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Background The Long-ter M O U tcomes after the Multisystem Inflammatory S yndrome I n C hildren (MUSIC) study aims to characterize the frequency and time course of acute and long-term cardiac and non-cardiac sequelae in multisystem inflammatory syndrome in children associated with COVID-19 (MIS-C), which are currently poorly understood. Methods This multicenter observational cohort study will enroll at least 600 patients Conclusion The MUSIC study, with the largest cohort of MIS-C patients and the longest follow-up period to date, will make an important contribution to our understanding of the acute cardiac and non-cardiac manifestations of MIS-C and the long-term effects of this public health emergency.

The many forms of vasculitis are characterized by inflammation of blood vessels, leading to potentially long-term sequelae including vision loss, aneurysm formation and kidney failure. Accurate estimation of the incidence and prevalence has been hampered by the absence of reliable diagnostic criteria and the rarity of these conditions; however, much progress has been made over the past two decades, although data are still lacking from many parts of the world including the Indian subcontinent, China, Africa and South America. Giant cell arteritis occurs in those aged 50 years and over and seems to mainly affect persons of northern European ancestry, whereas Takayasu arteritis occurs mainly in those aged under 40 years. By contrast, Kawasaki disease mainly occurs in children aged under 5 years and is most common in children of Asian ancestry, and IgA vasculitis occurs in children and adolescents. Although much less common than giant cell arteritis, the different forms of antineutrophil cytoplasmic antibody-associated vasculitis are being increasingly recognized in most populations and occur more frequently with increasing age. Behçet syndrome occurs most commonly along the ancient silk road between Europe and China. Much work needs to be done to better understand the influence of ethnicity, geographical location, environment and social factors on the development of vasculitis., Vasculitis, inflammation of the blood vessels, takes many forms and can affect every organ system, potentially causing kidney failure, vision loss and death. This Review describes current knowledge on the global incidence and prevalence patterns for various types of vasculitis., Key points Vasculitis is a group of generally uncommon diseases of generally unknown aetiology.Vasculitis mainly occurs at the ends of the age spectrum, in young children and older adults.Kawasaki disease is most common in children aged 5 years or less and occurs most commonly in Japan and in children of Southeast Asian ancestry.Giant cell arteritis is the most common form of vasculitis in elderly individuals, particularly in those of Northern European ancestry.The three types of antineutrophil cytoplasmic antibody-associated vasculitis are rare; of the three types, granulomatosis with polyangiitis is the most prevalent.Behçet syndrome has the highest prevalence along the ancient silk road, which stretches from the Mediterranean through the Middle East to East Asia.

ObjectivesDrug reaction with eosinophilia and systemic symptoms (DRESS) is a severe, delayed hypersensitivity reaction (DHR). We observed DRESS to inhibitors of interleukin 1 (IL-1) or IL-6 in a small group of patients with Still’s disease with atypical lung disease. We sought to characterise features of patients with Still’s disease with DRESS compared with drug-tolerant Still’s controls. We analysed human leucocyte antigen (HLA) alleles for association to inhibitor-related DHR, including in a small Kawasaki disease (KD) cohort.MethodsIn a case/control study, we collected a multicentre series of patients with Still’s disease with features of inhibitor-related DRESS (n=66) and drug-tolerant Still’s controls (n=65). We retrospectively analysed clinical data from all Still’s subjects and typed 94/131 for HLA. European Still’s-DRESS cases were ancestry matched to International Childhood Arthritis Genetics Consortium paediatric Still’s cases (n=550) and compared for HLA allele frequencies. HLA association also was analysed using Still’s-DRESS cases (n=64) compared with drug-tolerant Still’s controls (n=30). KD subjects (n=19) were similarly studied.ResultsStill’s-DRESS features included eosinophilia (89%), AST-ALT elevation (75%) and non-evanescent rash (95%; 88% involving face). Macrophage activation syndrome during treatment was frequent in Still’s-DRESS (64%) versus drug-tolerant Still’s (3%; p=1.2×10−14). We found striking enrichment for HLA-DRB1*15 haplotypes in Still’s-DRESS cases versus INCHARGE Still’s controls (p=7.5×10-13) and versus self-identified, ancestry-matched Still’s controls (p=6.3×10−10). In the KD cohort, DRB1*15:01 was present only in those with suspected anakinra reactions.ConclusionsDRESS-type reactions occur among patients treated with IL-1/IL-6 inhibitors and strongly associate with common HLA-DRB1*15 haplotypes. Consideration of preprescription HLA typing and vigilance for serious reactions to these drugs are warranted.

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.

We described a human regulatory T cell (Treg) population activated by IgG+ B cells presenting peptides of the heavy C region (Fc) via processing of the surface IgG underlying a model for B cell–Treg cooperation in the human immune regulation. Functionally, Treg inhibited the polarization of naive T cells toward a proinflammatory phenotype in both a cognate and a noncognate fashion. Their fine specificities were similar in healthy donors and patients with rheumatoid arthritis, a systemic autoimmune disease. Four immunodominant Fc peptides bound multiple HLA class II alleles and were recognized by most subjects in the two cohorts. The presentation of Fc peptides that stimulate Treg through the processing of IgG by dendritic cells (DC) occurred in myeloid DC classical DC 1 and classical DC 2. Different routes of Ag processing of the IgG impacted Treg expansion in rheumatoid arthritis patients.

In the 2017 American Heart Association (AHA) Kawasaki disease (KD) guidelines, risk levels (RLs) for long-term management are defined by both maximal and current coronary artery (CA) dimensions normalized as z-scores. We sought to determine the degree to which current recommended practice differs from past actual practice, highlighting areas for knowledge translation efforts. The International KD Registry (IKDR) included 1651 patients with CA aneurysms (z-score > 2.5) from 1999 to 2016. Patients were classified by AHA RL using maximum CA z-score (RL 3 = small, RL 4 = medium, RL 5 = large/giant) and subcategorized based on decreases over time. Medical management provided was compared to recommendations. Low-dose acetylsalicylic acid (ASA) use ranged from 86 (RL 3.1) to 95% (RL 5.1) for RLs where use was “indicated.” Dual antiplatelet therapy (ASA + clopidogrel) use ranged from 16% for RL 5.2 to 9% for RL 5.4. Recommended anticoagulation (warfarin or low molecular weight heparin) use was 65% for RL 5.1, while 12% were on triple therapy (anticoagulation + dual antiplatelet). Optional statin use ranged from 2 to 8% depending on RL. Optional beta-blocker use was 2–25% for RL 5, and 0–5% for RLs 3 and 4 where it is not recommended. Generally, past practice was consistent with the latest AHA guidelines, taking into account the flexible wording of recommendations based on the limited evidence, as well as unmeasured patient-specific factors. In addition to strengthening the overall evidence base, knowledge translation efforts may be needed to address variation in thromboprophylaxis management.

