A Comprehensive Update on Kawasaki Disease Vasculitis and Myocarditis

Platelets in vascular inflammation: fire-fighters or pyromaniacs?

PURPOSE OF REVIEW

In this review, we aim to highlight recent insights into the mechanisms through which platelets contribute to vascular inflammation. We will discuss how platelets interact with other cellular players in the vascular milieu, their role in shaping inflammatory responses, and the potential therapeutic implications of targeting platelet function in inflammatory vascular diseases.

RECENT FINDINGS

Platelets are essential components in the processes of hemostasis and thrombosis. Their role is now widely acknowledged as far more complex than merely acting as "band-aids" or helping to "clog a pipe". Platelets are now recognized as crucial mediators in inflammatory reactions, particularly in various diseases of the vasculature, where they contribute to the onset and progression of injury. Through their interactions with leukocytes, vascular cells, and by supporting the coagulation cascade, platelets are able to finely regulate the extent and intensity of vascular damage.

SUMMARY

Recent findings underscore the remarkable diversity and functionality of platelets in vascular diseases. Mechanistic studies in preclinical models reveal promising therapeutic opportunities, which require further validation before being translated into clinical practice.

Multisystem inflammatory syndrome in children and Kawasaki disease

This narrative review aims to analyze and compare the current literature on multisystem inflammatory syndrome in children (MIS-C) and Kawasaki disease (KD), with a focus on case definitions, clinical features, diagnostic approaches, treatment strategies, and outcomes. Through a comprehensive review of relevant studies, including screening titles, abstracts, and full-text articles, key similarities and differences were identified. Both MIS-C and KD involve immune system dysregulation and share clinical manifestations such as rash, gastrointestinal symptoms, and cardiovascular involvement, with treatments often centered around immunomodulatory therapies. However, significant differences were observed, particularly in terms of age distribution, demographic prevalence, clinical presentation, and diagnostic criteria, with KD primarily affecting younger children and being associated more prominently with coronary artery abnormalities. While both diseases raise concerns about severe cardiac involvement and the need for intensive care, their pathogenic mechanisms have not been fully understood. Ongoing research is critical to elucidating these mechanisms, refining diagnostic criteria, and optimizing therapeutic approaches to improve outcomes for affected children. This comparative analysis is essential for advancing the understanding of both conditions, as accurately distinguishing between MIS-C and KD has significant implications for clinical decision-making and patient management. Given their overlapping yet distinct clinical features, precise differentiation is critical for ensuring timely diagnosis, optimizing therapeutic strategies, and improving patient outcomes. The concern among pediatric patients stems from the potential for severe complications, particularly cardiac involvement, which underscores the need for heightened awareness, early recognition, and evidence-based treatment strategies to minimize long-term morbidity and mortality.

Establishment and validation of a nomogram for coronary artery lesions in children with Kawasaki disease

BACKGROUND

The nomogram is a powerful and robust tool in disease risk prediction that summarizes complex variables into a visual model that is interpretable with a quantified risk probability. In the current study, a nomogram was developed to predict the occurrence of coronary artery lesions (CALs) among patients with Kawasaki disease (KD). This is especially valuable in the early identification of the risk of CALs, which will lead to proper diagnosis and treatment to reduce their associated complications.

METHODS

Retrospective clinical data of 677 children diagnosed with KD who were treated in the Children's Hospital Affiliated with Shandong University were analyzed. All the participants were divided into the CAL group and no CAL group according to their coronary echocardiography results. Least absolute shrinkage and selection operator (LASSO) regression was applied for the identification of the most informative predictors of CAL. Based on this, a nomogram was developed for accurate risk estimation.

RESULTS

The data were divided into a training set and a validation set. Receiver operating characteristic analysis, calibration curves, and decision curve analysis all supported the high accuracy and clinical utility of this model. LASSO regression highlighted five key predictors: sodium, hemoglobin, platelet count, D-dimer, and cystatin C. A nomogram based on these predictors was established and successfully validated in both datasets. In the training set, the AUC was 0.819 and in the validation set it was 0.844. The C-index of the calibration curve in the training set was 0.820, while in the validation set it was 0.844. In the decision curve analysis, the predictive benefit of the model was greater than zero when the threshold probability was below 95% in the training set and below 92% in the validation set.

CONCLUSION

The predictive factors identified through the LASSO regression approach and the development of the nomogram are important contributions in this respect. This model had a high predictive accuracy and reliability for identifying high-risk children in the very early stage of disease with remarkable precision, laying the foundation for personalized treatment strategies and targeted treatment and providing a strong scientific basis for precise therapeutic intervention.

MRI Diagnosis of Coronary Artery Lesions in Children With Kawasaki Disease and Their Correlation With Inflammatory Factors

BACKGROUND

Ultrasonography (US), as a routine examination for evaluating coronary artery lesions (CAL) in children with Kawasaki disease (KD), has strong subjectivity and limitations. Non-contrast enhanced coronary magnetic resonance angiography (NCE-CMRA) is sensitive and reliable in displaying the segments of coronary arteries (CA).

PURPOSE

To evaluate the CA using NCE-CMRA, to compare NCE-CMRA with US, and to assess the correlation between KD-related inflammatory factors and the occurrence of CAL.

STUDY TYPE

Retrospective.

POPULATION

61 children with KD who had undergone NCE-CMRA. Ultimately, 52 cases were included (32 males and 20 females), with an average of 5.9 ± 0.3 years old.

FIELD STRENGTH/SEQUENCE

3-T, 3D balanced turbo field echo sequence.

ASSESSMENT

NCE-CMRA and US coronary visualization rates were compared in 41 children who were imaged with both techniques. Inflammatory factors were compared between CAL and normal coronary artery (NCA) subgroups. In the CAL group, correlations of these inflammatory factors with CAL parameters were investigated.

STATISTICAL TESTS

Comparison between groups was performed by the two independent samples t-test; the comparison of enumeration data between groups was performed by chi-square test. Receiver operating characteristic (ROC) curve analysis was performed to determine the sensitivity of inflammatory factors for detecting CAL. The correlation between CAL and inflammatory indexes was analyzed by multiple linear regression. A P value <0.05 was considered statistically significant.

RESULTS

NCE-CMRA visualized significantly more segments than US (76% vs. 46%). There were significant differences in PLT, CRP, ESR, and D-dimer between the CAL and NCA groups. ROC curve analysis showed that the sensitivities of these four indicators in diagnosing CAL were 39%, 44%, 72%, and 61%, respectively, at cut-off points of 562.5 × 109/L, 48.93 mg/L, 45.5 mm/h, and 0.5 mg/L, respectively.

DATA CONCLUSION

The combination of NCE-CMRA and inflammatory factors is helpful for the early diagnosis and disease severity of CAL in children with KD.

LEVEL OF EVIDENCE

3 TECHNICAL EFFICACY: Stage 2.

Unraveling the gut: the pivotal role of intestinal mechanisms in Kawasaki disease pathogenesis

Kawasaki disease (KD), an acute systemic vasculitis that primarily affects children under 5 years of age, is the leading cause of acquired heart disease in this age group. Recent studies propose a novel perspective on KD's etiology, emphasizing the gastrointestinal (GI) tract, particularly the role of gut permeability. This review delves into how disruptions in gut barrier function trigger systemic inflammatory responses, exacerbate vascular inflammation, and contribute to coronary artery aneurysms. Evidence suggests that children with KD often exhibit increased gut permeability, leading to an imbalance in gut immunity and subsequent gut barrier damage. These changes impact vascular endothelial cells, promoting platelet aggregation and activation, thereby advancing severe vascular complications, including aneurysms. Additionally, this review highlights the correlation between GI symptoms and increased resistance to standard treatments like intravenous immunoglobulin (IVIG), indicating that GI involvement may predict therapeutic outcomes. Advocating for a new paradigm, this review calls for integrated research across gastroenterology, immunology, and cardiology to examine KD through the lens of GI health. The goal is to develop innovative therapeutic interventions targeting the intestinal barrier, potentially revolutionizing KD management and significantly improving patient outcomes.

