Epidemiology, Treatments, and Cardiac Complications in Patients with Kawasaki Disease: The Nationwide Survey in Japan, 2017-2018

A case of incomplete Kawasaki disease - A 2-month-old infant with 1 day of fever who developed multiple arterial aneurysms

Kawasaki disease (KD) is a systemic vasculitis and is the most frequent pediatric acquired heart disease in developed countries. The diagnosis of KD is typically made by the: ≧ 5 of 6 principal signs. However, approximately 20% of KD patients present with less than 5 of these diagnostic signs but may be suffering from coronary artery aneurysms and have been diagnosed with incomplete KD. In this case report, we describe a 2-month-old infant who showed just fever without any other signs of KD but was suffered from multiple arterial aneurysms, including coronary, pulmonary, and carotid arteries. Because she did not respond to intravenous immunoglobulin infusion, we placed her on plasma exchange that has successfully brought defervescence without any significant complications. This case may represent the end spectrum of incomplete KD in very young infants.

[Coronary Artery Visualization by Using the 64-row MDCT in Pediatric Patients]

PURPOSE

We retrospectively evaluated the visualization of pediatric coronary computed tomography angiography (CCTA) images by using the 64-detector row CT scanner between the electrocardiogram-gated helical scan and non-electrocardiogram-gated helical scan.

METHODS

From January 2015 to March 2019, 100 children who underwent CT angiography examination were retrospectively enrolled. Group A consisted of 50 patients with electrocardiogram-gated helical scan. Group B consisted of 50 patients with non-electrocardiogram-gated helical scan. All patients were scanned using a 64-detector row CT scanner (LightSpeed VCT), and helical scans were acquired. The CT scanning parameters were 0.4-s rotation, 0.625-mm slice thickness, 0.24 (group A) helical pitch (beam pitch), 1.375 (group B) helical pitch (beam pitch), 80 kVp, and 50-300 mA (noise index 40). A retrospective method was used for electrocardiogram gated. To compare the radiation dose, CT volume dose index (CTDI_vol) and dose length product (DLP) displayed on the console were recorded. The visualization scores of the coronary artery images were compared between each group.

RESULTS

In group A, CTDI_vol and DLP values were 6.74 (1.05-11.97) mGy and 79.87 (15.90-146.65) mGy·cm, respectively. In group B, CTDI_vol and DLP values were 0.51 (0.39-0.95) mGy and 8.15 (6.30-17.50) mGy·cm, respectively. There were significant differences in CTDI_vol and DLP values between both groups (p<0.05). The visualization rates for the proximal and distal coronary arteries were 88% and 54% for the right coronary artery, 84% and 58% for the left anterior descending artery, and 66% and 30% for the left circumflex branch in group A, respectively. The visualization rates for the proximal and distal coronary arteries were 52% and 0% for the right coronary artery, 56% and 0% for the left anterior descending artery, and 32% and 0% for the left circumflex branch in group B.

CONCLUSION

In 64-row multidetector computed tomography (MDCT), the visualization rates for the proximal and distal coronary arteries were significantly higher in the electrocardiogram-gated scan, but the exposure dose was several times higher in the pediatric CCTA. For accurate diagnosis in pediatric coronary arteries, electrocardiogram-gated helical scan should be performed.

Risk scores for Kawasaki disease, a management tool developed by the KAWA-RACE cohort

INTRODUCTION/OBJECTIVES

Asian scores developed to predict unresponsiveness to intravenous immunoglobulin (IVIG) or development of coronary artery aneurysms (CAA) in patients with Kawasaki disease (KD) are not appropriate in Western populations. The purpose of this study is to develop 2 scores, to predict unresponsiveness to IVIG and development of CAA, appropriate for Spanish population.

METHOD

Data of 625 Spanish children with KD collected retrospectively (2011-2016) were used to identify variables to develop the 2 scores of interest: unresponsiveness to IVIG and development of CAA. A statistical model selected best variables to create the scores, and scores were validated with data from 98 patients collected prospectively.

RESULTS

From 625 patients of the retrospective cohort, final analysis was performed in 439 subjects: 37 developed CAA, and 212 were unresponsive to IVIG. For the score to predict CAA, a cutoff ≥ 8 was considered for high risk, considering a score system with a different weight for each of the eight variables. External validation showed a sensitivity of 22% and a specificity of 75%. The score to predict unresponsiveness to IVIG established a cutoff ≥ 8 for high risk, considering a score system with a different weight for each of the nine variables. External validation showed a sensitivity of 78% and a specificity of 50%.

CONCLUSIONS

Two risk scores for KD were developed from Spanish population, to predict development of CAA and unresponsiveness to IVIG; validation in other cohorts could help to implement these tools in the management of KD in other Western populations.

Association of Acute Anti-inflammatory Treatment With Medium-term Outcomes for Coronary Artery Aneurysms in Kawasaki Disease

Background

The impact of adjunctive anti-inflammatory treatment on outcomes for patients with Kawasaki disease (KD) and coronary artery aneurysms (CAAs) is unknown.

Methods

Using data from the International KD Registry in patients with ≥ medium CAA we evaluate associations of treatment with outcomes and major adverse cardiac events (MACE).

Results

Medium or large CAA was present in 527 (32%) patients. All were treated with intravenous immunoglobulin (IVIG), 70% were male, and the median age was 1.3 years (interquartile range: 0.4-4.0 years). The most common acute therapies included single IVIG alone in 243 (46%), multiple IVIG in 100 (19%), multiple IVIG + corticosteroids in 75 (14%), and multiple IVIG + infliximab + corticosteroids in 44 (8%) patients. Patients who received therapy beyond single IVIG had a larger CA z-score at baseline (P < 0.001) and a higher rate of bilateral CAA (P < 0.001). Compared with IVIG alone, early adjunctive treatments (within 3 days of initial IVIG) were not associated with time to CAA regression or MACE, whereas later adjunctive therapy was associated with MACE and longer time to CAA regression. Patients receiving IVIG plus steroids vs IVIG alone had a trend towards shorter time to CAA regression and lower risk of MACE (P = 0.07). A larger CAA z-score at baseline was the strongest predictor of an increase in the CAA z-score over follow-up, lower likelihood of CAA regression, and higher risk of MACE.

Conclusions

Persistence of CAA and MACE are more strongly associated with baseline severity CAA than with acute adjuvant anti-inflammatory therapy. Patients who received late adjunctive therapy are at higher risk for worse outcomes.

Serum alanine aminotransferase level and intravenous immunoglobulin resistance in patients with kawasaki disease

INTRODUCTION/OBJECTIVES

Serum alanine aminotransferase (ALT) elevation is considered a risk factor for resistance to initial intravenous immunoglobulin (IVIG) treatment in patients with Kawasaki disease (KD). However, serum ALT levels change dramatically during acute KD illness. We tested the hypothesis that risk assessment for initial IVIG resistance based on serum ALT elevation may differ by examination day after KD onset.

METHODS

We analyzed 18,492 population-based patients who developed KD throughout Japan. First, we epidemiologically evaluated the serum ALT variation at 1‒10 days after disease onset. Second, we conducted multivariable logistic regression to determine the association between serum ALT level and initial IVIG resistance according to timing of initial hospital visit by stratifying the patients into an early group (1‒5 days after onset) and a late group (6‒10 days after onset).

RESULTS

Serum ALT rapidly increased after KD onset, peaked at day 4 of illness, and then declined regardless of IVIG responsiveness. The adjusted odds ratio (OR) increased with increasing serum ALT in the early group (adjusted OR [95% CI]: 1.44 [1.25-1.66], 1.94 [1.65-2.28], and 2.22 [1.99-2.48] for serum ALT 50-99, 100-199, and ≥ 200 IU/L, respectively; reference ALT level: 1-49 IU/L). No significant association was observed in the late group.

CONCLUSIONS

The findings indicate that risk assessment for initial IVIG resistance based on serum ALT level may only be reliable for patients with KD who visit hospitals during early illness, specifically 1-5 days after disease onset. Key Points Serum alanine aminotransferase level differed markedly according to examination days after Kawasaki disease onset. Serum alanine aminotransferase level declined toward normal range after day 5 of illness regardless of intravenous immunoglobulin responsiveness. Elevated serum alanine aminotransferase level was no longer a significant risk factor for initial intravenous immunoglobulin resistance when measured on delayed hospital visits. Risk assessment for initial intravenous immunoglobulin resistance based on serum alanine aminotransferase level may only be reliable for patients who visit hospitals during early illness, specifically 1-5 days after disease onset.

Analysis of Age, Sex, Lack of Response to Intravenous Immunoglobulin, and Development of Coronary Artery Abnormalities in Children With Kawasaki Disease in Japan

IMPORTANCE

Initial intravenous immunoglobulin (IVIG)-refractory status and prolonged fever are established risk factors for the development of coronary artery abnormalities (CAAs) among patients with acute-phase Kawasaki disease (KD). However, whether different risk factors exist for initial unresponsiveness to IVIG and CAA development remains unclear.

