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

Clinical prediction model: Multisystem inflammatory syndrome in children versus Kawasaki disease

BACKGROUND

Multisystem inflammatory syndrome in children (MIS-C) is a rare but serious complication of severe acute respiratory syndrome coronavirus 2 infection. Features of MIS-C overlap with those of Kawasaki disease (KD).

OBJECTIVE

The study objective was to develop a prediction model to assist with this diagnostic dilemma.

METHODS

Data from a retrospective cohort of children hospitalized with KD before the coronavirus disease 2019 pandemic were compared to a prospective cohort of children hospitalized with MIS-C. A bootstrapped backwards selection process was used to develop a logistic regression model predicting the probability of MIS-C diagnosis. A nomogram was created for application to individual patients.

RESULTS

Compared to children with incomplete and complete KD (N = 602), children with MIS-C (N = 105) were older and had longer hospitalizations; more frequent intensive care unit admissions and vasopressor use; lower white blood cell count, lymphocyte count, erythrocyte sedimentation rate, platelet count, sodium, and alanine aminotransferase; and higher hemoglobin and C-reactive protein (CRP) at admission. Left ventricular dysfunction was more frequent in patients with MIS-C, whereas coronary abnormalities were more common in those with KD. The final prediction model included age, sodium, platelet count, alanine aminotransferase, reduction in left ventricular ejection fraction, and CRP. The model exhibited good discrimination with AUC 0.96 (95% confidence interval: [0.94-0.98]) and was well calibrated (optimism-corrected intercept of -0.020 and slope of 0.99).

CONCLUSIONS

A diagnostic prediction model utilizing admission information provides excellent discrimination between MIS-C and KD. This model may be useful for diagnosis of MIS-C but requires external validation.

Differentiating Multisystem Inflammatory Syndrome in Children from Kawasaki Disease During the Pandemic

OBJECTIVE

We aimed to delineate the distinctive characteristics that aid in distinguishing between Kawasaki disease (KD) and multisystem inflammatory syndrome in children (MIS-C) with KD-like manifestations during the pandemic.

MATERIALS AND METHODS

We evaluated KD patients and MIS-C patients with KD-like symptoms admitted during the pandemic (between January 2021 and December 2022).

RESULTS

Thirty-three MIS-C patients and 15 KD patients were included. Kawasaki disease patients were younger than MIS-C patients (3.4 vs. 7.6 years). Rash (P = .044, 100% vs. 75.7%), oral mucosal changes (P = .044, 100% vs. 75.7%), and cervical lymphadenopathy (P = .001, 93.3% vs. 42.4%) were more common in KD. Multisystem inflammatory syndrome in children: patients had more hypotension (P = .002, 45.4% vs. 0), gastrointestinal (P .001, 72.7% vs. 13.3%), and respiratory symptoms (P = .044, 24.2% vs. 0). Multisystem inflammatory syndrome in children patients also had low lymphocyte and thrombocyte counts and elevated levels of d-dimer, ferritin, and cardiac parameters, unlike KD patients. Multisystem inflammatory syndrome in children patients exhibited a notable reduction in left ventricular systolic function in echocardiography. Another significant difference with regard to management was the anakinra treatment, which was prescribed for MIS-C patients.

CONCLUSION

Although MIS-C patients might display a clinical resemblance to KD, several features could help differentiate between MIS-C and classical KD. Specific clinical (hypotension, gastrointestinal, and respiratory symptoms) and laboratory (low lymphocyte and thrombocyte counts with higher C-reactive protein, ferritin, d-dimer, and cardiac parameters) features are characteristic of MIS-C. In addition, divergence in management strategies is evident between the 2 diseases, as biologic drugs were more prevalently employed in MIS-C patients than in classical KD patients.