Kawasaki Disease: A Rare Case of a Non-pediatric Patient

Kawasaki disease (KD) is an inflammatory condition more common in children but rare in adults, where diagnosis can be challenging due to nonspecific symptoms. Early recognition is essential to prevent severe complications. We present the case of a 26-year-old male with adult-onset KD who initially presented with vague symptoms, resulting in diagnostic delays. The condition progressed to life-threatening cardiovascular complications, including coronary artery aneurysms, underscoring the critical need for prompt identification and management. Timely treatment with intravenous immunoglobulin and corticosteroids led to clinical improvement and prevention of further cardiac damage. This case highlights the importance of heightened clinical awareness of KD in adults and the necessity of a proactive diagnostic approach. Future research should aim to refine diagnostic criteria for adult KD and explore strategies for improving early detection and long-term cardiovascular outcomes in this rare population.

Diagnostic value of syndecan-1 for coronary artery lesions and correlation analysis of laboratory indicators in Kawasaki disease patients

BACKGROUND

To explore the application value of syndecan-1 (SDC-1) in the diagnosis of coronary artery lesions (CALs) in Kawasaki disease (KD) patients and the correlation of multiple laboratory indicators in KD patients.

METHODS

86 pediatric Kawasaki disease (KD) patients and 52 healthy controls admitted from January 2018 to December 2023 were retrospectively analyzed. Venous blood samples from KD patients were analyzed for white blood cells (WBC), platelets (PLT), C-reactive protein (CRP), interleukin-6 (IL-6), syndecan-1 (SDC-1), coagulation parameters, and lipid profiles. Correlations between these laboratory indicators were assessed. Receiver operating characteristic (ROC) curve analysis determined the diagnostic value of SDC-1 for coronary artery lesions (CALs) in KD patients. SDC-1 levels were further compared across different CAL severity groups.

RESULTS

The levels of ALT, AST, WBC, PLT, CRP, IL-6, and SDC-1 in the KD group were significantly higher than those in the control group (P < 0.05). Coagulation function analysis showed that APTT, TT and FIB levels were significantly increased in the KD group compared with the control group (P < 0.05). Lipid profile analysis revealed that TC, HDL-C, and ApoA1 were significantly decreased, whereas TG, LDL-C, and ApoB100 were significantly increased in the KD group (P < 0.05). Refractory KD patients exhibited significantly higher levels of ALT, AST, SDC-1, CRP, WBC, and TG compared to responsive KD patients (P < 0.05). Correlation analysis indicated a strong positive correlation between PLT and LDL-C (r = 0.227, P = 0.035) and between IL-6 and TG (r = 0.491, P = 0.000), while CRP was negatively correlated with ApoA1 (r = -0.265, P = 0.014). Among the 86 KD patients, 41 (47.67%) developed CALs, with 19 classified as mild, 15 as moderate, and 7 as severe. For predicting CALs among KD patients, the threshold of SDC-1 was identified as 5.5 ng/ml, with a sensitivity of 70.7%, specificity of 64.4%, positive predictive value of 65.91%, negative predictive value of 69.05%, and an AUC of 0.762 (95% confidence interval 0.662-0.861, P < 0.001). SDC-1 levels significantly differed among the CAL severity groups (P = 0.008), with higher levels observed in moderate compared to mild CALs, and in severe compared to moderate CALs.

CONCLUSION

In conclusion, SDC-1 has strong clinical value in the diagnosis of CALs in KD patients, and there is a close relationship between the levels of inflammatory factors, coagulation function and lipid levels in KD patients.

scRNA+TCR-seq reveals the pivotal role of dual receptor T lymphocytes in the pathogenesis of Kawasaki disease and during IVIG treatment

Introduction

Kawasaki disease (KD), a common cause of acquired heart disease in children in developed countries, is primarily treated with intravenous immunoglobulin (IVIG), but some children demonstrate IVIG resistance with increased coronary artery injury risk. T cells have been demonstrated to be involved in the pathogenesis of KD and its treatment with IVIG. However, the role and mechanism of dual TCR T lymphocytes in the occurrence of KD and IVIG therapy remain unclear.

Methods

This study, based on scRNA-seq combined with TCR-seq technology, clustered the peripheral blood mononuclear cells of 3 healthy controls and 6 KD patients before and after IVIG treatment. Comparative analysis was conducted to investigate the differences in the proportion of single/dual receptor T cells, the characteristics of CDR3 repertoires, cell types, and the expression of transcription factors among the three groups. The study aimed to explore the correlation between dual TCR T cells and KD as well as IVIG treatment.

Results

In our experimental results, we observed the presence of dual TCR T cells in all three groups. However, compared to the healthy control group and the IVIG-treated group, the KD patients before IVIG treatment exhibited a lower proportion of dual TCR T cells, with variability between samples, ranging from 4% to 15%. Notably, after IVIG treatment, the proportion of dual TCR T cells significantly increased, stabilizing above 12%, and these T cells also exhibited clonal expansion and a preference for V gene usage. In addition we found differences in dual TCR T cell subsets among the three groups, for example, IVIG treatment increases the proportion of dual TCR Treg cells, but it still remains below that of healthy control groups, significantly higher proportions of both dual TCR CD8 central and effector memory T cells in IVIG-treated KD patients, and differences in the expression of transcription factors between single and dual TCR T cells. These results suggest dual TCR T cells correlate with KD and IVIG treatment.

Conclusion

Dual TCR T lymphocytes, especially dual TCR CD8 T cells and Treg cells, play crucial roles in the pathogenesis of KD and during IVIG treatment, providing strong support for further elucidating KD pathogenesis and optimizing treatment strategies.

Platelets in Kawasaki disease: mediators of vascular inflammation

Kawasaki disease, a systemic vasculitis that affects young children and can result in coronary artery aneurysms, is the leading cause of acquired heart disease among children. A hallmark of Kawasaki disease is increased blood platelet counts and platelet activation, which is associated with an increased risk of developing resistance to intravenous immunoglobulin and coronary artery aneurysms. Platelets and their releasate, including granules, microparticles, microRNAs and transcription factors, can influence innate immunity, enhance inflammation and contribute to vascular remodelling. Growing evidence indicates that platelets also interact with immune and non-immune cells to regulate inflammation. Platelets boost NLRP3 inflammasome activation and IL-1β production by human immune cells by releasing soluble mediators. Activated platelets form aggregates with leukocytes, such as monocytes and neutrophils, enhancing numerous functions of these cells and promoting thrombosis and inflammation. Leukocyte-platelet aggregates are increased in children with Kawasaki disease during the acute phase of the disease and can be used as biomarkers for disease severity. Here we review the role of platelets in Kawasaki disease and discuss progress in understanding the immune-effector role of platelets in amplifying inflammation related to Kawasaki disease vasculitis and therapeutic strategies targeting platelets or platelet-derived molecules.

Incomplete Kawasaki disease with muscular weakness and bladder retention: a case report

BACKGROUND

Kawasaki disease (KD) is an acute systemic immune vasculitis affecting multiple organs and systems in children, and is prevalent in children under 5 years of age. Muscular weakness is a rare manifestation of KD, and only 11 pediatric patients with KD combined with muscular weakness have been reported, of which evidence of myositis was found in 2/3 of the patients, and 1/3 could not be explained by myositis, the mechanism of which is still unclear. Cases of KD combined with bladder retention are even more rare, and there has been only 1 case report of KD combined with bladder retention in a child with no previous underlying disease.

