequently excluded patients without CAA and did not compare outcomes to a comparison group.

CONCLUSIONS

Studies demonstrate >90% survival up to 30 years follow-up. MACE is observed in children with CAA, but is not well studied in those without CAA.

Global epidemiology of vasculitis

The many forms of vasculitis are characterized by inflammation of blood vessels, leading to potentially long-term sequelae including vision loss, aneurysm formation and kidney failure. Accurate estimation of the incidence and prevalence has been hampered by the absence of reliable diagnostic criteria and the rarity of these conditions; however, much progress has been made over the past two decades, although data are still lacking from many parts of the world including the Indian subcontinent, China, Africa and South America. Giant cell arteritis occurs in those aged 50 years and over and seems to mainly affect persons of northern European ancestry, whereas Takayasu arteritis occurs mainly in those aged under 40 years. By contrast, Kawasaki disease mainly occurs in children aged under 5 years and is most common in children of Asian ancestry, and IgA vasculitis occurs in children and adolescents. Although much less common than giant cell arteritis, the different forms of antineutrophil cytoplasmic antibody-associated vasculitis are being increasingly recognized in most populations and occur more frequently with increasing age. Behçet syndrome occurs most commonly along the ancient silk road between Europe and China. Much work needs to be done to better understand the influence of ethnicity, geographical location, environment and social factors on the development of vasculitis.

Air pollution and airborne infection with mycobacterial bioaerosols: a potential attribution of soot

Atmospheric pollutants are hypothesized to enhance the viability of airborne microbes by preventing them from degradation processes, thereby enhancing their atmospheric survival. In this study, Mycobacterium smegmatis is used as a model airborne bacteria, and different amounts of soot particles are employed as model air pollutants. The toxic effects of soot on aerosolized M. smegmatis are first evaluated and excluded by introducing them separately into a chamber, being sampled on a filter, and then cultured and counted. Secondly, the bacteria-soot mixture is exposed to UV with different durations and then cultured for bacterial viability evaluations. The results show that under UV exposure, the survival rates of the low-, medium-, and high-soot groups are 1.1 (±0.8) %, 70.9 (±4.3) %, and 61.0 (±17.6) %, respectively. This evidence significantly enhanced survival rates by soot at all UV exposures, though the combinations of UV exposure and soot amounts revealed a changing pattern of survival rates. The possible influence by direct and indirect effects of UV-damaging mechanisms is proposed. This study indicates the soot-induced survival rate enhancements of M. smegmatis under UV stress conditions, representing the possible relations between air pollution and the extended pathogenic viability and, therefore, increased airborne infection probability.

Temporal clustering of Kawasaki disease cases around the world

In a single-site study (San Diego, CA, USA), we previously showed that Kawasaki Disease (KD) cases cluster temporally in bursts of approximately 7 days. These clusters occurred more often than would be expected at random even after accounting for long-term trends and seasonality. This finding raised the question of whether other locations around the world experience similar temporal clusters of KD that might offer clues to disease etiology. Here we combine data from San Diego and nine additional sites around the world with hospitals that care for large numbers of KD patients, as well as two multi-hospital catchment regions. We found that across these sites, KD cases clustered at short time scales and there were anomalously long quiet periods with no cases. Both of these phenomena occurred more often than would be expected given local trends and seasonality. Additionally, we found unusually frequent temporal overlaps of KD clusters and quiet periods between pairs of sites. These findings suggest that regional and planetary range environmental influences create periods of higher or lower exposure to KD triggers that may offer clues to the etiology of KD.

Hygiene Hypothesis as the Etiology of Kawasaki Disease: Dysregulation of Early B Cell Development

Kawasaki disease (KD) is an acute systemic vasculitis that occurs predominantly in children under 5 years of age. Despite much study, the etiology of KD remains unknown. However, epidemiological and immunological data support the hygiene hypothesis as a possible etiology. It is thought that more sterile or clean modern living environments due to increased use of sanitizing agents, antibiotics, and formula feeding result in a lack of immunological challenges, leading to defective or dysregulated B cell development, accompanied by low IgG and high IgE levels. A lack of B cell immunity may increase sensitivity to unknown environmental triggers that are nonpathogenic in healthy individuals. Genetic studies of KD show that all of the KD susceptibility genes identified by genome-wide association studies are involved in B cell development and function, particularly in early B cell development (from the pro-B to pre-B cell stage). The fact that intravenous immunoglobulin is an effective therapy for KD supports this hypothesis. In this review, I discuss clinical, epidemiological, immunological, and genetic studies showing that the etiopathogenesis of KD in infants and toddlers can be explained by the hygiene hypothesis, and particularly by defects or dysregulation during early B cell development.