Coronavirus disease 2019 (COVID-19) is an infectious disease caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) with substantial cardiovascular implications. Although infection with SARS-CoV-2 is usually mild in children, some children later develop a severe inflammatory disease that can have manifestations similar to toxic shock syndrome or Kawasaki disease. This syndrome has been defined by the US Centers for Disease Control and Prevention as multisystem inflammatory syndrome in children. Although the prevalence is unknown, >600 cases have been reported in the literature. Multisystem inflammatory syndrome in children appears to be more common in Black and Hispanic children in the United States. Multisystem inflammatory syndrome in children typically occurs a few weeks after acute infection and the putative etiology is a dysregulated inflammatory response to SARS-CoV-2 infection. Persistent fever and gastrointestinal symptoms are the most common symptoms. Cardiac manifestations are common, including ventricular dysfunction, coronary artery dilation and aneurysms, arrhythmia, and conduction abnormalities. Severe cases can present as vasodilatory or cardiogenic shock requiring fluid resuscitation, inotropic support, and in the most severe cases, mechanical ventilation and extracorporeal membrane oxygenation. Empirical treatments have aimed at reversing the inflammatory response using immunomodulatory medications. Intravenous immunoglobulin, steroids, and other immunomodulatory agents have been used frequently. Most patients recover within days to a couple of weeks and mortality is rare, although the medium- and long-term sequelae, particularly cardiovascular complications, are not yet known. This review describes the published data on multisystem inflammatory syndrome in children, focusing on cardiac complications, and provides clinical considerations for cardiac evaluation and follow-up.

Clinical features of Kawasaki disease (KD) display overlap with common pediatric viral illnesses, leading some to hypothesize that a viral infection is the inciting event for KD. To investigate viral infection history in KD patients, we performed comprehensive serological profiling using a high-throughput phage immunoprecipitation sequencing assay covering the complete reference protein sequences of known viruses with human tropism. KD and matched febrile control sera did not demonstrate differences in antiviral antibody profiles. We conclude that in the acute and subacute phases of disease, KD patients do not exhibit serologic evidence of exposure to known viruses that differs from controls.

We present a case in which emergency medical services (EMS) intervened on a critically ill child with known giant coronary aneurysms as sequela to her severe complicated Kawasaki disease. This patient's severe shock ultimately ended in cardiac arrest and death. We discuss the keys to recognition, and critical importance to early intervention of pediatric shock in prehospital care. We also detail the cardiac ramifications of Kawasaki disease, steps for prompt identification of high risk complaints in these patients, and opportunities for treatment.

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The autoantibody profile associated with known autoimmune diseases in patients with COVID-19 or multisystem inflammatory syndrome in children (MIS-C) remains poorly defined. Here we show that adults with COVID-19 had a moderate prevalence of autoantibodies against the lung antigen KCNRG, and SLE-associated Smith autoantigen. Children with COVID-19 rarely had autoantibodies; one of 59 children had GAD65 autoantibodies associated with acute insulin-dependent diabetes. While autoantibodies associated with SLE/Sjögren’s syndrome (Ro52, Ro60, and La) and/or autoimmune gastritis (gastric ATPase) were detected in 74% (40/54) of MIS-C patients, further analysis of these patients and of children with Kawasaki disease (KD), showed that the administration of intravenous immunoglobulin(IVIG) was largely responsible for detection of these autoantibodies in both groups of patients. Monitoringin vivodecay of the autoantibodies in MIS-C children showed that the IVIG-derived Ro52, Ro60, and La autoantibodies declined to undetectable levels by 45-60 days, but gastric ATPase autoantibodies declined more slowly requiring >100 days until undetectable. Together these findings demonstrate that administration of high-dose IVIG is responsible for the detection of several autoantibodies in MIS-C and KD. Further studies are needed to investigate autoantibody production in MIS-C patients, independently from IVIG administration.

Author(s): Hoshino, Shinsuke; Jain, Sonia; Shimizu, Chisato; Roberts, Samantha; He, Feng; Daniels, Lori; Kahn, Andrew; Gordon, John; Burns, Jane; Tremoulet, Adriana | Abstract: Background: Myocardial histology from autopsies of young adults with giant coronary artery aneurysms following Kawasaki disease (KD) shows bridging fibrosis beyond the territories supplied by the aneurysmal arteries. The etiology of this fibrosis is unknown, but persistent, low-level myocardial inflammation and microcirculatory ischemia are both possible contributing factors. To investigate the possibility of subclinical myocardial inflammation or fibrosis, we measured validated biomarkers in young adults with a remote history of KD. Methods: We measured plasma calprotectin, galectin-3 (Gal-3), growth differentiation factor-15 (GDF-15), soluble ST2 (sST2), and serum procollagen type 1C-terminal propeptide (P1CP) in 91 otherwise healthy young adults with a remote history of KD and in 88 age-similar, healthy controls. KD subjects were stratified by coronary artery aneurysm (CAA) status and history of remote myocardial infarction (MI). Results: After correction for multiple testing, calprotectin, Gal-3, and GDF-15 levels were significantly higher in subjects with persistent CAA (nn=n26) compared with KD subjects with remodeled CAA (nn=n20, pn=n0.005, 0.001, 0.0036, respectively). In a multivariable regression model with CA status as the main predictor and adjusting for sex, MI history, and interval from KD onset, CA status was a significant predictor (Persistent CAA vs KD Normal CA) of calprotectin, Gal-3, GDF-15 and sST2 levels (pn=n0.004, l0.001, 0.007, and 0.049, respectively). Conclusions: These results suggest that ongoing inflammation and fibrosis may be occurring in individuals with persistent CAA. Longitudinal follow-up is needed to clarify the clinical significance of these elevated biomarker levels in this patient population that requires life-long monitoring.

Multisystem inflammatory syndrome in children following severe acute respiratory syndrome coronavirus 2 infection is characterized by fever, elevated inflammatory markers, and multisystem organ involvement. Presentations are variable but often include gastrointestinal symptoms. We describe 5 children with fever and gastrointestinal symptoms initially concerning for multisystem inflammatory syndrome in children who were ultimately diagnosed with bacterial enteritis, highlighting the diagnostic challenges presented by the severe acute respiratory syndrome coronavirus 2 pandemic.

Background Although intravenous immunoglobulin (IVIG) is effective therapy for Kawasaki disease (KD), the most common cause of acquired heart disease in children, 10–20% of patients are IVIG-resistant and require additional therapy. This group has an increased risk of coronary artery aneurysms (CAA) and there has been no adequately powered, randomized clinical trial in a multi-ethnic population to determine the optimal therapy for IVIG-resistant patients. Objectives The primary outcome is duration of fever in IVIG-resistant patients randomized to treatment with either infliximab or a second IVIG infusion. Secondary outcomes include comparison of inflammatory markers, duration of hospitalization, and coronary artery outcome. An exploratory aim records parent-reported outcomes including signs, symptoms and treatment experience. Methods The KIDCARE trial is a 30-site randomized Phase III comparative effectiveness trial in KD patients with fever ≥36 h after the completion of their first IVIG treatment. Eligible patients will be randomized to receive either a second dose of IVIG (2 g/kg) or infliximab (10 mg/kg). Subjects with persistent or recrudescent fever at 24 h following completion of the first study treatment will cross-over to the other treatment arm. Subjects will exit the study after their first outpatient visit (5–18 days following last study treatment). The parent-reported outcomes, collected daily during hospitalization and at home, will be compared by study arm. Conclusion This trial will contribute to the management of IVIG-resistant patients by establishing the relative efficacy of a second dose of IVIG compared to infliximab and will provide data regarding the patient/parent experience of these treatments.