CASE PRESENTATION

We report a 22-month-old Asian child with incomplete Kawasaki disease (IKD) who initially presented with fever and progressive muscular weakness in the lower extremities, followed by the bladder and bowel retention abnormalities and rapid onset of heart failure, respiratory failure and shock. The child developed coronary artery ectasia (CAA) without the main clinical features of KD such as rash, conjunctival congestion, desquamation of the extremity endings, orofacial changes and enlarged lymph nodes in the neck. Creatine kinase and electromyography were normal. Temperature gradually normalized and muscle strength recovered slightly after intravenous immunoglobulin. The child could be helped to walk after 1 week of aspirin combined with steroid therapy.

CONCLUSIONS

We present the case of a 22-month-old child with IKD. The child began with progressive muscular weakness in the extremities, followed by the bladder and bowel retention abnormalities, and rapidly developed heart failure, respiratory failure, and shock. Despite early failure to detect the disease, the child recovered rapidly and had a favorable prognosis. KD comorbidities with muscular weakness as the main manifestation are uncommon. This is the first case report of IKD combined with both muscular weakness and bladder and bowel retention, which may provide clinicians with diagnostic and therapeutic ideas, as well as a basis for future exploration of the mechanisms of KD combined with muscular weakness or bladder and bowel retention abnormalities.

Long-term cardiovascular inflammation and fibrosis in a murine model of vasculitis induced by Lactobacillus casei cell wall extract

Background

Kawasaki disease (KD), an acute febrile illness and systemic vasculitis, is the leading cause of acquired heart disease in children in industrialized countries. KD leads to the development of coronary artery aneurysms (CAA) in affected children, which may persist for months and even years after the acute phase of the disease. There is an unmet need to characterize the immune and pathological mechanisms of the long-term complications of KD.

Methods

We examined cardiovascular complications in the Lactobacillus casei cell wall extract (LCWE) mouse model of KD-like vasculitis over 4 months. The long-term immune, pathological, and functional changes occurring in cardiovascular lesions were characterized by histological examination, flow cytometric analysis, immunofluorescent staining of cardiovascular tissues, and transthoracic echocardiogram.

Results

CAA and abdominal aorta dilations were detected up to 16 weeks following LCWE injection and initiation of acute vasculitis. We observed alterations in the composition of circulating immune cell profiles, such as increased monocyte frequencies in the acute phase of the disease and higher counts of neutrophils. We determined a positive correlation between circulating neutrophil and inflammatory monocyte counts and the severity of cardiovascular lesions early after LCWE injection. LCWE-induced KD-like vasculitis was associated with myocarditis and myocardial dysfunction, characterized by diminished ejection fraction and left ventricular remodeling, which worsened over time. We observed extensive fibrosis within the inflamed cardiac tissue early in the disease and myocardial fibrosis in later stages.

Conclusion

Our findings indicate that increased circulating neutrophil counts in the acute phase are a reliable predictor of cardiovascular inflammation severity in LCWE-injected mice. Furthermore, long-term cardiac complications stemming from inflammatory cell infiltrations in the aortic root and coronary arteries, myocardial dysfunction, and myocardial fibrosis persist over long periods and are still detected up to 16 weeks after LCWE injection.

[Role and mechanisms of CHI3L1 in coronary artery lesions in a mouse model of Kawasaki disease-like vasculitis]

OBJECTIVES

To explore the role and potential mechanisms of chitinase-3-like protein 1 (CHI3L1) in coronary artery lesions in a mouse model of Kawasaki disease (KD)-like vasculitis.

METHODS

Four-week-old male SPF-grade C57BL/6 mice were randomly divided into a control group and a model group, with 10 mice in each group. The model group mice were intraperitoneally injected with 0.5 mL of lactobacillus casei cell wall extract (LCWE) to establish a mouse model of KD-like vasculitis, while the control group mice were injected with an equal volume of normal saline. The general conditions of the mice were observed on the 3rd, 7th, and 14th day after injection. Changes in coronary artery tissue pathology were observed using hematoxylin-eosin staining. The level of CHI3L1 in mouse serum was measured by enzyme-linked immunosorbent assay. Immunofluorescence staining was used to detect the expression and localization of CHI3L1, von Willebrand factor (vWF), and α-smooth muscle actin (α-SMA) in coronary artery tissue. Western blot analysis was used to detect the expression of CHI3L1, vWF, vascular endothelial cadherin (VE cadherin), Caspase-3, B cell lymphoma-2 (Bcl-2), Bcl-2 associated X protein (Bax), nuclear factor κB (NF-κB), and phosphorylated NF-κB (p-NF-κB) in coronary artery tissue.

RESULTS

The serum level of CHI3L1 in the model group was significantly higher than that in the control group (P<0.05). Compared to the control group, the expression of CHI3L1 in the coronary artery tissue was higher, while the expression of vWF was lower in the model group. The relative expression levels of CHI3L1, Bax, Caspase-3, NF-κB, and p-NF-κB were significantly higher in the model group than in the control group (P<0.05). The relative expression levels of vWF, VE cadherin, and Bcl-2 were lower in the model group than in the control group (P<0.05).

CONCLUSIONS

In the LCWE-induced mouse model of KD-like vasculitis, the expression levels of CHI3L1 in serum and coronary arteries increase, and it may play a role in coronary artery lesions through endothelial cell apoptosis mediated by inflammatory reactions.

Identification of hub biomarkers and immune-related pathways participating in the progression of Kawasaki disease by integrated bioinformatics analysis

BACKGROUND

Kawasaki disease (KD) is a systemic vasculitis that commonly affects children and its etiology remains unknown. Growing evidence suggests that immune-mediated inflammation and immune cells in the peripheral blood play crucial roles in the pathophysiology of KD. The objective of this research was to find important biomarkers and immune-related mechanisms implicated in KD, along with their correlation with immune cells in the peripheral blood.

MATERIAL/METHODS

Gene microarray data from the Gene Expression Omnibus (GEO) was utilized in this study. Three datasets, namely GSE63881 (341 samples), GSE73463 (233 samples), and GSE73461 (279 samples), were obtained. To find intersecting genes, we employed differentially expressed genes (DEGs) analysis and weighted gene co-expression network analysis (WGCNA). Subsequently, functional annotation, construction of protein-protein interaction (PPI) networks, and Least Absolute Shrinkage and Selection Operator (LASSO) regression were performed to identify hub genes. The accuracy of these hub genes in identifying KD was evaluated using the receiver operating characteristic curve (ROC). Furthermore, Gene Set Variation Analysis (GSVA) was employed to explore the composition of circulating immune cells within the assessed datasets and their relationship with the hub gene markers.

RESULTS

WGCNA yielded eight co-expression modules, with one hub module (MEblue module) exhibiting the strongest association with acute KD. 425 distinct genes were identified. Integrating WGCNA and DEGs yielded a total of 277 intersecting genes. By conducting LASSO analysis, five hub genes (S100A12, MMP9, TLR2, NLRC4 and ARG1) were identified as potential biomarkers for KD. The diagnostic value of these five hub genes was demonstrated through ROC curve analysis, indicating their high accuracy in diagnosing KD. Analysis of the circulating immune cell composition within the assessed datasets revealed a significant association between KD and various immune cell types, including activated dendritic cells, neutrophils, immature dendritic cells, macrophages, and activated CD8 T cells. Importantly, all five hub genes exhibited strong correlations with immune cells.