Incidence of Chronic Immune-Mediated Inflammatory Diseases After Diagnosis with Kawasaki Disease: A Population-Based Cohort Study

OBJECTIVES

Kawasaki disease (kDa) is an immune-mediated vasculitis of childhood with multi-organ inflammation. We determined the risk of subsequent immune-mediated inflammatory disease (IMID), including arthritis, type 1 diabetes, inflammatory bowel disease (IBD), autoimmune liver disease (ALD), primary sclerosing cholangitis (PSC) and multiple sclerosis (MS).

METHODS

We conducted a matched population-based cohort study using health administrative data from Ontario, Canada. Children aged <18 years born between 1991-2016 diagnosed with kDa (n = 3,753) were matched to 5 non-kDa controls from the general population (n = 18 749). We determined the incidence of IMIDs after resolution of kDa. Three- and 12-month washout periods were used to exclude kDa-related symptoms.

RESULTS

There was an elevated risk of arthritis in kDa patients compared with non-kDa controls starting three months after index date (103.0 vs 12.7 per 100 000 person-years (PYs); incidence rate ratio (IRR) 8.07 (95% CI 4.95-13.2); hazard ratio (HR) 8.08 (95% CI 4.95-13.2), resulting in the overall incidence of IMIDs being elevated in kDa patients (175.1 vs 68.0 per 100 000 PYs; IRR 2.58 (95% CI 1.93-3.43); HR 2.58, 95% CI 1.94-3.43). However, there was no increased risk for diabetes, IBD, ALD, PSC or MS in kDa patients. Similar results were observed using a 12-month washout period.

CONCLUSIONS

Children diagnosed with kDa were at increased risk of arthritis following the acute kDa event, but not other IMIDs. Health care providers should monitor for arthritis in children following a diagnosis of kDa.

An AI-guided signature reveals the nature of the shared proximal pathways of host immune response in MIS-C and Kawasaki disease

A significant surge in cases of multisystem inflammatory syndrome in children (MIS-C, also called Pediatric Inflammatory Multisystem Syndrome - PIMS) has been observed amidst the COVID-19 pandemic. MIS-C shares many clinical features with Kawasaki disease (KD), although clinical course and outcomes are divergent. We analyzed whole blood RNA sequences, serum cytokines, and formalin fixed heart tissues from these patients using a computational toolbox of two gene signatures, i.e., the 166-gene viral pandemic (ViP) signature, and its 20-gene severe (s)ViP subset that were developed in the context of SARS-CoV-2 infection and a 13-transcript signature previously demonstrated to be diagnostic for KD. Our analyses revealed that KD and MIS-C are on the same continuum of the host immune response as COVID-19. While both the pediatric syndromes converge upon an IL15/IL15RA -centric cytokine storm, suggestive of shared proximal pathways of immunopathogenesis, they diverge in other laboratory parameters and cardiac phenotypes. The ViP signatures also revealed 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.

Associations between the spatiotemporal distribution of Kawasaki disease and environmental factors: evidence supporting a multifactorial etiologic model

The etiology of Kawasaki Disease (KD), the most common cause of acquired heart disease in children in developed countries, remains elusive, but could be multifactorial in nature as suggested by the numerous environmental and infectious exposures that have previously been linked to its epidemiology. There is still a lack of a comprehensive model describing these complex associations. We present a Bayesian disease model that provides insight in the spatiotemporal distribution of KD in Canada from 2004 to 2017. The disease model including environmental factors had improved Watanabe-Akaike information criterion (WAIC) compared to the base model which included only spatiotemporal and demographic effects and had excellent performance in recapitulating the spatiotemporal distribution of KD in Canada (98% and 86% spatial and temporal correlations, respectively). The model suggests an association between the distribution of KD and population composition, weather-related factors, aeroallergen exposure, pollution, atmospheric concentration of spores and algae, and the incidence of healthcare encounters for bacterial pneumonia or viral intestinal infections. This model could be the basis of a hypothetical data-driven framework for the spatiotemporal distribution of KD. It also generates novel hypotheses about the etiology of KD, and provides a basis for the future development of a predictive and surveillance model.

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.

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.

