The use of interleukin 1 receptor antagonist (anakinra) in Kawasaki disease: A retrospective cases series

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.

The Central Role of Interleukin-1 Signalling in the Pathogenesis of Kawasaki Disease Vasculitis: Path to Translation

Kawasaki disease (KD) manifests as an acute febrile condition and systemic vasculitis, the etiology of which remains elusive. Primarily affecting children under 5 years of age, if untreated KD can lead to a significant risk of coronary artery aneurysms and subsequent long-term cardiovascular sequelae, including myocardial ischemia and myocardial infarction. Intravenous immunoglobulin therapy mitigates the risk of aneurysm formation, but a subset of patients exhibit resistance to this treatment, increasing the susceptibility of coronary artery lesions. Furthermore, the absence of a KD-specific diagnostic test or biomarkers complicates early detection and appropriate treatment. Experimental murine models of KD vasculitis have substantially improved our understanding of the disease pathophysiology, revealing the key roles of the NLRP3 inflammasome and interleukin-1 (IL-1) signalling pathway. This review aims to delineate the pathophysiologic findings of KD while summarising the findings for the emerging key role of IL-1β in its pathogenesis, derived from both human data and experimental murine models, and the translational potential of these findings for anti-IL-1 therapies for children with KD.

Cardiovascular involvement in children with COVID-19 temporally related multisystem inflammatory syndrome (MIS-C): can cardiac magnetic resonance arrive to the heart of the problem?

BACKGROUND

Multisystem inflammatory syndrome in children (MIS-C) shows a significant overlap of symptoms with other hyper-inflammatory diseases such as Kawasaki disease (KD), but the real difference of the two conditions is still matter of debate. Coronary artery lesions (CAL) are the most relevant complication in KD. Nonetheless, CAL, myocarditis, pericarditis, arrhythmia are the main cardiovascular complications in MIS-C. A close clinical assessment is mandatory, both at the diagnosis and during the follow-up, by ECG and echocardiography. Cardiac magnetic resonance (MRI) adds important data to ultrasound findings. However, cardiac MRI studies in MIS-C are limited to a small number of cohorts.

METHODS

We enrolled 20 children (age:1-16 years; 11 F; 9 M) with cardiac involvement secondary to MIS-C, all evaluated by cardiac MRI.

RESULTS

8 children showed pathological cardiac MRI: 2 showed pericardial effusion; 2 showed myocardial oedema; 1 showed aortic insufficiency; 3 showed delayed enhancement (one for acute myocarditis with oedema; 2 for myocardial fibrosis). Delayed enhancement was reduced significantly 5.6-9 months after the first MRI evaluation. 25% of patients with pathological MRI had CAL associated with valvular insufficiency of 2 valves. 17% of patients with normal MRI had CAL, associated with valvular insufficiency of 1 valve in 1 patient. The correlations between haematological, clinical, cardiologic parameters, treatment, did not reach the statistical significance. 4 patients were treated with anakinra. Among those, 2 patients showed a normal cardiac MRI. Cardiac lesions resolved in all the patients during the follow-up. Some patients with pathological cardiac MRI could not underwent a control with MRI, for the low compliance. However, echocardiography and ECG, documented the resolution of the pathological data in these cases.

CONCLUSIONS

A higher risk of CAL was documented in patients with an association of other cardiac lesions. Cardiac MRI is difficult to perform routinely; however, it is useful for evaluating the acute myocardial damage and the outcome of patients with MIS-C.

Efficacy and safety of infliximab in the treatment of Kawasaki disease: A systematic review and meta-analysis

Infliximab is a monoclonal antibody specifically binding tumor necrosis factor-alpha and has been approved for the treatment of several inflammatory disorders. However, the efficacy of infliximab in primary treatment of Kawasaki disease (KD) or retreatment of intravenous immunoglobulin (IVIG)-resistant KD in children is controversial. Therefore, we conducted a meta-analysis to compare the efficacy of infliximab alone or in combination with IVIG to IVIG. Eligible randomized and non-randomized trials were retrieved by searching literature databases prior to May 31, 2023. Pooled odds ratio (OR) and 95% confidence interval (95% CI) were calculated for dichotomous variables, and mean difference (MD) with 95% CI was estimated for continuous variables. A total of 14 eligible studies comprising 1257 participants were included. In refractory KD, infliximab alone was associated with a higher effectiveness rate (OR = 4.48, 95% CI 2.67-7.52) and defervescence rate (OR = 5.01, 95% CI 2.99-8.37) and resulted in a 1.08-day-shorter duration of fever (95% CI 0.61-1.55, P < 0.001) and 1.36-day-shorter length of hospital stay (95% CI 0.65-2.08) compared with IVIG. Incidences of coronary artery lesions (CALs), newly developing CALs, and CAL regression did not differ between both groups. For initial treatment of KD, infliximab in addition to IVIG led to a nominally significant higher effectiveness rate (OR = 2.26, 95% CI 1.02-5.01) and a larger reduction of right coronary artery Z score (MD = -0.24, 95% CI -0.27 to -0.21) but did not show additional efficacy in improving other outcomes. The safety profile was similar between both groups.   Conclusion: The meta-analysis demonstrates that infliximab alone is a well-tolerated and effective treatment for IVIG-resistant KD. The additional efficacy of infliximab to IVIG for initial treatment of KD is limited. More large and high-quality trials are needed to confirm the efficacy of infliximab, especially for intensification of primary treatment for KD. What is Known: • Infliximab is a novel monoclonal antibody specifically blocking tumor necrosis factor-alpha and is approved for treatment of several immune-mediated inflammatory disorders. • The efficacy of infliximab in treating children with Kawasaki disease is controversial. What is New: • Infliximab is an effective and safe treatment for children with refractory Kawasaki disease but adds limited efficacy to intravenous immunoglobulin for initial treatment of Kawasaki disease.

Transient anti-cytokine autoantibodies superimpose the hyperinflammatory response in Kawasaki disease and multisystem inflammatory syndrome in children: a comparative cohort study on correlates of disease

BACKGROUND

Children with SARS-CoV-2 related Multisystem Inflammatory Syndrome in Children (MIS-C) often present with clinical features that resemble Kawasaki disease (KD). Disease severity in adult COVID-19 is associated to the presence of anti-cytokine autoantibodies (ACAAs) against type I interferons. Similarly, ACAAs may be implicated in KD and MIS-C. Therefore, we explored the immunological response, presence of ACAAs and disease correlates in both disorders.

METHODS

Eighteen inflammatory plasma protein levels and seven ACAAs were measured in KD (n = 216) and MIS-C (n = 56) longitudinally by Luminex and/or ELISA. Levels (up to 1 year post-onset) of these proteins were related to clinical data and compared with healthy paediatric controls.

FINDINGS

ACAAs were found in both patient groups. The presence of ACAAs lagged behind the inflammatory plasma proteins and peaked in the subacute phase. ACAAs were mostly directed against IFN-γ (>80%) and were partially neutralising at best. KD presented with a higher variety of ACAAs than MIS-C. Increased levels of anti-IL-17A (P = 0·02) and anti-IL-22 (P = 0·01) were inversely associated with ICU admission in MIS-C. Except for CXCL10 in MIS-C (P = 0·002), inflammatory plasma proteins were elevated in both KD and MIS-C. Endothelial angiopoietin-2 levels were associated with coronary artery aneurysms in KD (P = 0·02); and sCD25 (P = 0·009), angiopoietin-2 (P = 0·001), soluble IL-33-receptor (ST2, P = 0·01) and CXCL10 (P = 0·02) with ICU admission in MIS-C.

INTERPRETATION

Markers of endothelial activation (E-selectin, angiopoietin-2), and innate and adaptive immune responses (macrophages [CD163, G-CSF], neutrophils [lipocalin-2], and T cells [IFN-γ, CXCL10, IL-6, IL-17]), are upregulated in KD and MIS-C. ACAAs were detected in both diseases and, although only partly neutralising, their transient presence and increased levels in non-ICU patients may suggest a dampening role on inflammation.

FUNDING

The Kawasaki study is funded by the Dutch foundation Fonds Kind & Handicap and an anonymous donor. The sponsors had no role in the study design, analysis, or decision for publication.