Emerging evidence of microbial infection in causing systematic immune vasculitis in Kawasaki disease

Kawasaki disease (KD) is a systematic vasculitis that is often complicated by coronary artery lesions and is a leading cause of acquired heart disease in developed countries. Previous studies have suggested that genetic susceptibility, together with an inducing infectious agent, could be involved in KD pathogenesis; however, the precise causative agent of this disease remains unknown. Moreover, there are still debates concerning whether KD is an infectious disease or an autoimmune disease, although many studies have begun to show that various pathogens functioning as critical inducers could activate different kinds of immune cells, consequently leading to the dysfunction of endothelial cells and systematic vasculitis. Here in this review, we attempt to summarize all the available evidence concerning pathogen infections associated with KD pathogenesis. We also discuss the related mechanisms, present a future perspective, and identify the open questions that remain to be investigated, thereby providing a comprehensive description of pathogen infections and their correlations with the host immune system in leading to KD.

Clinical and Laboratory Characteristics of Kawasaki Disease and COVID-19-Related Multisystem Inflammatory Syndrome in Children

Geographical and racial factors constitute important distinctions between Kawasaki disease (KD) and multisystem inflammatory syndrome in children (MIS-C), but no study has been conducted in Vietnam. Forty-one children with KD from January 2018 to July 2020 and 42 with KD/MIS-C from August 2020 to December 2022 were included in this study. Of the patients, 52.3% were aged between 12 and 35 months. Only two were aged over 5 years, and both were belong to the KD/MIS-C group. A 59.5% of the patients were male. Apart from fever, all symptoms tended to be more frequent in patients with KD/MIS-C. The prevalence of diffuse skin rash, hand and foot edema or erythema and gastrointestinal signs was significantly higher in patients hospitalized with KD/MIS-C. There was no significant difference in laboratory findings between the two groups. Coronary artery dilation was more frequently observed in patients with KD/MIS-C compared to those with KD (40.5% vs. 14.6%, P = 0.009).

Paediatric inflammatory multisystem syndrome in Canada: population-based surveillance and role of SARS-CoV-2 linkage

BACKGROUND

Paediatric inflammatory multisystem syndrome (PIMS) is a rare condition temporally associated with SARS-CoV-2 infection. Using national surveillance data, we compare presenting features and outcomes among children hospitalized with PIMS by SARS-CoV-2 linkage, and identify risk factors for intensive care (ICU).

METHODS

Cases were reported to the Canadian Paediatric Surveillance Program by a network of >2800 pediatricians between March 2020 and May 2021. Patients with positive versus negative SARS-CoV-2 linkages were compared, with positive linkage defined as any positive molecular or serologic test or close contact with confirmed COVID-19. ICU risk factors were identified with multivariable modified Poisson regression.

RESULTS

We identified 406 children hospitalized with PIMS, including 49.8% with positive SARS-CoV-2 linkages, 26.1% with negative linkages, and 24.1% with unknown linkages. The median age was 5.4 years (IQR 2.5-9.8), 60% were male, and 83% had no comorbidities. Compared to cases with negative linkages, children with positive linkages experienced more cardiac involvement (58.8% vs. 37.4%; p < 0.001), gastrointestinal symptoms (88.6% vs. 63.2%; p < 0.001), and shock (60.9% vs. 16.0%; p < 0.001). Children aged ≥6 years and those with positive linkages were more likely to require ICU.

CONCLUSIONS

Although rare, 30% of PIMS hospitalizations required ICU or respiratory/hemodynamic support, particularly those with positive SARS-CoV-2 linkages.

IMPACT

We describe 406 children hospitalized with paediatric inflammatory multisystem syndrome (PIMS) using nationwide surveillance data, the largest study of PIMS in Canada to date. Our surveillance case definition of PIMS did not require a history of SARS-CoV-2 exposure, and we therefore describe associations of SARS-CoV-2 linkages on clinical features and outcomes of children with PIMS. Children with positive SARS-CoV-2 linkages were older, had more gastrointestinal and cardiac involvement, and hyperinflammatory laboratory picture. Although PIMS is rare, one-third required admission to intensive care, with the greatest risk amongst those aged ≥6 years and those with a SARS-CoV-2 linkage.