Management of severe hyperinflammation in the COVID-19 era: the role of the rheumatologist

Objectives

The objectives of this study were (i) to describe the clinical presentation, treatment and outcome of paediatric inflammatory multisystem syndrome temporally related to Sars-CoV-2 (PIMS-TS) in children; (ii) to propose a framework to guide multidisciplinary team (MDT) management; and (iii) to highlight the role of the paediatric rheumatologist in this context.

Methods

This study involved a retrospective case notes review of patients referred to a single specialist paediatric centre with suspected PIMS-TS, with a focus on clinical presentation, laboratory parameters, treatment, and outcome in the context of an MDT framework.

Results

Nineteen children of median age 9.1 years fulfilled the definition of PIMS-TS and were managed within an MDT framework: 5/19 were female; 14/19 were of Black, Asian or minority ethnicity; 9/19 also fulfilled diagnostic criteria for complete or incomplete Kawasaki disease (KD). Severe systemic inflammation, shock, and abdominal pain were ubiquitous. Treatment was stratified within an MDT framework and included CSs in all; i.v. immunoglobulin in all; anakinra in 4/19; infliximab in 1/19; and antiviral (aciclovir) in 4/19.

Conclusions

We observed significant diagnostic equipoise using a current definition of PIMS-TS, overlapping with KD. Outside of clinical trials, an MDT approach is vital. The role of the paediatric rheumatologist is to consider differential diagnoses of hyperinflammation in the young, to advise on empiric immunomodulatory therapy, to set realistic therapeutic targets, to gauge therapeutic success, to oversee timely step-down of immunomodulation, and to contribute to the longer-term MDT follow-up of any late inflammatory sequelae.

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.

Inflammasomes and Childhood Autoimmune Diseases: A Review of Current Knowledge

Inflammasomes are multiprotein complexes capable of sensing pathogen-associated molecular patterns (PAMPs), danger-associated molecular patterns (DAMPs), and cellular perturbations. Upon stimulation, the inflammasomes activate the production of the pro-inflammatory cytokines IL-1β and IL-18 and induce gasdermin D-mediated pyroptosis. Dysregulated inflammasome signaling could lead to hyperinflammation in response to environmental triggers, thus contributing to the pathogenesis of childhood autoimmune/autoinflammatory diseases. In this review, we group childhood rheumatic diseases into the autoinflammation to autoimmunity spectrum and discuss about the involvement of inflammasomes in disease mechanisms. Genetic mutations in inflammasome components cause monogenic autoinflammatory diseases, while inflammasome-related genetic variants have been implicated in polygenic childhood rheumatic diseases. We highlight the reported associations of inflammasome signaling-related genetic polymorphisms/protein levels with pediatric autoimmune disease susceptibility and disease course. Furthermore, we discuss about the use of IL-1 receptor antagonist as an adjunctive therapy in several childhood autoimmune diseases, including macrophage activation syndrome (MAS) and multisystem inflammatory syndrome in children (MIS-C) related to COVID-19. A comprehensive multi-cohort comparison on inflammasome gene expression profile in different pediatric rheumatic diseases is needed to identify patient subsets that might benefit from the adjunctive therapy of IL-1β inhibitors.

High-Throughput Screening of Kawasaki Disease Sera for Antiviral Antibodies

Clinical features of Kawasaki disease (KD) display overlap with common pediatric viral illnesses, leading some to hypothesize that a viral infection is the inciting event for KD. To investigate viral infection history in KD patients, we performed comprehensive serological profiling using a high-throughput phage immunoprecipitation sequencing assay covering the complete reference protein sequences of known viruses with human tropism. KD and matched febrile control sera did not demonstrate differences in antiviral antibody profiles. We conclude that in the acute and subacute phases of disease, KD patients do not exhibit serologic evidence of exposure to known viruses that differs from controls.

Association between Kawasaki Disease and Prenatal Exposure to Ambient and Industrial Air Pollution: A Population-Based Cohort Study

BACKGROUND

Environmental factors may contribute to the development of Kawasaki disease in children, but prenatal environmental exposures are understudied.

OBJECTIVE

We used a population-based cohort to investigate whether prenatal exposure to outdoor air pollution is associated with the incidence of Kawasaki disease in childhood.

