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

Exploring Causal Correlations Between Inflammatory Cytokines and Kawasaki Disease: A Mendelian Randomization

BACKGROUND

The role of inflammatory cytokines in Kawasaki disease (KD) pathogenesis is known, but causal relationships are unclear. This study investigates these connections using Mendelian randomization (MR).

METHODS

Genetic variations associated with KD were obtained from a GWAS including 119 cases and 6071 controls of European ancestry. Genetic data on inflammatory cytokines were sourced from a GWAS of 8,293 healthy participants.

RESULTS

The study identified significant associations between higher levels of macrophage colony stimulating factor (M-CSF), monocyte chemotactic protein-1 (MCP-1), and tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) and increased risk of KD. The odds ratios (OR) were 1.04 (95% CI: 1.01-1.08, p = 0.010) for M-CSF, 1.03 (95% CI: 1.01-1.05, p = 0.026) for MCP-1, and 1.02 (95% CI: 1.01-1.04, p = 0.027) for TRAIL.

CONCLUSION

This study suggests that M-CSF, MCP-1, and TRAIL are potentially involved in the etiology of KD.

Update on Diagnosis and Management of Kawasaki Disease: A Scientific Statement From the American Heart Association

Kawasaki disease (KD), an acute self-limited febrile illness that primarily affects children <5 years old, is the leading cause of acquired heart disease in developed countries, with the potential of leading to coronary artery dilation and coronary artery aneurysms in 25% of untreated patients. This update summarizes relevant clinical data published since the 2017 American Heart Association scientific statement on KD related to diagnosis, cardiac imaging in acute KD treatment, and long-term management. Criteria defining North American patients at high risk for developing coronary artery aneurysms who may benefit from more intensive initial treatment have been published. Advances in cardiovascular imaging have improved the ability to identify coronary artery stenosis in patients with KD, yet knowledge gaps remain regarding optimal frequency of serial imaging and the best imaging modality to identify those at risk for inducible myocardial ischemia. Recent data have advanced the understanding of safety and dosing for several anti-inflammatory therapies in KD. New anticoagulation medication, myocardial infarction management, transition of health care for patients with KD, and future directions in research are discussed.

An Update on Kawasaki Disease

PURPOSE

To summarize advances in research on the epidemiology, pathogenesis, diagnosis, and treatment of Kawasaki Disease (KD), a systemic inflammatory illness of unknown etiology that affects children globally.

RECENT FINDINGS

The epidemiology of KD was affected by the COVID-19 pandemic and advances in molecular immunology and machine learning have enabled research into its pathogenesis. There is ongoing research into agents that can be used to intensify initial treatment and accumulating evidence supporting the use of certain rescue regimens for refractory disease over others. There is promise surrounding a new coronary artery aneurysm prediction model. Research into the post-acute morbidity of KD continues. The COVID-19 pandemic temporarily reduced the incidence of KD. The NLRP3 inflammasome plays a key role in KD pathogenesis. Intensified initial treatment benefits high-risk patients, yet no intensification regimen shows superiority over another. Corticosteroids, infliximab, or combination therapy with IVIg plus another agent may be superior rescue regimens compared to IVIg alone for refractory KD. The Son score, developed in North America, predicted coronary artery lesions in Japanese and Italian cohorts. Patients with a history of KD may carry long-term physical and emotional burdens that persist into adulthood yet appear to have typical neurocognitive development. Successful transition to adult healthcare presents a challenge.

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.

Redundant role of PAD2 and PAD4 in the development of cardiovascular lesions in a mouse model of Kawasaki disease vasculitis