CONCLUSION

Activated dendritic cells, neutrophils, and macrophages were closely associated with the pathogenesis of KD. Furthermore, the hub genes (S100A12, MMP9, TLR2, NLRC4, and ARG1) are likely to participate in the pathogenic mechanisms of KD through immune-related signaling pathways.

Adult Kawasaki disease: a rare and challenging diagnosis-a case report

Background

Kawasaki disease (KD) is an acute systemic vasculitis which predominantly occurs in childhood but rarely in adulthood. Diagnosis relies on the presence of typical clinical features; however, patients may present atypically, increasing the challenge of timely diagnosis for physicians.

Case summary

We report a case of a 40-year-old male presenting with persistent fever, rash, and unilateral neck swelling. Initial investigations were suggestive of necrotizing lymphadenitis, with a presumed infective aetiology. However, extensive microbiology and immunological investigations remained negative. Cardiac injury was evident with elevated troponin T and NT-proBNP; however, left ventricular systolic function was normal. After 4 days, clinical features consistent with KD were noted and the results of a lymph node biopsy supported this diagnosis. Despite timely treatment with intravenous immunoglobulins (IVIG) and high-dose aspirin, follow-up computed tomography (CT) coronary angiography demonstrated two sequential aneurysms (max 6 mm) in the right coronary artery, plus one small subtle aneurysm in the proximal left anterior descending artery (4 mm).

Discussion

Diagnosis of adult KD remains challenging, as symptoms often present sequentially over time rather than simultaneously and many of the clinical features necessary for diagnosis share commonality with other infectious disease processes.

Platelets exacerbate cardiovascular inflammation in a murine model of Kawasaki disease vasculitis

Kawasaki disease (KD) is the leading cause of acquired heart disease among children. Increased platelet counts and activation are observed during the course of KD, and elevated platelet counts are associated with higher risks of developing intravenous immunoglobulin resistance and coronary artery aneurysms. However, the role of platelets in KD pathogenesis remains unclear. Here, we analyzed transcriptomics data generated from the whole blood of patients with KD and discovered changes in the expression of platelet-related genes during acute KD. In the Lactobacillus casei cell wall extract (LCWE) murine model of KD vasculitis, LCWE injection increased platelet counts and the formation of monocyte-platelet aggregates (MPAs), upregulated the concentration of soluble P-selectin, and increased circulating thrombopoietin and interleukin 6 (IL-6). Furthermore, platelet counts correlated with the severity of cardiovascular inflammation. Genetic depletion of platelets (Mpl-/- mice) or treatment with an anti-CD42b antibody significantly reduced LCWE-induced cardiovascular lesions. Furthermore, in the mouse model, platelets promoted vascular inflammation via the formation of MPAs, which likely amplified IL-1B production. Altogether, our results indicate that platelet activation exacerbates the development of cardiovascular lesions in a murine model of KD vasculitis. These findings enhance our understanding of KD vasculitis pathogenesis and highlight MPAs, which are known to enhance IL-1B production, as a potential therapeutic target for this disorder.

Kawasaki disease in children: a retrospective cross-sectional study

Introduction

Kawasaki disease (KD) is a systemic vasculitis, seen mostly in children. Epidemiology of KD is dependent on geographical location and seasonality. Although many years have passed since the first report of KD, multiple related factors are still unknown.

Material and methods

We investigated the clinical, paraclinical, and therapeutic aspects of KD in Kerman, Iran by performing a retrospective, descriptive, cross-sectional study on all children hospitalized due to KD between 2007 and 2020.

Results

A total of 340 patients with mean ±SD age of 29.83 ±22.55 months participated in the study. Most of our patients were two to five years old. The male : female ratio was ~ 1.4 : 1. A few of our patients had a family history of KD or vasculitis (0.3%, 1.7%). Typical KD was more common by a large margin (316 patients with typical KD). More than half of our patients had a duration of hospitalization of under ten days. All of our patients were febrile. Hand/foot and lip/mouth changes were the second and third most common clinical findings in more than 60% of our patients. Other manifestations were conjunctivitis in 40%, skin rashes in 34.8%, gastrointestinal manifestations in 33.9%, and lymphadenopathy in 25.3%. Echocardiography revealed abnormalities in 78.6% of the participants; coronary artery aneurysm (CAA) was the most frequent (22.5%) and follow-up echocardiography revealed that all of them regressed within 6 months after treatment. The two laboratory tests with the highest ratio of abnormality were erythrocyte sedimentation rate (95%) and hemoglobin (83.3%). C-reactive protein and liver function tests were also abnormal in most patients. All of our patients received intravenous immunoglobulin and acetylsalicylic acid.

Conclusions

Kawasaki disease must be considered in every febrile child, especially those with risk factors, because timely diagnosis and treatment are essential to prevent complications. Health policies should focus on appropriate diagnosis and treatment to prevent the occurrence of sequelae.

Comparison of Clinical Manifestations of Kawasaki Disease According to SARS-CoV-2 Antibody Positivity

BACKGROUND

Kawasaki disease (KD) is the most common cause of acquired heart disease in paediatric patients, with infectious agents being the main cause. This study aimed to determine whether there are differences in the clinical manifestations of KD between patients with and without severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) antibodies.

METHODS

From January 1, 2021 to August 15, 2022, 82 patients with analysable echocardiographic data were diagnosed with KD. Twelve patients with multisystem inflammatory syndrome in children were excluded. Serologic tests were performed by chemiluminescence immunoassay for both the nucleocapsid (N) and the spike (S) proteins in blood samples. Among the 70 patients diagnosed with KD at Jeonbuk University Children's Hospital, the SARS-CoV-2 antibody test was performed in 41 patients.

RESULTS

The SARS-CoV-2 antibody test results for the N antigen were positive in 12 patients, while those for S protein were positive in 14 patients. N antigen SARS-CoV-2 antibody-positive KD was different from N antigen SARS-CoV-2 antibody-negative KD in terms of sex (male predominance in the positive group, 83.3% vs. female predominance in the negative group 62.1%, P = 0.008) and the incidence of refractory KD (41.7% vs. 10.3%, P = 0.034). The pro-B-type natriuretic peptide level was lower in the N-antigen SARS-CoV-2 antibody-positive KD group than that in the negative group (518.9 ± 382.6, 1,467.0 ± 2,417.6, P = 0.049). No significant differences in the echocardiographic findings between both groups were noted. In the multi-variable analysis, SARS-CoV-2 antibody (N antigen) was the only predictor of refractory KD (odds ratio, 13.70; 95% confidence interval, 1.63-115.44; P = 0.016).

CONCLUSION

High incidence of intravenous immunoglobulin-refractory KD may occur in up to 40% of the patients having recent history of coronavirus disease 2019. For patients having KD with N-type SARS-CoV-2 antibody positivity, adjunctive treatment, such as corticosteroids, can be considered as the first line of treatment.

Comparison of COVID-19 Vaccine-Associated Myocarditis and Viral Myocarditis Pathology

The COVID-19 pandemic has led to significant loss of life and severe disability, justifying the expedited testing and approval of messenger RNA (mRNA) vaccines. While found to be safe and effective, there have been increasing reports of myocarditis after COVID-19 mRNA vaccine administration. The acute events have been severe enough to require admission to the intensive care unit in some, but most patients fully recover with only rare deaths reported. The pathways involved in the development of vaccine-associated myocarditis are highly dependent on the specific vaccine. COVID-19 vaccine-associated myocarditis is believed to be primarily caused by uncontrolled cytokine-mediated inflammation with possible genetic components in the interleukin-6 signaling pathway. There is also a potential autoimmune component via molecular mimicry. Many of these pathways are similar to those seen in viral myocarditis, indicating a common pathophysiology. There is concern for residual cardiac fibrosis and increased risk for the development of cardiomyopathies later in life. This is of particular interest for patients with congenital heart defects who are already at increased risk for fibrotic cardiomyopathies. Though the risk for vaccine-associated myocarditis is important to consider, the risk of viral myocarditis and other injury is far greater with COVID-19 infection. Considering these relative risks, it is still recommended that the general public receive vaccination against COVID-19, and it is particularly important for congenital heart defect patients to receive vaccination for COVID-19.