Multisystem inflammatory syndrome in children (MIS-C) and sepsis differentiation by a clinical and analytical score: MISSEP score

Differential diagnosis between Multisystem Inflammatory Syndrome in Children (MIS-C) and other causes of systemic inflammatory response such as sepsis is complex. The aims were to evaluate the differences between pediatric patients with MIS-C and sepsis and to develop a score to distinguish both entities. This was a retrospective study that compared demographic, clinical, diagnostic, and therapeutic data of pediatric patients with MIS-C (cohort 2020-2022) and sepsis (cohorts 2010-2014 and 2017-2018) admitted to a Pediatric Intensive Care Unit (PICU) of a tertiary care hospital. A diagnostic score was developed with variables that differentiated the two conditions. Twenty-nine patients with MIS-C were identified, who were matched 1:3 with patients with sepsis (n = 87). Patients with MIS-C were older (10 vs. 4 years old), and the majority were male (69%). Clinical characteristics that demonstrated differences were prolonged fever and signs and symptoms affecting skin-mucosa and gastrointestinal system. Leukocytes, PCT, and ferritin were higher in sepsis, while thrombocytopenia, lymphopenia, and elevated fibrinogen and adrenomedullin (biomarker with a role for the detection of invasive infections) were more frequent in MIS-C. MIS-C patients presented greater myocardial dysfunction (p < 0.001). Five criteria were selected and included in the MISSEP score after fitting them into a multivariate logistic regression model: fever > 48 hours (20 points), thrombocytopenia < 150 × 103/µL (6 points), abdominal pain (15 points), conjunctival erythema (11 points), and Vasoactive Inotropic Score (VIS) > 10 (7 points). The cutoff > 25 points allowed to discriminate MIS-C from sepsis with a sensitivity of 0.89 and specificity of 0.95.     Conclusion: MIS-C phenotype overlaps with sepsis. MISSEP score could be useful to distinguish between both entities and direct specific treatment. What is Known: • Differential diagnosis between Multisystem Inflammatory Syndrome in Children (MIS-C) and other causes of systemic inflammatory response such as sepsis is complex. • It is essential to establish an accurate initial diagnosis and early specific treatment in both cases of MIS-C and sepsis to improve the prognosis of these patients. What is New: • Patients with MIS-C are older and have characteristic symptoms of prolonged fever, gastrointestinal symptoms, skin-mucosal involvement, and greater myocardial dysfunction, compared to patients with sepsis. • The use of diagnostic scores, such as the MISSEP score, can be very useful to distinguish between the two entities and help direct specific treatment.

Multisystem inflammatory syndrome in children and Kawasaki disease; comparison of their clinical findings and one-year follow-up-a cross-sectional study

BACKGROUND

Studies on Multisystem Inflammatory Syndrome in Children (MIS-C) and Kawasaki Disease (KD) have yielded inconsistent results and are lacking in Asian and African countries. This study aimed to compare the laboratory and clinical features, short-term outcomes, and one-year follow-ups of a large cohort of MIS-C and KD patients.

METHODS

Data from 176 MIS-C and 56 KD patients admitted to Tehran Children's Medical Center between January 2021 and January 2022 were collected. Patients were followed up until January 2023.

RESULTS

While lymphopenia and thrombocytopenia were more prevalent in MIS-C (73.2% vs. 20% in KD, p < 0.001), KD patients exhibited a higher median white blood cell count and prevalence of anemia, along with higher fibrinogen and erythrocyte sedimentation rate levels (p < 0.001, p < 0.001, p = 0.005, p < 0.001, respectively). MIS-C patients also exhibited lower ejection fraction, a greater occurrence of pericardial effusion, and a higher incidence of coronary aneurysms and ectasia, and ascites. Echocardiography after seven days of treatment showed a reduction in pathologies for both groups, but it was significant only for MIS-C. After one year, coronary artery abnormalities remained in only six cases.