OBJECTIVE

To evaluate whether different risk factors exist for initial unresponsiveness to IVIG and CAA development among patients with KD (stratified by age at disease onset).

DESIGN, SETTING, AND PARTICIPANTS

This retrospective cohort study included a consecutive sample of 2414 patients from a database of patients with KD from October 1, 1999, to September 30, 2019. The data were based on annual surveys (response rate, 100%) using hospital medical records across Wakayama Prefecture, Japan. Data were analyzed from March 6 to March 26, 2022.

EXPOSURES

The patient's age and diagnosis of KD by board-certified pediatricians using the criteria established by the Japan KD Research Committee.

MAIN OUTCOMES AND MEASURES

Initial unresponsiveness to IVIG, defined as treatment with optional or advanced therapies, and development of CAAs. Echocardiograms performed 1 month after KD onset using the Japanese Ministry of Health criteria evaluated the presence or absence of CAAs. Odds ratios (ORs) with 95% CIs of patient age at KD onset for unresponsiveness to IVIG and developing CAAs were calculated using multivariable logistic regression models.

RESULTS

A total of 2414 patients (1403 male patients [58.1%]; median age at onset of KD, 25 months [range, 1-212 months]) were included in the study: 550 younger than 12 months, 1342 aged 12 to 47 months, and 522 older than 47 months. A total of 535 patients (22.2%) received optional or advanced treatment and 68 patients (2.8%) developed CAAs 1 month after disease onset. The sex-adjusted OR among patients younger than 12 months for unresponsiveness to IVIG was 0.77 (95% CI, 0.59-0.99) and for development of CAAs was 1.94 (95% CI, 1.07-3.52); among those older than 47 months, the OR for unresponsiveness to IVIG was 1.32 (95% CI, 1.05-1.67) and for development of CAAs was 2.47 (95% CI, 1.39-4.39). After adjusting for IVIG administration, ORs among boys older than 47 months for unresponsiveness to IVIG was 1.14 (95% CI, 0.84-1.56) and for development of CAAs was 2.15 (95% CI, 1.08-4.30); among girls younger than 12 months, the OR for unresponsiveness to IVIG was 1.02 (95% CI, 0.65-1.60) and for development of CAAs was 3.79 (95% CI, 1.21-11.90).

CONCLUSIONS AND RELEVANCE

The results of this study suggest that risks of unresponsiveness to IVIG and the development of CAAs differ between infants with KD and older patients with KD. Residual risk factors for KD-related CAAs other than initial unresponsiveness to IVIG should be addressed, particularly in infants.

Clinical Manifestations and Laboratory Findings of Kawasaki Disease: Beyond the Classic Diagnostic Features

Kawasaki disease (KD) has shown a marked increase in trend over the globe, especially within the last two decades. Kawasaki disease is often seen in the paediatric population below five years old, while it is rare for those who are beyond that age. Up to this date, no exact causes has been identified although KD was found more than half a century ago. The underlying pathogenesis of the disease is still unelucidated, and researchers are trying to unlock the mystery of KD. To further complicate the diagnosis and the prompt management, a specific biomarker for the diagnosis of KD is yet to be discovered, making it hard to differentiate between KD and other diseases with a similar presentation. Nonetheless, since its discovery, clinicians and scientists alike had known more about the different clinical aspects of typical KD. Thus, this article intends to revisit and review the various clinical manifestations and laboratory characteristics of KD in order to guide the diagnosis of KD.

Melatonin alleviates vascular endothelial cell damage by regulating an autophagy-apoptosis axis in Kawasaki disease

Objectives

Melatonin has been reported to be an appropriate candidate for mitigating various cardiovascular injuries, owing to its versatility. This study aimed to explore the role of melatonin in Kawasaki disease (KD)‐associated vasculitis and its underlying mechanisms.

Material and Methods

The role of melatonin was evaluated in human coronary artery endothelial cells (HCAECs), peripheral blood mononuclear cells from KD patients, human THP1 cell line in vitro, and a Candida albicans water‐soluble fraction (CAWS)‐induced KD mouse model in vivo. Cell proliferation assay, cell apoptosis assay, cell co‐culture, RNA extraction, RNA sequencing, reverse transcription quantitative PCR, enzyme‐linked immunosorbent assay (ELISA), transwell assay, western blot, dual‐luciferase reporter assay, and autophagic flux assay were performed to investigate the function and regulatory mechanisms of melatonin in vitro, while haematoxylin and eosin staining, Verhoeff's van Gieson staining, ELISA, and immunohistochemical analysis were performed to detect the effect of melatonin in vivo.

Results

Melatonin suppressed cell apoptosis directly reduced the expression of endothelial cell damage markers in HCAECs, and alleviated vasculitis in the CAWS‐induced KD mouse model. Mechanistically, melatonin promoted autophagy by activating the melatonin/ melatonin receptor (MT)/cAMP‐response element binding protein (CREB) pathway and upregulating the expression of autophagy‐related gene‐3, thereby suppressing cell apoptosis in an autophagy‐dependent manner. Additionally, melatonin decreased the production of pro‐inflammatory cytokines in macrophages and indirectly reduced the immunopathological damage of HCAECs.

Conclusions

This study revealed that melatonin protects vascular endothelial cells in KD, by suppressing cell apoptosis in an autophagy‐dependent manner and reducing the immunopathological damage mediated by macrophages.

Risk Factors and Predictive Models for Intravenous Immunoglobulin Resistance in Children with Recurrent Kawasaki Disease

Purpose

To explore the risk factors and develop predictive models for intravenous immunoglobulin (IVIG) resistance in children with recurrent Kawasaki disease (KD).

Patients and Methods

Patients with recurrent KD were retrospectively reviewed. Clinical and laboratory data at recurrence were collected and compared between patients with and without IVIG resistance. The patients were randomly divided into training and validation cohorts for model development and validation. All variables were subjected to standard Lasso and its variant group Lasso analyses, respectively, to construct predictive models. Model performance was evaluated by receiver operating characteristics (ROC) curves, calibration curves, and Hosmer-Lemeshow tests.

Results

A total of 90 children with recurrent KD were included. A total of 16 cases were IVIG resistant. The patients with IVIG resistance had higher age and IVIG resistance probability at the first episode, increased CRP levels, neutrophil count, neutrophil percentage, direct bilirubin level, prothrombin time, and international normalized ratio, and decreased lymphocyte count, lymphocyte percentage, and serum sodium levels. Five variables including age and IVIG resistance at the first episode, lymphocytes count, serum sodium levels, and CRP levels were finally selected by standard Lasso (lLasso model) and four variables including age and IVIG resistance at the first episode, neutrophil percentage, and CRP levels were selected by group Lasso (gLasso). ROC curves suggested lLasso and gLasso models had similar excellent discrimination in both the training cohort (0.895 vs 0.906) and the validation cohort (0.855 vs 0.909). Hosmer-Lemeshow tests suggested the two models exerted a good calibration. Two nomograms were also constructed to facilitate the potential application of the two models.

Conclusion

Age and IVIG resistance at the first episode and some laboratory variables may be risk factors for IVIG resistance in recurrent KD. Two predictive models for IVIG resistance with excellent performance were established in recurrent KD. External validation should be performed before clinical use.

The Significance of Symptoms in Predicting Coronary Artery Aneurysms of Kawasaki Disease, Especially in Female Patients

Background

Kawasaki disease (KD) is an acute febrile systemic vasculitis of unknown etiology that occurs during early childhood, commonly involving the coronary artery, and can lead to coronary artery aneurysms (CAAs).

Methods

The demographic, clinical, and laboratory data of KD patients without coronary artery lesions (N-CAL) and with CAA were collected during 2005–2020 at the Second Affiliated Hospital of Wenzhou Medical University. The patients were divided into the development cohort and the validation cohort. First, we compared the general information, symptoms, and laboratory data of N-CAL and CAA patients in the development cohort and the total cohort and screened out the different indices by logistic regression analysis. Then, we established three models and compared the area under the curve (AUC) values of the receiver operating characteristic (ROC) curves to identify meaningful models for CAA, which were further verified by decision curve analysis (DCA). Second, taking into account previous reports on the importance of gender to CAA, gender stratification was conducted.

Results

The analysis of clinical and blood indices revealed the following novel features: (i) Many factors were found to be related to CAA, including IVIG resistance and the symptoms of rash, oral changes, and cervical lymphadenopathy. (ii) The development cohort was analyzed by logistic regression, and three models were established. The ROC curves showed that Model 2, composed of IVIG resistance, rash, oral changes, and cervical lymphadenopathy, had a better AUC value and easily to evaluate in the prediction of CAA. (iii) The selected model for predicting CAA in the development cohort was further confirmed in the validation cohort through DCAs. (iv)We further compared the items enrolled in the three models above between the N-CAL and CAA groups by sex, and the results indicated that female KD patients without rash, oral changes, and cervical lymphadenopathy were more likely to develop CAA.

Conclusion

The absence of rash, oral changes, and cervical lymphadenopathy are risk factors for CAA, especially in female KD patients. Accurately recognizing symptoms, early diagnosis, and standard treatment for KD are key to reducing the incidence of CAA.