Have we got the optimal treatment for refractory Kawasaki disease in very young infants? A case report and literature review

A small group of patients with Kawasaki disease (KD) demonstrates resistance to standard therapy, putting them at high risk for an unfavorable prognosis, especially regarding coronary artery aneurysms. Although adding corticosteroids to first-line i.v. immunoglobulins (IVIGs) is considered beneficial, and despite timely treatment initiation, very young infants, in particular, can present an unfavorable clinical course. We report on a 3-month-old boy with a clinically severe KD phenotype involving the early development of giant coronary artery aneurysms. Because of his poor response to the first course of IVIG and prednisolone, we administered infliximab. His clinical condition improved after that, and his temperature dropped. Inflammatory markers however did not recover completely, and he remained subfebrile. In addition, as the coronary artery dimensions deteriorated, a second IVIG course was administered and prednisolone continued at the initial dosage. Although fever and routine inflammatory parameters normalized, close follow-up investigations revealed both still increasing coronary artery dimensions and renewed rise in inflammatory parameters, necessitating two more infliximab administrations in addition to continuous prednisolone. Because of the coronary artery dimensions (left anterior descending artery, 4.9 mm, Z-score 11.1; right coronary artery 5.8 mm, Z-score 15.5), dual platelet inhibitory therapy with ASA and later clopidogrel combined with low-molecular heparin was indicated. Four weeks after his initial KD diagnosis, we detected no renewed increase in inflammatory markers; at that time, we observed a slight reduction in coronary dimensions. In summary, despite timely guideline-fulfilling therapy, the prolonged clinical course of this very young infant with KD entailing the development of giant coronary artery aneurysms makes us question whether this age group may benefit from early, even more intense therapy.

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.

Exosomal non-coding RNAs: Emerging therapeutic targets in atherosclerosis

Atherosclerosis is an LDL-driven and inflammatory disorder of the sub-endothelial space. Available data have proposed that various factors could affect atherosclerosis pathogenesis, including inflammation, oxidation of LDL particles, endothelial dysfunction, foam cell formation, proliferation, and migration of vascular smooth muscle cells (VSMCs). In addition, other research indicated that the crosstalk among atherosclerosis-induced cells is a crucial factor in modulating atherosclerosis. Extracellular vesicles arenanoparticleswith sizes ranging from 30-150 nm, playing an important role in various pathophysiological situations. Exosomes, asa form of extracellular vesicles, could affect the crosstalk between sub-endothelial cells. They can transport bioactive components like proteins, lipids, RNA, and DNA. As an important cargo in exosomes, noncoding RNAs (ncRNAs) including microRNAs, long noncoding RNAs, and circular RNAs could modulate cellular functions by regulating the transcription, epigenetic alteration, and translation. The current work aimed to investigate the underlying molecular mechanisms of exosomal ncRNA as well as their potential as a diagnostic biomarker and therapeutic target in atherosclerosis.

Ten-month follow-up of patients with covid-19 temporally related multi-system inflammatory syndrome in children: the experience of the children hospital of Palermo

BACKGROUND

In Sicily, the first wave of COVID-19 showed a low epidemic impact in paediatric population, while the second and the third waves had a higher impact on clinical presentation of COVID-19 in children and a significantly higher severe outcome in patients with multisystem inflammatory syndrome in children (MIS-C), with a frequent life-threatening progression.

METHODS

We describe a cohort of 22 Sicilian children (11 M; 11 F; age: 1.4-14 years), presenting with clinical features compatible with MIS-C. Patients with negative swab had a history of recent personal or parental infection.

RESULTS

The following diagnostic criteria were detected: fever (100%); cheilitis and/or pharyngeal hyperaemia (86%); latero-cervical lymphadenitis (82%); rash (73%); abdominal pain and/or vomiting and/or diarrhoea (64%); conjunctivitis (64%); hands and feet oedema (18%). 59% showed cardiac involvement (6 pericardial effusion; 8 mitral valve insufficiency; 4 insufficiency of two valves; 3 coronary artery lesions (CAL)). In all the patients, treatment was started within 72 h after the admission, with intravenous immunoglobulins (IVIG) (2 g/Kg/dose), methylprednisolone (2 mg/Kg/day in 73% of patients; 30 mg/Kg/day for 3 days, followed by 2 mg/Kg/day in 27% of patients). Two patients were treated with enoxaparin. Two patients with shock, were additionally treated with vasoactive drugs, albumin, diuretics. Cardiac involvement evolved into the complete resolution of lesions in most of the patients. All the patients were included in a follow-up, to investigate on clinical outcome and resolution of organ involvement. Cardiac valve insufficiency persisted only in 18% of children, CAL persisted only in 33% of children with coronary involvement, however without the evolution into aneurisms.

CONCLUSIONS

The preferred treatment strategy was more aggressive at the diagnosis of MIS-C, to block the cytokine cascade. Most of our patients, in fact, received a first-line treatment with IVIG and steroids. This approach could explain the favourable prognosis, the rapid restoring of cardiac function also in patients with MAS or shock, and the good outcome during the 10 months follow-up in all the patients.

Intravenous immunoglobulin for the treatment of Kawasaki disease

BACKGROUND

Kawasaki disease (KD) is an acute systemic vasculitis (inflammation of the blood vessels) that mainly affects children. Symptoms include fever, chapped lips, strawberry tongue, red eyes (bulbar conjunctival injection), rash, redness, swollen hands and feet or skin peeling; and enlarged cervical lymph nodes. High fevers and systemic inflammation characterise the acute phase. Inflammation of the coronary arteries causes the most serious complication of the disease, coronary artery abnormalities (CAAs). The primary treatment is intravenous immunoglobulin (IVIG) and acetylsalicylic acid (ASA/aspirin), with doses and regimens differing between institutions. It is important to know which regimens are the safest and most effective in preventing complications.

OBJECTIVES

To evaluate the efficacy and safety of IVIG in treating and preventing cardiac consequences of Kawasaki disease.

SEARCH METHODS

The Cochrane Vascular Information Specialist searched the Cochrane Vascular Specialised Register, CENTRAL, MEDLINE, Embase, and CINAHL databases, and the World Health Organization International Clinical Trials Registry Platform and ClinicalTrials.gov trials registers to 26 April 2022.

SELECTION CRITERIA

We included randomised controlled trials (RCTs) investigating the use of IVIG for the treatment of KD. We included studies involving treatment for initial or refractory KD, or both.

DATA COLLECTION AND ANALYSIS

We used standard Cochrane methods. Our primary outcomes were incidence of CAAs and incidence of any adverse effects after treatment. Our secondary outcomes were acute coronary syndromes, duration of fever, need for additional treatment, length of hospital stay, and mortality. We used GRADE to assess the certainty of the evidence for each outcome.