CONCLUSIONS

In conclusion, this study highlights differences between MIS-C and KD, including laboratory indices as well as echocardiographic and abdominal ultrasound findings. These findings contribute valuable data on Iranian patients to the existing literature on this topic and have significant implications for accurate diagnosis and improved management of pediatric patients presenting with these conditions.

French national diagnostic and care protocol for Kawasaki disease

Kawasaki disease (KD) is an acute vasculitis with a particular tropism for the coronary arteries. KD mainly affects male children between 6 months and 5 years of age. The diagnosis is clinical, based on the international American Heart Association criteria. It should be systematically considered in children with a fever, either of 5 days or more, or of 3 days if all other criteria are present. It is important to note that most children present with marked irritability and may have digestive signs. Although the biological inflammatory response is not specific, it is of great value for the diagnosis. Because of the difficulty of recognising incomplete or atypical forms of KD, and the need for urgent treatment, the child should be referred to a paediatric hospital as soon as the diagnosis is suspected. In the event of signs of heart failure (pallor, tachycardia, polypnea, sweating, hepatomegaly, unstable blood pressure), medical transfer to an intensive care unit (ICU) is essential. The standard treatment is an infusion of IVIG combined with aspirin (before 10 days of fever, and for a minimum of 6 weeks), which reduces the risk of coronary aneurysms. In case of coronary involvement, antiplatelet therapy can be maintained for life. In case of a giant aneurysm, anticoagulant treatment is added to the antiplatelet agent. The prognosis of KD is generally good and most children recover without sequelae. The prognosis in children with initial coronary involvement depends on the progression of the cardiac anomalies, which are monitored during careful specialised cardiological follow-up.

A Ukrainian infant with giant coronary aneurysms: A case report and literature review

Key Clinical Message

COVID may manifest multisystem inflammatory syndrome in children (MIS-C) which mimics Kawasaki disease (KD). Differentiating KD and MIS-C is difficult. Immunomodulatory treatment should be initiated promptly without accurate diagnosis.

Abstract

A febrile Ukrainian infant developed giant aneurysms in coronary arteries. Differentiating between Kawasaki disease and multisystem inflammatory syndrome in children was difficult. In both illnesses, coronary aneurysm may develop unless treated promptly. Therefore, guidelines should synthesize these clinical entities so that treatment can be initiated before rigorous diagnosis.

Inborn errors of OAS-RNase L in SARS-CoV-2-related multisystem inflammatory syndrome in children

Multisystem inflammatory syndrome in children (MIS-C) is a rare and severe condition that follows benign COVID-19. We report autosomal recessive deficiencies of OAS1, OAS2, or RNASEL in five unrelated children with MIS-C. The cytosolic double-stranded RNA (dsRNA)-sensing OAS1 and OAS2 generate 2'-5'-linked oligoadenylates (2-5A) that activate the single-stranded RNA-degrading ribonuclease L (RNase L). Monocytic cell lines and primary myeloid cells with OAS1, OAS2, or RNase L deficiencies produce excessive amounts of inflammatory cytokines upon dsRNA or severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) stimulation. Exogenous 2-5A suppresses cytokine production in OAS1-deficient but not RNase L-deficient cells. Cytokine production in RNase L-deficient cells is impaired by MDA5 or RIG-I deficiency and abolished by mitochondrial antiviral-signaling protein (MAVS) deficiency. Recessive OAS-RNase L deficiencies in these patients unleash the production of SARS-CoV-2-triggered, MAVS-mediated inflammatory cytokines by mononuclear phagocytes, thereby underlying MIS-C.