The rs7404339 AA Genotype in CDH5 Contributes to Increased Risks of Kawasaki Disease and Coronary Artery Lesions in a Southern Chinese Child Population

Background

Kawasaki disease (KD) is an acute, self-limited febrile illness of unknown cause. And it predominantly affects children <5 years and the main complication is coronary artery lesion (CAL). Studies demonstrated that vascular endothelial cells (VECs) played a very important role in the CAL of KD. VE-cad encoded by CDH5 may exert a relevant role in endothelial cell biology through controlling the cohesion of the intercellular junctions. The pathogenesis of KD remains unclear and genetic factors may increase susceptibility of KD. However, the relationship between CDH5 polymorphisms and KD susceptibility has not been reported before. The present study is aimed at investigating whether the rs7404339 polymorphism in CDH5 is associated with KD susceptibility and CAL in a southern Chinese child population.

Methods and Results

We recruited 1,335 patients with KD and 1,669 healthy children. Each participant had supplied 2 mL of fresh blood in the clinical biologic bank at our hospital for other studies. Multiplex PCR is used to assess the genotypes of rs7404339 polymorphism in CDH5. According to the results, we found significant correlated relationship between rs7404339 polymorphism in CDH5 and KD susceptibility [AA vs. GG: adjusted odds ratio (OR) = 1.43, 95% confidence interval (CI) = 1.00-2.05; p = 0.0493; recessive model: adjusted OR = 1.44, 95% CI = 1.01-2.06, P = 0.0431]. In further stratified analysis, we found that children younger than 60 months (adjusted OR = 1.46, 95% CI = 1.01-2.10; p = 0.0424) and male (adjusted OR = 1.70, 95% CI = 1.09-2.65; p = 0.0203) with the rs7404339 AA genotype in CDH5 had a higher risk of KD than carriers of the GA/GG genotype. Furthermore, stratification analysis revealed that patients with the rs7404339 AA genotype exhibited the significantly higher onset risk for CAL than carriers of the GA/GG genotype (adjusted age and gender odds ratio = 1.56, 95% CI = 1.01-2.41; P = 0.0433).

Conclusion

Our results showed that rs7404339 AA genotype in CDH5 is significant associated with KD susceptibility. And children younger than 60 months and male with the rs7404339 AA genotype had a higher risk of KD than carriers with the GA/GG genotype. Furthermore, patients with the rs7404339 AA genotype exhibited a significantly higher risk of CAL complication than carriers of the GA/GG genotype.

Etiological and pathophysiological enigmas of severe coronavirus disease 2019, multisystem inflammatory syndrome in children, and Kawasaki disease

During the coronavirus disease 2019 (COVID-19) pandemic, a novel multisystem inflammatory syndrome in children (MIS-C) has been reported worldwide since the first cases were reported in Europe in April 2020. MIS-C is temporally associated with severe acute respiratory syndrome coronavirus 2 infection and shows Kawasaki disease (KD)-like features. The epidemiological and clinical characteristics in COVID-19, KD, and MIS-C differ, but severe cases of each disease share similar clinical and laboratory findings such as a protracted clinical course, multiorgan involvement, and similar activated biomarkers. These findings suggest that a common control system of the host may act against severe disease insult. To solve the enigmas, we proposed the protein-homeostasis-system hypothesis in that every disease involves etiological substances and the host's immune system controls them by their size and biochemical properties. Also, it is proposed that the etiological agents of KD and MIS-C might be certain strains in the microbiota of human species and etiological substances in severe COVID-19, KD, and MIS-C originate from pathogen-infected cells. Since disease severity depends on the amounts of inflammation-inducing substances and corresponding immune activation in the early stage of the disease, an early proper dose of corticosteroids and/or intravenous immunoglobulin (IVIG) may help reduce morbidity and possibly mortality among patients with these diseases. Corticosteroids are low cost and an analogue of host-origin cortisol among immune modulators. This study's findings will help clinicians treating severe COVID-19, KD, and MIS-C, especially in developing countries, where IVIG and biologics supplies are insufficient.

Myocardial Infarction in Children after COVID-19 and Risk Factors for Thrombosis

Acute myocardial infarction (AMI) in children is rather anecdotic. However, following COVID-19, some conditions may develop which may favor thrombosis, myocardial infarction, and death. Such a condition is Kawasaki-like disease (K-lD). K-lD appears in children as a subgroup of the multisystem inflammatory syndrome (MIS-C). In some cases, K-lD patients may develop giant coronary aneurysms. The evolution and characteristics of coronary aneurysms from K-lD appear to be different from classical Kawasaki disease (KD) aneurysms. Differences include a lower percentage of aneurysm formation than in non-COVID-19 KD, a smaller number of giant forms, a tendency towards aneurysm regression, and fewer thrombotic events associated with AMI. We present here a review of the literature on the thrombotic risks of post-COVID-19 coronary aneurysms, starting from a unique clinical case of a 2-year-old boy who developed multiple coronary aneurysms, followed by AMI. In dehydration conditions, 6 months after COVID-19, the boy developed anterior descending artery occlusion and a slow favorable outcome of the AMI after thrombolysis. This review establishes severity criteria and risk factors that predispose to thrombosis and AMI in post-COVID-19 patients. These may include dehydration, thrombophilia, congenital malformations, chronic inflammatory conditions, chronic kidney impairment, acute cardiac failure, and others. All these possible complications should be monitored during acute illness. Ischemic heart disease prevalence in children may increase in the post-COVID-19 era, due to an association between coronary aneurysm formation, thrombophilia, and other risk factors whose presence will make a difference in long-term prognosis.

Non-coding RNAs in Kawasaki disease: Molecular mechanisms and clinical implications

Kawasaki disease (KD) is an acute self-limiting vasculitis with coronary complications, usually occurring in children. The incidence of KD in children is increasing year by year, mainly in East Asian countries, but relatively stably in Europe and America. Although studies on KD have been reported, the pathogenesis of KD is unknown. With the development of high-throughput sequencing technology, growing number of regulatory noncoding RNAs (ncRNAs) including microRNA (miRNA), long noncoding RNA (lncRNA), and circular RNA (circRNA) have been identified to involved in KD. However, the role of ncRNAs in KD has not been comprehensively elucidated. Therefore, it is significative to study the regulatory role of ncRNA in KD, which might help to uncover new and effective therapeutic strategies for KD. In this review, we summarize recent studies on ncRNA in KD from the perspectives of immune disorders, inflammatory disorders, and endothelial dysfunction, and highlight the potential of ncRNAs as therapeutic targets for KD.

KD Diagnosis Does Not Increase Cardiovascular Risk in Children According to Dynamic Intima-Media Roughness Measurements

Background: Kawasaki Disease (KD) is a generalized vasculitis in childhood with possible long-term impact on cardiovascular health besides the presence of coronary artery lesions. Standard vascular parameters such as carotid intima–media thickness (cIMT) have not been established as reliable markers of vascular anomalies after KD. The carotid intima–media roughness (cIMR) representing carotid intimal surface structure is considered a promising surrogate marker for predicting cardiovascular risk even beyond cIMT. We therefore measured cIMR in patients with a history of KD in comparison to healthy controls to investigate whether KD itself and/or KD key clinical aspects are associated with cIMR alterations in the long-term. Methods: We assessed cIMR in this case-control study (44 KD, mean age in years (SD); 13.4 (7.5); 36 controls, mean age 12.1 (5.3)) approximately matched by sex and age. Different clinical outcomes such as the coronary artery status and acute phase inflammation data were analyzed in association with cIMR values. Results: When comparing all patients with KD to healthy controls, we detected no significant difference in cIMR. None of the clinical parameters indicating the disease severity, such as the persistence of coronary artery aneurysm, were significantly associated with our cIMR values. However, according to our marginally significant findings (p = 0.044), we postulate that the end-diastolic cIMR may be rougher than the end-systolic values in KD patients. Conclusions: We detected no significant differences in cIMR between KD patients and controls that could confirm any evidence that KD predisposes patients to a subsequent general arteriopathy. Our results, however, need to be interpreted in the light of the low number of study participants.

Kawasaki disease in children younger than 6 months of age: characteristics of a Spanish cohort

A retrospective study that compared children younger than 6 months versus older children of a Spanish cohort of patients diagnosed with Kawasaki disease between 2011 and 2016 (Kawa-Race study). From the 598 patients recruited, 42 patients were younger than 6 months (7%) and presented more frequently with an incomplete diagnosis of Kawasaki disease (52.4 vs 27.9%, p = 0.001). Cardiac abnormalities detected by echocardiography were more common in younger patients (52.4 vs 30%, p = 0.002). These younger patients presented with a higher proportion of coronary aneurysms as well (19 vs 8.6%, p < 0.001). Shock at diagnosis (9.5 vs 1.9%, p = 0.016) and admission to intensive care units (17.7 vs 4.1%, p = 0.003) were more frequent in patients younger than 6 months. There were no statistically significant differences in relation to infections, non-response to IVIG, or mid- or long-term outcomes.Conclusion: Data of the Spanish cohort are consistent with other American and Asian studies, although Spanish children younger than 6 months had a lower rate of non-response to IVIG and better clinical outcomes. A high index of suspicion should be considered for this population due to a higher risk of coronary abnormalities, presentation of shock, and admission to the intensive care unit. What is Known: •Children below 6 months of age with Kawasaki disease (KD) have different features compared to older. •Younger patients usually have an incomplete form of KD and coronary artery abnormalities. What is New: •Younger than 6 months with KD presented with shock and required admission to PICU more frequently compared to older. •Infections play a similar role in KD despite the age of the patients.