METHODS

We performed a longitudinal cohort study of all children born in Quebec, Canada, between 2006 and 2012. Children were followed for Kawasaki disease from birth until 31 March 2018. We assigned prenatal air pollutant exposure according to the residential postal code at birth. The main exposure was annual average concentration of ambient fine particulate matter [PM ≤2.5μm in aerodynamic diameter (PM2.5) and nitrogen dioxide (NO2) from satellite-based estimates and land-use regression models. As secondary exposures, we considered industrial PM2.5, NO2, and sulfur dioxide (SO2) emissions estimated from dispersion models. We estimated hazard ratios (HRs) using Cox proportional hazards models, adjusted for maternal age, parity, sex, multiple birth, maternal smoking during pregnancy, socioeconomic status, birth year, and rural residence. We considered single and multipollutant models. We performed several sensitivity analyses, including assessing modifying effects of maternal comorbidities (e.g., diabetes, preeclampsia).

RESULTS

The cohort comprised 505,336 children, including 539 with Kawasaki disease. HRs for each interquartile range increase in ambient air pollution were 1.16 (95% CI: 0.96, 1.39) for PM2.5 and 1.12 (95% CI: 0.96, 1.31) for NO2. For industrial air pollution, HRs were 1.07 (95% CI: 1.01, 1.13) for SO2, 1.09 (95% CI: 0.99, 1.20) for NO2, and 1.01 (95% CI: 0.97, 1.05) for PM2.5. In multipollutant models, associations for ambient PM2.5 and NO2 (i.e., from all sources) were robust to adjustment for industrial pollution, and vice versa.

DISCUSSION

In this population-based cohort study, both prenatal exposure to ambient and industrial air pollution were associated with the incidence of Kawasaki disease in childhood. Further studies are needed to consolidate the observed associations. https://doi.org/10.1289/EHP6920.

Structure equation model and neural network analyses to predict coronary artery lesions in Kawasaki disease: a single-centre retrospective study

A new method to predict coronary artery lesions (CALs) in Kawasaki disease (KD) was developed using a mean structure equation model (SEM) and neural networks (Nnet). There were 314 admitted children with KD who met at least four of the six diagnostic criteria for KD. We defined CALs as the presence of a maximum z score of ≥ 3.0. The SEM using age, sex, intravenous immunoglobulin resistance, number of steroid pulse therapy sessions, C-reactive protein level, and urinary β2-microglobulin (u-β2MG/Cr) values revealed a perfect fit based on the root mean square error of approximation with an R² value of 1.000 and the excellent discrimination of CALs with a sample score (SS) of 2.0 for a latent variable. The Nnet analysis enabled us to predict CALs with a sensitivity, specificity and c-index of 73%, 99% and 0.86, respectively. This good and simple statistical model that uses common parameters in clinical medicine is useful in deciding the appropriate therapy to prevent CALs in Japanese KD patients.

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.

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.

Mapping the Trends of Kawasaki Disease in Hawai'i from 1996 to 2018

Kawasaki disease is a systemic vasculitis of unknown etiology and is the leading cause of acquired heart disease in children in the developed world. Historically, Hawai'i has had the highest incidence of Kawasaki disease in the United States, likely due to the population's unique ancestral composition. To analyze the epidemiology, demographics and spatiotemporal distribution of Kawasaki disease in Hawai'i, a retrospective chart review was conducted utilizing data from Kapi'olani Medical Center for Women and Children encompassing the period of 1996-2018. A total of 858 patients were analyzed with 877 episodes of Kawasaki disease. On average, 37 episodes of Kawasaki disease were diagnosed annually over the 23-year period. The annual incidence was 32 per 100 000 children <5 years of age. Asian children (66.1%) accounted for the majority of cases, followed by Native Hawaiians and Other Pacific Islanders (16.6%). Unlike Japan and the continental United States, there was no characteristic seasonal pattern in the distribution of Kawasaki disease in Hawai'i, which may be attributed to its tropical climate or the recent changes in global weather patterns. Local geographical differences in the incidence of Kawasaki disease demonstrated that the Windward (Eastern) coast of O'ahu had a higher rate, while the Leeward (Western) coast displayed a lower incidence rate. This could be explained by variations in ethnic composition and weather patterns of certain areas. Future studies could provide geographical weather data and statistical analysis to determine what environmental triggers are correlated with Kawasaki disease trends in the State of Hawai'i.

Clinical observation of noncoronary cardiac abnormalities in Chinese children with Kawasaki disease

BACKGROUND

Kawasaki disease (KD) is an acute, self-limited vasculitis. Coronary artery aneurysm (CAA) serves as a major contributor to the long-term prognosis of KD. In addition, acute KD usually also leads to several kinds of noncoronary cardiac abnormalities (NCA) involving the pericardium, myocardium and endocardium.

