Adriana H. Tremoulet

Resistance to intravenous immunoglobulin in children with Kawasaki disease

OBJECTIVES To explore the increased incidence of intravenous immunoglobulin- (IVIG) resistance among San Diego County patients with Kawasaki disease (KD) in 2006 and to evaluate a scoring system to predict IVIG-resistant patients with KD. STUDY DESIGN We performed a retrospective review of patients with KD treated within 10 days of fever onset. With multivariate analysis, independent predictors of IVIG-resistance were combined into a scoring system. RESULTS In 2006, 38.3% of patients with KD in San Diego County were IVIG-resistant, a significant increase over previous years. IVIG-resistance was not associated with a particular brand or lot of IVIG. Resistant patients were diagnosed earlier, had higher percent bands, and higher concentrations of C-reactive protein, alanine aminotransferase, and gamma-glutamyl transferase. They also had lower platelet counts and age-adjusted hemoglobin concentrations and were more likely to have aneurysms (P = .0008). A scoring system developed to predict IVIG-resistant patients using illness day, percent bands, gamma-glutamyl transferase, and age-adjusted hemoglobin had a sensitivity of 73.3% and specificity of 61.9%. CONCLUSIONS An unexplained increase in IVIG-resistance was noted among patients with KD in San Diego County in 2006. Scoring systems based on demographic and laboratory data were insufficiently accurate to be clinically useful in our ethnically diverse population.

Infliximab for intensification of primary therapy for Kawasaki disease: a phase 3 randomised, double-blind, placebo-controlled trial

BACKGROUND Kawasaki disease, the most common cause of acquired heart disease in developed countries, is a self-limited vasculitis that is treated with high doses of intravenous immunoglobulin. Resistance to intravenous immunoglobulin in Kawasaki disease increases the risk of coronary artery aneurysms. We assessed whether the addition of infliximab to standard therapy (intravenous immunoglobulin and aspirin) in acute Kawasaki disease reduces the rate of treatment resistance. METHODS We undertook a phase 3, randomised, double-blind, placebo-controlled trial in two childrens hospitals in the USA to assess the addition of infliximab (5 mg per kg) to standard therapy. Eligible participants were children aged 4 weeks-17 years who had a fever (temperature ≥38·0°C) for 3-10 days and met American Heart Association criteria for Kawasaki disease. Participants were randomly allocated in 1:1 ratio to two treatment groups: infliximab 5 mg/kg at 1 mg/mL intravenously over 2 h or placebo (normal saline 5 mL/kg, administered intravenously). Randomisation was based on a randomly permuted block design (block sizes 2 and 4), stratified by age, sex, and centre. Patients, treating physicians and staff, study team members, and echocardiographers were all masked to treament assignment. The primary outcome was the difference between the groups in treatment resistance defined as a temperature of 38·0°C or higher at 36 h to 7 days after completion of the infusion of intravenous immunoglobulin. Analysis was by intention to treat. This trial is registered with ClinicalTrials.gov, NCT00760435. FINDINGS 196 patients were enrolled and randomised: 98 to the infliximab group and 98 to placebo. One patient in the placebo group was withdrawn from the study because of hypotension before receiving treatment. Treatment resistance rate did not differ significantly (11 [11·2%] for infliximab and 11 [11·3%] for placebo; p=0·81). Compared with the placebo group, participants given infliximab had fewer days of fever (median 1 day for infliximab vs 2 days for placebo; p<0·0001). At week 2, infliximab-treated patients had greater mean reductions in erythrocyte sedimentation rate (p=0·009) and a two-fold greater decrease in Z score of the left anterior descending artery (p=0·045) than did those in the placebo group, but this difference was not significant at week 5. Participants in the infliximab group had a greater mean reduction in C-reactive protein concentration (p=0·0003) and in absolute neutrophil count (p=0·024) at 24 h after treatment than did those given placebo, but by week 2 this difference was not significant. At week 5, none of the laboratory values differed significantly compared with baseline. No significant differences were recorded between the two groups at any timepoint in proximal right coronary artery Z scores, age-adjusted haemoglobin values, duration of hospital stay, or any other laboratory markers of inflammation measured. No reactions to intravenous immunoglobulin infusion occurred in patients treated with infliximab compared with 13 (13·4%) patients given placebo (p<0·0001). No serious adverse events were directly attributable to infliximab infusion. INTERPRETATION The addition of infliximab to primary treatment in acute Kawasaki disease did not reduce treatment resistance. However, it was safe and well tolerated and reduced fever duration, some markers of inflammation, left anterior descending coronary artery Z score, and intravenous immunoglobulin reaction rates. FUNDING US Food and Drug Administration, Robert Wood Johnson Foundation, and Janssen Biotech.