Follow up of Kawasaki disease based on nationwide survey data in Japan: Mortality among those with a history of Kawasaki disease in Japan: Results of a 30-year follow up: Mortality among those with a history of Kawasaki disease in Japan: Results of a 30-year follow up

BACKGROUND

The long-term prognosis of those with a history of Kawasaki disease (KD) is still unknown.

METHODS

Using a permanent registry system in Japan (koseki), 6,576 persons with a history of KD were followed up. The average follow-up period was 30 years. The endpoint was death.

RESULTS

With a 99.5% follow-up rate, 68 deaths (48 males and 20 females) were observed. The overall standardized mortality ratio, of which reference was vital statistics in Japan, was not elevated. However, the observation according to the presence or absence of cardiac sequelae showed that the standardized mortality ratio for those with cardiac sequelae significantly elevated. Nine persons, all of whom were males, died of KD (including those cases where KD was suspected), but all deaths occurred in individuals who were under 30 years of age.

CONCLUSIONS

This study revealed the long-term prognosis for KD, but almost all participants were younger than 40 years. Continuing follow up of this cohort is required to clarify whether a history of KD relates to the development of atherosclerosis when participants become middle aged or older.

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.

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.

Poor response to intravenous immunoglobulin in patients with a parental history of Kawasaki disease

BACKGROUND

Patients whose parents had a history of Kawasaki disease (KD) often show a poor response to intravenous immunoglobulin (IVIG). There are very few reports describing the clinical characteristics and no reports on changes in C-reactive protein (CRP) level after IVIG administration in such cases.

METHODS

A single-center cohort study including 950 patients hospitalized for KD and treated with IVIG was conducted. The patients were divided into two groups: patients whose parents had a history of KD (PHK) (N = 16) and patients whose parents had no history of KD (NPHK) (N = 934). The clinical characteristics and responsiveness to IVIG were compared between the two groups.

RESULTS

The PHK group had higher CRP levels before administering IVIG than the NPHK group (P = 0.0010). CRP levels after IVIG administration were higher in the PHK group than in the NPHK group (P = 0.0094). The percentage of patients who received a second administration of IVIG on day 2 after the initial IVIG therapy was higher in the PHK group than in the NPHK group (P = 0.0016). The percentage of patients who required plasma exchange therapy in the PHK group was significantly higher than that in the NPHK group (P = 0.0010).

CONCLUSIONS

Patients in the PHK group had severe KD before IVIG administration, and these patients showed poor responsiveness to IVIG therapy.

Status of treatment and outcome in Kawasaki disease in the Kinki area of Japan

BACKGROUND

The treatment guidelines for acute Kawasaki disease (KD) have been revised several times. Moreover, the criterion used to define coronary artery abnormalities (CAAs) has changed from the coronary artery's internal diameter to the Z-score. Treatment for KD and methods for evaluating CAAs vary between hospitals, so we investigated the actual status of acute KD treatment and development of CAAs under the 2012 Japanese treatment guidelines for acute KD.

METHODS

The 24th Japanese Nationwide Survey on Kawasaki Disease yielded 2618 patients who developed KD in the Kinki area in 2016. We sent a secondary questionnaire to each participating hospital and used the resulting data to investigate the frequency of CAAs according to Z-score, treatment by KD treatment stage, and predictors of CAAs.

RESULTS

The response rate was 80.0%. The data for 1426 patients without major data deficiencies were examined. The frequency of CAAs was 3.0% when based on coronary artery internal diameters and 8.8% when based on Z-scores. Intravenous immunoglobulins combined with corticosteroids were administered as an initial treatment in 12.8% of cases and as a second-line treatment in 16.8% of cases. Corticosteroids, cyclosporine A, infliximab, and plasma exchange were used at similar frequencies for third-line treatment. A pretreatment maximum coronary artery Z-score of ≥1.9 and age <1 year were associated with significantly higher incidences of CAAs.

CONCLUSIONS

Using the Z-score resulted in a threefold increase in the number of patients diagnosed with CAAs. A pretreatment maximum coronary artery Z-score of ≥1.9 and age <1 year are useful predictors of CAAs.

The possible association between epidemics of hand-foot-and-mouth disease and responsiveness to immunoglobulin therapy in Kawasaki disease

BACKGROUND

Enterovirus causing hand-foot-mouth disease (HFMD) has been reported to be associated with the development of Kawasaki disease (KD), whereas the involvement of enterovirus in the clinical course of KD is uncertain. The aim of this study is to investigate the association between the clinical course of KD and HFMD epidemics.

METHODS

This study included 108 patients who developed KD during HFMD epidemic seasons (July and August) from 2010 to 2014 and who were initially treated with high-dose intravenous immunoglobulin (IVIG). A mean of ≥5.0 HFMD patients reported weekly from each sentinel medical facility was considered to represent a large HFMD epidemic. We compared the clinical characteristics of KD patients in summers of years with and without large HFMD epidemics.

RESULTS

Large HFMD epidemics occurred in 2011 and 2013. The number of KD patients in summer was the highest in 2011. The proportion of patients with resistance to the IVIG therapy in summers of years with the large epidemics (14%) was significantly lower than that in summers of other years (31%, P = 0.030), whereas the proportion of patients with coronary artery abnormalities did not differ to a statistically significant extent. The development of KD during large HFMD epidemics was significantly associated with a lower risk of resistance to the IVIG therapy (incidence rate ratio 0.92, P = 0.049).

CONCLUSION

Patients developing KD during large HFMD epidemic may have good responsiveness to IVIG. It is important to identify microbes from KD patients to predict responsiveness to IVIG therapy.

Predictors for Intravenous Immunoglobulin Resistance in Patients with Kawasaki Disease

BACKGROUND

Between 10 and 20% of Kawasaki disease (KD) patients are resistant to treatment with initial intravenous immunoglobulin (IVIG) and have a high risk of developing coronary artery lesions. Some studies have been conducted to identify predictive factors. However, the results are controversial. This study aims to identify the risk factors for IVIG-resistant KD patients in a Chinese population.

METHODS

We performed a retrospective analysis of medical records of consecutive KD patients from two medical centers in South China from January 2015 to December 2017. A total of 1281 KD patients were eligible for inclusion in this study and maintained follow-up for over 12 months. The KD patients were divided into two groups based on IVIG response. Clinical characteristics and laboratory variables were compared between the two groups. Multivariate logistic regression analysis was performed to identify the risk factors of IVIG resistance in KD patients.

RESULTS

Of the 1281 KD patients, 141 (11.0%) cases who were IVIG resistant to adjunctive therapies for primary treatment were classified as group 1. The remaining patients were in group 2 (n = 1140), classified as the control group. There was a significant difference in male to female ratio and the length of hospital stay between the two groups (P < 0.05). Group 1 had a higher white blood cell count (P=0.01) and C-reactive protein level (P < 0.01) before IVIG treatment than in group 2. Group 1 had a significantly higher white blood cell count and percentage of neutrophils after the IVIG infusion than in group 2 (P < 0.001). In addition, the mean values of C-reactive protein level and neutrophil percentage before and after treatment difference comparison were significantly different. Multivariate analysis showed that patients presenting with coronary artery lesions in the acute phase and a C-reactive protein level >100 mg/L at diagnosis were associated with IVIG resistance in KD. During the 12-month follow-up period, group 1 had an obviously higher incidence of coronary artery lesions than group 2, and the difference between the groups was statistically significant (P < 0.001).

CONCLUSIONS

Patients presenting with coronary artery lesions in the acute phase and elevated C-reactive protein levels before IVIG treatment might be a useful and important value for predicting IVIG resistance in KD. Risk assessment based on coronary artery lesions and C-reactive protein levels prior to the treatment may improve the outcome of IVIG resistance.

Acute phase of Kawasaki disease: a review of national guideline recommendations

Key aspects of the medical management of Kawasaki disease (KD) are not yet supported by a high evidence level, thus making room for individual recommendations. We performed a structured comparison of existing international KD guidelines to analyze potential differences in the implementation of evidence-based KD recommendations regarding diagnosis and therapy. To identify country-specific guidelines, we took a multilateral approach including a comprehensive PubMed literature, online research, and directly contacting national pediatric associations. We then ran a structured guidelines' analysis and evaluated the diagnostic and therapeutic differences in the context of evidence-based medicine. In this structured guideline analysis, we identified nine national and one European guidelines. According to them all, the diagnosis of KD still relies on its clinical presentation with no reliable biomarker recommended. First-line treatment consistently involves only intravenous immunoglobulin (IVIG) therapy. Recommendations in terms of acetylsalicylic acid, corticosteroids, and additional therapeutic options vary considerably.