MAIN RESULTS

We identified 31 RCTs involving a total of 4609 participants with KD. Studies compared IVIG with ASA, another dose or regimen of IVIG, prednisolone, or infliximab. The majority of studies reported on primary treatment, so those results are reported below. A limited number of studies investigated secondary or tertiary treatment in IVIG-resistant patients. Doses and regimens of IVIG infusion varied between studies, and all studies had some concerns related to risk of bias. Primary treatment with IVIG compared to ASA for people with KD Compared to ASA treatment, IVIG probably reduces the incidence of CAAs in people with KD up to 30 days (odds ratio (OR) 0.60, 95% confidence interval (CI) 0.41 to 0.87; 11 studies, 1437 participants; moderate-certainty evidence). The individual studies reported a range of adverse effects, but there was little to no difference in numbers of adverse effects between treatment groups (OR 0.57, 95% CI 0.17 to 1.89; 10 studies, 1376 participants; very low-certainty evidence). There was limited evidence for the incidence of acute coronary syndromes, so we are uncertain of any effects. Duration of fever days from treatment onset was probably shorter in the IVIG group (mean difference (MD) -4.00 days, 95% CI -5.06 to -2.93; 3 studies, 307 participants; moderate-certainty evidence). There was little or no difference between groups in need for additional treatment (OR 0.27, 95% CI 0.05 to 1.57; 3 studies, 272 participants; low-certainty evidence). No study reported length of hospital stay, and no deaths were reported in either group. Primary treatment with IVIG compared to different infusion regimens of IVIG for people with KD Higher-dose regimens of IVIG probably reduce the incidence of CAAs compared to medium- or lower-dose regimens of IVIG up to 30 days (OR 0.60, 95% CI 0.40 to 0.89; 8 studies, 1824 participants; moderate-certainty evidence). There was little to no difference in the number of adverse effects between groups (OR 1.11, 95% CI 0.52 to 2.37; 6 studies, 1659 participants; low-certainty evidence). No study reported on acute coronary syndromes. Higher-dose IVIG may reduce the duration of fever compared to medium- or lower-dose regimens (MD -0.71 days, 95% CI -1.36 to -0.06; 4 studies, 992 participants; low-certainty evidence). Higher-dose regimens may reduce the need for additional treatment (OR 0.29, 95% CI 0.10 to 0.88; 4 studies, 1125 participants; low-certainty evidence). We did not detect a clear difference in length of hospital stay between infusion regimens (MD -0.24, 95% CI -0.78 to 0.30; 3 studies, 752 participants; low-certainty evidence). One study reported mortality, and there was little to no difference detected between regimens (moderate-certainty evidence). Primary treatment with IVIG compared to prednisolone for people with KD The evidence comparing IVIG with prednisolone on incidence of CAA is very uncertain (OR 0.60, 95% CI 0.24 to 1.48; 2 studies, 140 participants; very low-certainty evidence), and there was little to no difference between groups in adverse effects (OR 4.18, 95% CI 0.19 to 89.48; 1 study; 90 participants; low-certainty evidence). We are very uncertain of the impact on duration of fever, as two studies reported this outcome differently and showed conflicting results. One study reported on acute coronary syndromes and mortality, finding little or no difference between groups (low-certainty evidence). No study reported the need for additional treatment or length of hospital stay.

AUTHORS' CONCLUSIONS

The included RCTs investigated a variety of comparisons, and the small number of events observed during the study periods limited detection of effects. The certainty of the evidence ranged from moderate to very low due to concerns related to risk of bias, imprecision, and inconsistency. The available evidence indicated that high-dose IVIG regimens are probably associated with a reduced risk of CAA formation compared to ASA or medium- or low-dose IVIG regimens. There were no clinically significant differences in incidence of adverse effects, which suggests there is little concern about the safety of IVIG. Compared to ASA, high-dose IVIG probably reduced the duration of fever, but there was little or no difference detected in the need for additional treatment. Compared to medium- or low-dose IVIG, there may be reduced duration of fever and reduced need for additional treatment. We were unable to draw any conclusions regarding acute coronary syndromes, mortality, or length of hospital stay, or for the comparison IVIG versus prednisolone. Our findings are in keeping with current guideline recommendations and evidence from long-term epidemiology studies.

Inositol-Triphosphate 3-Kinase C and DNA Methylation Involvement in NLRP3 Inflammasome Activation in Kawasaki Disease

OBJECTIVE

To evaluate ITPKC and NLRP3 expression in children with Kawasaki disease (KD) and investigate the relationship between serum pro-inflammatory cytokines triggered by NLRP3 and inflammatory indices. Simultaneously, the methylation level in the ITPKC promoter was evaluated in children with KD.

METHODS

Children who satisfied the American Heart Association diagnostic criteria for KD were enrolled in the study from August 2018 to January 2019. The levels of ITPKC, NLRP3, IL-1β, and IL-18 were measured. The effect of DNA methylation on the activity of the ITPKC promoter was observed. Methylation-specific PCR was used to verify methylation modification of the ITPKC promoter region in children with KD.

RESULTS

ITPKC expression was downregulated in patients with KD, whereas NLRP3 was upregulated. Expression of the downstream cytokine, IL-18, was significantly upregulated in children with KD and correlated positively with inflammatory indices. Modifying DNA methylation significantly decreased the luciferase activity of the plasmid containing the ITPKC promoter region and thus, may inhibit ITPKC gene promoter activity. Furthermore, methylation modification was observed in the ITPKC promoter region of children with KD.

CONCLUSION

Modification of DNA methylation inhibits ITPKC promoter activity and is involved in NLRP3 inflammasome activation in children with KD.

Functions and therapeutic interventions of non-coding RNAs associated with TLR signaling pathway in atherosclerosis

Nowadays, emerging data demonstrate that the toll-like receptor (TLR) signaling pathway plays an important role in the progression of inflammatory atherosclerosis. Indeed, dysregulated TLR signaling pathway could be a cornerstone of inflammation and atherosclerosis, which contributes to the development of cardiovascular diseases. It is interesting to note that this pathway is heavily controlled by several mechanisms, such as epigenetic factors in which the role of non-coding RNAs (ncRNAs), particularly microRNAs and long noncoding RNAs as well as circular RNAs in the pathogenesis of atherosclerosis has been well studied. Recent years have seen a significant surge in the amount of research exploring the interplay between ncRNAs and TLR signaling pathway downstream targets in the development of atherosclerosis; however, there is still considerable room for improvement in this field. The current study was designed to review underlying mechanisms of TLR signaling pathway and ncRNA interactions to shed light on therapeutic implications in patients with atherosclerosis.

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.

MicroRNAs in Kawasaki disease: An update on diagnosis, therapy and monitoring

Kawasaki disease (KD) is an acute autoimmune vascular disease featured with a long stage of febrile. It predominantly afflicts children under 5 years old and causes an increased risk of cardiovascular combinations. The onset and progression of KD are impacted by many aspects, including genetic susceptibility, infection, and immunity. In recent years, many studies revealed that miRNAs, a novel class of small non-coding RNAs, may play an indispensable role in the development of KD via differential expression and participation in the central pathogenesis of KD comprise of the modulation of immunity, inflammatory response and vascular dysregulation. Although specific diagnose criteria remains unclear up to date, accumulating clinical evidence indicated that miRNAs, as small molecules, could serve as potential diagnostic biomarkers and exhibit extraordinary specificity and sensitivity. Besides, miRNAs have gained attention in affecting therapies for Kawasaki disease and providing new insights into personalized treatment. Through consanguineous coordination with classical therapies, miRNAs could overcome the inevitable drug-resistance and poor prognosis problem in a novel point of view. In this review, we systematically reviewed the existing literature and summarized those findings to analyze the latest mechanism to explore the role of miRNAs in the treatment of KD from basic and clinical aspects retrospectively. Our discussion helps to better understand the pathogenesis of KD and may offer profound inspiration on KD diagnosis, treatment, and prognosis.

Kawasaki Disease and Coronary Artery Involvement: A Narrative Review

Kawasaki disease is a systemic vasculitis with a risk of developing coronary artery lesions if left untreated. Kawasaki disease can be diagnosed clinically with classical symptoms (conjunctivitis, rash, lymphadenopathy, mucositis, edema of hands and feet), but predicting the risk of developing coronary artery aneurysm remains challenging. The coronary sequelae of Kawasaki disease have significant morbidity and mortality and are the second most common cause of acquired cardiac disease in children. Several genetic and immune factors are involved in the inflammation of coronary artery lesions in Kawasaki disease. Inositol trisphosphate 3-Kinase (ITPKC), Foxp3+, circular RNAs, mannose-binding lectin 2 (MBL2), complement factor H (CFH), kininogen 1 (KNG1), serpin family C member 1 (SERPINC1) and fibronectin 1 (FN1) are the essential genes identified in the pathogenesis of coronary artery lesions in Kawasaki disease. The addition of methylprednisolone to a combination of aspirin and intravenous immunoglobulins and biological agents like anakinra, etanercept, infliximab, and immunosuppressants like cyclosporine prevents the occurrence of coronary artery aneurysms in Kawasaki disease. Since the coronary artery lesions form the second most common cause of acquired cardiac disease in children and the incidence of myocardial infarction is a late complication, the risk stratification for coronary artery aneurysms and follow-up protocols for the prevention of cardiac thrombosis were proposed by the American Heart Association in 2017.