We report two patients with Multisystem Inflammatory Syndrome in Children (MIS-C) with evidence of hyponatremia on admission. Despite fluid resuscitation and resolution of dehydration, the hyponatremia worsened. Serum and urine studies were evaluated and demonstrated evidence of syndrome of inappropriate antidiuretic hormone (SIADH). Fluid restriction and anti-inflammatory therapy were initiated with resolution of hyponatremia.

Although intravenous immunoglobulin (IVIG) is effective therapy for Kawasaki disease, 10-20% of patients have recrudescent fever as a sign of persistent inflammation and require additional treatment. We aimed to compare infliximab with a second infusion of IVIG for treatment of resistant Kawasaki disease.In this multicentre comparative effectiveness trial, patients (aged 4 weeks to 17 years) with IVIG resistant Kawasaki disease and fever at least 36 h after completion of their first IVIG infusion were recruited from 30 hospitals across the USA. Patients were randomly assigned (1:1) to second IVIG (2 g/kg over 8-12 h) or intravenous infliximab (10 mg/kg over 2 h without premedication), by using a randomly permuted block randomisation design with block size of two or four. Patients with fever 24 h to 7 days following completion of first study treatment crossed over to receive the other study treatment. The primary outcome measure was resolution of fever at 24 h after initiation of study treatment with no recurrence of fever attributed to Kawasaki disease within 7 days post-discharge. Secondary outcome measures included duration of fever from enrolment, duration of hospitalisation after randomisation, and changes in markers of inflammation and coronary artery Z score. Efficacy was analysed in participants who received treatment and had available outcome values. Safety was analysed in all randomised patients who did not withdraw consent. This clinical trial is registered with ClinicalTrials.gov, NCT03065244.Between March 1, 2017, and Aug 31, 2020, 105 patients were randomly assigned to treatment and 103 were included in the intention-to-treat population (54 in the infliximab group, 49 in the second IVIG group). Two patients randomised to infliximab did not receive allocated treatment. The primary outcome was met by 40 (77%) of 52 patients in the infliximab group and 25 (51%) of 49 patients in the second IVIG infusion group (odds ratio 0·31, 95% CI 0·13-0·73, p=0·0076). 31 patients with fever beyond 24 h received crossover treatment: nine (17%) in the infliximab group received second IVIG and 22 (45%) in second IVIG group received infliximab (p=0·0024). Three patients randomly assigned to infliximab and two to second IVIG with fever beyond 24h did not receive crossover treatment. Mean fever days from enrolment was 1·5 (SD 1·4) for the infliximab group and 2·5 (2·5) for the second IVIG group (p=0·014). Mean hospital stay was 3·2 days (2·1) for the infliximab group and 4·5 days (2·5) for the second IVIG group (p0·001). There was no difference between treatment groups for markers of inflammation or coronary artery outcome. 24 (44%) of 54 patients in the infliximab group and 33 (67%) of 49 in the second IVIG group had at least one adverse event. A drop in haemoglobin concentration of at least 2g/dL was seen in 19 (33%) of 58 patients who received IVIG as either their first or second study treatment (three of whom required transfusion) and in three (7%) of 43 who received only infliximab (none required transfusion; p=0·0028). Haemolytic anaemia was the only serious adverse events deemed definitely or probably related to study treatment, and was reported in nine (15%) of 58 patients who received IVIG as either their first or second study treatment and none who received infliximab only.Infliximab is a safe, well tolerated, and effective treatment for patients with IVIG resistant Kawasaki disease, and results in shorter duration of fever, reduced need for additional therapy, less severe anaemia, and shorter hospitalisation compared with second IVIG infusion.Patient Centered Outcomes Research Institute.

A significant surge in cases of multisystem inflammatory syndrome in children (MIS-C, also called Pediatric Inflammatory Multisystem Syndrome - PIMS) has been observed amidst the COVID-19 pandemic. MIS-C shares many clinical features with Kawasaki disease (KD), although clinical course and outcomes are divergent. We analyzed whole blood RNA sequences, serum cytokines, and formalin fixed heart tissues from these patients using a computational toolbox of two gene signatures, i.e., the 166-gene viral pandemic (ViP) signature, and its 20-gene severe (s)ViP subset that were developed in the context of SARS-CoV-2 infection and a 13-transcript signature previously demonstrated to be diagnostic for KD. Our analyses revealed that KD and MIS-C are on the same continuum of the host immune response as COVID-19. While both the pediatric syndromes converge upon anIL15/IL15RA-centric cytokine storm, suggestive of shared proximal pathways of immunopathogenesis, they diverge in other laboratory parameters and cardiac phenotypes. The ViP signatures also revealed unique targetable cytokine pathways in MIS-C, place MIS-C farther along in the spectrum in severity compared to KD and pinpoint key clinical (reduced cardiac function) and laboratory (thrombocytopenia and eosinopenia) parameters that can be useful to monitor severity.

KD is an acute febrile illness and systemic vasculitis of unknown etiology among young children, which can cause coronary artery abnormalities and aneurysms (CAA) and is the leading cause of acquired heart disease among children in the US. Lactobacillus casei cell wall extract (LCWE) induces in mice a vasculitis following intraperitoneal injection defined by the activation of macrophages, dendritic cells and CD8+ cytotoxic T cells leading to aortitis, coronary arteritis, aneurysms and myocarditis that strongly mimic the immunopathology and the cardiac lesions observed in children with Kawasaki disease (KD). To address a potential pathogenic role of LCWE-specific T cells in human vascular inflammation, we studied the activation of circulating CD4+ and CD8+ T cells ex vivo in response to LCWE in 3 cohorts: (1) KD children 2–3 weeks after fever onset, (2) age-similar healthy children controls, (3) healthy adult controls. In all subjects studied, pro-inflammatory CD4+ and CD8+T cells responded to LCWE with no significant differences. Peripherally-induced regulatory T cells (iTreg) also responded to LCWE and potentially reverted to Th17, as suggested by the detection of IL-17 in culture supernatants. Central memory T cells were also detectable and were more abundant in adults. The potential homing to the vessels of LCWE-specific T cells was suggested by the expression of CCR6 and CD31. In conclusion, a non-pathogenic, LCWE-specific T cell repertoire could lead to KD depending upon priming conditions, genetic factors and immune activation by other antigens.

Kawasaki disease (KD) is a paediatric vasculitis associated with coronary artery aneurysms (CAA). Genetic variants influencing susceptibility to KD have been previously identified, but no risk alleles have been validated that influence CAA formation. We conducted a genome-wide association study (GWAS) for CAA in KD patients of European descent with 200 cases and 276 controls. A second GWAS for susceptibility pooled KD cases with healthy paediatric controls from vaccine trials in the UK (n = 1609). Logistic regression mixed models were used for both GWASs. The susceptibility GWAS was meta-analysed with 400 KD cases and 6101 controls from a previous European GWAS, these results were further meta-analysed with Japanese GWASs at two putative loci. The CAA GWAS identified an intergenic region of chromosome 20q13 with multiple SNVs showing genome-wide significance. The risk allele of the most associated SNV (rs6017006) was present in 13% of cases and 4% of controls; in East Asian 1000 Genomes data, the allele was absent or rare. Susceptibility GWAS with meta-analysis with previously published European data identified two previously associated loci (ITPKC and FCGR2A). Further meta-analysis with Japanese GWAS summary data from the CASP3 and FAM167A genomic regions validated these loci in Europeans showing consistent effects of the top SNVs in both populations. We identified a novel locus for CAA in KD patients of European descent. The results suggest that different genes determine susceptibility to KD and development of CAA and future work should focus on the function of the intergenic region on chromosome 20q13.