Kawasaki disease (KD) is the leading cause of acquired heart disease in children. While circulating neutrophils are increased and activated during acute KD, it is unclear whether neutrophils and neutrophil extracellular traps (NETs) contribute to the pathogenesis of KD. Peptidylarginine deiminase 4 (PAD4), an enzyme involved in protein citrullination and essential for NETs formation, is implicated in the pathogenesis of various diseases. Here, we used the Lactobacillus casei cell wall extract (LCWE)-induced mouse model of KD vasculitis to determine the contribution of PAD4 in KD vasculitis. We found that the pan-PADs inhibitor, Cl-amidine, significantly reduced LCWE-induced cardiovascular lesions, but neutrophil-specific Padi4 KO mice did not impact the development of KD vasculitis. While in vitro treatment of macrophages, which highly express Padi4, with Cl-amidine inhibited IL-1β secretion, macrophage-specific Padi4 KO mice did not reduce the lesions. Padi4-/- mice also developed KD vasculitis, AFM30a, a PAD2 inhibitor, significantly reduced KD vasculitis in Padi4-/- mice, indicating a compensatory role of PAD2 in PAD4 deficiency. We also identified several citrullinated proteins in macrophages with constitutively active NLRP3 inflammasome that were inhibited by Cl-amidine treatment, suggesting that protein citrullination participates in NLRP3 inflammasome activation. These data indicate a dispensable role for PAD4-dependent NETs formation, and a redundant role of PAD2 and PAD4 in this murine KD vasculitis. The cardioprotective effects of Cl-amidine to reduce the severity of murine KD vasculitis are not limited to PAD4 inhibition and may include decreased citrullination in the inflammasome pathway.

FCGR2/3 polymorphisms are associated with susceptibility to Kawasaki disease but do not predict intravenous immunoglobulin resistance and coronary artery aneurysms

Introduction

Kawasaki disease (KD) is a pediatric vasculitis that can result in coronary artery aneurysm (CAA) formation, which is a dangerous complication. Treatment with intravenous immunoglobulin (IVIg) significantly decreases the risk of CAA, possibly through competitive binding to Fc-gamma receptors (FcγRs), which reduces the binding of pathological immune complexes. However, ~20% of children have recrudescence of fever and have an increased risk of CAA. Therefore, we aimed to identify genetic markers at the FCGR2/3 locus associated with susceptibility to KD, IVIg resistance, or CAA.

Materials and methods

We investigated the association of single-nucleotide polymorphisms (SNPs) and copy number variations (CNVs) at the FCGR2/3 locus with KD susceptibility, IVIg resistance, and CAA risk using a family-based test (KD susceptibility) and case-control analyses (IVIg resistance and CAA risk) in different cohorts, adding up to a total of 1,167 KD cases. We performed a meta-analysis on IVIg resistance and CAA risk including all cohorts supplemented by previous studies identified through a systematic search.

Results

FCGR2A-p.166His was confirmed to be strongly associated with KD susceptibility (Z = 3.17, p = 0.0015). In case-control analyses, all of the investigated genetic variations at the FCGR2/3 locus were generally not associated with IVIg resistance or with CAA risk, apart from a possible association in a Polish cohort for the FCGR3B-NA2 haplotype (OR = 2.15, 95% CI = 1.15-4.01, p = 0.02). Meta-analyses of all available cohorts revealed no significant associations of the FCGR2/3 locus with IVIg resistance or CAA risk.

Discussion

FCGR2/3 polymorphisms are associated with susceptibility to KD but not with IVIg resistance and CAA formation. Currently known genetic variations at the FCGR2/3 locus are not useful in prediction models for IVIg resistance or CAA risk.

Physiologically Based Pharmacokinetic Modelling in Critically Ill Children Receiving Anakinra While on Extracorporeal Life Support

BACKGROUND AND OBJECTIVE

Because of the pathophysiological changes associated with critical illness and the use of extracorporeal life support (ECLS) such as continuous renal replacement therapy (CRRT) and extracorporeal membrane oxygenation (ECMO), the pharmacokinetics of drugs are often altered. The objective of this study was to develop a physiologically based pharmacokinetic (PBPK) model for anakinra in children that accounts for the physiological changes associated with critical illness and ECLS technology to guide appropriate pharmacotherapy.

METHODS

A PBPK model for anakinra was first developed in healthy individuals prior to extrapolating to critically ill children receiving ECLS. To account for the impact of anakinra clearance by the dialysis circuit, a CRRT compartment was added to the pediatric PBPK model and parameterized using data from a previously published ex-vivo study. Additionally, an ECMO compartment was added to the whole-body structure to create the final anakinra ECLS-PBPK model. The final model structure was validated by comparing predicted concentrations with observed patient data. Due to limited information in guiding anakinra dosing in this population, in-silico dose simulations were conducted to provide baseline recommendations.