CONCLUSION

According to all guidelines, KD is diagnosed clinically with some variance in defining incomplete KD and being a non-responder to treatment. First-line treatment consistently includes IVIG. Recommendations for additional therapeutic strategies are more heterogeneous.

WHAT IS KNOWN

• The diagnosis of KD relies on the clinical presentation, entailing challenges in timely diagnosis. • Other treatment options then IVIG are not supported by a high evidence level, making room for individual recommendations.

WHAT IS NEW

• Definition of incomplete KD and being non-responsive to an initial treatment vary to some extent between the national guidelines. • Only IVIG is consistently proposed throughout all guidelines, further therapeutic recommendations vary between the national recommendations.

New predictors to identify severe cases during intravenous immunoglobulin therapy in Kawasaki disease

BACKGROUND

The purpose of this study was to predict which patients would require plasma exchange therapy (PEX) using laboratory findings during intravenous immunoglobulin (IVIG) therapy in Kawasaki disease.

METHODS

A retrospective, single-center, cohort study was conducted. Of the 621 IVIG-treated patients, 166 patients who received a second IVIG dose on the second day after initiation of IVIG were included. The endpoint was PEX. Participants were divided into two groups: 10 patients who received PEX and 156 patients who did not. The variables were C-reactive protein (CRP), white blood cell count (WBC), and neutrophil fraction (NEUT) at three time points: pre-initial IVIG, pre-second IVIG, and post-second IVIG. The change ratio (post-IVIG value/pre-IVIG value) of each variable, with each IVIG dose, was calculated. Receiver operating characteristic analysis determined the area under the curve (AUC) and cut-off values.

RESULTS

The variables with an AUC > 0.9 were CRP (post-second IVIG), change ratio of CRP (CRP value post-second IVIG/CRP value pre-second IVIG), NEUT (pre-second IVIG), and NEUT (post-second IVIG). Among these, the variables with high sensitivity were CRP (post-second IVIG) and the change ratio of CRP (second IVIG), with cut-off values of 9.52 mg/dL and 0.99, respectively. The sensitivity and specificity of these variables were 100% and 91%, and 100% and 80%, respectively. The combined sensitivity and specificity (95% confidence intervals) of these two variables were 100% (59-100) and 94% (89-97).

CONCLUSION

High CRP levels and the change ratio of CRP after the second IVIG dose were associated with PEX.

Albumin level and progression of coronary artery lesions in Kawasaki disease: A retrospective cohort study

BACKGROUND

Albumin (ALB) level is closely associated with the occurrence of intravenous immunoglobulin (IVIG) resistance and coronary artery lesions (CALs) in Kawasaki disease (KD). The association between ALB level and CALs progression, is critical to the prognosis of KD patients. But little is known about it. This study aims to investigate the effect of the ALB level on CALs progression in KD patients.

METHODS

A total of 3,479 KD patients from 1 January 2005 to 30 November 2020, in Wenzhou, China were recruited. A total of 319 KD patients who had CALs and ALB data, and finish the follow-up as requested were enrolled in this study. They were classified into the low ALB group and the normal ALB group, divided by 30 g/L. CALs outcomes were classified into two categories according to the CALs changes from the time that CALs were detected within 48 h before or after IVIG treatment to 1 month after disease onset: progressed and no progressed. Multiple logistic regression models were used to assess the independent effect of ALB level on CALs progression among KD patients. Stratified analysis was performed to verify the ALB level on CALs progression among patients in different subgroups.

RESULTS

Higher proportion of IVIG resistance (P < 0.001), receiving non-standard therapy (P < 0.001), and receiving delayed IVIG treatment (P = 0.020) were detected in patients with lower ALB level. Patients with lower ALB level had higher C-reactive protein (CRP) level (P = 0.097) and white blood cell count (WBC) (P = 0.036). After adjustment for confounders, patients with lower ALB level had higher odds of CALs progression; the adjusted odds ratio (OR) was 3.89 (95% CI: 1.68, 9.02). Similar results were found using stratification analysis and sensitivity analysis. Male gender and age over 36 months, as covariates in multiple logistic regression models, were also associated with CALs progression.

CONCLUSION

Low ALB level is identified as an independent risk factor for CALs progression in KD patients. Male gender and age over 36 months are also proved to be risk factors for CALs progression. Further investments are required to explore its mechanisms.

Kawasaki Disease and Pediatric Infectious Diseases During the Coronavirus Disease 2019 Pandemic

OBJECTIVE

To assess the epidemiologic association between Kawasaki disease and common pediatric infectious diseases (PIDs) identified during the coronavirus disease 2019 (COVID-19) pandemic period to confirm whether the infection-triggered theory is a plausible hypothesis for the pathogenesis of Kawasaki disease.

STUDY DESIGN

A retrospective epidemiologic study was conducted using datasets obtained from Web-based surveillance of Kawasaki disease and PIDs in Japan. We compared weekly numbers of patients who developed Kawasaki disease and specific PIDs between 2020 and 2017-2019 and evaluated the association between the percent reduction in the number of patients with these diseases.

RESULTS

A total of 868 patients developed Kawasaki disease in 2020. During the social distancing period in 2020, the number of patients with Kawasaki disease was approximately 35% lower than in 2017-2019. Time from the onset of Kawasaki disease until the first hospital visit did not differ significantly among the examined years. The proportion of older children with Kawasaki disease decreased more than that of infants with Kawasaki disease (age <1 year), resulting in a significant difference in the proportion of infant patients between 2020 and 2017-2019 (24% vs 19%; P < .01). The number of patients with incomplete Kawasaki disease was unchanged from that of previous years. The weekly percent reduction in patient numbers differed between Kawasaki disease and PIDs during 2020, with no strong correlation between the 2 diseases.

CONCLUSIONS

Our data indicate that parents of patients with Kawasaki disease did not avoid hospital visits during the COVID-19 pandemic period. The findings indicate the possibility that triggering Kawasaki disease might be associated with presently unidentified respiratory pathogen(s) that potentially might be acquired from both within and outside the household.

Association of left ventricular systolic dysfunction with coronary artery dilation in Kawasaki disease patients: Assessment with cardiovascular magnetic resonance

PURPOSE

To quantify global and regional left ventricular (LV) strain parameters in patients with Kawasaki disease (KD) using cardiovascular magnetic resonance (CMR) tissue tracking and assess the association of coronary artery dilation (CA dilation) with LV systolic dysfunction.

METHODS

Thirty-one KD patients with CA dilation, 22 patients without CA dilation and 27 age- and sex-matched normal controls underwent 3.0 T CMR examination. Z score of >2 was defined as CA dilation. Global LV strain parameters and regional LV strain parameters in 16 American Heart Association segmentation, including radial, circumferential and longitudinal peak strain (PS) and LV function were measured and compared among groups.

RESULTS

No significant difference in LV ejection fraction has been observed among controls, KD patients with CA dilation and without CA dilation (all p > 0.05). However, global longitudinal PS (GLPS) was lower in groups with CA dilation than those without CA dilation (-12.6 ± 4.1% vs -14.9 ± 2.6%, p < 0.05). For regional strain parameters, the segments with CA dilation (n = 301) were lower than those in both normal controls (n = 416) and segments without CA dilation (n = 547) in regional radial, circumferential and longitudinal PS (all p < 0.05). The severity of CA dilation was positively correlated to GLPS and regional longitudinal PS (r = 0.388 and r = 0.222; both p < 0.05) in KD patients. After adjusting for clinical characteristics, the multivariate analysis demonstrated that Z score was independently associated with GLPS in KD patients (β = 0.469, p = 0.000, model R² = 0.355).

CONCLUSIONS

CMR tissue tracking could sensitively identify subclinical LV dysfunction in KD patients with CA dilation. LV systolic dysfunction occurs particularly in the myocardium dominated by the dilated coronary artery. CA dilation is an independent predictor of LV systolic dysfunction.

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.

Multi-inflammatory syndrome and Kawasaki disease in children during the COVID-19 pandemic: A nationwide register-based study and time series analysis

Aim

We investigated whether the ongoing COVID‐19 pandemic was associated with the occurrence of Kawasaki disease or with multi‐inflammatory syndrome in children (MIS‐C).

Methods

This national Finnish register‐based study was based on laboratory‐confirmed severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2) infections, MIS‐C and Kawasaki disease cases. We performed a time series analysis on the occurrence of Kawasaki disease in 2016–2020.

Results

In 2020, there were 5170 laboratory‐confirmed COVID‐19 cases in children under 18 years of age and five fulfilled the MIS‐C case definition. The occurrence of MIS‐C was 0.97 per 1000 (95% confidence interval: 0.31‐2.26) laboratory‐confirmed SARS‐CoV‐2 infections in children. Our time series analysis showed that Kawasaki disease cases decreased during the COVID‐19 pandemic. The seasonally adjusted incidence rate ratio was 0.49 (95% confidence interval: 0.32‐0.74) when it was compared to pre‐pandemic levels. This coincided with a reduced occurrence of respiratory infections, due to social distancing in the population.