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

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

CONCLUSION

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

WHAT IS KNOWN

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

WHAT IS NEW

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

Efficacy of Anakinra on Multiple Coronary Arteries Aneurysms in an Infant with Recurrent Kawasaki Disease, Complicated by Macrophage Activation Syndrome

Kawasaki disease (KD) is rare in infants less than 3 months of age, and its recurrence is exceptional. Infants with KD are at higher risk of severe clinical presentation, therapy failure, complications and coronary aneurysms (CAAs), and this is the reason they deserve more aggressive therapy and a strict clinical follow-up. We report a 2-month-old male with KD, complicated by Macrophage Activation Syndrome (MAS). Despite timely and aggressive therapy with immunoglobulins, steroids and aspirin, multiple CAAs developed. Two-month therapy with anakinra completely reverted all the aneurysms. After six months, the infant experienced KD relapse and was successfully re-treated with immunoglobulins, steroids and aspirin. A strict echocardiographic follow-up did not show recurrence of aneurysms. Two years later, the child is healthy, without cardiac sequelae. In our experience, anakinra was effective in reverting multiple aneurysms and its effect proved to be long-lasting, even in front of KD recurrence. Based on this evidence, it seems reasonable to hypothesize not to limit the use of anakinra as rescue therapy for complicated or refractory KD, but to consider the possibility of adding it to first-line therapies for some subgroups of very-high-risk patients, in order to strengthen the prevention of CAAs.

American College of Rheumatology Clinical Guidance for Multisystem Inflammatory Syndrome in Children Associated With SARS-CoV-2 and Hyperinflammation in Pediatric COVID-19: Version 3

OBJECTIVE

To provide guidance on the management of Multisystem Inflammatory Syndrome in Children (MIS-C), a condition characterized by fever, inflammation, and multiorgan dysfunction that manifests late in the course of SARS-CoV-2 infection. Recommendations are also provided for children with hyperinflammation during COVID-19, the acute, infectious phase of SARS-CoV-2 infection.

METHODS

The Task Force is composed of 9 pediatric rheumatologists and 2 adult rheumatologists, 2 pediatric cardiologists, 2 pediatric infectious disease specialists, and 1 pediatric critical care physician. Preliminary statements addressing clinical questions related to MIS-C and hyperinflammation in COVID-19 were developed based on evidence reports. Consensus was built through a modified Delphi process that involved anonymous voting and webinar discussion. A 9-point scale was used to determine the appropriateness of each statement (median scores of 1-3 for inappropriate, 4-6 for uncertain, and 7-9 for appropriate). Consensus was rated as low, moderate, or high based on dispersion of the votes. Approved guidance statements were those that were classified as appropriate with moderate or high levels of consensus, which were prespecified before voting.

RESULTS

The guidance was approved in June 2020 and updated in November 2020 and October 2021, and consists of 41 final guidance statements accompanied by flow diagrams depicting the diagnostic pathway for MIS-C and recommendations for initial immunomodulatory treatment of MIS-C.

CONCLUSION

Our understanding of SARS-CoV-2-related syndromes in the pediatric population continues to evolve. This guidance document reflects currently available evidence coupled with expert opinion, and will be revised as further evidence becomes available.

Anakinra Treatment in Patients with Acute Kawasaki Disease with Coronary Artery Aneurysms: A Phase I/IIa Trial

OBJECTIVES

To determine the safety, pharmacokinetics, and immunomodulatory effects of 2-6 weeks of anakinra therapy in patients with acute Kawasaki disease with a coronary artery aneurysm (CAA).

STUDY DESIGN

We performed a Phase I/IIa dose-escalation study of anakinra (2-11 mg/kg/day) in 22 patients with acute Kawasaki disease with CAA. We measured interleukin (IL)-1RA concentrations after the first dose and trough levels up to study week 6. Markers of inflammation and coronary artery z-scores were assessed pretreatment and at 48 hours, 2 weeks, and 6 weeks after initiation of therapy.

RESULTS

Up to 6 weeks of anakinra (up to 11 mg/kg/day) was safe and well tolerated by the 22 participants (median age, 1.1 years), with no serious adverse events attributable to the study drug. All participants were treated with intravenous immunoglobulin (IVIG), and 20 also received infliximab (10 mg/kg) before initiation of anakinra. Serum levels of IL-6, IL-8, and tumor necrosis factor α decreased similarly in patients with Kawasaki disease treated with IVIG, infliximab, and anakinra compared with age- and sex-matched patients with Kawasaki disease treated only with IVIG and infliximab. Anakinra clearance increased with illness day at diagnosis. Simulations demonstrated that more frequent intravenous (IV) dosing may result in more sustained concentrations without significantly increasing the peak concentration compared with subcutaneous (SC) dosing.

CONCLUSIONS

Both IV and SC anakinra are safe in infants and children with acute Kawasaki disease and CAA. IV dosing every 8-12 hours during the acute hospitalization of patients with Kawasaki disease may result in a sustained concentration while avoiding frequent SC injections. The efficacy of a short course of IV therapy during hospitalization should be studied. TRIAL REGISTRATION CLINICALTRIALS.GOV: NCT02179853.

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.

Efficacy of sildenafil and high-dose anakinra in an MIS-C patient with pulmonary vasculitis: A case report

Multisystem inflammatory syndrome in children (MIS-C) is a newly identified clinical entity still not very well known in terms of epidemiology, pathogenesis, and long-term outcome. Pulmonary involvement with acute respiratory failure is an unusual life-threatening complication of MIS-C, often a reason for admission to the pediatric intensive care unit (PICU) and the use of mechanical ventilation. We present a case of a 7-year-old male patient, previously healthy, hospitalized for MIS-C, treated with intravenous immunoglobulins (IVIG), high dose methylprednisolone, and anakinra. After 2 days of the aforementioned therapy, the patient presented with hypoxia (SatO₂: 85% in ambient air room) and breathing difficulties. A chest computed tomography (CT) scan showed the presence of multiple bilateral basal parenchymal thickening and small basal pleural effusion and an arterial blood gas analysis revealed severe hypoxia (PaO₂/FiO₂ ratio, 170 mmHg). Because of a worsening of respiratory distress, the patient was transferred to the PICU, where invasive mechanical ventilation and a continuous infusion of anakinra (12 mg/kg/day) were started. An echocardiogram was performed, which showed an increase in pulmonary pressure (40 mmHg) with normal heart ejection fraction (55%), and the hypothesis of pulmonary vasculitis involving the pulmonary arterioles was made. Therefore, therapy with sildenafil (0.15 mg/kg/day) was promptly set up, with an immediate improvement of the clinical picture of respiratory failure, reduction of pulmonary pressure (23 mmHg), and subsequent extubation at 36 h with a regular clinical course until discharge. As far as we know, our case represents the first report of pulmonary vasculitis in an MIS-C patient. The use of sildenafil and high-dose continuous anakinra may represent a rescue therapy in cases of MIS-C with pulmonary vasculitis or with difficulty in extubation, allowing a short-term hospitalization in intensive care and improving the long-term outcome in these patients.

Who Would Have Predicted Multisystem Inflammatory Syndrome in Children?

PURPOSE OF REVIEW

Multisystem inflammatory disease in children (MIS-C) is a novel post-infectious phenomenon following coronavirus disease-19 (COVID-19). Herein, we present an in-depth review of the latest MIS-C literature related to clinical findings, pathophysiology, imaging and laboratory studies, treatment algorithms, and disease outcomes.

RECENT FINDINGS

With its non-specific presentation of fever, gastrointestinal symptoms, cardiovascular injury and shock, systemic inflammation, and Kawasaki disease (KD)-like features, MIS-C can be a diagnostic challenge, overlapping with KD and active COVID-19 infection. However, common laboratory features, imaging findings, and historical clues can lead to accurate diagnosis and allow for appropriate treatment with a variety of immunomodulatory therapies, including intravenous immunoglobulin (IVIG). Aggressive treatment of MIS-C leads to good outcomes. Longitudinal studies continue to illuminate long-term cardiac sequelae and recovery. MIS-C presents with fever, KD features, gastrointestinal symptoms, cardiac inflammation, and shock. Early recognition and prompt institution of IVIG and glucocorticoids provide for rapid improvement.