A comparison of pediatric inflammatory multisystem syndrome temporarily-associated with SARS-CoV-2 and Kawasaki disease

The connection between Pediatric Inflammatory Multisystem Syndrome (PIMS) and Kawasaki Disease (KD) is not yet fully understood. Using the same national registry, clinical features and outcome of children hospitalized in Germany, and Innsbruck (Austria) were compared. Reported to the registry were 395 PIMS and 69 KD hospitalized patients. Patient age in PIMS cases was higher than in KD cases (median 7 [IQR 4-11] vs. 3 [IQR 1-4] years). A majority of both PIMS and KD patients were male and without comorbidities. PIMS patients more frequently presented with organ dysfunction, with the gastrointestinal (80%), cardiovascular (74%), and respiratory (52%) systems being most commonly affected. By contrast, KD patients more often displayed dermatological (99% vs. 68%) and mucosal changes (94% vs. 64%), plus cervical lymph node swelling (51% vs. 34%). Intensive care admission (48% vs. 19%), pulmonary support (32% vs. 10%), and use of inotropes/vasodilators (28% vs. 3%) were higher among PIMS cases. No patients died. Upon patient discharge, potentially irreversible sequelae-mainly cardiovascular-were reported (7% PIMS vs. 12% KD). Despite differences in age distribution and disease severity, PIMS and KD cases shared many common clinical and prognostic characteristics. This supports the hypothesis that the two entities represent a syndrome continuum.

Rash and Gastrointestinal Dysfunction May Indicate Cardiac Involvement in Children with Multisystem Inflammatory System Associated with Coronavirus Disease 2019

This study aims to investigate the management of children diagnosed with “multisystem inflammatory syndrome” (MIS-C) potentially associated with coronavirus disease 2019 (COVID-19) at a tertiary health center. This is a retrospective review of 34 children who were diagnosed with MIS-C at the pediatrics department of the study center from August 2021 to December 2021. Data related to age, sex, body mass index, vital findings, laboratory data, clinical symptoms, ultrasonography, and echocardiography findings were acquired from hospital records. Cardiac markers were compared with respect to clinical symptoms and imaging. Fever (91.2%), rash (50%), and abdominal pain (44.1%) were the most observed symptoms. Echocardiography visualized mild mitral regurgitation in 12 patients (35.3%), pericardial effusion in 9 patients (26.5%), and mild coronary dilatation in 9 patients (26.5%). All patients received corticosteroids, whereas acetylsalicylic acid was prescribed in 29 patients (85.3%) and intravenous immunoglobulins were administered in 21 patients (61.8%). Serum probrain natriuretic peptide concentrations were significantly higher in MIS-C patients with rash than those without rash (9,592.2 ± 7,764.5 vs. 1,501.2 ± 1,385.4 pg/mL, p = 0.021). Serum troponin T concentrations were significantly higher in MIS-C patients with ileitis than those without ileitis (0.026 ± 0.024 vs. 0.008 ± 0.003 µg/L, p = 0.013). Serum troponin T concentrations were also significantly higher in MIS-C patients with pericardial effusion than those without pericardial effusion (0.022 ± 0.020 vs. 0.008 ± 0.007 µg/L, p = 0.036). The presence of rash and sonographic visualization of ileitis might act as signs for cardiac involvement in children exposed to COVID-19. To assess the cardiac involvement in MIS-C patients, cardiac enzymes should be measured and echocardiography examination should be performed.

Similarities and differences between MIS-C and KD: a systematic review and meta-analysis

BACKGROUND

Multisystem inflammatory syndrome in children (MIS-C) is a new syndrome with some clinical manifestations similar to Kawasaki disease (KD), which is difficult to distinguish.

OBJECTIVE

The study aimed to characterize the demographic characteristics, clinical characteristics, laboratory features, cardiac complications, and treatment of MIS-C compared with KD.

STUDY DESIGN

Studies were selected by searching the PubMed, EMBASE and so on before February 28, 2022. Statistical analyses were performed using Review Manager 5.4 software and STATA 14.0.