BACKGROUNDMultisystem inflammatory syndrome in children (MIS-C) is a rare but potentially severe illness that follows exposure to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Kawasaki disease (KD) shares several clinical features with MIS-C, which prompted the use of intravenous immunoglobulin (IVIG), a mainstay therapy for KD. Both diseases share a robust activation of the innate immune system, including the IL-1 signaling pathway, and IL-1 blockade has been used for the treatment of both MIS-C and KD. The mechanism of action of IVIG in these 2 diseases and the cellular source of IL-1s have not been defined.METHODSThe effects of IVIG on peripheral blood leukocyte populations from patients with MIS-C and KD were examined using flow cytometry and mass cytometry (CyTOF) and live-cell imaging.RESULTSCirculating neutrophils were highly activated in patients with KD and MIS-C and were a major source of IL-1s. Following IVIG treatment, activated IL-1s+ neutrophils were reduced in the circulation. In vitro, IVIG was a potent activator of neutrophil cell death via PI3K and NADPH oxidase, but independently of caspase activation.CONCLUSIONSActivated neutrophils expressing IL-1s can be targeted by IVIG, supporting its use in both KD and MIS-C to ameliorate inflammation.FUNDINGPatient Centered Outcomes Research Institute; NIH; American Asthma Foundation; American Heart Association; Novo Nordisk Foundation; NIGMS; American Academy of Allergy, Asthma and Immunology Foundation.

1. Acute inflammation, including myocarditis, correlated with high numbers of circulating myeloid dendritic cells in older children with acute Kawasaki disease. 2. Low numbers of CD4+ ILT‐4+ tolerogenic myeloid dendritic cells (tmDC) correlated with enlarged lymph nodes as the initial clinical presentation. 3. CD4+ and CD8+ T cell lymphocytosis and lymphopenia did not correlate with any specific pattern within the innate populations., Summary Kawasaki disease (KD) is an acute pediatric vasculitis of unknown etiology that can cause coronary artery aneurysms, and is the leading cause of acquired heart disease in children. We studied aspects of the innate and adaptive immune response in 17 acute KD children prior to treatment with intravenous immunoglobulin. Distinct patterns within the innate immune response correlated with specific clinical features. Proinflammatory myeloid dendritic cells (mDC) were abundant in four of 17 (23·5%) subjects who were older and manifested severe inflammation with clinical myocarditis and elevated hepatobiliary enzyme levels. Of the nine subjects with low levels of anti‐inflammatory, tolerogenic mDC, six had enlarged cervical lymph nodes at diagnosis. In contrast, the adaptive immune repertoire varied greatly with no discernible patterns or associations with clinical features. Two subjects with aneurysms had numerous circulating CD8+ T cells. Ten subjects showed low CD4+ T cell numbers and seven subjects had CD4+ T cells in the normal range. CD4+ T cells expressed interleukin‐7 receptor (IL‐7R), suggesting repeated antigenic stimulation. Thymic‐derived regulatory T cells (nTreg) and peripherally induced regulatory T cells (iTreg) were also enumerated, with the majority having the nTreg phenotype. Natural killer (NK) and NK T cell numbers were similar across all subjects. Taken together, the results of the immune monitoring suggest that KD may have multiple triggers that stimulate different arms of the innate and adaptive compartment in KD patients. Thus, it is possible that diverse antigens may participate in the pathogenesis of KD.

Objective To test the hypothesis that cases of Kawasaki disease within a temporal cluster have a similar pattern of host response that is distinct from cases of Kawasaki disease in different observed clusters and randomly constructed clusters. Study design We designed a case-control study to analyze 47 clusters derived from 1332 patients with Kawasaki disease over a 17-year period (2002-2019) from a single clinical site and compared the cluster characteristics with those of 2 control groups of synthetic Kawasaki disease clusters. We defined a “true” Kawasaki disease cluster as at least 5 patients within a 7-day moving window. The observed and synthetic Kawasaki disease clusters were compared with respect to demographic and clinical characteristics and median values for standard laboratory data using univariate analysis and a multivariate, rotated empirical orthogonal function analysis. Results In a univariate analysis, the median values for age, coronary artery z-score, white blood cell count, erythrocyte sedimentation rate, C-reactive protein, and age-adjusted hemoglobin for several of the true Kawasaki disease clusters exceeded the 95th percentile for the 2 synthetic clusters. REOF analyses revealed distinct patterns of demographic and clinical measures within clusters. Conclusions Cases of Kawasaki disease within a cluster were more similar with respect to demographic and clinical features and levels of inflammation than would be expected by chance. These observations suggest that different triggers and/or different intensities of exposures result in clusters of cases of Kawasaki disease that share a similar response pattern. Analyzing cases within clusters or cases who share demographic and clinical features may lead to new insights into the etiology of Kawasaki disease.

Background Coronary artery aneurysms (CAAs) may occur after Kawasaki disease (KD) and lead to important morbidity and mortality. As CAA in patients with KD are rare and heterogeneous lesions, prognostication and risk stratification are difficult. We sought to derive the cumulative risk and associated factors for cardiovascular complications in patients with CAAs after KD. Methods and Results A 34‐institution international registry of 1651 patients with KD who had CAAs (maximum CAA Z score ≥2.5) was used. Time‐to‐event analyses were performed using the Kaplan–Meier method and Cox proportional hazard models for risk factor analysis. In patients with CAA Z scores ≥10, the cumulative incidence of luminal narrowing (>50% of lumen diameter), coronary artery thrombosis, and composite major adverse cardiovascular complications at 10 years was 20±3%, 18±2%, and 14±2%, respectively. No complications were observed in patients with a CAA Z score Z score and a greater number of coronary artery branches affected were associated with increased risk of all types of complications. At 10 years, normalization of luminal diameter was noted in 99±4% of patients with small (2.5≤ Z Z Z ≥10). CAAs in the left anterior descending and circumflex coronary artery branches were more likely to normalize. Risk factor analysis of coronary artery branch level outcomes was performed with a total of 893 affected branches with Z score ≥10 in 440 patients. In multivariable regression models, hazards of luminal narrowing and thrombosis were higher for patients with CAAs of the right coronary artery and left anterior descending branches, those with CAAs that had complex architecture (other than isolated aneurysms), and those with CAAs with Z scores ≥20. Conclusions For patients with CAA after KD, medium‐term risk of complications is confined to those with maximum CAA Z scores ≥10. Further risk stratification and close follow‐up, including advanced imaging, in patients with large CAAs is warranted.