MATERIALS AND METHODS

A total of 142 Chinese children with KD were recruited from July 2015 to April 2018. Blood samples were collected at 24 hours pre-intravenous immunoglobulin (IVIG) therapy. Several inflammatory mediators and biomarkers for acute myocardial infarction were detected. Echocardiography and electrocardiography (ECG) were performed.

RESULTS

Plasma white blood cell counts (WBC) were significantly increased in patients with IVIG-nonresponsive KD when compared with their IVIG-responsive counterparts. A total of 106 children (74.65%) suffered from NCA, including 8 patients (5.63%) with pericardial effusion, 23 patients (16.20%) with acute myocarditis, 101 patients (71.13%) with valvular regurgitation and 8 patients (5.63%) with abnormal ECG. No significant differences were observed in the distribution of clinical classification and the response to IVIG therapy regardless of NCA exhibited or not.

CONCLUSIONS

Noncoronary cardiac abnormalities is almost universal in acute KD and mainly manifests as valvular regurgitation. However, it has no influence on clinical classification and the response to IVIG therapy.

Environmental Factors and Kawasaki Disease Onset in Emilia-Romagna, Italy

Kawasaki disease (KD)is an idiopathic acute febrile illness that primarily occurs in children <5 years of age and can lead to artery lesions if not promptly treated. Recent studies have shown possible correlations between KD onset and currents and air pollutants.The present study describes results on the correlation between environmental conditions, frequency, and variability ofKD onset in children under five years of age in Emilia-Romagna, a region of Northern Italy, over the period from 2000 to 2017. Since there are substantial climatic differences between the western-central (Emilia) and the eastern area (Romagna) of the region, the data for these areas are analyzed separately. The environmental factors considered are observed local surface daily temperature, daily precipitation, upper air wind regimes, and local air pollution. The results indicate that in Emilia-Romagna, KD onset occurs mainly during late autumn and early spring, which is in agreement with the literature. The frequency of KD onset in Emilia is significantly higher in months characterized by a high frequency of southerly flow, which is associated with milder than average night-time temperature, and in years with a prevailing south-westerly mean flow. These results are consistent with other studies, suggesting that certain wind conditions are more favorable for disease onset, which are possibly associated with one or more airborne agents.

On the interpretation of the atmospheric mechanism transporting the environmental trigger of Kawasaki Disease

Recent advances on the environmental determinants of Kawasaki Disease have pointed to the important role of the atmospheric transport of a still unknown agent potentially triggering the disease. The hypothesis arose from an innovative methodology combining expertise in climate dynamics, the analysis of ocean and atmosphere data, the use of dispersion models and the search for biological agents in air samples. The approach offered a new perspective to reveal the identity of the potential trigger, but at the same time, it increased the level of complexity, which could potentially lead to the misinterpretation of the mechanisms. Some years after it was originally formulated, we here provide a brief clarification on the approach and limits of the methodology in order to prevent an eventual misuse of our research ideas and theory, so that further research can better focus on the knowledge gaps that still remain open.

Report on advances for pediatricians in 2018: allergy, cardiology, critical care, endocrinology, hereditary metabolic diseases, gastroenterology, infectious diseases, neonatology, nutrition, respiratory tract disorders and surgery

This review reported notable advances in pediatrics that have been published in 2018. We have highlighted progresses in allergy, cardiology, critical care, endocrinology, hereditary metabolic diseases, gastroenterology, infectious diseases, neonatology, nutrition, respiratory tract disorders and surgery. Many studies have informed on epidemiologic observations. Promising outcomes in prevention, diagnosis and treatment have been reported. We think that advances realized in 2018 can now be utilized to ameliorate patient care.