Infliximab for Intravenous Immunoglobulin Resistance in Kawasaki Disease: A Retrospective Study

OBJECTIVE To test the hypothesis that first re-treatment with infliximab, compared with intravenous immunoglobulin (IVIG), might improve outcomes in IVIG-resistant Kawasaki disease. STUDY DESIGN In a two-center retrospective review from January 2000 to March 2008, we compared duration of fever and coronary artery dimensions in patients with IVIG-resistance whose first re-treatment was with IVIG compared with infliximab given for fever ≥38.0°C beyond 36 hours after first IVIG completion. RESULTS Patients in the IVIG group (n = 86, 2 g/kg) and infliximab group (n = 20, 5 mg/kg) were similar in demographics, days of fever at diagnosis, and baseline coronary artery dimensions. Patients had similar coronary dimensions 6 weeks after diagnosis, both in univariate and multivariate analysis. The infliximab group had fewer days of fever (median 8 days versus10 days, P = .028), and in a multivariate analysis, the infliximab group had 1.2 fewer days of fever (P = .033). Patients who received infliximab had shorter lengths of hospitalization (median 5.5 days versus 6 days, P = .040). Treatment groups did not differ significantly in adverse events (0% versus 2.3%, P = 1.0). CONCLUSIONS In our retrospective study, patients with IVIG-resistant Kawasaki disease whose first re-treatment was with infliximab, compared with IVIG, had faster resolution of fever and fewer days of hospitalization. Coronary artery outcomes and adverse events were similar; the power of the study was limited.

Transforming Growth Factor-β Signaling Pathway in Patients With Kawasaki Disease

Background—Transforming growth factor (TGF)-&bgr; is a multifunctional peptide that is important in T-cell activation and cardiovascular remodeling, both of which are important features of Kawasaki disease (KD). We postulated that variation in TGF-&bgr; signaling might be important in KD susceptibility and disease outcome. Methods and Results—We investigated genetic variation in 15 genes belonging to the TGF-&bgr; pathway in a total of 771 KD subjects of mainly European descent from the United States, the United Kingdom, Australia, and the Netherlands. We analyzed transcript abundance patterns using microarray and reverse transcriptase–polymerase chain reaction for these same genes, and measured TGF-&bgr;2 protein levels in plasma. Genetic variants in TGFB2, TGFBR2, and SMAD3 and their haplotypes were consistently and reproducibly associated with KD susceptibility, coronary artery aneurysm formation, aortic root dilatation, and intravenous immunoglobulin treatment response in different cohorts. A SMAD3 haplotype associated with KD susceptibility replicated in 2 independent cohorts and an intronic single nucleotide polymorphism in a separate haplotype block was also strongly associated (A/G, rs4776338) (P=0.000022; odds ratio, 1.50; 95% confidence interval, 1.25 to 1.81). Pathway analysis using all 15 genes further confirmed the importance of the TGF-&bgr; pathway in KD pathogenesis. Whole-blood transcript abundance for these genes and TGF-&bgr;2 plasma protein levels changed dynamically over the course of the illness. Conclusions—These studies suggest that genetic variation in the TGF-&bgr; pathway influences KD susceptibility, disease outcome, and response to therapy, and that aortic root and coronary artery Z scores can be used for phenotype/genotype analyses. Analysis of transcript abundance and protein levels further support the importance of this pathway in KD pathogenesis.