Clinical characteristics and short-term outcomes of multisystem inflammatory syndrome in a country with a high prevalence of KD

BACKGROUND

The COVID-19 pandemic has spread continuously. Multisystem inflammatory syndrome in children (MIS-C), like Kawasaki disease (KD), is a potentially severe illness in children that appears to be a delayed, post-infectious complication of COVID-19. However, based on the relatively low MIS-C prevalence and high KD prevalence in Asian children, the clinical features of MIS-C are not fully recognized, especially after the spread of the Omicron variant. Here, we aimed to identify the clinical characteristics of MIS-C in a country with high KD prevalence.

METHODS

We retrospectively analyzed 98 children diagnosed with KD and MIS-C admitted to Jeonbuk National University Hospital between January 1, 2021, and October 15, 2022. Twenty-two patients were diagnosed with MIS-C, following CDC diagnostic criteria for MIS-C. We reviewed medical records for clinical features, laboratory findings, and echocardiography.

RESULTS

Age, height, and weight were higher for patients with MIS-C than for those with KD. Lymphocytes percentage was lower, and the segmented neutrophil percentage was higher in the MIS-C group. The inflammation marker C-reactive protein was higher in the MIS-C group. Prothrombin time was prolonged in the MIS-C group. Albumin level was lower in the MIS-C group. The MIS-C group had lower potassium, phosphorus, chloride, and total calcium. Twenty-five percent of patients diagnosed with MIS-C had positive RT-PCR, and all the patients were N-type SARS-CoV-2 antibody-positive. Albumin ≤3.85 g/dl effectively predicted MIS-C. Regarding echocardiography, the right coronary artery z-score, the absolute value of apical 4-chamber left ventricle longitudinal strain, and the ejection fraction (EF) was significantly lower in the MIS-C group. A month after diagnosis using echocardiographic data, all coronary artery z-scores had reduced significantly. EF and fractional shortening (FS) also improved one month after diagnosis.

CONCLUSION

Albumin values can differentiate MIS-C and KD. In addition, a decrease in the absolute LV longitudinal strain value, EF, and FS was observed in the MIS-C group using echocardiography. Coronary artery dilatation was not evident at the initial diagnosis; however, a change in coronary artery size, EF, and FS was observed on follow-up echocardiography a month after diagnosis.

[Clinical experience in the treatment of incomplete Kawasaki disease with no response to intravenous immunoglobulin: a case report]

This article reports a case of incomplete Kawasaki disease with no response to intravenous immunoglobulin (IVIG). A girl, aged 1 year, had the symptoms of fever, rash, finger desquamation, and coronary artery ectasia. She still had fever at 36 hours after the first dose of IVIG treatment, and her temperature returned to normal after the second dose of IVIG treatment. The follow-up after 1 month showed that the coronary artery diameter returned to normal. This article summarizes the experience in the treatment of incomplete Kawasaki disease with no response to IVIG in order to reduce the incidence of coronary artery damage.

The Role of Host-Cellular Responses in COVID-19 Endothelial Dysfunction

SARS-CoV2, Severe acute respiratory syndrome coronavirus 2, is a novel member of the human coronavirus family that has recently emerged worldwide to cause COVID-19 disease. COVID-19 disease has been declared a worldwide pandemic with over 270 million total cases, and >5 million deaths as of this writing. Although co-morbidities and preexisting conditions have played a significant role in the severity of COVID-19, the hallmark feature of severe disease associated with SARS-CoV2 is respiratory failure. Recent findings have demonstrated a key role for endothelial dysfunction caused by SARS-CoV2 in these clinical outcomes, characterized by endothelial inflammation, the persistence of a pro-coagulative state, and major recruitment of leukocytes and other immune cells to localized areas of endothelial dysfunction. Though it is generally recognized that endothelial impairment is a major contributor to COVID-19 disease, studies to examine the initial cellular events involved in triggering endothelial dysfunction are needed. In this article, we review the general strategy of pathogens to exploit endothelial cells and the endothelium to cause disease. We discuss the role of the endothelium in COVID-19 disease and highlight very recent findings that identify key signaling and cellular events that are associated with the initiation of SARS-CoV2 infection. These studies may reveal specific molecular pathways that can serve as potential means of therapeutic development against COVID-19 disease.

Long-term effect of SARS-CoV-2 infection on cardiovascular outcomes and all-cause mortality

Since the very beginning of the coronavirus disease 2019 (COVID-19) pandemic in early 2020, it was evident that patients with cardiovascular disease (CVD) were at an increased risk of developing severe illness, and complications spanning cerebrovascular disorders, dysrhythmias, acute coronary syndrome, ischemic and non-ischemic heart disease, pericarditis, myocarditis, heart failure, thromboembolic disease, stroke, and death. Underlying these was excessive systemic inflammation and coagulopathy due to SARS-COV-2 infection, the effects of which also continued long-term as evidenced by post-COVID-19 cardiovascular complications. The acute and chronic cardiovascular effects of COVID-19 occurred even among those who were not hospitalized and had no previous CVD or those with mild symptoms. This comprehensive review summarizes the current understanding of molecular mechanisms triggered by the SARS-CoV-2 virus on various cells that express the angiotensin-converting enzyme 2, leading to endothelial dysfunction, inflammation, myocarditis, impaired coagulation, myocardial infarction, arrhythmia and a multisystem inflammatory syndrome in children or Kawasaki-like disease.

Inflammatory responses in SARS-CoV-2 associated Multisystem Inflammatory Syndrome and Kawasaki Disease in children: An observational study

Multisystem Inflammatory Syndrome in Children (MIS-C) is a severe inflammatory disease in children related to SARS-CoV-2 with multisystem involvement including marked cardiac dysfunction and clinical symptoms that can resemble Kawasaki Disease (KD). We hypothesized that MIS-C and KD might have commonalities as well as unique inflammatory responses and studied these responses in both diseases. In total, fourteen children with MIS-C (n=8) and KD (n=6) were included in the period of March-June 2020. Clinical and routine blood parameters, cardiac follow-up, SARS-CoV-2-specific antibodies and CD4+ T-cell responses, and cytokine-profiles were determined in both groups. In contrast to KD patients, all MIS-C patients had positive Spike protein-specific CD3+CD4+ T-cell responses. MIS-C and KD patients displayed marked hyper-inflammation with high expression of serum cytokines, including the drug-targetable interleukin (IL)-6 and IFN-γ associated chemokines CXCL9, 10 and 11, which decreased at follow-up. No statistical differences were observed between groups. Clinical outcomes were all favourable without cardiac sequelae at 6 months follow-up. In conclusion, MIS-C and KD-patients both displayed cytokine-associated hyper-inflammation with several high levels of drug-targetable cytokines.