Anti-inflammatory Treatment of Kawasaki Disease: Comparison of Current Guidelines and Perspectives

Kawasaki disease (KD), an acute, generalized vasculitis, is associated with an increased risk of coronary heart disease and is the most common cause of acquired heart disease in childhood. The incidence of KD is increasing worldwide. There are numerous international treatment guidelines. Our study aims to perform the first one so far comparison of them. While the gold standard therapy remains still the same (intravenous immunoglobulins and aspirin), there is currently a lack of evidence for choosing optimal treatment for high-risk patients and refractory KD. In this review, we also discuss the treatment of complications of KD and Kawasaki-like phenotypes, present an anti-inflammatory treatment in the light of new scientific data, and present novel potential therapeutic targets for KD.

Pyroptosis: Mechanisms and Links with Fibrosis

Fibrosis is responsible for approximately 45% of deaths in the industrialized world and has been a major global healthcare burden. Excessive fibrosis is the primary cause of organ failure. However, there are currently no approved drugs available for the prevention or treatment of fibrosis-related diseases. It has become evident that fibrosis is characterized by inflammation. In a large number of studies of various organs in mice and humans, pyroptosis has been found to play a significant role in fibrosis. Pyroptosis is a form of programmed cell death mediated by the N-terminal fragment of cysteinyl aspartate-specific proteinase (caspase)-1-cleaved gasdermin D (GSDMD, producing GSDMD-N) that gives rise to inflammation via the release of some proinflammatory cytokines, including IL-1β, IL-18 and HMGB1. These cytokines can initiate the activation of fibroblasts. Inflammasomes, an important factor upstream of GSDMD, can activate caspase-1 to trigger the maturation of IL-1β and IL-18. Moreover, the inhibition of inflammasomes, proinflammatory cytokines and GSDMD can prevent the progression of fibrosis. This review summarizes the growing evidence indicating that pyroptosis triggers fibrosis, and highlights potential novel targets for antifibrotic therapies.

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

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

A 7-Year-Old Boy and a 14-Year-Old Girl Initially Diagnosed with Toxic Shock Syndrome and Tested Positive for SARS-CoV-2 Infection, Supporting a Diagnosis of Multisystem Inflammatory Syndrome in Children (MIS-C)

BACKGROUND Multisystem inflammatory syndrome in children (MIS-C) has recently been described in children infected with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). This report describes 2 children with MIS-C who were initially diagnosed with toxic shock syndrome but who tested positive for SARS-CoV-2 infection on reverse transcription-polymerase chain reaction, supporting the diagnosis of MIS-C. CASE REPORT Case 1. A 7-year-old boy with fever, cough, and dyspnea was treated with oxygen, intravenous immunoglobulin (IVIG) infusion, and methylprednisolone and showed a worsening of clinical conditions, persistent fever, hypotension, and hematological parameters compatible with macrophage activation syndrome (MAS). Three intravenous boluses of methylprednisolone (30 mg/kg/day) were followed by a progressive resolution. Case 2. A 14-year-old girl with syncope, fever, diarrhea, oliguria, and increased creatinine levels required fluid infusion and correction of electrolyte imbalance. The increase of creatine phosphokinase (CPK), myoglobin, troponin, and creatine kinase-MB (CK-MB) was associated with grade I atrioventricular block and pericardial effusion. The patient showed myositis and severe muscular weakness, with hematological parameters compatible with MIS-C. She started IVIG and 3 intravenous boluses of methylprednisolone. However, bradycardia, tachypnea, severe hypotension, loss of consciousness, oliguria, bilateral ground-glass pneumonia, bilateral pleural, and peritoneal effusion, in the absence of thromboembolism, required treatment with furosemide, albumin, and enoxaparin, and was followed by a prompt resolution. CONCLUSIONS These 2 pediatric cases highlight the importance of SARS-CoV-2 testing in all patients with acute symptoms and signs of infection during the COVID-19 pandemic. As new variants of SARS-CoV-2 emerge, cases of MIS-C can become more prevalent, and pediatricians should be aware of diagnostic and management guidelines.

Pediatric Rheumatologic Effects of COVID-19

A multisystem inflammatory syndrome (MISC) can result from COVID-19 infection in previously healthy children and adolescents. It is potentially life threatening and is treated initially with intravenous immunoglobulin and aspirin but may require anti-inflammatory monoclonal antibody treatment in severe cases. SARS-CoV-2 infection can cause macrophage activation syndrome, chilblains, and flares of existing rheumatologic diseases. The pandemic has led to later presentation of some rheumatologic conditions as parents and patients have avoided health care settings. PubMed and Google scholar have been utilized to review the literature on the rheumatologic conditions resulting from COVID-19 and the current treatment options.

COVID-19 associated Multisystem Inflammatory Syndrome in Children (MIS-C) guidelines; revisiting the Western New York approach as the pandemic evolves

Multisystem inflammatory syndrome of children (MIS-C) continues to be a highly concerning diagnosis in those recently infected with SARS-CoV-2. The diagnosis of MIS-C cases will likely become even more challenging as vaccine uptake and natural immunity in previously infected persons leads to lower circulating rates of SARS-CoV-2 infection and will make cases sporadic. Febrile children presenting with cardiac dysfunction, symptoms overlapping Kawasaki disease or significant gastrointestinal complaints warrant a thorough screen in emergency departments, urgent care centers, and outpatient pediatric or family medicine practices. An increased index of suspicion and discussion regarding higher level of care (transferring to pediatric tertiary care centers or to intensive care) continues to be recommended. Herein we outline a broad approach with a multidisciplinary team for those meeting the case definition and believe such an approach is crucial for successful outcomes.

Off-label use of anti-IL-1 drugs in rheumatic diseases

Interleukin-1 (IL-1) plays a key role in the pathogenesis of different rheumatic diseases. There are now several agents available on the market capable of blocking IL-1. The proven effectiveness and excellent safety of these drugs makes them a possible therapeutic option in the treatment of IL-1 driven diseases, when previous therapies are contraindicated or ineffective. This article discusses the European wide off-label use of these drugs for the treatment of rheumatic diseases.

Management of COVID-19-associated multisystem inflammatory syndrome in children: A comprehensive literature review

Background

The prevalence and severity of COVID-19 are greatly reduced in children, yet some pediatric patients develop a syndrome resembling Kawasaki Disease (KD), termed Multisystem Inflammatory Syndrome in Children (MIS-C). With an estimated incidence of 2/100,000 children, MIS-C is relatively rare but can be fatal. Clinical features can include fever, hyperinflammatory state, gastrointestinal symptoms, myocardial dysfunction, and shock. The pathogenesis of MIS-C, although yet to be completely elucidated, appears to be distinct from KD in terms of epidemiology, severity, and biochemical signature.

Aim of Review

Although efficacy of treatments for MIS-C have largely not yet been investigated, we aim to conduct a comprehensive literature search of numerous medical databases (AMED, EBM Reviews, Embase, Healthstar, MEDLINE, ERIC, and Cochrane) to highlight treatments used around the world, their rationale, and outcomes to better inform guidelines in the future. Using the findings, an approach to MIS-C management will be outlined.

Key Scientific Concepts of Review

•

MIS-C appears to be a SARS-CoV-2 related post-infection phenomenon that is distinct from Kawasaki disease.

•

Although outcomes are largely favorable, there is significant variation in MIS-C treatment. Most management regimens reported to date mirror that of KD; however, targeted therapy based on specific MIS-C phenotypes may have the potential to improve outcomes.

•

We recommend close monitoring by a multidisciplinary team, symptomatic treatment (e.g., intravenous immunoglobulin for KD-like symptoms, steroids/immunotherapy for multisystem inflammation), and long-term follow-up.

•

Further research is required to evaluate the effectiveness of current MIS-C treatments and to determine more refined therapies.