RESULTS

By accounting for changes in physiology and the addition of ECLS compartments, the final ECLS-PBPK model predicted the observed plasma concentrations in an adolescent receiving subcutaneous anakinra. Furthermore, dosing simulations suggest that anakinra exposure in adolescents receiving ECLS is similar to that in healthy counterparts.

CONCLUSION

The anakinra ECLS-PBPK model developed in this study is the first to predict plasma concentrations in a population receiving simultaneous CRRT and ECMO. Dosing simulations provided may be used to inform anakinra use in critically ill children and guide future clinical trial planning.

Mycoplasma pneumoniae-induced Kawasaki disease via PINK1/Parkin-mediated mitophagy

Kawasaki disease (KD) is a systemic vasculitis with an unknown cause that primarily affects children. The objective of this study was to explore the function and underlying mechanism of mitophagy in Mycoplasma pneumoniae (MP)-induced KD. To create MP-induced KD models, Human coronary endothelial cells (HCAECs) and DBA/2 mice were employed and treated with Mp-Lipid-associated membrane proteins （LAMPs）. Lactate dehydrogenase (LDH) levels were tested to determine cellular damage or death. The inflammatory cytokines tumor necrosis factor (TNF)--α and interleukin (IL)-6 were measured using the Enzyme-Linked Immunosorbent Assay (ELISA) method. RT-qPCR and Western blotting were used to determine the expression of Intercellular Adhesion Molecule(ICAM)-1, vascular cell adhesion molecule (VCAM)-1, inducible nitric oxide synthase(iNOS), LC3, p62, PINK1(a mitochondrial serine/threonine-protein kinase), and PARKIN(a cytosolic E3-ubiquitin ligase). The adenosine triphosphate （ATP）, reactive oxygen species （ROS）, and mitochondrial membrane potential（MMP） levels were measured to determine mitochondrial function. Mitophagy was investigated using immunofluorescence and a mitophagy detection test. Autophagosome and mitochondrial morphology were examined using transmission electron microscopy. To identify inflammatory cell infiltration, hematoxylin and eosin staining was utilized. Mp-LAMPs increased the levels of TNF-α, IL-6, ICAM-1, VCAM-1, and iNOS in an HCAEC cell model, along with LDH release. After Mp-LAMPs exposure, there was a rise in LC3 and a reduction in p62. Meanwhile, the expression of PINK1 and Parkin was increased. Cyclosporin A dramatically increased ATP synthesis and MMP in HCAEC cells treated with Mp-LAMPs, while suppressing ROS generation, demonstrating excessive mitophagy-related mitochondrial dysfunction. Additionally, neither body weight nor artery tissue were affected due to PINK1 and Parkin suppression Cyclosporin A in Mp-LAMPs-treated mice. These findings indicated that PINK1/Parkin-mediated mitophagy inhibition may be a therapeutic target for MP-induced KD.

Subcutaneous anakinra in the management of refractory MIS-C in France

Introduction

Multisystemic inflammatory syndrome in children (MIS-C) is a therapeutic emergency and can lead to myocardial dysfunction (17%-75%) and heart failure (52%-53%). Intravenous immunoglobulins (IVIG) and corticosteroids (CST) have been validated for the management of this condition. Recent reports suggest that an interleukin-1 (IL-1) receptor antagonist, namely anakinra, may be a valuable add-on to the 2019 novel coronavirus disease (COVID-19) treatment for refractory patients. The purpose of this study was to describe the clinico-biological characteristics of patients treated with anakinra as well as the efficacy and safety of subcutaneous anakinra therapy in this condition.

Methods

The prospective multicentre study of children hospitalized for MIS-C between March 2020 and September 2022, including 23 international paediatric centres, followed for a mean duration of 3.072 ± 3.508 months. The patient data were extracted from the Juvenile Inflammatory Rheumatism (JIR) cohort. The clinico-pathological characteristics, cardiac ultrasound data, and adverse events were reported in patients receiving anakinra.