RESULTS

Fourteen studies with 2928 participants were included. MIS-C patients tended to be older and there was no significant difference in the sex ratio. In terms of clinical characteristics, MIS-C patients were more frequently represented with respiratory, gastrointestinal symptoms and shock. At the same time, they had a lower incidence of conjunctivitis than KD patients. MIS-C patients had lower lymphocyte counts, platelet (PLT) counts, erythrocyte sedimentation rates (ESRs), alanine transaminase (ALT), and albumin levels and had higher levels of aspartate transaminase (AST), N-terminal pro-B-type natriuretic peptide (NT-pro-BNP), troponin, C-reactive protein (CRP), D-dimer, fibrinogen, ferritin, and creatinine. MIS-C patients had a higher incidence of left ventricle (LV) dysfunction, valvular regurgitation, pericardial effusion, myocarditis, and pericarditis. The incidence of coronary artery lesion (CAL) was lower in MIS-C patients [OR (95% CI): 0.52 (0.29, 0.93), p =0.03], while it was similar in the acute period. MIS-C patients had higher utilization of glucocorticoids (GCs) and lower utilization of intravenous immune globulin (IVIG).

CONCLUSIONS

There were specific differences between MIS-C and KD, which might assist clinicians with the accurate recognition of MIS-C and further mechanistic research.

Comparable bidirectional neutrophil immune dysregulation between Kawasaki disease and severe COVID-19

Kawasaki disease (KD), a multisystem inflammatory syndrome that occurs in children, and severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2 or COVID-19) may share some overlapping mechanisms. The purpose of this study was to analyze the differences in single-cell RNA sequencing between KD and COVID-19. We performed single-cell RNA sequencing in KD patients (within 24 hours before IVIG treatment) and age-matched fever controls. The single-cell RNA sequencing data of COVID-19, influenza, and health controls were downloaded from the Sequence Read Archive (GSE149689/PRJNA629752). In total, 22 single-cell RNA sequencing data with 102,355 nuclei were enrolled in this study. After performing hierarchical and functional clustering analyses, two enriched gene clusters demonstrated similar patterns in severe COVID-19 and KD, heightened neutrophil activation, and decreased MHC class II expression. Furthermore, comparable dysregulation of neutrophilic granulopoiesis representing two pronounced hyperinflammatory states was demonstrated, which play a critical role in the overactivated and defective aging program of granulocytes, in patients with KD as well as those with severe COVID-19. In conclusion, both neutrophil activation and MHC class II reduction play a crucial role and thus may provide potential treatment targets for KD and severe COVID-19.

Enoxaparin Thromboprophylaxis in Children Hospitalized for COVID-19: A Phase 2 Trial

BACKGROUND

Evidence regarding the safety and efficacy of anticoagulant thromboprophylaxis among pediatric patients hospitalized for coronavirus disease 2019 (COVID-19) is limited. We sought to evaluate safety, dose-finding, and preliminary efficacy of twice-daily enoxaparin as primary thromboprophylaxis among children hospitalized for symptomatic COVID-19, including primary respiratory infection and multisystem inflammatory syndrome in children (MISC).

METHODS

We performed a phase 2, multicenter, prospective, open-label, single-arm clinical trial of twice-daily enoxaparin (initial dose: 0.5mg/kg per dose; max: 60mg; target anti-Xa activity: 0.20-0.49IU/mL) as primary thromboprophylaxis for children <18 years of age hospitalized for symptomatic COVID-19. Study endpoints included: cumulative incidence of International Society of Thrombosis and Haemostasis-defined clinically relevant bleeding; enoxaparin dose-requirements; and cumulative incidence of venous thromboembolism within 30-days of hospital discharge. Descriptive statistics summarized endpoint estimates that were further evaluated by participant age (±12 years) and clinical presentation.

RESULTS

Forty children were enrolled and 38 met analyses criteria. None experienced clinically relevant bleeding. Median (interquartile range) dose to achieve target anti-Xa levels was 0.5 mg/kg (0.48-0.54). Dose-requirement did not differ by age (0.5 [0.46-0.52] mg/kg for age ≥12 years versus 0.52 [0.49-0.55] mg/kg for age <12 years, P = .51) but was greater for participants with MISC (0.52 [0.5-0.61] mg/kg) as compared with primary COVID-19 (0.48 [0.39-0.51] mg/kg, P = .010). Two children (5.3%) developed central-venous catheter-related venous thromboembolism. No serious adverse events were related to trial intervention.