BACKGROUND Randomized controlled trials previously provided different conclusions about the superiority of adding corticosteroids to initial intravenous immunoglobulin treatment for the prevention of coronary artery abnormalities in patients with Kawasaki disease (KD). To further assess this issue, we analyzed large-scale data from nationwide KD surveys in Japan, where combination treatment (corticosteroids added to initial standard intravenous immunoglobulin treatment) has become commonly used for patients at high risk for KD. METHODS AND RESULTS Standard intravenous immunoglobulin treatment and combination treatment were compared using data from time periods with and without combination treatment. Outcome measures were coronary artery abnormalities and initial intravenous immunoglobulin treatment failure. Hospitals where ≥20% of patients received combination treatment were identified, and treatment and control groups were selected via matching by age, sex, illness day at initial treatment, and KD recurrence. Matched group selection and subsequent analyses were conducted 1000 times to minimize sampling bias and potential confounders (bootstrapping). From 115 hospitals, 1593 patients with KD in the treatment group and 1593 controls were selected for each of the 1000 sample iterations. The median proportion of patients who developed coronary artery abnormalities among the treatment group and controls were 4.6% (95% CI, 3.8%-5.8%) and 8.8% (95% CI, 7.5%-10.0%), respectively: an estimated risk ratio of 0.53 (0.41-0.67). A median of 14.1% (95% CI, 12.4%-15.9%) of the patients in the treatment group and 21.7% (95% CI, 19.8%-23.4%) in the controls had treatment failure: an estimated risk ratio of 0.65 (0.56-0.75). CONCLUSIONS Combination treatment reduced coronary artery abnormality risk by an estimated 47% and treatment failure by 35%. Multiple-dose corticosteroids may provide benefit in selected patients at high risk for KD.

Author(s): Oyamada, Jun; Shimizu, Chisato; Kim, Jihoon; Williams, Matthew R; Png, Eileen; Hibberd, Martin L; Tremoulet, Adriana H; Perry, James C; Burns, Jane C | Abstract: BackgroundWe previously described the association of genetic variants in calcium channel genes and susceptibility to Kawasaki disease (KD), an acute, self-limited vasculitis, and the most common cause of acquired cardiac disease in children. Abnormal repolarization of cardiomyocytes and changes in T wave morphology have been reported in KD but have not been studied systematically.MethodsWe analyzed acute and convalescent ECG T wave morphology in two independent cohorts of KD subjects and studied the association between bifid T waves and genetic variants in previously reported genes with SNVs associated with cardiac repolarization.ResultsBifid T waves in limb leads were identified in 24% and 27% of two independent cohorts of acute KD subjects. Calcium channel voltage-dependent beta 2 subunit gene (CACNB2) (rs1409207) showed association with bifid T waves in both cohorts (nominal P = .04 and P = .0003, respectively). This CACNB2 polymorphism also showed association with KD susceptibility in a previously published KD genome wide association study data (nominal P = .009).ConclusionThis genotype/phenotype association study uncovered a variant in CACNB2 that may be associated with both KD susceptibility and bifid T waves, a novel signature of altered myocardial repolarization. The present study combined with published reports suggests that genetic variants in calcium channels and intracellular calcium signaling play a prominent role in shaping susceptibility to KD.

Objective To evaluate practice variation in pharmacologic management in the International Kawasaki Disease Registry (IKDR). Study design Practice variation in intravenous immunoglobulin (IVIG) therapy, anti-inflammatory agents, statins, beta-blockers, antiplatelet therapy, and anticoagulation was described. Results We included 1627 patients from 30 IKDR centers with maximum coronary artery aneurysm (CAA) z scores 2.5-4.99 in 848, 5.0-9.99 in 349, and ≥10.0 (large/giant) in 430 patients. All centers reported IVIG and acetylsalicylic acid (ASA) as primary therapy and use of additional IVIG or steroids as needed. In 23 out of 30 centers, (77%) infliximab was also used; 11 of these 23 centers reported using it in 20% of patients. Nonsteroidal anti-inflammatory agents were used in >10% of patients in only nine centers. Beta-blocker (8.8%, all patients) and abciximab (3.6%, all patients) were mainly prescribed in patients with large/giant CAAs. Statins (2.7%, all patients) were mostly used in one center and only in patients with large/giant CAAs. ASA was the primary antiplatelet modality for 99% of patients, used in all centers. Clopidogrel (18%, all patients) was used in 24 centers, 11 of which used it in >50% of their patients with large/giant CAAs. Conclusions In the IKDR, IVIG and ASA therapy as primary therapy is universal with common use of a second dose of IVIG for persistent fever. There is practice variation among centers for adjunctive therapies and anticoagulation strategies, likely reflecting ongoing knowledge gaps. Randomized controlled trials nested in a high-quality collaborative registry may be an efficient strategy to reduce practice variation.

Patients with coronary artery aneurysms (CAAs) resulting from Kawasaki disease (KD) are at risk for thrombosis and myocardial infarction. Current guidelines recommend CAA diameter ≥8 mm as the criterion for initiating systemic anticoagulation. Transluminal attenuation gradient (TAG) analysis has been proposed as a noninvasive method for evaluating functional significance of coronary stenoses using computerized tomography angiography (CTA), but has not previously been used in CAA. We hypothesized that abnormal hemodynamics in CAA caused by KD could be quantified using TAG analysis. We studied 23 patients with a history of KD who had undergone clinically indicated CTA. We quantified TAG in the major coronary arteries and aneurysm geometry was characterized using maximum diameter, aneurysm shape index, and sphericity index. A total of 55 coronary arteries were analyzed, 25 of which had at least 1 aneurysmal region. TAG in aneurysmal arteries was significantly lower than in normal arteries (− 23.5 ± 10.7 vs −10.5 ± 9.0, p = 0.00002). Aneurysm diameter, aneurysm shape index, and sphericity index were weakly correlated with TAG (r2 = 0.01, p = 0.6; r2 = 0.15, p = 0.06; r2 = 0.16, p = 0.04). This is the first application of TAG analysis to CAA caused by KD, and demonstrates significantly different TAG values in aneurysmal versus normal arteries. Lack of correlation between TAG and CAA geometry suggests that TAG may provide hemodynamic information not available from anatomy alone. TAG represents a possible extension to standard CTA for KD patients who may improve thrombotic risk stratification and aid in clinical decision making.

Background Coronary artery aneurysms and myocarditis are well‐recognized complications of Kawasaki disease ( KD ) but no systematic evaluation of the consequences of myocarditis has been performed in the subset presenting with low ejection fraction ( EF ). We postulated that more severe myocardial inflammation as evidenced by low EF during the acute phase could lead to late myocardial fibrosis. Methods and Results We measured the carboxyterminal propeptide of procollagen type I ( PIPC ), soluble suppressor of tumorigenicity 2, galectin‐3 (Gal‐3), growth‐differentiation factor‐15, and calprotectin by ELISA in late convalescent blood samples from 16 KD patients who had an EF ≤55% on their initial echocardiogram. Results were compared with samples from sex‐ and age‐matched KD patients with initial EF >60%. In the univariate analysis, the median Gal‐3 and PIPC levels in the low EF group were significantly higher than those in the normal EF group (Gal‐3: low EF 6.216 versus normal EF 4.976 mg/dL P =0.038, PIPC : low EF 427.4 versus normal EF 265.2 mg/dL, P =0.01). In a multivariable analysis, there were significant differences for Gal‐3 and PIPC levels between the low and normal EF groups, adjusting for age, sex, and worst z score. Conclusions Convalescent KD patients with a history of low EF during the acute illness had significantly elevated levels of Gal‐3 and PIPC when compared with matched‐control KD patients with normal EF . These findings raise concern for myocardial fibrosis as a potential late sequela of the more severe myocarditis experienced by a subset of KD patients during the acute phase.