Results

Of the 470 children admitted with MIS-C, 18 French patients (50% girls) with a mean age of 10.06 ± 3.9 years were treated with subcutaneous anakinra. Anakinra was used in two situations, macrophage activation syndrome (MAS) (4 patients) and heart failure (14 patients) with a median left ventricular ejection fraction (LVEF) of 39.5% (30%-45%). The average dose of anakinra received was 2.53 ± 1.3 mg/kg/day for a median duration of 3 days. Prior to introduction, 78% (n = 14/18) of the patients had received CST and 56% (n = 10/18) had received IVIG. Only two patients received IVIG alone and six received CST alone plus anakinra. In 10% of cases, IVIG was poorly tolerated from a cardiovascular point of view and was discontinued. Transient elevations in serum transaminases were noted in four patients on anakinra without the need for treatment or dose modification. In all patients, rapid (48 h) improvement in myocardial function was observed (LVEF > 55%) with a concomitant significant decrease in myocardial enzymes (p < 0.05). All patients survived with complete recovery of cardiac function without sequelae.

Conclusions

Subcutaneous anakinra appears to be a safe and effective treatment for the management of heart failure or MAS in MIS-C patients. The value of IVIG in these two situations remains to be reviewed.

Risk factors and an early predictive model for Kawasaki disease shock syndrome in Chinese children

BACKGROUND

Kawasaki disease shock syndrome (KDSS), though rare, has increased risk for cardiovascular complications. Early diagnosis is crucial to improve the prognosis of KDSS patients. Our study aimed to identify risk factors and construct a predictive model for KDSS.

METHODS

This case-control study was conducted from June, 2015 to July, 2023 in two children's hospitals in China. Children initially diagnosed with KDSS and children with Kawasaki disease (KD) without shock were matched at a ratio of 1:4 by using the propensity score method. Laboratory results obtained prior to shock syndrome and treatment with intravenous immunoglobulin were recorded to predict the onset of KDSS. Univariable logistic regression and forward stepwise logistic regression were used to select significant and independent risk factors associated with KDSS.

RESULTS

After matching by age and gender, 73 KDSS and 292 KD patients without shock formed the development dataset; 40 KDSS and 160 KD patients without shock formed the validation dataset. Interleukin-10 (IL-10) > reference value, platelet counts (PLT) < 260 × 109/L, C-reactive protein (CRP) > 80 mg/ml, procalcitonin (PCT) > 1ng/ml, and albumin (Alb) < 35 g/L were independent risk factors for KDSS. The nomogram model including the above five indicators had area under the curves (AUCs) of 0.91(95% CI: 0.87-0.94) and 0.90 (95% CI: 0.71-0.86) in the development and validation datasets, with a specificity and sensitivity of 80% and 86%, 66% and 77%, respectively. Calibration curves showed good predictive accuracy of the nomogram. Decision curve analyses revealed the predictive model has application value.

CONCLUSIONS

This study identified IL-10, PLT, CRP, PCT and Alb as risk factors for KDSS. The nomogram model can effectively predict the occurrence of KDSS in Chinese children. It will facilitate pediatricians in early diagnosis, which is essential to the prevention of cardiovascular complications.

COVID-19-Related Multi-systemic Inflammatory Syndrome in Children (MIS-C)

Multisystem inflammatory syndrome in children (MIS-C) is a severe complication of SARS-CoV-2 infections in children. This syndrome manifests about a month after the initial viral infection and is characterized by fever, multiorgan dysfunction, and systemic inflammation. This chapter will review the emergence, epidemiology, clinical characteristics, diagnosis, pathophysiology, immunomodulatory treatment, prognosis, outcomes, and prevention of MIS-C. While the pathophysiology of MIS-C remains to be defined, it is a post-infection, hyperinflammatory syndrome of childhood with elevated inflammatory cytokines.

Risk factors for coronary artery abnormalities and resistance to immunoglobulin plus ciclosporin A therapy in severe Kawasaki disease: subanalysis of the KAICA trial, randomized trial for cicrosporin A as the first-line treatment

Background

To investigate risk factors for coronary arterial abnormalities (CAAs) and resistance to treatment in patients with Kawasaki disease (KD) receiving intravenous immunoglobulin (IVIG) plus ciclosporin A (CsA) as the first-line treatment, we performed a subanalysis of baseline data of participants in the KAICA trial, a phase 3, randomized study (JMA-ILA00174).