COVID-19 Management in the Pediatric Age: Consensus Document of the COVID-19 Working Group in Paediatrics of the Emilia-Romagna Region (RE-CO-Ped), Italy

Since December 2019, coronavirus disease (COVID-19) caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has rapidly spread, becoming the first pandemic of the 21st century by number of deaths (over 2,000,000 worldwide). Many aspects of SARS-CoV-2 infection in children and adolescents remain unclear, and optimal treatment has not yet been defined. Therefore, our goal was to develop a consensus document, practically synthesizing the accumulated data and clinical experience of our expert group. Literature research was carried out using the keywords "COVID-19" or "SARS-CoV-2" and "children" or "pediatrics" and "prevention" or "diagnosis" or "MIS-C" or "treatment" in electronic databases (MEDLINE, PUBMED), existing guidelines and gray literature. The fact that the majority of the problems posed by SARS-CoV-2 infection in pediatric age do not need hospital care and that, therefore, infected children and adolescents can be managed at home highlights the need for a strengthening of territorial pediatric structures. The sharing of hospitalization and therapeutic management criteria for severe cases between professionals is essential to ensure a fair approach based on the best available knowledge. Moreover, the activity of social and health professionals must also include the description, management and limitation of psychophysical-relational damage resulting from the SARS-CoV-2 pandemic on the health of children and adolescents, whether or not affected by COVID-19. Due to the characteristics of COVID-19 pathology in pediatric age, the importance of strengthening the network between hospital and territorial pediatrics, school, educational, social and family personnel both for strictly clinical management and for the reduction in discomfort, with priority in children of more frail families, represents a priority.

Distinctive Features of Kawasaki Disease Following SARS-CoV-2 Infection: a Controlled Study in Paris, France

BACKGROUND

An outbreak of multisystem inflammatory syndrome in children, including Kawasaki disease (KD), emerged during COVID-19 pandemic. We explored whether Kawasaki-like disease (KD), when associated with confirmed SARS-CoV-2 infection, has specific characteristics.

METHODS

We included children and adolescents with KD criteria admitted in the department of general pediatrics of a university hospital in Paris, France, between January 1, 2018, and May 26, 2020. The incidence of KD was compared between the outbreak and a pre-outbreak control period (January 1, 2018, to April 25). Characteristics of patients with positive SARS-CoV-2 testing (KD-SARS-CoV-2) were compared to those of the pre-outbreak period (classic KD).

RESULTS

A total of 30 and 59 children with KD were admitted during the outbreak and pre-outbreak periods, respectively (incidence ratio 13.2 [8.3-21.0]). During the outbreak, 23/30 (77%) children were diagnosed as KD-SARS-CoV-2. When compared with patients with classic KD, those with KD-SARS-CoV-2 were more frequently of sub-Saharan African ancestry (OR 4.4 [1.6-12.6]) and older (median 8.2 vs. 4.0 years, p < 0.001), had more often initial gastrointestinal (OR 84 [4.9-1456]) and neurological (OR 7.3 [1.9-27.7] manifestations, and shock syndrome (OR 13.7 [4.2-45.1]). They had significantly higher CRP and ferritin levels. Noticeably, they had more frequently myocarditis (OR 387 [38-3933]).

CONCLUSIONS

Children and adolescents with KD-SARS-CoV-2 have specific features when compared with those with classic KD. These findings should raise awareness and facilitate the study of their pathogenesis.

American College of Rheumatology Clinical Guidance for Multisystem Inflammatory Syndrome in Children Associated With SARS-CoV-2 and Hyperinflammation in Pediatric COVID-19: Version 2

OBJECTIVE

To provide guidance on the management of Multisystem Inflammatory Syndrome in Children (MIS-C), a condition characterized by fever, inflammation, and multiorgan dysfunction that manifests late in the course of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. Recommendations are also provided for children with hyperinflammation during coronavirus disease 2019 (COVID-19), the acute, infectious phase of SARS-CoV-2 infection.

METHODS

The Task Force was composed of 9 pediatric rheumatologists and 2 adult rheumatologists, 2 pediatric cardiologists, 2 pediatric infectious disease specialists, and 1 pediatric critical care physician. Preliminary statements addressing clinical questions related to MIS-C and hyperinflammation in COVID-19 were developed based on evidence reports. Consensus was built through a modified Delphi process that involved anonymous voting and webinar discussion. A 9-point scale was used to determine the appropriateness of each statement (median scores of 1-3 for inappropriate, 4-6 for uncertain, and 7-9 for appropriate). Consensus was rated as low, moderate, or high based on dispersion of the votes. Approved guidance statements were those that were classified as appropriate with moderate or high levels of consensus, which were prespecified before voting.

RESULTS

The first version of the guidance was approved in June 2020, and consisted of 40 final guidance statements accompanied by a flow diagram depicting the diagnostic pathway for MIS-C. The document was revised in November 2020, and a new flow diagram with recommendations for initial immunomodulatory treatment of MIS-C was added.

CONCLUSION

Our understanding of SARS-CoV-2-related syndromes in the pediatric population continues to evolve. This guidance document reflects currently available evidence coupled with expert opinion, and will be revised as further evidence becomes available.

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.

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

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

Multifocal neutrophilic meningoencephalitis: a novel disorder responsive to anakinra

We report a 57-year-old man with recurrent meningoencephalitis resulting in bouts of altered consciousness, encephalopathy, tremors, focal seizures, and paraparesis. The neurological manifestations were accompanied by fever and leukocytosis in the absence of other systemic manifestations. MRI abnormalities of the brain, brainstem, spinal cord and meninges and CSF pleocytosis and elevated protein were observed. Exhaustive studies failed to reveal an etiology. Brain biopsy revealed nodules of neutrophils and macrophages, but no vasculitis. The lesions were not vasocentric as would be expected with neuro-Behcet's disease and neuro-Sweet's disease. The disorder was responsive to high-dose corticosteroid therapy and, ultimately, to anakinra, an IL-1α and IL-1β receptor antagonist.

The revisited role of interleukin-1 alpha and beta in autoimmune and inflammatory disorders and in comorbidities

The interleukin (IL) 1 family of cytokines is noteworthy to have pleiotropic functions in inflammation and acquired immunity. Over the last decades, several progresses have been made in understanding the function and regulation of the prototypical inflammatory cytokine (IL-1) in human diseases. IL-1α and IL-1β deregulated signaling causes devastating diseases manifested by severe acute or chronic inflammation. In this review, we examine and compare the key aspects of IL-1α and IL-1β biology and regulation and discuss their importance in the initiation and maintenance of inflammation that underlie the pathology of many human diseases. We also report the current and ongoing inhibitors of IL-1 signaling, targeting IL-1α, IL-1β, their receptor or other molecular compounds as effective strategies to prevent or treat the onset and progression of various inflammatory disorders.

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

Objectives

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

Methods

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

Results

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

Conclusions

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

Multisystem inflammatory syndrome in children

PURPOSE OF REVIEW

Here we summarize current knowledge about multisystem inflammatory syndrome in children (MIS-C), a presumed postinfectious inflammatory condition that has emerged as an important COVID-19-associated complication, to help clinicians identify and manage cases.

RECENT FINDINGS

Clinical presentation of MIS-C is dominated by significant inflammation. Fever, gastrointestinal symptoms, cardiac dysfunction, and hypotension are common features. Kawasaki disease-like findings are common, but epidemiologic data and recent mechanistic studies suggest that distinct inflammatory pathways mediate Kawasaki disease and MIS-C. A broad diagnostic approach is recommended, given overlapping presentations between MIS-C and many other disease processes. Current management of MIS-C is highly variable, depending on illness severity, and can range from supportive care to aggressive immune modulation. A multidisciplinary approach with early involvement of multiple pediatric subspecialists is recommended for complicated cases.

SUMMARY

Several studies have described the clinical manifestations of MIS-C, but definitive diagnosis remains challenging. Robust information about long-term outcomes awaits further study, as do immunologic data to refine diagnostic and therapeutic strategies.

Interleukin-1 Blockade in Polygenic Autoinflammatory Disorders: Where Are We now?