Kawasaki disease (KD) is an inflammatory disorder of young children, associated with vasculitis of the coronary arteries with subsequent aneurysm formation in up to one-third of untreated patients. Those who develop aneurysms are at life-long risk of coronary thrombosis or the development of stenotic lesions, which may lead to myocardial ischaemia, infarction or death. The incidence of KD is increasing worldwide, and in more economically developed countries, KD is now the most common cause of acquired heart disease in children. However, many clinicians in the UK are unaware of the disorder and its long-term cardiac complications, potentially leading to late diagnosis, delayed treatment and poorer outcomes. Increasing numbers of patients who suffered KD in childhood are transitioning to the care of adult services where there is significantly less awareness and experience of the condition than in paediatric services. The aim of this document is to provide guidance on the long-term management of patients who have vascular complications of KD and guidance on the emergency management of acute coronary complications. Guidance on the management of acute KD is published elsewhere.

The presence in cerebrospinal fluid of antibodies to EV peptides at higher levels than non-AFM controls supports the plausibility of a link between EV infection and AFM that warrants further investigation and has the potential to lead to strategies for diagnosis and prevention of disease., Acute flaccid myelitis (AFM) has caused motor paralysis in >560 children in the United States since 2014. The temporal association of enterovirus (EV) outbreaks with increases in AFM cases and reports of fever, respiratory, or gastrointestinal illness prior to AFM in >90% of cases suggest a role for infectious agents. Cerebrospinal fluid (CSF) from 14 AFM and 5 non-AFM patients with central nervous system (CNS) diseases in 2018 were investigated by viral-capture high-throughput sequencing (VirCapSeq-VERT system). These CSF and serum samples, as well as multiple controls, were tested for antibodies to human EVs using peptide microarrays. EV RNA was confirmed in CSF from only 1 adult AFM case and 1 non-AFM case. In contrast, antibodies to EV peptides were present in CSF of 11 of 14 AFM patients (79%), significantly higher than controls, including non-AFM patients (1/5 [20%]), children with Kawasaki disease (0/10), and adults with non-AFM CNS diseases (2/11 [18%]) (P = 0.023, 0.0001, and 0.0028, respectively). Six of 14 CSF samples (43%) and 8 of 11 sera (73%) from AFM patients were immunoreactive to an EV-D68-specific peptide, whereas the three control groups were not immunoreactive in either CSF (0/5, 0/10, and 0/11; P = 0.008, 0.0003, and 0.035, respectively) or sera (0/2, 0/8, and 0/5; P = 0.139, 0.002, and 0.009, respectively).

BackgroundThe clinical features of Kawasaki disease (KD) overlap with those of other paediatric febrile illnesses. A missed or delayed diagnosis increases the risk of coronary artery damage. Our computer algorithm for KD and febrile illness differentiation had a sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) of 94.8%, 70.8%, 93.7% and 98.3%, respectively, in a single-centre validation study. We sought to determine the performance of this algorithm with febrile children from multiple institutions across the USA.MethodsWe used our previously published 18-variable panel that includes illness day, the five KD clinical criteria and readily available laboratory values. We applied this two-step algorithm using a linear discriminant analysis-based clinical model followed by a random forest-based algorithm to a cohort of 1059 acute KD and 282 febrile control patients from five children’s hospitals across the USA.ResultsThe algorithm correctly classified 970 of 1059 patients with KD and 163 of 282 febrile controls resulting in a sensitivity of 91.6%, specificity of 57.8% and PPV and NPV of 95.4% and 93.1%, respectively. The algorithm also correctly identified 218 of the 232 KD patients (94.0%) with abnormal echocardiograms.InterpretationThe expectation is that the predictive accuracy of the algorithm will be reduced in a real-world setting in which patients with KD are rare and febrile controls are common. However, the results of the current analysis suggest that this algorithm warrants a prospective, multicentre study to evaluate its potential utility as a physician support tool.

Author(s): Rypdal, Martin; Rypdal, Veronika; Burney, Jennifer A; Cayan, Daniel; Bainto, Emelia; Skochko, Shannon; Tremoulet, Adriana H; Creamean, Jessie; Shimizu, Chisato; Kim, Jihoon; Burns, Jane C | Abstract: A correction to this article has been published and is linked from the HTML and PDF versions of this paper. The error has not been fixed in the paper.

Background Thrombosis is a major adverse outcome associated with coronary artery aneurysms (CAAs) resulting from Kawasaki disease (KD). Clinical guidelines recommend initiation of anticoagulation therapy with maximum CAA diameter (Dmax) ≥8 mm or Z-score ≥ 10. Here, we investigate the role of aneurysm hemodynamics as a superior method for thrombotic risk stratification in KD patients. Methods and results We retrospectively studied ten KD patients with CAAs, including five patients who developed thrombosis. We constructed patient-specific anatomic models from cardiac magnetic resonance images and performed computational hemodynamic simulations using SimVascular. Our simulations incorporated pulsatile flow, deformable arterial walls and boundary conditions automatically tuned to match patient-specific arterial pressure and cardiac output. From simulation results, we derived local hemodynamic variables including time-averaged wall shear stress (TAWSS), low wall shear stress exposure, and oscillatory shear index (OSI). Local TAWSS was significantly lower in CAAs that developed thrombosis (1.2 ± 0.94 vs. 7.28 ± 9.77 dynes/cm2, p = 0.006) and the fraction of CAA surface area exposed to low wall shear stress was larger (0.69 ± 0.17 vs. 0.25 ± 0.26%, p = 0.005). Similarly, longer residence times were obtained in branches where thrombosis was confirmed (9.07 ± 6.26 vs. 2.05 ± 2.91 cycles, p = 0.004). No significant differences were found for OSI or anatomical measurements such us Dmax and Z-score. Assessment of thrombotic risk according to hemodynamic variables had higher sensitivity and specificity compared to standard clinical metrics (Dmax, Z-score). Conclusions Hemodynamic variables can be obtained non-invasively via simulation and may provide improved thrombotic risk stratification compared to current diameter-based metrics, facilitating long-term clinical management of KD patients with persistent CAAs.

Background: The sequelae of Kawasaki disease (KD) vary widely with the greatest risk for future cardiovascular events among those who develop giant coronary artery aneurysms (CAA). We sought to define the molecular signature associated with different outcomes in pediatric and adult KD patients. Methods: Molecular profiling was conducted using mass spectrometry–based shotgun proteomics, transcriptomics, and glycomics methods on 8 pediatric KD patients at the acute, subacute, and convalescent time points. Shotgun proteomics was performed on 9 KD adults with giant CAA and matched healthy controls. Plasma calprotectin was measured by ELISA in 28 pediatric KD patients 1 year post-KD, 70 adult KD patients, and 86 healthy adult volunteers. Results: A characteristic molecular profile was seen in pediatric patients during the acute disease, which resolved at the subacute and convalescent periods in patients with no coronary artery sequelae but persisted in 2 patients who developed giant CAA. We, therefore, investigated persistence of inflammation in KD adults with giant CAA by shotgun proteomics that revealed a signature of active inflammation, immune regulation, and cell trafficking. Correlating results obtained using shotgun proteomics in the pediatric and adult KD cohorts identified elevated calprotectin levels in the plasma of patients with CAA. Investigation of expanded pediatric and adult KD cohorts revealed elevated levels of calprotectin in pediatric patients with giant CAA 1 year post-KD and in adult KD patients who developed giant CAA in childhood. Conclusions: Complex patterns of biomarkers of inflammation and cell trafficking can persist long after the acute phase of KD in patients with giant CAA. Elevated levels of plasma calprotectin months to decades after acute KD and infiltration of cells expressing S100A8 and A9 in vascular tissues suggest ongoing, subclinical inflammation. Calprotectin may serve as a biomarker to inform the management of KD patients following the acute illness.