Methods

All data of the patients enrolled in the KAICA trial, who had a Gunma score ≥5 at diagnosis and had been randomly assigned to either IVIG (2 g/kg/24 h) plus CsA (5 mg/kg/day for 5 days) (n = 86) or IVIG alone (n = 87), were subjected to this study. CAA was defined by a Z score ≥2.5 observed within 4 weeks after treatment initiation. Baseline data including genotypes of KD susceptibility genes were compared between subgroups of patients for CAA or treatment response for each treatment group. Backword-forward stepwise logistic regression analyses were performed.

Results

Pre-Z-max, defined as the maximum among Z scores on four coronary artery branches before treatment, was higher in patients with CAA in both treatment groups and was associated with CAA in IVIG plus CsA treatment group [odds ratio (OR) = 17.0]. High serum total bilirubin level was relevant to treatment resistance only in the IVIG plus CsA group (OR = 2.34).

Conclusions

Coronary artery enlargement before treatment is a major determinant of CAA even in KD patients treated with initial IVIG treatment intensified by addition of CsA. Baseline serum total bilirubin level was a risk factor associated with resistance to IVIG plus CsA.

Infliximab for intensification of primary therapy for patients with Kawasaki disease and coronary artery aneurysms at diagnosis

OBJECTIVE

Children with Kawasaki disease (KD) and an initial echocardiogram that demonstrates coronary artery aneurysms (CAAs, Z score ≥2.5) are at high risk for severe cardiovascular complications. We sought to determine if primary adjunctive infliximab treatment at a dose of either 5 or 10 mg/kg, compared with intravenous immunoglobulin (IVIG) alone, is associated with a greater likelihood of CAA regression in patients with KD with CAA at the time of diagnosis.

DESIGN AND SETTING

Single-centre observational study.

PATIENTS

Children with acute KD and Z score ≥2.5 at baseline.

INTERVENTIONS

Primary adjunctive infliximab (5 or 10 mg/kg) within 48 hours of initiating IVIG 2 g/kg.

MAIN OUTCOME MEASURES

Incidence of CAA regression to Zmax <2 within 2 months of disease onset.

RESULTS

Of the 168 patients with KD, 111 received IVIG alone and 57 received primary adjunctive infliximab therapy: 39 received 5 mg/kg and 18 received 10 mg/kg. Incidence of CAA regression to Zmax <2 within 2 months was statistically significant at 52%, 62% and 83% in the IVIG alone, IVIG+infliximab 5 mg/kg and IVIG+infliximab 10 mg/kg, respectively. The multivariable logistic regression model adjusting for age, sex, baseline Zmax and bilateral CAA at baseline showed that IVIG plus 10 mg/kg infliximab was significantly associated with a greater likelihood of CAA regression (adjusted OR: 4.45, 95% CI 1.17 to 16.89, p=0.028) compared with IVIG alone. The difference between IVIG+infliximab 5 mg/kg and IVIG alone was not significant.

CONCLUSIONS

Primary adjunctive high-dose 10 mg/kg infliximab treatment was associated with a greater likelihood of CAA regression in patients with CAA at the time of diagnosis.

Medium-vessel and large-vessel vasculitis in children

PURPOSE OF REVIEW

This article serves as an up-to-date examination of the latest findings in the field of paediatric large-vessel and medium-vessel vasculitis.

RECENT FINDINGS

Over the last 2 years and in the wake of SARS-CoV2 pandemic, a multitude of studies have increased our insight into these conditions. Although large-vessel and medium-vessel vasculitis are uncommon amongst children, they are a complex and multisystem with a constantly evolving landscape. Increasing numbers of reports from low-income and middle-income countries are shaping our understanding of the epidemiology of vasculitis in children. The influence of infectious disease and the microbiome are of particular interest in unravelling pathogenetic aspects. Improved understanding of the genetics and immunology offer opportunities for better diagnostic options and biomarkers of disease as well as targeted therapies.