Role of Endomyocardial Biopsy in Diagnostics of Myocarditis

Endomyocardial biopsy as the cornerstone of diagnostics has been re-evaluated throughout the years, leaving unanswered questions on the precedence of it. The reported incidence of myocarditis has increased during the pandemic of coronavirus disease 2019 (COVID-19), reinforcing discussions on appropriate diagnostics of myocarditis. By analysis of evidence-based literature published within the last demi-decade, we aimed to summarize the most recent information in order to evaluate the current role of endomyocardial biopsy in diagnostics and management of myocarditis. For the most part, research published over the last five years showed ongoing uncertainty regarding the use, informativeness, safety and necessity of performing a biopsy. Special circumstances, such as fulminant clinical course or failure to respond to empirical treatment, were reconfirmed as justified indications, with a growing applicability of non-invasive diagnostic approaches for most other cases. We concluded that endomyocardial biopsy, if performed properly and with adjunct diagnostic methods, holds a critical role for treatment correction in specific histological subtypes of myocarditis and for differential diagnosis between immune-mediated myocarditis and secondary infections due to immunosuppressive treatment. A high level of possible misdiagnosing was detected, indicating the need to review terminology used to describe findings of myocardial inflammation that did not meet Dallas criteria.

Evaluation of left ventricular myocardial stratified strain in patients with Kawasaki disease using two-dimensional speckle tracking imaging

Kawasaki disease (KD) is an acute autoimmune self-limited disease of unknown etiology. We aimed to evaluate the left ventricular myocardial stratified strains in children with KD in different stages using two-dimensional speckle tracking imaging, and to find the index that can early predict myocardial function injury in children with KD. A total of 73 children with KD were divided into acute, convalescent, and chronic stages according to the disease course. All children had no coronary artery damage. Further, 64 normal children were selected as the control group. The longitudinal and circumferential strain peaks of each myocardium were recorded, and the left ventricular global longitudinal strain (LVGLS), global circumferential strain (LVGCS), and transmural gradient between endocardium and epicardium (ΔGLS, ΔGCS) were calculated. Compared with the control group, LVGLS, GLS-Endo, GLS-Mid, GLS-Epi, and ΔGLS decreased in acute KD; LVGLS, GLS-Endo, GLS-Mid, GLS-Epi, ΔGLS, LVGCS, GCS-Mid, and GCS-Epi decreased in the convalescent stage; and only GLS-Endo was lower in children with chronic KD (P < 0.05). ROC curve was used to calculate the stratified strain parameters so as to predict left ventricular systolic function in children with acute KD; the area under the LVGLS curve was the largest (AUC = 0.953, P < 0.001). When the cutoff value of LVGLS was −19.89%, the sensitivity and specificity were 95.8% and 83.2%, respectively.

Multisystem Inflammatory Syndrome in Children and Long COVID: The SARS-CoV-2 Viral Superantigen Hypothesis

Multisystem inflammatory syndrome in children (MIS-C) is a febrile pediatric inflammatory disease that may develop weeks after initial SARS-CoV-2 infection or exposure. MIS-C involves systemic hyperinflammation and multiorgan involvement, including severe cardiovascular, gastrointestinal (GI) and neurological symptoms. Some clinical attributes of MIS-C-such as persistent fever, rashes, conjunctivitis and oral mucosa changes (red fissured lips and strawberry tongue)-overlap with features of Kawasaki disease (KD). In addition, MIS-C shares striking clinical similarities with toxic shock syndrome (TSS), which is triggered by bacterial superantigens (SAgs). The remarkable similarities between MIS-C and TSS prompted a search for SAg-like structures in the SARS-CoV-2 virus and the discovery of a unique SAg-like motif highly similar to a Staphylococcal enterotoxin B (SEB) fragment in the SARS-CoV-2 spike 1 (S1) glycoprotein. Computational studies suggest that the SAg-like motif has a high affinity for binding T-cell receptors (TCRs) and MHC Class II proteins. Immunosequencing of peripheral blood samples from MIS-C patients revealed a profound expansion of TCR β variable gene 11-2 (TRBV11-2), which correlates with MIS-C severity and serum cytokine levels, consistent with a SAg-triggered immune response. Computational sequence analysis of SARS-CoV-2 spike further identified conserved neurotoxin-like motifs which may alter neuronal cell function and contribute to neurological symptoms in COVID-19 and MIS-C patients. Additionally, autoantibodies are detected during MIS-C, which may indicate development of post-SARS-CoV-2 autoreactive and autoimmune responses. Finally, prolonged persistence of SARS-CoV-2 RNA in the gut, increased gut permeability and elevated levels of circulating S1 have been observed in children with MIS-C. Accordingly, we hypothesize that continuous and prolonged exposure to the viral SAg-like and neurotoxin-like motifs in SARS-CoV-2 spike may promote autoimmunity leading to the development of post-acute COVID-19 syndromes, including MIS-C and long COVID, as well as the neurological complications resulting from SARS-CoV-2 infection.

Targeting IRE1 endoribonuclease activity alleviates cardiovascular lesions in a murine model of Kawasaki disease vasculitis

Kawasaki disease (KD) is the leading cause of non-congenital heart disease in children. Studies in mice and humans propound the NLRP3-IL-1β pathway as the principal driver of KD pathophysiology. Endoplasmic reticulum (ER) stress can activate the NLRP3 inflammasome, but the potential implication of ER stress in KD pathophysiology has not been investigated. We used human patient data and the Lactobacillus casei cell wall extract (LCWE) murine model of KD vasculitis to characterize the impact of ER stress on the development of cardiovascular lesions. KD patient transcriptomics and single-cell RNA sequencing of the abdominal aorta from LCWE-injected mice revealed changes in the expression of ER stress genes. Alleviating ER stress genetically, by conditional deletion of Inositol Requiring Enzyme-1 (IRE1) in myeloid cells, or pharmacologically, by inhibition of IRE1 endoribonuclease (RNase) activity, led to significant reduction of LCWE-induced cardiovascular lesion formation as well as reduced caspase-1 activity and IL-1β secretion. These results demonstrate the causal relationship of ER stress to KD pathogenesis, and highlight IRE1 RNase activity as a potential new therapeutic target.

Mitochondrial Quality Surveillance: Mitophagy in cardiovascular health and disease

Selective autophagy of mitochondria, known as mitophagy, is a major quality control pathway in the heart that is involved in removing unwanted or dysfunctional mitochondria from the cell. Baseline mitophagy is critical for maintaining fitness of the mitochondrial network by continuous turnover of aged and less-functional mitochondria. Mitophagy is also critical in adapting to stress associated with mitochondrial damage or dysfunction. The removal of damaged mitochondria prevents reactive oxygen species-mediated damage to proteins and DNA and suppresses activation of inflammation and cell death. Impairments in mitophagy are associated with the pathogenesis of many diseases, including cancers, inflammatory diseases, neurodegeneration, and cardiovascular disease. Mitophagy is a highly regulated and complex process that requires the coordination of labeling dysfunctional mitochondria for degradation while simultaneously promoting de novo autophagosome biogenesis adjacent to the cargo. In this review, we provide an update on our current understanding of these steps in mitophagy induction and discuss the physiological and pathophysiological consequences of altered mitophagy in the heart.

Effect of COVID-19 on Kawasaki Disease: Decrease Age of Onset and Increase Skin Manifestation

BACKGROUND

Kawasaki Disease (KD) is the most common childhood vasculitis and cause of acquired heart disease for no apparent reason. There is some evidence indicating infectious agents as possible triggers for KD. During the COVID-19 pandemic, vasculitis has been a presentation of COVID-19 in children. We performed this study to assess the association between KD and COVID-19. We evaluated KD hospitalized children during February to September 2020 for COVID-19 (group one) and compared their demographic, clinical, laboratory, and echocardiographic findings with KD patients from the same period time in 2019 (group two). We also compared the same data in COVID-19 positive and COVID-19 negative KD patients in 2020 pandemic period in Shiraz Namazi referral hospital at southwest of Iran.