Coronary artery thrombosis is the major risk associated with Kawasaki disease (KD). Long-term management of KD patients with persistent aneurysms requires a thrombotic risk assessment and clinical decisions regarding the administration of anticoagulation therapy. Computational fluid dynamics has demonstrated that abnormal KD coronary artery hemodynamics can be associated with thrombosis. However, the underlying mechanisms of clot formation are not yet fully understood. Here we present a new model incorporating data from patient-specific simulated velocity fields to track platelet activation and accumulation. We use a system of Reaction-Advection-Diffusion equations solved with a stabilized finite element method to describe the evolution of non-activated platelets and activated platelet concentrations [AP], local concentrations of adenosine diphosphate (ADP) and poly-phosphate (PolyP). The activation of platelets is modeled as a function of shear-rate exposure and local concentration of agonists. We compared the distribution of activated platelets in a healthy coronary case and six cases with coronary artery aneurysms caused by KD, including three with confirmed thrombosis. Results show spatial correlation between regions of higher concentration of activated platelets and the reported location of the clot, suggesting predictive capabilities of this model towards identifying regions at high risk for thrombosis. Also, the concentration levels of ADP and PolyP in cases with confirmed thrombosis are higher than the reported critical values associated with platelet aggregation (ADP) and activation of the intrinsic coagulation pathway (PolyP). These findings suggest the potential initiation of a coagulation pathway even in the absence of an extrinsic factor. Finally, computational simulations show that in regions of flow stagnation, biochemical activation, as a result of local agonist concentration, is dominant. Identifying the leading factors to a pro-coagulant environment in each case—mechanical or biochemical—could help define improved strategies for thrombosis prevention tailored for each patient., Author Summary Computational studies aiming to model thrombosis often rely on an arterial wall injury. Collagen and other extracellular matrix components are exposed to the bloodstream, which facilitates platelet adhesion to the wall and subsequent clot formation. However, these models are not adequate to explain thrombosis in other settings where even in the absence of a focal lesion, clots may still form under certain flow conditions. Coronary artery aneurysm thrombosis following KD is an example of the need to understand the mechanisms of thrombus initiation in the absence of an extrinsic factor. This study provides a new framework to investigate thrombus initiation in KD from a patient-specific perspective, which integrates fluid mechanics and biochemistry and which could help quantify the pro-coagulant environment induced by the aneurysm and become a predictive tool. The work presented here has broad relevance to other clinical situations where flow stagnation and transport are driving factors in thrombus formation.

The decision to move forward with three clinical trials of IL-1 blockade for treatment of acute Kawasaki disease is a case study in translational science. These trials were born on the one hand from transcriptome studies of host response during the acute disease coupled with animal model investigations of key immune signaling pathways and, on the other hand, out of clinical desperation to intervene in patients with severe inflammation in the setting of acute Kawasaki disease. The convergence of laboratory science and clinical observations led to the clinical trials described here and serves as a model for how such observations can be translated into new therapies. This article is protected by copyright. All rights reserved.

O RIGINAL C ONTRIBUTION Building a Natural Language Processing Tool to Identify Patients With High Clinical Suspicion for Kawasaki Disease from Emergency Department Notes Son Doan, PhD, Cleo K. Maehara, MD, MMSc, Juan D. Chaparro, MD, Sisi Lu, MS, Ruiling Liu, MS, Amanda Graham, MPH, Erika Berry, Chun-Nan Hsu, PhD, John T. Kanegaye, MD, David D. Lloyd, MD, Lucila Ohno-Machado, MD, Jane C. Burns, MD, Adriana H. Tremoulet, MD, MAS, and the Pediatric Emergency Medicine Kawasaki Disease Research Group Abstract Objective: Delayed diagnosis of Kawasaki disease (KD) may lead to serious cardiac complications. We sought to create and test the performance of a natural language processing (NLP) tool, the KD-NLP, in the identification of emergency department (ED) patients for whom the diagnosis of KD should be considered. Methods: We developed an NLP tool that recognizes the KD diagnostic criteria based on standard clinical terms and medical word usage using 22 pediatric ED notes augmented by Unified Medical Language System vocabulary. With high suspicion for KD defined as fever and three or more KD clinical signs, KD-NLP was applied to 253 ED notes from children ultimately diagnosed with either KD or another febrile illness. We evaluated KD-NLP performance against ED notes manually reviewed by clinicians and compared the results to a simple keyword search. Results: KD-NLP identified high-suspicion patients with a sensitivity of 93.6% and specificity of 77.5% compared to notes manually reviewed by clinicians. The tool outperformed a simple keyword search (sensitivity = 41.0%; specificity = 76.3%). Conclusions: KD-NLP showed comparable performance to clinician manual chart review for identification of pediatric ED patients with a high suspicion for KD. This tool could be incorporated into the ED electronic health record system to alert providers to consider the diagnosis of KD. KD-NLP could serve as a model for decision support for other conditions in the ED. ACADEMIC EMERGENCY MEDICINE 2016;23:628–636 © 2016 by the Society for Academic Emergency Medicine From the Department of Biomedical Informatics, University of California (SD, CKM, JDC, CNH, LOM), San Diego, CA; the Depart- ment of Computer Science, University of Pittsburgh (SL), Pittsburgh, PA; The University of Texas Health Science Center at Hous- ton (RL), Houston, TX; Children’s Healthcare of Atlanta (AG, DDL), Atlanta, GA; the Department of Pediatrics, University of California at San Diego (EB, JTK, JCB, AHT, PEMKDRG), La Jolla, CA; Rady Children’s Hospital San Diego (JTK, JCB, AHT, PEMKDRG), San Diego, CA; and the Emory University School of Medicine (DDL), Atlanta, GA. Members of the Pediatric Emergency Medicine Kawasaki Disease Research Group included Lindsay T. Grubensky, RN, MSN, CPNP-PC, Jim R. Harley, MD, MPH, Paul Ishimine, MD, Jamie Lien, MD, Simon J. Lucio, MD, Seema Shah, MD, and Stacey Ulrich, MD. Received August 4, 2015; revision received November 29, 2015; accepted December 30, 2015. Part of this work was presented in poster format at the Pediatric Academic Societies Annual Meeting in San Diego, CA, on April This work was supported in part by the Patient-Centered Outcomes Research Institute (PCORI), contract CDRN-1306-04819 and NIH grant U54HL108460. The authors have no potential conflicts to disclose. Supervising Editor: Damon Kuehl, MD. Address for correspondence and reprints: Adriana H. Tremoulet; e-mail: atremoulet@ucsd.edu. ISSN 1069-6563 PII ISSN 1069-6563583 © 2016 by the Society for Academic Emergency Medicine doi: 10.1111/acem.12925

Dear Dr. Menegazzi, Thank you for allowing us to respond to Dr. Dahdah’s letter to the editor. Dear Dr. Dahdah, thank you for taking the time to critically review our case presentation and offer pe...