Conclusion

This nationwide register‐based study found that MIS‐C was a rare complication of the SARS‐CoV‐2 infection. The occurrence of Kawasaki disease and respiratory infections decreased during the pandemic. This suggests that transmissible microbes may play an important role in Kawasaki disease and social distancing may have a protective effect.

Kawasaki Disease Hospitalizations in the United States 2016-2020: A Comparison of Before and During the Coronavirus Disease 2019 Era

BACKGROUND

Kawasaki disease (KD) is an acute vasculitis of young children. A comparison of US hospitalization rates and epidemiologic features of KD in 2020 to those of precoronavirus disease years has yet to be reported.

METHODS

Using a large, inpatient database, we conducted a retrospective cohort study and analyzed data for patients with (1) diagnosis coding for KD, (2) IV immunoglobulin treatment administered during hospitalization and (3) discharge date between January 1, 2016, and December 30, 2020. Severe cases were defined as those requiring adjunctive therapy or IV immunoglobulin-resistant therapy.

RESULTS

The annual number of KD hospitalizations were stable from 2016 to 2019 (n = 1652, 1796, 1748, 1692, respectively) but decreased in 2020 (n = 1383). KD hospitalizations demonstrated seasonal variation with an annual peak between December and April. A second peak of KD admissions was observed in May 2020. The proportion of KD cases classified as severe increased to 40% in 2020 from 33% during the years 2016-2019 (P < 0.01). Median age in years increased from 2.9 in subjects hospitalized from 2016 to 2019 to 3.2 in 2020 (P = 0.002).

CONCLUSIONS

Compared with the previous 4 years, the annual number of pediatric KD admissions decreased, and children discharged with diagnostic codes for KD in 2020 were generally older and more likely to have severe morbidity possibly reflective of misdiagnosed multisystem inflammatory syndrome in children. Clinicians should be wary of a possible rise in KD rates in the postcoronavirus disease 2019 era as social distancing policies are lifted and other viruses associated with KD return.

Evaluation of a Kawasaki Disease Risk Model for Predicting Coronary Artery Aneurysms in a Japanese Population: An Analysis of Post RAISE

OBJECTIVES

To test the performance of the Son risk score, which was created to predict coronary artery abnormalities from baseline variables in North American patients with Kawasaki disease.

STUDY DESIGN

The dataset from Post RAISE, the largest prospective cohort study of Japanese patients with Kawasaki disease to date, was used for the present study. With high risk defined as ≥3 points, sensitivity, specificity, positive predictive value, and negative predictive value for coronary artery abnormality development were calculated. To evaluate the effect of each risk factor in the Son score, the OR and 95% CIs were calculated using logistic regression analysis with the presence of coronary artery abnormality at 1 month after disease onset.

RESULTS

Post RAISE enrolled 2628 consecutive patients with Kawasaki disease, and 304 patients had a high-risk score, of whom 15.1% showed coronary artery abnormality. At the cutoff ≥3 points, the sensitivity was 37.7%, and the specificity was 87.2%. The maximum z score at baseline ≥2.0 (OR 3.5, 95% CI 2.3-5.2) and age <6 months at disease onset (OR 3.2, 95% CI 1.9-5.4), were significantly associated with coronary artery abnormality development. However, a high concentration of C-reactive protein was not associated with coronary artery abnormality. The area under the receiver operating characteristic curve for the Son score was 0.65 (95% CI 0.59-0.71).

CONCLUSIONS

The Son score had insufficient sensitivity and good specificity in a Japanese cohort of patients with Kawasaki disease. Among the variables comprising the Son score, a large baseline z score and young age at disease onset were significant, independent predictors of coronary artery abnormality development.

Shaanxi Provincial Diagnosis and Treatment Center of Kawasaki Disease

Kawasaki disease is an acute, self-limited vascuitis that mainly occurs in children under 5 years of age. Intravenous immunoglobulin (IVIG) has become an effective treatment regimen, which can effectively reduce the incidence of cardiovascular complications. However, there has been no consensus or clinical guidelines for the application of IVIG in children with Kawasaki disease till now. This consensus is developed based on the current research progress on the application of IVIG in children with Kawasaki disease in China and overseas, with reference to the diagnosis and treatment guidelines for Kawasaki disease in China and overseas, and the opinions of experts. This consensus provides recommendations on the clinical application strategy of IVIG in children with Kawasaki disease and the prevention and treatment of its adverse reactions. Citation.

Live attenuated vaccine efficacy six months after intravenous immunoglobulin therapy for Kawasaki disease

BACKGROUND

Due to the presence of maternal passive antibodies, the measles vaccine is ineffective if administered before age 12-15 months. The optimal timing for administering a live attenuated vaccine (LAV) after intravenous immunoglobulin therapy (IVIG) for Kawasaki disease (KD) has not been fully investigated. The recommended interval between vaccination and IVIG therapy for KD differs by country. The present study aimed to evaluate efficacy of LAV six months after IVIG therapy for KD in Japan.

METHODS

The present, single-arm, prospective, interventional study included patients aged 6 months or older with no medical history of measles, rubella, varicella or mumps or vaccinations against these diseases. The subjects received these vaccinations for the first time at six months after IVIG therapy. Virus-specific IgG levels for each virus measured by EIA was examined at nine months after IVIG therapy. If the results were negative, the subjects received a booster vaccination at 12 months after IVIG therapy. The primary outcome was the prevalence of positivity for antibodies after the initial and booster vaccinations.

RESULTS

The present study enrolled 32 subjects, 31% of whom were female, with an average age of 10.8 (standard deviation 2.8) months at IVIG therapy. At six months after IVIG therapy, 9% and 6% of the subjects were seropositive for measles and varicella titers, respectively, but were seronegative for the mumps and rubella titers. The seroconversion rate for measles, mumps, rubella, and varicella after the initial vaccination was 88%, 6%, 78%, and 16%, respectively. The seroconversion rate after a booster vaccination was 100% for measles and rubella, 97% for mumps, and 77% for varicella.

CONCLUSIONS

The seroconversion rate was low for LAV at six months after a single dose of IVIG for KD, but seroconversion was achievable with a booster vaccination at 12 months.

CLINICAL TRIAL REGISTRATION

UMIN-CTR, UMIN000007174, https://upload.umin.ac.jp/cgi-open-bin/ctr/ctr_view.cgi?recptno=R000008452.

Z-score is a possible predictor of the risk of coronary artery lesion development in patients with Kawasaki disease in Japan

Risk factors for coronary artery lesion (CAL) development in patients with Kawasaki disease (KD) include male sex, age < 12 months, intravenous immunoglobulin (IVIG) resistance, and delayed diagnosis.. We aimed to explore the relationship between CAL development and Z-score. We enrolled 281 patients with KD who were treated with our protocol. Echocardiography was performed in three phases: pre-treatment (P1), post-treatment (P2), and 4 weeks after onset (P3). The highest Z-score of the right, left main, left anterior descending, and left circumflex coronary arteries was expressed as Zmax at each phase. P3-Zmax ≥ 2.5 represented CAL development. Clinical parameters, such as laboratory data and Z-scores, were retrospectively compared between patients with and without CAL development. Sixty-seven patients (23.8%) showed a P1-Zmax ≥ 2.0, and CAL development occurred in 21 patients (7.5%). Independent risk factors associated with CAL development were P1-Zmax, a ΔZmax (P2-Zmax - P1-Zmax) ≥ 1, male sex, < 12 months of age, and resistant to the first intravenous immunoglobulin (IVIG) administration (adjusted odds ratio [95% confidence interval]: 198 [1.01-3.92], 4.04 [1.11-14.7], 6.62 [1.33-33.04], 4.71 [1.51-14.68], 5.26 [1.62-17.13], respectively). Using receiver operating characteristic curve analysis, a P1-Zmax ≥ 1.43 detected CAL development with an area under the curve of 0.64 (sensitivity = 81.0%; specificity = 48.1%).Conclusion: Our results suggest that P1-Zmax and a ΔZmax (P2-Zmax - P1-Zmax) ≥ 1 may predict CAL development. What is Known: • KD is an acute vasculitis predominantly affecting the coronary artery of young children. • Although P1 Z-max ≥ 2.0 has been a predictor of CAL development, it has not yet been shown in Japan. What is New: • P1-Zmax and a ΔZmax ≥ 1 are presumably associated with CAL development. • In the ROC curve analysis, P1-Zmax ≥ 1.43 detected CAL development, a sensitivity (81%) and a specificity (48%). We need to consider intensified initial therapy for patients with these risk factors.

Correlation of Coronary Artery Abnormalities with Fever Pattern in Patients with Kawasaki Disease

OBJECTIVE

To investigate the incidence of coronary artery abnormalities (CAAs) by fever pattern after intravenous immunoglobulin (IVIG) therapy in patients with Kawasaki disease.