CONCLUSIONS

Among children hospitalized for COVID-19, thromboprophylaxis with twice-daily enoxaparin appears safe and warrants further investigation to assess efficacy.

An Immunological Axis Involving Interleukin 1β and Leucine-Rich-α2-Glycoprotein Reflects Therapeutic Response of Children with Kawasaki Disease: Implications from the KAWAKINRA Trial

Purpose

A recent phase II open-label study of the interleukin 1 (IL-1) receptor antagonist (IL-1Ra) anakinra in treating IVIG-resistant Kawasaki disease (KD) patients reported promising results. Here, we aimed to characterize the immunological impact of IL-1 blockade in this unique study population.

Methods

Patients’ and control sera and supernatants of cells (whole blood, neutrophils, coronary artery endothelial cells) stimulated with recombinant IL-1β were analyzed for single or multiple marker (n = 22) expression by ELISA or multiplexed bead array assay. Data were analyzed using unsupervised hierarchical clustering, multiple correlation, and multi-comparison statistics and were compared to retrospective analyses of KD transcriptomics.

Results

Inflammation in IVIG-resistant KD (n = 16) is hallmarked by over-expression of innate immune mediators (particularly IL-6 > CXCL10 > S100A12 > IL-1Ra). Those as well as levels of immune or endothelial cell activation markers (sICAM-1, sVCAM-1) declined most significantly in course of anakinra treatment. Prior as well as following IL-1R blockade, over-expression of leucine-rich-α2-glycoprotein 1 (LRG1) associated best with remnant inflammatory activity and the necessity to escalate anakinra dosage and separated inflammatory KD patients from sJIA-MAS (n = 13) and MIS-C (n = 4). Protein as well as retrospective gene expression analyses indicated tight association of LRG1 with IL-1β signaling and neutrophilia, while particularly neutrophil stimulation with recombinant IL-1β resulted in concentration-dependent LRG1 release.

Conclusion

Our study identifies LRG1 as known trigger of endothelial activation and cardiac re-modeling to associate with IL-1β signaling in KD. Besides a potential patho-mechanistic implication of these findings, our data suggest blood leukocyte and neutrophil counts to best predict response to IL-1Ra treatment in IVIG-resistant KD.

Supplementary Information

The online version contains supplementary material available at 10.1007/s10875-022-01301-w.

Síndrome inflamatória multissistêmica (SIMS) pós-COVID-19

INTRODUÇÃO: A potencial associação da COVID-19 com fenômenos inflamatórios e autoimunes abre um novo capítulo na prática clínica. Entre várias condições inflamatórias descritas no pós-COVID-19, destacam-se a doença de Kawasaki e uma nova afecção denominada síndrome inflamatória multissistêmica.OBJETIVOS: Revisar, de forma prática e concisa, conceito e critérios diagnósticos da síndrome inflamatória multisistêmica, as sobreposições com a doença de Kawasaki, assim como a imunopatogênese e o tratamento desta nova e intrigante enfermidade.MÉTODOS: Revisão da literatura disponível na base de dados Pubmed, com ênfase em revisões sistemáticas com metaanálises.RESULTADOS: A síndrome inflamatória multisistêmica se configura como uma condição hiperinflamatória multiorgânica pós-viral. A condição é primordialmente pediátrica, e os primeiros casos foram descritos na Inglaterra em maio de 2020. Os critérios diagnósticos são ainda imprecisos, e incluem algumas manifestações doença de Kawasaki-símiles. A síndrome inflamatória multisistêmica difere da doença de Kawasaki, entretanto, por geralmente acometer crianças acima cinco anos e de raças negras ou hispânicas; em termos clínicos, se distingue pela alta frequência de gastroenteropatia, miocardiopatia e choque. O diagnóstico diferencial inclui sepse bacteriana, síndrome de ativação macrofágica e formas sistêmicas de artrite reumatoide. Uma hiperexpressão de interferons e de outras citocinas inflamatórias caracteriza patogenicamente a síndrome inflamatória mulsistêmica. A enfermidade é, via de regra, responsiva a cuidados de terapia intensiva, corticóides, imunoglobulina intravenosa e imunobiológicos.CONCLUSÕES: A síndrome inflamatória multisistêmica é uma nova e complexa afecção hiperinflamatória associada à exposição prévia ao SARS-CoV-2. Apresenta instigantes interfaces com a doença de Kawasaki. Apesar da descrição recente, a literatura já é quantitativamente robusta, e algumas pendências de imunopatogênese, critérios diagnósticos e terapêutica deverão ser esclarecidas em breve.