Unidad de excelencia María de Maeztu MdM-2015-0552 Recent advances on the environmental determinants of Kawasaki Disease have pointed to the important role of the atmospheric transport of a still unknown agent potentially triggering the disease. The hypothesis arose from an innovative methodology combining expertise in climate dynamics, the analysis of ocean and atmosphere data, the use of dispersion models and the search for biological agents in air samples. The approach offered a new perspective to reveal the identity of the potential trigger, but at the same time, it increased the level of complexity, which could potentially lead to the misinterpretation of the mechanisms. Some years after it was originally formulated, we here provide a brief clarification on the approach and limits of the methodology in order to prevent an eventual misuse of our research ideas and theory, so that further research can better focus on the knowledge gaps that still remain open.

The exact classification of Kawasaki disease (KD) has been debated. Infectious disease specialists have claimed it as an infection with a classic immune responses to an as yet unidentified pathogen that localizes to the coronary arteries. Others have favored an autoreactive hypothesis that KD is triggered by an antigen that shares homology with structures in the vascular wall, and molecular mimicry resulting in an immune response directed to that tissue. Rheumatologists have classified it as a systemic vasculitis, while some immunologists have stressed the robust nature of the innate immune response that causes both systemic inflammation as well as damage to the coronary arterial wall and questioned whether KD falls within the spectrum of autoinflammatory diseases. This review will describe the evidences available up to now regarding these hypotheses.

Using epidemiological investigation to characterise a disease in space and time can be a powerful tool to generate hypotheses about aetiology. Reports from Japan1 and the UK2 underscore the distinct seasonality of Kawasaki disease (KD) in two geographically distant regions of the northern hemisphere. The reports also document an increasing incidence of KD over time. While the seasonality of KD both in Japan and globally has been previously well documented, further analyses of patient characteristics and outcomes by season are yielding a more granular picture of the interaction between the environment and clinical features.3–5 In the report by Shimizu and colleagues1, the authors analysed 744 patients admitted to six hospitals in a single metropolitan region in Japan. Although details of the completeness of the reporting are lacking, this type of regional analysis may be more complete than the nationwide KD surveys in Japan that have an ~75% response rate. In addition, the authors had access to more detailed clinical information than is …

IMPORTANCE: American Heart Association guidelines recommend echocardiography in Kawasaki disease at baseline, 1 to 2 weeks, and 4 to 6 weeks after treatment to detect coronary artery abnormalities. However, these examinations are expensive and may require sedation in young children, which is burdensome and carries some risk. OBJECTIVE: To assess the benefit of additional echocardiographic imaging at 6 weeks in patients with uncomplicated Kawasaki disease who had previously normal coronary arteries. DESIGN, SETTING, AND PARTICIPANTS: This is a retrospective review of patients with Kawasaki disease who were cared for between 1995 and 2014 in 2 academic pediatric referral practices Eligibility criteria included receiving intravenous immunoglobulin treatment for acute Kawasaki disease at a center; the absence of significant congenital heart disease; available echocardiographic measurements of both the right and left anterior descending coronary arteries at 10 days or less after diagnosis (baseline), 2 (±1) weeks, and 6 (±3) weeks of illness; and normal coronary arteries at baseline and 2 weeks, defined as maximum coronary artery z scores less than 2.0 and no distal aneurysms. Data analysis was completed from March 2015 to November 2015. MAIN OUTCOMES AND MEASURES: The number of patients with right coronary artery or left anterior descending coronary artery z scores of 2.0 or more at 6 weeks. RESULTS: The median age of the 464 included patients was 3.3 years (interquartile range, 1.8-5.4 years); 264 (56.9%) were male, 351 of 414 for whom data were available (84.8%) had complete Kawasaki disease, and 66 (14.2%) received additional intravenous immunoglobulin treatment. At 6 weeks of illness, 456 patients (98.3%) who had had normal coronary artery z scores at baseline and 2 weeks continued to have normal z scores. Of the remaining 8 patients (1.7%), the maximum z score within 6 weeks was 2.0 to 2.4 in 5 patients (1.2%), 2.5 to 2.9 in 1 patient (0.2%), and 3.0 or more in 2 patients (0.4% [95% CI, 0.1%-1.5%]). Coronary artery dimensions ultimately normalized in all but 1 patient, who had minimal dilation at 6 weeks (right coronary artery z score, 2.1). Sensitivity analyses using less restrictive cut points (eg, a maximum z score

BackgroundInfliximab, a monoclonal antibody directed against tumor necrosis factor-α, is being evaluated as adjunctive therapy to intravenous immunoglobulin (IVIG) for treatment of young children with acute Kawasaki disease (KD).ObjectiveThe aim of this study was to develop a population pharmacokinetic (PopPK) model for infliximab in children with KD, and to evaluate the impact of covariates on infliximab disposition. Specifically, we wanted to investigate the effect of body weight and IVIG administration on PK parameters.MethodsIn the current PopPK analysis, 70 subjects with a median (interquartile range) age of 2.9years (1.3-4.4) were included from two randomized controlled trials. Infliximab concentration-time data were best described by a two-compartment model with first-order elimination using non-linear mixed-effects modeling (NONMEM 7.3).ResultsThe clearance, volume of distribution of the central (V1) and peripheral (V2) compartment, and intercompartmental clearance estimates (95% confidence interval) from the PopPK analysis were 0.117 (0.091-0.134) L/day, 0.801 (0.545-0.960) L, 0.962 (0.733-1.759) L, and 0.692 (0.482-1.779) L/day, respectively. Allometric body weight was included on all parameters of the structural model and a covariate analysis revealed that administering infliximab after IVIG, as opposed to before, resulted in a 50% decrease in V2.ConclusionsOur study shows that the timing of infliximab administration relative to IVIG administration affects the disposition of the monoclonal antibody. These results may have important implications for other monoclonal antibodies administered in combination with IVIG for treating inflammatory diseases.

Source at https://doi.org/10.1038/s41598-018-33124-4. Kawasaki Disease (KD) is the most common cause of pediatric acquired heart disease, but its etiology remains unknown. We examined 1164 cases of KD treated at a regional children’s hospital in San Diego over a period of 15 years and uncovered novel structure to disease incidence. KD cases showed a well-defined seasonal variability, but also clustered temporally at much shorter time scales (days to weeks), and spatiotemporally on time scales of up to 10 days and spatial scales of 10–100 km. Temporal clusters of KD cases were associated with strongly significant regional-scale air temperature anomalies and consistent larger-scale atmospheric circulation patterns. Gene expression analysis further revealed a natural partitioning of KD patients into distinct groups based on their gene expression pattern, and that the different groups were associated with certain clinical characteristics that also exhibit temporal autocorrelation. Our data suggest that one or more environmental triggers exist, and that episodic exposures are modulated at least in part by regional weather conditions. We propose that characterization of the environmental factors that trigger KD in genetically susceptible children should focus on aerosols inhaled by patients who share common disease characteristics.