STUDY DESIGN

This retrospective cohort study included 172 patients with Kawasaki disease aged ≤12 years who underwent IVIG therapy and had no CAAs before treatment. Resistance to initial IVIG was defined as persistent fever ≥37.5 °C for ≥24 hours after therapy or the recurrence of Kawasaki disease after initial defervescence. The patients were divided into 3 groups: IVIG responders, nonresponders with persistent fever, and nonresponders with recurrent fever. CAAs were evaluated 2 or 4 weeks and 12 months after onset and were defined by a coronary artery z-score ≥2.5.

RESULTS

The incidence of CAAs within 12 months after onset was significantly higher in nonresponders with persistent fever (27%) compared with the other 2 groups. On multivariate logistic regression analysis, being a nonresponder with persistent fever was an independent risk factor for having CAAs within 12 months after the onset of Kawasaki disease (OR, 6.48; P = .007).

CONCLUSIONS

In patients with Kawasaki disease resistant to IVIG therapy, persistent fever, but not recurrent fever, was found to be a risk factor for the incidence of CAAs. Aggressive additional therapy may be beneficial to prevent CAA formation in patients with Kawasaki disease with persistent fever.

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.

Serum sodium level associated with coronary artery lesions in patients with Kawasaki disease

INTRODUCTION/OBJECTIVES

Hyponatremia is a potential risk factor for the development of coronary artery lesions (CALs) identified after acute Kawasaki disease (KD). However, the serum sodium distribution corresponding to the reference intervals differs between infants (< 1 year of age) and older children. We hypothesized the association of serum sodium level with CAL complications differs between infants and older patients with KD.

METHODS

We analyzed 21,610 population-based patients who developed KD throughout Japan during 2013-2014. We performed multivariable logistic regression analyses to evaluate the association between serum sodium and CAL complications. Additionally, we stratified the serum sodium distribution associated with CAL complications by infants and older patients.

RESULTS

CALs were identified in 158 (3.6%) infants and 302 (1.8%) older patients. Infants were more likely to develop CALs when within the normal sodium range compared with older patients (75% vs. 29%), whereas most older patients developed CALs with a sodium level lower than the reference interval. Serum sodium ≤ 130 mEq/L indicated significantly higher risk for development of CALs in both groups (adjusted odds ratio [95% confidence intervals] = 3.21 [1.65-6.25] in infants and 1.74 [1.18-2.57] in older patients).

CONCLUSIONS

Serum sodium distribution associated with CAL complications differed greatly between infants and older patients. Older patients developed CALs with sodium levels lower than the reference interval; however, among infants, hyponatremia was not necessarily a risk factor for developing coronary artery lesion. When considering risk assessments for CALs using serum sodium levels, infants with KD should be distinguished from older patients. Key Points • Hyponatremia is a potential risk factor for the development of coronary artery lesions (CALs) among patients with Kawasaki disease. • However, the serum sodium distribution corresponding to the reference intervals differs between infants (< 1 year of age) and older children. • Most infants developed CALs within the normal sodium range, whereas older patients developed at a range lower than the reference interval. • These findings highlight that when considering risk assessments for CALs using serum sodium levels, infants should be distinguished from older patients.

Kawasaki Disease and Vaccination: Prospective Case-Control and Case-Crossover Studies among Infants in Japan

The causal effects of vaccines on Kawasaki disease (KD) remain elusive. We aimed to examine the association between vaccines administered during infancy and the development of KD in Japan. We conducted a multicenter prospective case-control study using questionnaires and compared the vaccination status of infants (age: 6 weeks to 9 months) who developed KD (KD group; n = 102) and those who did not develop KD (non-KD group; n = 139). Next, we performed a case-crossover study of 98 cases in the KD group and compared the status of vaccinations between the case and control periods. We also compared the incidence of KD in children for each 5-year period before and after the addition of new vaccines (2012–2013) using data from the Nationwide Survey of KD. In the case-control study, the vaccination status of the KD and control groups did not differ to a statistically significant extent. Multivariable analysis of the vaccination status and patient backgrounds showed no significant association between vaccination and KD development. In the case-crossover study, the status of vaccinations during the case and control periods did not differ to a statistically significant extent. In the analysis of data from the Nationwide Survey of KD, the incidence of KD in children of ages subject to frequent vaccination showed no significant increases in the latter five years, 2014–2018. Based on these prospective analyses, we confirmed that vaccination in early infancy did not affect the risk of KD.

Seasonal Trends of Viral Prevalence and Incidence of Kawasaki Disease: A Korea Public Health Data Analysis

Kawasaki disease (KD) is a systemic vasculitis that occurs mainly in children under 5 years of age and is often accompanied by coronary artery lesions. The cause of the disease remains undetermined, but it is estimated to result from viral or bacterial infections. Certain studies have shown infection as a leading cause of KD. The purpose of this study was to investigate the relationship between KD incidence and viral infections in different pediatric age groups, using the Health Insurance Review and Assessment (HIRA) Open Access Big Data Platform, to confirm seasonal trends by analyzing monthly patterns. We investigated the HIRA data of KD patients (M30.3) who were treated with intravenous immunoglobulin from 2015 to 2018. Weekly virus positive detection rate data (PDR) for this period was obtained from the Korea Disease Control and Prevention Agency for human adenovirus (HAdV), human parainfluenza virus (HPIV), human respiratory syncytial virus (HRSV), influenza virus (IFV), human coronavirus (HCoV), human rhinovirus (HRV), human bocavirus (HBoV), human metapneumovirus (HMPV), rotavirus, norovirus, and astrovirus. We then analyzed the weekly/monthly virus PDR and its association with KD incidence, including monthly incidence patterns, and seasonal trends. Seasonal trend analysis of the virus PDR was performed using the time series analysis method through ARIMA (Autoregressive Integrated Moving Average). Correlations between KD incidence and PDR at 1- and 2-month intervals were analyzed using the Granger test. A total of 16,740 patients were diagnosed with KD during the study period, mainly young children, with a male-to-female ratio of 1.35. Specifically, 15,635 (93%) patients were under 5 years of age, with an incidence rate of 172.4/100,000 person-years. Annually, the cumulative number of cases per month was the highest in January, with an average of 469 cases, and was the lowest in September, with an average of 291 cases, although most were diagnosed with KD in winter (29.3%). Granger tests showed that PDR for HRSV, rotavirus, and norovirus were related with KD incidence by 1 month, while PDR for HRSV, HRV, rotavirus, and norovirus by 2 months. This study found that detection rates of respiratory and enteric viruses preceded KD by 1–2 months. Further research is needed to confirm the association between these viruses and KD.

All trans retinoic acid alleviates coronary stenosis by regulating smooth muscle cell function in a mouse model of Kawasaki disease

Coronary artery (CA) stenosis is a detrimental and often life-threatening sequela in Kawasaki disease (KD) patients with coronary artery aneurysm (CAA). Therapeutic strategies for these patients have not yet been established. All-trans-retinoic acid (atRA) is a modulator of smooth muscle cell functions. The purpose of this study was to investigate the effect of atRA on CA stenosis in a mouse model of KD. Lactobacillus casei cell wall extract (LCWE) was intraperitoneally injected into 5-week-old male C57BL/6 J mice to induce CA stenosis. Two weeks later, the mice were orally administered atRA (30 mg/kg) 5 days per week for 14 weeks (LCWE + atRA group, n = 7). Mice in the untreated group (LCWE group, n = 6) received corn oil alone. Control mice were injected with phosphate-buffered saline (PBS, n = 5). Treatment with atRA significantly suppressed CA inflammation (19.3 ± 2.8 vs 4.4 ± 2.8, p < 0.0001) and reduced the incidence of CA stenosis (100% vs 18.5%, p < 0.05). In addition, atRA suppressed the migration of human coronary artery smooth muscle cells (HCASMCs) induced by platelet-derived growth factor subunit B homodimer (PDGF-BB). In conclusion, atRA dramatically alleviated CA stenosis by suppressing SMC migration. Therefore, it is expected to have clinical applications preventing CA stenosis in KD patients with CAA.

Kawasaki disease and influenza-new lessons from old associations

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

Factors affecting the duration of coronary artery lesions in patients with the Kawasaki disease: a retrospective cohort study

BACKGROUND

Coronary artery lesions (CALs) are the most severe complication of Kawasaki disease (KD). Approximately 9-20% of the patients with KD develop CAL despite receiving regular treatment (intravenous immunoglobulin [IVIG] and aspirin). Some patients develop coronary aneurysms, leading to coronary artery stenosis or thrombosis, resulting in ischaemic heart disease and significantly affect the patients' lives. The purpose of this study was to investigate the factors associated with the duration of CAL in patients with KD.

METHODS

The data of 464 patients with KD and CAL admitted to the Children's Heart Centre, The Second Affiliated Hospital and Yuying Children's Hospital from 2010 to 2018 were retrospectively analysed. Demographic and clinical information and echocardiographic follow-up data were collected. Kaplan-Meier curves were used to estimate the overall CAL duration, and the log-rank test was used to compare statistical differences. Univariate and multivariate Cox regression models were used to identify variables related to the CAL duration.