Polygenic autoinflammatory diseases (AIDs), such as systemic juvenile idiopathic arthritis (sJIA), adult-onset Still's disease, Kawasaki disease, idiopathic recurrent pericarditis (IRP), Behçet’s Syndrome, Crystal-induced arthropatihes such as gout or Calcium pyrophosphate deposition disease are characterized by the overexpression of inflammasome-associated genes, leading to a dysregulation of the innate immune response. The IL-1 cytokine family (IL-1α, IL-1β, IL-1Ra, IL-18, IL-36Ra, IL-36α, IL-37, IL-36β, IL-36g, IL-38, IL-33) was defined to be principally responsible for the inflammatory nature of polygenic AIDs. Several clinical trials were initiated, and IL-1 blockade has been proven to cause a rapid reduction of clinical symptoms and normalization of laboratory parameters in the majority of cases. Randomized, placebo-controlled, clinical trials, together with registry-based clinical trials and open-label, retrospective and prospective observational studies, supported the efficacy and safety of IL-1 inhibitors in the treatment of polygenic AIDs. Most of the current data are focused on the therapeutic use of anakinra, an IL-1 receptor antagonist, canakinumab, an anti-IL-1β monoclonal antibody, and rilonacept, a soluble decoy receptor. However, other promising agents, such as gevokizumab, IL-1β blocking monoclonal antibody, tadekinig alfa, a human recombinant IL-18-binding protein, and tranilast, an analog of a tryptophan metabolite, are currently being tested. Anakinra, canakinumab and rilonacept caused impressive improvements in both systemic and musculoskeletal symptoms. Furthermore, the anti-IL-1 therapy allowed corticosteroid tapering and, in some cases, even withdrawal. This article reviews the current IL-1 inhibitors and the results of all clinical trials in which they have been tested for the management of broad spectrum of polygenic AIDs.

Interleukin 1α: a comprehensive review on the role of IL-1α in the pathogenesis and treatment of autoimmune and inflammatory diseases

The interleukin (IL)-1 family member IL-1α is a ubiquitous and pivotal pro-inflammatory cytokine. The IL-1α precursor is constitutively present in nearly all cell types in health, but is released upon necrotic cell death as a bioactive mediator. IL-1α is also expressed by infiltrating myeloid cells within injured tissues. The cytokine binds the IL-1 receptor 1 (IL-1R1), as does IL-1β, and induces the same pro-inflammatory effects. Being a bioactive precursor released upon tissue damage and necrotic cell death, IL-1α is central to the pathogenesis of numerous conditions characterized by organ or tissue inflammation. These include conditions affecting the lung and respiratory tract, dermatoses and inflammatory skin disorders, systemic sclerosis, myocarditis, pericarditis, myocardial infarction, coronary artery disease, inflammatory thrombosis, as well as complex multifactorial conditions such as COVID-19, vasculitis and Kawasaki disease, Behcet's syndrome, Sjogren Syndrome, and cancer. This review illustrates the clinical relevance of IL-1α to the pathogenesis of inflammatory diseases, as well as the rationale for the targeted inhibition of this cytokine for treatment of these conditions. Three biologics are available to reduce the activities of IL-1α; the monoclonal antibody bermekimab, the IL-1 soluble receptor rilonacept, and the IL-1 receptor antagonist anakinra. These advances in mechanistic understanding and therapeutic management make it incumbent on physicians to be aware of IL-1α and of the opportunity for therapeutic inhibition of this cytokine in a broad spectrum of diseases.

Phase II Open Label Study of Anakinra in Intravenous Immunoglobulin-Resistant Kawasaki Disease

OBJECTIVE

Anakinra has been shown to be successful in preventing and treating cardiovascular lesions both in experimental murine models of Kawasaki disease (KD) and in several studies on intravenous immunoglobulin (IVIG)- and steroid-resistant patients with KD. This study was undertaken to determine the safety of blocking interleukin-1 in patients with IVIG-resistant KD.

METHODS

Sixteen patients were included in the present study. Patients with KD who were not responsive to 1 or more courses of 2 mg/kg of IVIG received anakinra by subcutaneous daily injections. Starting doses were 2 mg/kg of IVIG (4 mg/kg in patients who were age <8 months and who weighed ≥5 kilograms), and the dose was increased up to 6 mg/kg every 24 hours if the patient's body temperature remained >38°C, indicative of a fever. Treatment duration was 14 days. The last visit was on day 45. Primary outcome was abatement of fever. Secondary measures included disease activity, coronary artery Z score, and C-reactive protein (CRP) levels.

RESULTS

Seventy-five percent of patients in the intention-to-treat group and 87.5% in the per-protocol group became afebrile within 48 hours of the last escalation dose of anakinra. Reduction of disease activity by 50% was indicated on 93.3% (95% confidence interval [95% CI] 68.1-99.8%) of physician evaluations and on 100% (95% CI 73.5-100%) of parent evaluations. CRP values normalized by day 30. At the initial screening, 12 of 16 patients had a maximum coronary artery Z score of >2, and 10 of 16 patients had a maximum Z score of >2.5. At day 45, 5 of 10 patients (50% [95% CI 18.7-81.3%]) and 6 of 12 patients (50% [95% CI 21.1-78.9%]) had achieved coronary artery Z scores of <2.5 and <2, respectively. Five serious adverse events were observed in 3 patients, but no serious infections or deaths occurred.

CONCLUSION

Anakinra was well tolerated in the study patients and may have some efficacy in reducing fever, markers of systemic inflammation, and coronary artery dilatation in individuals with IVIG-refractory KD.

Efficacy of immunosuppressive therapy in myocarditis: A 30-year systematic review and meta analysis

AIMS

Myocarditis is an inflammation of the heart muscle, due to infectious, toxic or autoimmune causes. Literature reported controversial results in relation to the effect of immunosuppression (IS)/immunomodulation (IM). We aimed at assessing the effect of IS/IM by meta analysis.

METHODS AND RESULTS

Using the P.R.I.S.M.A. approach, two researchers searched for relevant studies on PubMed, Embase, and the Central Registry of Controlled Trials of the Cochrane Library. Proposed MeSH terms were: "immunotherapy OR immune therapy OR immune modeling OR Immunosuppressive Agents" AND "combination OR combined with OR plus" AND "myocarditis OR cardiomyopathies OR inflammatory cardiomyopathy". The language was restricted to English. Reference lists of included articles and those relevant to the topic were hand searched for the identification of additional, potentially relevant articles. The cutoff date was from 1987 until 30th Nov 2019. Reported survival or mortality events or change of left ventricular ejection fraction (LVEF) after IS/IT were primary outcomes of the study; in addition, improvement of New York Heart Association class, follow-up biopsy (Bx) findings, viral genome clearance on Bx and recurrence of myocarditis were recorded if reported. Statistical analysis was conducted using Review Manager 5.3; 5452 studies were screened, of these 73 were assessed for eligibility, including 8 randomized control studies, 26 retrospective studies, 2 prospective studies and 1 case control study, 34 case reports and 2 case series. In prospective studies, the difference in mortality between the IS and control groups tended to be lower in the combined IS groups (12.5% vs. 18.2%) (95% CI of odds ratio 0.7(0.3, 1.64)) and the pooled difference of the increase of LVEF between the IS and control groups tended to be higher in the combined IS groups (95% CI 7.26 (-2.29, 16.81)). In retrospective studies, the difference of survival between the IS and control group was significantly in favor of IS (95%CI Hazard ratio 0.82(0.69, 0.96)).

CONCLUSIONS

A tailored IS may be considered in myocarditis, depending on the phase of the disease, and the type of underlying autoimmune or immune-mediated form.

Son MB, Tremoulet AH, Yeung RSM, Mudano AS, Turner AS, Karp DR, Mehta JJ. American College of Rheumatology Clinical Guidance for Multisystem Inflammatory Syndrome in Children Associated With SARS-CoV-2 and Hyperinflammation in Pediatric COVID-19: Version 1

OBJECTIVE

To provide guidance on the management of multisystem inflammatory syndrome in children (MIS-C), a condition characterized by fever, inflammation, and multiorgan dysfunction that manifests late in the course of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection, and to provide recommendations for children with hyperinflammation during coronavirus disease 2019 (COVID-19), the acute, infectious phase of SARS-CoV-2 infection.