Differences and similarities of multisystem inflammatory syndrome in children, Kawasaki disease and macrophage activating syndrome due to systemic juvenile idiopathic arthritis: a comparative study

To compare the clinical and laboratory findings of multisystem inflammatory syndrome in children (MIS-C), patients with Kawasaki disease (KD) and with macrophage activating syndrome due to systemic juvenile idiopathic arthritis (sJIA-MAS) on real-life data. Patients diagnosed with MIS-C, KD, and sJIA-MAS from 12 different centers in Turkey who were followed for at least 6 months were included in the study. Demographic, clinical, and laboratory findings of all patients were analyzed. A total of 154 MIS-C, 59 KD, and 31 sJIA-MAS patients were included. The median age of patients with MIS-C were higher than those with KD while lower than those with sJIA-MAS (8.2, 3, 12 years, respectively). Myalgia (39.6%), cardiac (50.6%), gastrointestinal (72.7%), and neurological (22.1%) involvements were more common in patients with MIS-C compared to others. MIS-C patients had lower levels of lymphocyte (950 vs 1700 cells/µl) and thrombocyte (173,000 vs 355,000 cells/µl) counts and higher pro-BNP (1108 vs 55 pg/ml) levels than KD. Ferritin levels were higher in patients with MIS-C compared to patients with KD while they were lower than patients with sJIA-MAS (440, 170, 10,442 ng/ml, respectively). Patients with MIS-C had a shorter duration of hospitalization than sJIA-MAS (p = 0.02) while they required intensive care unit admission more frequently (55 vs 8 patients, p < 0.001). The median MAS/sJIA score of MIS-C patients was − 1.64 (− 5.23 to 9.68) and the median MAS/sJIA score of sJIA-MAS patients was −2.81 ([− 3.79] to [− 1.27]). MIS-C patients displayed certain differences in clinical and laboratory features when compared to KD and sJIA-MAS. Definition of the differences and similarities between MIS-C and the other intense inflammatory syndromes of childhood such as KD and MAS will help the clinicians while making timely diagnosis.

Epidemiology of Kawasaki Disease in Europe

Aim of the review: To review major epidemiological aspects of Kawasaki disease (KD) in Europe, describing demographic characteristics, revising its incidence along with time trends and geographic variations, and describing migration studies to provide clues about its etiology. Recent findings: The annual incidence of KD in Europe is about 10-15 per 100,000 children under 5 years old and seems to be relatively stable over time and space. Demographic characteristics are in line with those in other countries of the world, with a higher incidence in children from Asia and possibly North African origin. All studies performed across Europe found a coherent seasonal distribution of KD onset peaking from winter to early spring. This seasonal distribution was consistent over the years and suggests a climate-related environmental trigger. The occurrence of peaks during pandemics, microbiological findings and a possible link with southerly winds support the hypothesis of an airborne infectious agent. Neither other airborne agents such as pollutants or pollens nor urbanization and industrialization seem to have major effect on the etiology. Conclusion: Discrepancies in KD incidence rates across studies were due more to methodological differences, variation in definitions and awareness of the disease than a real increase in incidence. Genetic predisposition is undeniable in KD, but environmental factors seem to play a pivotal role. Several lines of evidence support a non-exclusive airborne infectious agent with a protective immune response by the host as a key factor in inducing the inflammatory cascade responsible for symptoms and complications.