RESULTS

Thirty-two patients in group one compared with 44 patients in group two. Sixty-eight percent of group one KD patients were positive for COVID-19 during the pandemic period. KD Age of onset in the group one was lower than group two (4.38 years VS 5.5 years, P-value = 0.044). There was no difference in the demographic, clinical, laboratory, and echocardiographic features of the patients during and before the COVID-19 pandemic (p-value > 0.05). Moreover, Comparing COVID-19 positive and negative the incidence of rash was higher within COVID-19 positive cases (p < 0.05), and coronary artery abnormalities were more prevalent in COVID-19 negative cases (p < 0.05).

CONCLUSION

Admission rate of KD was almost similar during the COVID-19 pandemic but 68% of KD admitted patient were COVID-19 positive. Age of onset for KD during the COVID-19 pandemic was lower and skin manifestation was higher than the same period time in last year.

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.

Autophagy-mitophagy induction attenuates cardiovascular inflammation in a murine model of Kawasaki disease vasculitis

Kawasaki disease (KD) is the leading cause of acquired heart disease among children. Murine and human data suggest that the NLRP3-IL-1β pathway is the main driver of KD pathophysiology. NLRP3 can be activated during defective autophagy/mitophagy. We used the Lactobacillus casei cell wall extract (LCWE) murine model of KD vasculitis, to examine the role of autophagy/mitophagy on cardiovascular lesion development. LCWE-injected mice had impaired autophagy/mitophagy and increased levels of ROS in cardiovascular lesions, together with increased systemic 8-OHdG release. Enhanced autophagic flux significantly reduced cardiovascular lesions in LCWE-injected mice, whereas autophagy blockade increased inflammation. Vascular smooth muscle cell specific deletion of Atg16l1 and global Parkin-/- significantly increased disease formation, supporting the importance of autophagy/mitophagy in this model. Ogg1-/- mice had significantly increased lesions with increased NLRP3 activity, whereas treatment with MitoQ, reduced vascular tissue inflammation, ROS production and systemic 8-OHdG release. Treatment with MN58b or Metformin (increasing AMPK and reducing ROS), resulted in decreased disease formation. Our results demonstrate that impaired autophagy/mitophagy and ROS-dependent damage exacerbate the development of murine KD vasculitis. This pathway can be efficiently targeted to reduce disease severity. These findings enhance our understanding of KD pathogenesis and identify novel therapeutic avenues for KD treatment.

Similarities and Differences Between COVID-19-Related Multisystem Inflammatory Syndrome in Children and Kawasaki Disease

In December 2019, the first case of coronavirus disease (COVID-19) was first reported in Wuhan, China. As of March 2021, there were more than 120 million confirmed cases of COVID-19 and 2.7 million deaths. The COVID-19 mortality rate in adults is around 1-5%, and only a small proportion of children requires hospitalization and intensive care. Recently, an increasing number of COVID-19 cases in children have been associated with a new multisystem inflammatory syndrome. Its clinical features and laboratory characteristics are similar to those of Kawasaki disease (KD), KD shock syndrome, and toxic shock syndrome. However, this new disorder has some distinct clinical features and laboratory characteristics. This condition, also known as multisystem inflammatory syndrome in children (MIS-C) associated with COVID-19, has been observed mostly in Europe and the United States. This emerging phenomenon has raised the question of whether this disorder is KD triggered by SARS-CoV-2 or a syndrome characterized by multisystem inflammation that mimics KD. This narrative review is to discuss the differences between MIS-C and KD with the aim of increasing pediatricians' awareness of this new condition and guide them in the process of differential diagnosis.

Early anti IL-1 treatment replaces steroids in refractory Kawasaki disease: clinical experience from two case reports

Refractory Kawasaki disease (KD) is related to a major risk of coronary arteries abnormalities and its treatment is not standardized. In this regard, anakinra (ANA), an interleukin (IL)-1 receptor antagonist, represents an emerging therapeutic option. We report two cases of children, diagnosed with KD, nonresponsive to two doses of intravenous immunoglobulins, successfully treated with ANA, without a prior use of steroids. Patient 2 developed a coronary dilatation, that improved significantly after ANA therapy. Our experience highlights IL-1 blockade effectiveness in reducing KD inflammation and suggests ANA adoption as second-line therapy, with a timesaving and steroid-sparing strategy. Our results, combined with the evidence of the IL-1 key role in KD and coronary arteritis pathogenesis and to the recent clinical evidence reported by the KAWAKINRA trial, encourage an earlier recourse to ANA in patients with refractory KD, in order to fight inflammation, and to treat and prevent the development of coronary artery aneurysms. Further studies are needed to better define the place of IL-1 blockade in KD step-up treatment.

Is there an association between intravenous immunoglobulin resistance and coronary artery lesion in Kawasaki disease?-Current evidence based on a meta-analysis

Background

Coronary artery lesion (CAL) caused by Kawasaki disease (KD) is a leading cause of acquired heart disease in children. Initial treatment of intravenous immunoglobulin (IVIG) can reduce the incidence of CAL. Although most of the current studies have shown a certain correlation between CAL and IVIG resistance, the conclusions are not completely consistent. Thus, we performed this meta-analysis to evaluate the association between IVIG resistance and CAL in KD.

Methods

PubMed, EMBASE, the Cochrane Central Register of Controlled Trials, and China National Knowledge Infrastructure through April 21, 2020 were searched to detect relevant studies. Data analysis was performed with STATA 15.1.

Results

A total of 53 relevant studies were eligible to this analysis, including 30312 KD patients, of which 4750 were IVIG resistance and 25562 were responders. There was a significant difference found between IVIG resistance and IVIG response groups in the incidence of CAL (P < 0.001, odds ratio (OR), 3.89; 95% confidence interval (CI) (3.18, 4.75)). The heterogeneity test results showed that the I² value was 74.8%. The meta-regression analysis showed that the study regions might be the sources of heterogeneity. The subgroup analysis suggested that the incidence of CAL in the IVIG resistance group was still higher than that in the IVIG response group under different regions, IVIG resistance diagnostic criteria, CAL diagnostic criteria, and study types. Meanwhile, the sensitivity analysis did not find any significant impact from every single study.

Conclusions

This is the first meta-analysis to reveal the incidence of CAL was associated with IVIG resistance in KD patients. Further well-designed studies with uniform criteria are needed to evaluate the incidence of CAL in IVIG resistant patients.

Post-COVID-19 Outbreak of Severe Kawasaki-like Multisystem Inflammatory Syndrome in Children

With the continuation of the second wave of a novel coronavirus disease (COVID-19), which is likely to be even more devastating, there are several associated health problems. COVID-19 is usually mild and non-fatal in children. However, in rare cases, children could severely be affected, and clinical manifestations may differ from adults. A multisystem inflammatory syndrome in children (MIS-C) is a rare but serious complication associated with COVID-19, initiated by an overactive immune response in kids that usually hits weeks after exposure to the COVID-19. MIS-C is a disorder in which inflammation could occur in different parts of the body. The disease puts pressure on the heart, as blood vessels leading towards the heart get inflamed and incapable of carrying adequate blood, hence producing cardiac complications in children hospitalised with MIS-C. The problem seems to be associated with COVID-19 in children; however, the association between MIS-C and COVID-19 is still unidentified. There is very little understanding of what triggers the MIS-C, which necessitates a rigorous mapping of the disease and associated risk elements for better disease management and navigating through this crisis.

Characteristics of pediatric multi-system inflammatory syndrome (PMIS) associated with COVID-19: a meta-analysis and insights into pathogenesis

OBJECTIVES

There was an outbreak of pediatric multisystem inflammation syndrome (PMIS) was observed in multiple countries recently, and this syndrome was suspected to be associated with SARS-CoV-2 infection. At present, there is still no standardized diagnostic criteria and treatment regimen for PMIS, while the etiology and pathogenesis still remain unclear.