METHODS

A multidisciplinary task force was convened by the American College of Rheumatology (ACR) to provide guidance on the management of MIS-C associated with SARS-CoV-2 and hyperinflammation in COVID-19. The task force was composed of 9 pediatric rheumatologists, 2 adult rheumatologists, 2 pediatric cardiologists, 2 pediatric infectious disease specialists, and 1 pediatric critical care physician. Preliminary statements addressing clinical questions related to MIS-C and hyperinflammation in COVID-19 were developed based on evidence reports. Consensus was built through a modified Delphi process that involved 2 rounds of anonymous voting and 2 webinars. A 9-point scale was used to determine the appropriateness of each statement (median scores of 1-3 for inappropriate, 4-6 for uncertain, and 7-9 for appropriate), and consensus was rated as low, moderate, or high based on dispersion of the votes along the numeric scale. Approved guidance statements were those that were classified as appropriate with moderate or high levels of consensus, as prespecified prior to voting.

RESULTS

The ACR task force approved a total of 128 guidance statements addressing the management of MIS-C and hyperinflammation in pediatric COVID-19. These statements were refined into 40 final clinical guidance statements, accompanied by a flow diagram depicting the diagnostic pathway for MIS-C.

CONCLUSION

Our understanding of SARS-CoV-2-related syndromes in the pediatric population continues to evolve. The guidance provided in this "living document" reflects currently available evidence, coupled with expert opinion, and will be revised as further evidence becomes available.

The off-label use of anakinra in pediatric systemic autoinflammatory diseases

Interleukin 1 (IL-1), a central mediator of innate immunity, is considered a master cytokine of local and systemic inflammation. IL-1 has emerged as pivotal in the pathogenesis of autoinflammatory diseases (AIDs), and blockade of its pathway has become a crucial target for therapy. Anakinra (ANA), a recombinant IL-1β receptor antagonist, was the first anti-IL-1 agent employed in clinical practice. ANA is currently approved for the treatment of rheumatoid arthritis, systemic juvenile idiopathic arthritis, adult-onset Still’s disease, and cryopyrin-associated autoinflammatory syndrome. It has also been successfully used for off-label treatment of various monogenic, polygenic, or undefined etiology systemic AIDs.

This review describes currently available evidence for the off-label use of ANA in pediatric rheumatologic diseases. Specifically, the use of ANA in Kawasaki disease, idiopathic recurrent pericarditis, Behçet disease, monogenic AIDs, undifferentiated AIDs, chronic non-bacterial osteomyelitis, macrophage activation syndrome, and febrile infection-related epilepsy, in terms of its safety and efficacy. In selected pediatric rheumatic disorders, the off-label administration of ANA appears to be effective and safe. In order to control severe and/or relapsing disease, ANA should be considered as a valuable treatment option in children suffering from rare inflammatory diseases. However, currently available data consist of retrospective studies and short case series; thus, randomized controlled trials and larger series with long-term follow up are mandatory to better assess the efficacy and cost effectiveness of ANA in these challenging patients.

Anakinra And Etanercept Combination Treatment in a Child With Severe, Nonresponsive Kawasaki Disease

Kawasaki disease (KD) patients' resistance to treatment with intravenous immunoglobulins (IVIG) places them at high risk for an unfavorable progression of the disease. In these patients, there has been little evidence that alternative treatments are effective. Nevertheless, biologicals such as an interleukin-1-receptor blocker and tumor-necrosis-factor-α inhibitors increasingly have been used. If the patient does not respond to one of these therapeutics, a combination of 2 biologicals might be an alternative, but this is not yet generally accepted due to the potentially increased risk of infection. Here we report on a 3-month-old boy suffering from severe refractory KD. KD diagnosis was delayed due to the misinterpretation of a urinary tract infection and to the short and nonsimultaneous presence of classical KD symptoms. After complete KD later was able to be diagnosed, treatment with intravenous immunoglobulins was administered. However, the disease proved resistant to 2 courses of IVIG, as well as to corticosteroids. The patient developed giant coronary artery aneurysms early during the course of disease. Anakinra was initiated, but even with stepwise higher anakinra dosages, he remained febrile and coronary artery dimensions increased. Therefore, etanercept was added as a second biological. Only under combination treatment with anakinra and etanercept were his inflammation and fever able to be completely resolved. Coronary artery dimensions improved over time.

Kawasaki Disease: an Update

PURPOSE OF REVIEW

Provide the most recent updates on the epidemiology, pathogenesis, and treatment advances in Kawasaki disease.

RECENT FINDINGS

Treatment advances in complex, IVIG-refractory cases of Kawasaki disease. Multisystem inflammatory syndrome, a newly reported inflammatory condition with Kawasaki-like features and an association with the 2019 Coronavirus (COVID-19). Kawasaki disease (KD) is a rare systemic inflammatory disease that predominately affects children less than 5 years of age. Pathogenesis of KD remains unknown; the leading theory is that an unknown stimulus triggers an immune-mediated inflammatory cascade in a genetically susceptible child. Classic KD is a clinical diagnosis based on set criteria and excluding other similar clinical entities. Patients who do not fulfill complete diagnostic criteria for KD are often referred to as atypical (or incomplete) KD. The most feared complication of KD is coronary artery abnormality development, and patients with atypical KD are also at risk. Administration of intravenous immunoglobulin (IVIG) and aspirin has greatly reduced the incidence of coronary lesions in affected children. Several other immune-modulating therapies have recently been utilized in complex or refractory cases.

Coronary Vasculitis Induced in Mice by Cell Wall Mannoprotein Fractions of Clinically Isolated Candida Species

Kawasaki disease (KD) is an inflammatory disease that was identified by Professor Tomisaku Kawasaki in 1961. Candida albicans-derived substances (CADS) such as the hot water extract of C. albicans and Candida water-soluble fractions (CAWS) induce coronary vasculitis similar to KD in mice. An increasing proportion of deep-seated candidiasis cases are caused by non-albicans Candida and are often resistant to antifungal drugs. We herein investigated whether the mannoprotein fractions (MN fractions) of clinically isolated Candida species induce vasculitis in mice. We prepared MN fractions from 26 strains of Candida species by conventional hot water extraction and compared vasculitis in DBA/2 mice. The results obtained revealed that the induction of vasculitis and resulting heart failure were significantly dependent on the species; namely, death rates on day 200 were as follows: Candida krusei (100%), Candida albicans (84%), Candida dubliniensis (47%), Candida parapsilosis (44%), Candida glabrata (32%), Candida guilliermondii (20%), and Candida tropicalis (20%). Even for C. albicans, some strains did not induce vasculitis. The present results suggest that MN-induced vasculitis is strongly dependent on the species and strains of Candida, and also that the MN fractions of some non-albicans Candida induce similar toxicity to those of C. albicans.

Paediatric multisystem inflammatory syndrome temporally associated with SARS-CoV-2 mimicking Kawasaki disease (Kawa-COVID-19): a multicentre cohort

BACKGROUND

Current data suggest that COVID-19 is less frequent in children, with a milder course. However, over the past weeks, an increase in the number of children presenting to hospitals in the greater Paris region with a phenotype resembling Kawasaki disease (KD) has led to an alert by the French national health authorities.

METHODS

Multicentre compilation of patients with KD in Paris region since April 2020, associated with the detection of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) ('Kawa-COVID-19'). A historical cohort of 'classical' KD served as a comparator.

RESULTS

Sixteen patients were included (sex ratio=1, median age 10 years IQR (4·7 to 12.5)). SARS-CoV-2 was detected in 12 cases (69%), while a further three cases had documented recent contact with a quantitative PCR-positive individual (19%). Cardiac involvement included myocarditis in 44% (n=7). Factors prognostic for the development of severe disease (ie, requiring intensive care, n=7) were age over 5 years and ferritinaemia >1400 µg/L. Only five patients (31%) were successfully treated with a single intravenous immunoglobulin (IVIg) infusion, while 10 patients (62%) required a second line of treatment. The Kawa-COVID-19 cohort differed from a comparator group of 'classical' KD by older age at onset 10 vs 2 years (p<0.0001), lower platelet count (188 vs 383 G/L (p<0.0001)), a higher rate of myocarditis 7/16 vs 3/220 (p=0.0001) and resistance to first IVIg treatment 10/16 vs 45/220 (p=0.004).

CONCLUSION

Kawa-COVID-19 likely represents a new systemic inflammatory syndrome temporally associated with SARS-CoV-2 infection in children. Further prospective international studies are necessary to confirm these findings and better understand the pathophysiology of Kawa-COVID-19. Trial registration number NCT02377245.