Comparison of Clinical Symptoms and Cardiac Lesions in Children with Typical and Atypical Kawasaki Disease

The present study was performed to evaluate the clinical symptoms and cardiovascular complications in patients with typical and atypical Kawasaki disease (KD). This retrospective study was conducted on the medical records of 176 patients with KD for three years. The study population was divided into two groups of typical and atypical based on the KD clinical criteria. The two groups were compared in terms of demographic data, clinical symptoms, cardiac lesions, and laboratory markers. Based on the diagnostic criteria, 105 (60%) and 71 (40%) patients were diagnosed with typical and atypical KD, respectively. The mean age of the typical patients (38.16 months) was higher than that of the atypical group (24.03 months) at the time of diagnosis (p < 0.05). The results revealed no significant difference between the two groups regarding the seasonal distribution of KD onset (p = 0.422). However, the most common season for the diagnosis of the disease was spring, followed by winter. There was no significant difference between the two groups in terms of fever duration (p = 0.39). Furthermore, vomiting was more common in the atypical patients than in the typical group (p = 0.017). In terms of the cardiac lesions, ectasia (p = 0.005) and lack of tapering of the distal coronary vessels (p = 0.015) were more frequently detected in the atypical group than in the typical group. Considering the laboratory findings, thrombocytosis (p = 0.010) and anemia (p = 0.048) were more common in the atypical group, compared to those in the typical group. On the other hand, the typical group had a higher serum alanine aminotransferase level (adjusted for age) (p = 0.012) and Hyponatremia (serum sodium concentration ≤130 mmol/L) (p = 0.034). Based on the findings of the current study, the fever duration from onset to diagnosis was slightly more in atypical KD patients than in the typical group, but not statistically significant, possibly due to more timely diagnosis of atypical KD. There was no difference in coronary aneurysm between the two groups at the time of diagnosis. The atypical group had a higher frequency of coronary ectasia and lack of tapering, indicating cardiac involvement. Consequently, these conditions should be given more attention in the atypical patients. Furthermore, the higher frequency of anemia and thrombocytosis in the atypical patients can be useful for diagnosis of this kind of KD.

Prevalence and characteristics of arthritis in Kawasaki disease: a Chinese cohort study

Arthritis is a major complication of Kawasaki disease (KD). The aims of this study were to define the frequency and the clinical characteristics of arthritis in KD in China and to analyze the relation between arthritis and coronary outcome in KD. We included 1420 KD patients followed at Jiangxi Children's Hospital from January 2014 to December 2017. Demographic, clinical and laboratory features of KD were analyzed. Among the 1420 patients enrolled, 151 had arthritis. The median age of KD patients with arthritis was 29 months and older than those without arthritis (20 months). Of the 151 patients developed arthritis, 101 patients (66.9%) had oligoarticular involvement and 50 patients (33.1%) had polyarticular involvement. Early-onset and late-onset arthritis were, respectively, observed in 123 (81.45%) and 28 (18.54%) patients. The KD patients with arthritis had significantly increased levels of inflammatory markers, and we observed a higher incidence rate of coronary artery aneurysms among those with arthritis (7.28%) compared to those without arthritis (2.75%) (p = 0.003), but the prevalence of coronary artery lesions (CALs) was similar in the two groups. The arthritis in KD was self-limited, left no sequelae and did not require additional medications. KD patients with arthritis were more likely to get coronary artery aneurysms than the patients without arthritis, so examination of joints in KD was necessary.

The Gut Microbiota-Host Partnership as a Potential Driver of Kawasaki Syndrome

Kawasaki syndrome (KS) is a necrotizing vasculitis of small- and medium-sized vessels mostly affecting children under 5 years of age; a host of clinical and epidemiological data supports the notion that KS might result from an infectious disease. However, many efforts have failed to identify a potentially universal trigger of KS. The contribution of the intestinal microbial community-called the "microbiota"-to KS has been evaluated by an increasing number of studies, though limited to small cohorts of patients. Differences in the microbiota composition were found in children with KS, both its acute and non-acute phase, with abnormal colonization by Streptococcus species in the intestinal tract and a wider presence of Gram-positive cocci in jejunal biopsies. In particular, a higher number of Gram-positive cocci (of the genera Streptococcus and Staphylococcus), Eubacterium, Peptostreptococcus, and HSP60-producing Gram-negative microbes have been found in the stools of KS children, and their effects on the antigenic repertoire of specific T cells and Vβ2 T cell expansion have been assessed. Conversely, Lactobacilli were lacking in most children with KS compared with other febrile illnesses and healthy controls. All studies available to date have confirmed that an imbalance in the gut microbiota might indirectly interfere with the normal function of innate and adaptive immunity, and that variable microbiota interactions with environmental factors, mainly infectious agents, might selectively drive the development of KS in genetically susceptible children. Further investigations of the intestinal microflora in larger cohorts of KS patients will provide clues to disentangle the pathogenesis of this disease and probably indicate disease-modifying agents or more rational KS-specific therapies.