SUMMARY

In this review, we address recent findings in epidemiology, pathophysiology, clinical findings, bio-markers, imaging and treatment that have the potential to offer better management solutions for these uncommon 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.

Multisystem Inflammatory Syndrome therapies in children (MISTIC): A randomized trial

Background

Multisystem Inflammatory Syndrome in Children (MIS-C), which occurs 2-6 weeks after initial exposure to SARS-CoV-2, was first identified in early 2020 when patients presented with fever and significant inflammation, often requiring management in the intensive care unit. To date, there has been no clinical trial to determine the most effective treatment. This study compares anti-inflammatory treatments that were selected based on current treatments for Kawasaki disease, a coronary artery vasculitis that shares many clinical features with MIS-C.

Methods

This randomized, comparative effectiveness trial of children with MIS-C uses the small N Sequential Multiple Assignment Randomized Trial (snSMART) design for rare diseases to compare multiple therapies within an individual. Study participants were treated first with intravenous immunoglobulin (IVIG), and if needed, subjects were then randomized to one of three additional treatments (steroids, anakinra, or infliximab). Participants were re-randomized to remaining treatments if they did not demonstrate clinical improvement.

Conclusion

This trial continues to enroll eligible participants to determine the most effective therapies in addition to IVIG and best order in which to use them to treat MIS-C.

Trial Registration

NCT04898231.

Biologics and JAK inhibitors for the treatment of monogenic systemic autoinflammatory diseases in children

Systemic autoinflammatory diseases (SAIDs) are caused by aberrant activation of 1 or more inflammatory pathways in an antigen-independent manner. Monogenic forms of SAIDs typically manifest during childhood, and early treatment is essential to minimize morbidity and mortality. On the basis of the mechanism of disease and the dominant cytokine(s) that propagates inflammation, monogenic SAIDs can be grouped into major categories including inflammasomopathies/disorders of IL-1, interferonopathies, and disorders of nuclear factor-κB and/or aberrant TNF activity. This classification scheme has direct therapeutic relevance given the availability of biologic agents and small-molecule inhibitors that specifically target these pathways. Here, we review the experience of using biologics that target IL-1 and TNF as well as using Janus kinase inhibitors for the treatment of monogenic SAIDs in pediatric patients. We provide an evidence-based guide for the use of these medications and discuss their mechanism of action, safety profile, and strategies for therapeutic monitoring.

Biologic disease-modifying antirheumatic drugs to treat multisystem inflammatory syndrome in children

PURPOSE OF REVIEW

Multisystem inflammatory syndrome in children (MIS-C) is a postinfectious complication of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection primarily affecting children. MIS-C shares features with Kawasaki disease (KD) and cytokine storm syndrome (CSS) frequently requiring intensive care support. Although intravenous immunoglobulin (IVIg) and glucocorticoids (GCs) are effective therapeutics for most, refractory MIS-C is treated with various biologic disease-modifying antirheumatic drugs (bDMARDs). Understanding the clinical features, inflammatory cytokines, and genetic associations provides rationale for bDMARD in treating severe MIS-C.

RECENT FINDINGS

Children with MIS-C have clinical KD features and often present in hypovolemic and cardiogenic shock requiring volume repletion (gastrointestinaI losses) and cardiac pressor support (epinephrine). Investigation of MIS-C serum reveals elevated pro-inflammatory cytokines [interleukin (IL)-1, IL-6, IL-18, interferon gamma (IFNγ), tumor necrosis factor (TNF)], but to a lesser extent than other established CSS. Gene sequencing of MIS-C children identifies heterozygous mutations in CSS associated genes. Treatment of refractory (IVIg and GC) MIS-C with bDMARDs to IL-1, IL-6, and TNF is efficacious for survival as well as resolving cardiac and coronary artery inflammation.

SUMMARY

MIS-C is a postinfectious complication of SARS-CoV-2 resembling KD and CSS, both genetically and by pro-inflammatory cytokines. MIS-C that is refractory to IVIg and GC is routinely responsive to bDMARDs targeting IL-1, IL-6, and TNF.

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.

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.