RESULTS

The median CAL duration was 46 days (95% confidence interval: 41-54 days). CALs were observed in 61.5, 41.5, 33.3, 22.3, 10.3, and 7.7% of the patients at 1 month, 2 months, 3 months, 6 months, 1 year, and 2 years after the onset of KD, respectively. Univariate Cox regression model showed that sex (p = 0.016), rash symptoms (p = 0.035), delayed IVIG treatment (p = 0.022), CAL type (p < 0.001), degree of CAL (p < 0.001), white blood cell count before IVIG treatment (p = 0.019), and platelet count after IVIG treatment (p = 0.003) were statistically significant factors associated with the overall CAL duration. Multivariable Cox regression showed that delayed IVIG treatment (p = 0.020), multiple dilatations (p < 0.001), a greater degree of dilatation (p < 0.001), and higher platelet count after IVIG treatment (p = 0.007) were positively related to CAL duration.

CONCLUSIONS

CAL duration was affected by delayed IVIG treatment, type of CAL, degree of CAL, and platelet count after IVIG treatment. These factors should be monitored carefully during the follow-up and management of patients with KD and CAL.

Predictive model based on gene and laboratory data for intravenous immunoglobulin resistance in Kawasaki disease in a Chinese population

BACKGROUND

Here, we investigated the predictive efficiency of a newly developed model based on single nucleotide polymorphisms (SNPs) and laboratory data for intravenous immunoglobulin (IVIG) resistance in Kawasaki disease (KD) in a Chinese population.

METHODS

Data relating to children with KD were acquired from a single center between December 2015 and August 2019 and used to screen target SNPs. We then developed a predictive model of IVIG resistance using previous laboratory parameters. We then validated our model using data acquired from children with KD attending a second center between January and December 2019.

RESULTS

Analysis showed that rs10056474 GG, rs746994GG, rs76863441GT, rs16944 (CT/TT), and rs1143627 (CT/CC), increased the risk of IVIG-resistance in KD patients (odds ratio, OR > 1). The new predictive model, which combined SNP data with a previous model derived from laboratory data, significantly increased the area under the receiver-operator-characteristic curves (AUC) (0.832, 95% CI: 0.776-0.878 vs 0.793, 95%CI:0.734-0.844, P < 0.05) in the development dataset, and (0.820, 95% CI: 0.730-0.889 vs 0.749, 95% CI: 0.652-0.830, P < 0.05) in the validation dataset. The sensitivity and specificity of the new assay were 65.33% (95% CI: 53.5-76.0%) and 86.67% (95% CI: 80.2-91.7%) in the development dataset and 77.14% (95% CI: 59.9-89.6%) and 86.15% (95% CI: 75.3-93.5%) in the validation dataset.

CONCLUSION

Analysis showed that rs10056474 and rs746994 in the SMAD5 gene, rs76863441 in the PLA2G7 gene, and rs16944 or rs1143627 in the interleukin (IL)-1B gene, were associated with IVIG resistant KD in a Chinese population. The new model combined SNPs with laboratory data and improved the predictve efficiency of IVIG-resistant KD.

Intimal thickening and disruption of the media occur in the arterial walls of coronary arteries not associated with coronary arterial aneurysms in patients with Kawasaki disease

Background

Coronary artery aneurysm (CAA) is an important complication of Kawasaki disease (KD) that is associated with arterial structure damage. However, few studies have examined structural changes in coronary arteries that are not associated with CAA.

Methods

We examined coronary arteries in KD patients with CAAs who underwent follow-up coronary angiography (CAG) and optical coherence tomography (OCT). Coronary arterial branches with no abnormal findings during the most recent CAG were classified into two groups. Arteries with an acute-phase CAA that later regressed were classified as group R; arteries with no abnormal findings on either acute or convalescent phase CAG were classified as group N. Coronary arterial wall structural changes were compared between groups using OCT.

Results

Fifty-seven coronary arterial branches in 23 patients were evaluated by OCT. Thirty-six branches showed no abnormality during the most recent CAG. Both groups R and N comprised 18 branches. Maximum intimal thicknesses in groups R and N were 475 and 355 µm, respectively (p = 0.007). The incidences of media disruption were 100% and 67%, respectively (p = 0.02). Calcification, macrophage accumulation, and thrombus were not found in either group.

Conclusions

Intimal thickening and disruption of the media occur in coronary arteries with acute phase CAAs that later regress in the convalescent phase, as well as in arteries with normal CAG findings in the acute and convalescent phases.

Clinical Characteristics of Patients With Kawasaki Disease Whose Siblings Had the Same Disease

BACKGROUND

Some patients with Kawasaki disease (KD) have siblings who developed the same disease. Using a large-scale epidemiologic dataset, the present study aimed to determine the clinical characteristics of this population.

METHODS

We analyzed 89,725 patients diagnosed with KD during 2011-2018 who were registered in the nationwide Japanese KD survey database. Multivariable logistic regression analyses were performed to determine factors associated with sibling history of KD.

RESULTS

Of the 89,725 patients, 1777 (2%) had sibling history of KD. Annual prevalence ranged from 1.5% to 2.3% during the study period and showed a tendency toward an increasing trend. Patients with recurrent KD and parental history of KD were significantly associated with sibling history of KD (adjusted odds ratio [95% confidence interval] = 2.15 [1.82-2.54] and 2.64 [2.02-3.47], respectively). Although patients with a sibling history of KD were significantly associated with initial intravenous immunoglobulin treatment resistance (1.14 [1.02-1.28]), no significant association was found between sibling history and coronary artery abnormality development. Among patients with a sibling history of KD, male patients were less likely to have recurrent KD than female patients (0.68 [0.49-0.96]).

CONCLUSIONS

The significant association between sibling history and parental history may indicate genetic susceptibility to KD onset. Among those with a sibling history, recurrent KD was more likely to occur in female patients. Further studies focusing on this population may contribute toward identification of the cause of KD onset.

SARS-CoV-2-related MIS-C: A key to the viral and genetic causes of Kawasaki disease?

Multisystem inflammatory syndrome in children (MIS-C) emerged in April 2020 in communities with high COVID-19 rates. This new condition is heterogenous but resembles Kawasaki disease (KD), a well-known but poorly understood and clinically heterogenous pediatric inflammatory condition for which weak associations have been found with a myriad of viral illnesses. Epidemiological data clearly indicate that SARS-CoV-2 is the trigger for MIS-C, which typically occurs about 1 mo after infection. These findings support the hypothesis of viral triggers for the various forms of classic KD. We further suggest that rare inborn errors of immunity (IEIs) altering the immune response to SARS-CoV-2 may underlie the pathogenesis of MIS-C in some children. The discovery of monogenic IEIs underlying MIS-C would shed light on its pathogenesis, paving the way for a new genetic approach to classic KD, revisited as a heterogeneous collection of IEIs to viruses.

COVID-19 and multisystem inflammatory syndrome in children: A systematic review and meta-analysis

BACKGROUND

Multisystem inflammatory syndrome in children (MIS-C) associated with coronavirus disease 2019 has been increasingly recognized. However, the clinical features of MIS-C and the differences from Kawasaki disease remain unknown. The study aims to investigate the epidemiology and clinical course of MIS-C.

METHODS

PubMed and EMBASE were searched through August 30, 2020. Observational studies describing MIS-C were included. Data regarding demographic features, clinical symptoms, laboratory, echocardiography and radiology findings, treatments, and outcomes were extracted. Study-specific estimates were combined using one-group meta-analysis in a random-effects model.

RESULTS

A total of 27 studies were identified including 917 MIS-C patients. The mean age was 9.3 (95% confidence interval [CI], 8.4-10.1). The pooled proportions of Hispanic and Black cases were 34.6% (95% CI, 28.3-40.9) and 31.5% (95% CI, 24.8-38.1), respectively. The common manifestations were gastrointestinal symptoms (87.3%; 95% CI, 82.9-91.6) and cardiovascular involvement such as myocardial dysfunction (55.3%; 95% CI, 42.4-68.2), coronary artery aneurysms (21.7%; 95% CI, 12.8-30.1) and shock (65.8%; 95% CI, 51.1-80.4), with marked elevated inflammatory and cardiac markers. The majority of patients received intravenous immunoglobulin (81.0%; 95% CI, 75.0-86.9), aspirin (67.3%; 95% CI, 48.8-85.7), and corticosteroids (63.6%; 95% CI, 53.4-73.8) with a variety of anti-inflammatory agents. Although myocardial dysfunction improved in 55.1% (95% CI, 33.4-76.8) at discharge, the rate of extracorporeal membrane oxygenation use was 6.3% (95% CI, 2.8-9.8) and the mortality was 1.9% (95% CI, 1.0-2.8).

CONCLUSION

Our findings suggest that MIS-C leads to multiple organ failure, including gastrointestinal manifestations, myocardial dysfunction and coronary abnormalities, and has distinct features from Kawasaki disease.