METHODS

We performed a systematic review on PubMed and Embase from the time of inception to June 24th 2020 in order to find relevant cases.

RESULTS

There are seven studies included, and 80% of patients suffered persistent fever and 90% appeared gastrointestinal symptoms. IgG antibody against SARS-CoV-2 was positive on 81% of patients, while 37% of the patients were nucleic acid positive. C-reactive protein, IL-6 and PCT were elevated and intravenous immunoglobulin was a routine treatment for PMIS. There were more than half of patients required inotropic supports and mechanical ventilation were applied to 33% of patients. The median length of hospital stay was 10.66 days and 74% had admitted to accept intensive care.

CONCLUSIONS

Our study documented three common types of PMIS clinical presentation: persistent fever and gastrointestinal symptoms, shocked with heart dysfunction and Kawasaki disease-like syndrome. PMIS patients proved with a marked inflammatory state were possibly associated with SARS-CoV-2 infection.

MicroRNA-223 Regulates the Development of Cardiovascular Lesions in LCWE-Induced Murine Kawasaki Disease Vasculitis by Repressing the NLRP3 Inflammasome

Kawasaki disease (KD), an acute febrile childhood illness and systemic vasculitis of unknown etiology, is the leading cause of acquired heart disease among children. Experimental data from murine models of KD vasculitis and transcriptomics data generated from whole blood of KD patients indicate the involvement of the NLRP3 inflammasome and interleukin-1 (IL-1) signaling in KD pathogenesis. MicroRNA-223 (miR-223) is a negative regulator of NLRP3 activity and IL-1β production, and its expression has been reported to be upregulated during acute human KD; however, the specific role of miR-223 during KD vasculitis remains unknown. Here, using the Lactobacillus casei cell wall extract (LCWE) murine model of KD vasculitis, we demonstrate increased miR-223 expression in LCWE-induced cardiovascular lesions. Compared with control WT mice, LCWE-injected miR-223-deficient mice (miR223 ^-/y ) developed more severe coronary arteritis and aortitis, as well as more pronounced abdominal aorta aneurysms and dilations. The enhanced cardiovascular lesions and KD vasculitis observed in LCWE-injected miR223 ^-/y mice correlated with increased NLRP3 inflammasome activity and elevated IL-1β production, indicating that miR-223 limits cardiovascular lesion development by downmodulating NLRP3 inflammasome activity. Collectively, our data reveal a previously unappreciated role of miR-223 in regulating innate immune responses and in limiting KD vasculitis and its cardiovascular lesions by constraining the NLRP3 inflammasome and the IL-1β pathway. These data also suggest that miR-223 expression may be used as a marker for KD vasculitis pathogenesis and provide a novel therapeutic target.

Pharmacotherapy of Acute COVID-19 Infection and Multisystem Inflammatory Syndrome in Children: Current State of Knowledge

Background: The Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) pandemic is a health care emergency across the world. Although mitigation measures, such as social distancing and face masks, have attempted to slow the spread of the infection, cases continue to rise. Children who are otherwise healthy tend to develop a milder acute Coronavirus disease 2019 (COVID-19) infection and have lower mortality rates compared with adults. Methods: Guidelines and current primary and secondary literature on the treatment of COVID-19 and the multisystem inflammatory syndrome in children were searched and reviewed. There are 6 published pediatric series that included 252 children with acute COVID-19 infection and describe various treatments and outcomes. Results: Guidelines recommend treating pediatric patients similarly to adult patients. Currently, no prophylactic drug therapy has been shown to reduce the spread of infection. Treatment options for acute COVID-19 are limited to remdesivir and glucocorticoids for patients who require oxygen and/or mechanical ventilation. The efficacy of hydroxychloroquine, chloroquine, and azithromycin has not been proven and their safety has been a concern. Other therapies that are being explored include interleukin (IL)-1 and IL-6 inhibitors. In children, an atypical Kawasaki-like disease emerged after recent exposure to SARS-CoV-2 and has been named Multisystem Inflammatory Syndrome in Children (MIS-C). Nine case series, including 418 pediatric patients, described pharmacotherapies used and patient outcomes. These pharmacotherapies included intravenous immune globulin and glucocorticoids and in some patients, IL-1 and IL-6 inhibitors. Conclusion: Given the paucity of data in children, this article presents currently recommended pharmacotherapies for the treatment of acute COVID-19 infection in adult patients and whenever available, in pediatric patients. Pharmacotherapies used in the treatment of MIS-C in children are also reviewed.

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

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

Increased concentrations of growth differentiation factor-15 in children with Kawasaki disease

BACKGROUND

We investigated the serum concentrations of growth differentiation factor-15 (GDF-15) in children with acute Kawasaki disease (KD) and evaluate its role in predicting coronary artery lesions (CALs) and no response KD.

METHODS

We obtained blood sample from 30 healthy children and 131 children with KD before intravenous immunoglobulin therapy. Serum GDF-15 concentrations were measured using ELISA kits. Univariate and multivariate logistic regression analysis were conducted to evaluate the potential association between GDF-15 and the occurrence of CALs and treatment responses.

RESULTS

Serum GDF-15 concentrations in KD were remarkably increased compared with healthy control. Serum GDF-15 concentrations in KD with CALs were also increased compared with no CALs, and in no response KD compared with response KD. Serum of GDF-15 concentrations was positively correlated with white blood cell count, C-reactive protein (CRP) and erythrocyte sedimentation rate (ESR), and negatively associated with albumin and pre-albumin in all patients with KD. GDF-15 was an independent predictor of CALs and no response KD. GDF-15 was superior to CRP and ESR, while it was not inferior to the combination of CRP and ESR for predicting CALs.

CONCLUSIONS

Serum of GDF-15 concentrations was significantly increased in acute KD patients, especially in KD with CALs and no response KD. GDF-15 could sever as an independent predictor for CALs and no response KD.

Clinical manifestations of Kawasaki disease in different age groups: retrospective data from Southwest China

OBJECTIVES

The aim of the present study is to identify the clinical manifestations and laboratory findings of children with Kawasaki disease (KD) in different age groups and to recognize and treat KD in a timely manner.

METHODS

A total of 213 children with KD were divided into the following age groups: (1) infants, (2) toddlers, and (3) preschool age. Retrospective analysis of clinical data was performed among the groups. Categorical data were statistically compared by Chi-square analysis, and measurement data were compared using one-way ANOVA analysis.

RESULTS

Our study showed that (1) cough (40.5%), diarrhea (16.9%), and vomiting (8.5%) were also very common in KD patients. (2) Patients in the infant group more commonly developed cough and diarrhea, but were less frequently documented with lymphadenopathy and skin rash. (3) Elevation of platelets was more common in the infant group. When urine tests were compared among the three groups, the toddler group had a higher proportion of sterile pyuria, and infants younger than 1 year old had a lower proportion of proteinuria and positive urine ketones.

CONCLUSION

Cough, diarrhea, vomiting, and sterile pyuria were very common in infant KD patients less than 1 year old. They should be noted in patients with suspected KD for earlier diagnosis and timely treatments. Key Points • Patients with Kawasaki disease (KD) in different age groups showed different clinical manifestations and laboratory findings. • Cough, diarrhea, vomiting, and sterile pyuria were very common in infant KD patients less than 1 year old. • Paying more attentions to respiratory, gastrointestinal, and urinary manifestations or abnormalities might be helpful for earlier diagnosis of KD, especially incomplete KD, though they were not list in the diagnostic criteria.