Recognition of a Kawasaki Disease Shock Syndrome

OBJECTIVE. We sought to define the characteristics that distinguish Kawasaki disease shock syndrome from hemodynamically normal Kawasaki disease. METHODS. We collected data prospectively for all patients with Kawasaki disease who were treated at a single institution during a 4-year period. We defined Kawasaki disease shock syndrome on the basis of systolic hypotension for age, a sustained decrease in systolic blood pressure from baseline of ≥20%, or clinical signs of poor perfusion. We compared clinical and laboratory features, coronary artery measurements, and responses to therapy and analyzed indices of ventricular systolic and diastolic function during acute and convalescent Kawasaki disease. RESULTS. Of 187 consecutive patients with Kawasaki disease, 13 (7%) met the definition for Kawasaki disease shock syndrome. All received fluid resuscitation, and 7 (54%) required vasoactive infusions. Compared with patients without shock, patients with Kawasaki disease shock syndrome were more often female and had larger proportions of bands, higher C-reactive protein concentrations, and lower hemoglobin concentrations and platelet counts. Evidence of consumptive coagulopathy was common in the Kawasaki disease shock syndrome group. Patients with Kawasaki disease shock syndrome more often had impaired left ventricular systolic function (ejection fraction of <54%: 4 of 13 patients [31%] vs 2 of 86 patients [4%]), mitral regurgitation (5 of 13 patients [39%] vs 2 of 83 patients [2%]), coronary artery abnormalities (8 of 13 patients [62%] vs 20 of 86 patients [23%]), and intravenous immunoglobulin resistance (6 of 13 patients [46%] vs 32 of 174 patients [18%]). Impairment of ventricular relaxation and compliance persisted among patients with Kawasaki disease shock syndrome after the resolution of other hemodynamic disturbances. CONCLUSIONS. Kawasaki disease shock syndrome is associated with more-severe laboratory markers of inflammation and greater risk of coronary artery abnormalities, mitral regurgitation, and prolonged myocardial dysfunction. These patients may be resistant to immunoglobulin therapy and require additional antiinflammatory treatment.

Calcineurin Inhibitor Treatment of Intravenous Immunoglobulin–Resistant Kawasaki Disease

OBJECTIVE To describe the clinical course and outcome of 10 patients with Kawasaki disease (KD) treated with a calcineurin inhibitor after failing to respond to multiple therapies. STUDY DESIGN Demographic and clinical data were prospectively collected using standardized case report forms. T-cell phenotypes were determined by flow cytometry, and KD risk alleles in ITPKC (rs28493229), CASP3 (rs72689236), and FCGR2A (rs1801274) were genotyped. RESULTS Intravenous followed by oral therapy with cyclosporine (CSA) or oral tacrolimus was well tolerated and resulted in defervescence and resolution of inflammation in all 10 patients. There were no serious adverse events, and a standardized treatment protocol was developed based on our experiences with this patient population. Analysis of T-cell phenotype by flow cytometry in 2 subjects showed a decrease in circulating activated CD8(+) and CD4(+) T effector memory cells after treatment with CSA. However, suppression of regulatory T-cells was not seen, suggesting targeting of specific, proinflammatory T-cell compartments by CSA. CONCLUSION Treatment of refractory KD with a calcineurin inhibitor appears to be a safe and effective approach that achieves rapid control of inflammation associated with clinical improvement.

Diagnostic Test Accuracy of a 2-Transcript Host RNA Signature for Discriminating Bacterial vs Viral Infection in Febrile Children

IMPORTANCE Because clinical features do not reliably distinguish bacterial from viral infection, many children worldwide receive unnecessary antibiotic treatment, while bacterial infection is missed in others. OBJECTIVE To identify a blood RNA expression signature that distinguishes bacterial from viral infection in febrile children. DESIGN, SETTING, AND PARTICIPANTS Febrile children presenting to participating hospitals in the United Kingdom, Spain, the Netherlands, and the United States between 2009-2013 were prospectively recruited, comprising a discovery group and validation group. Each group was classified after microbiological investigation as having definite bacterial infection, definite viral infection, or indeterminate infection. RNA expression signatures distinguishing definite bacterial from viral infection were identified in the discovery group and diagnostic performance assessed in the validation group. Additional validation was undertaken in separate studies of children with meningococcal disease (n = 24) and inflammatory diseases (n = 48) and on published gene expression datasets. EXPOSURES A 2-transcript RNA expression signature distinguishing bacterial infection from viral infection was evaluated against clinical and microbiological diagnosis. MAIN OUTCOMES AND MEASURES Definite bacterial and viral infection was confirmed by culture or molecular detection of the pathogens. Performance of the RNA signature was evaluated in the definite bacterial and viral group and in the indeterminate infection group. RESULTS The discovery group of 240 children (median age, 19 months; 62% male) included 52 with definite bacterial infection, of whom 36 (69%) required intensive care, and 92 with definite viral infection, of whom 32 (35%) required intensive care. Ninety-six children had indeterminate infection. Analysis of RNA expression data identified a 38-transcript signature distinguishing bacterial from viral infection. A smaller (2-transcript) signature (FAM89A and IFI44L) was identified by removing highly correlated transcripts. When this 2-transcript signature was implemented as a disease risk score in the validation group (130 children, with 23 definite bacterial, 28 definite viral, and 79 indeterminate infections; median age, 17 months; 57% male), all 23 patients with microbiologically confirmed definite bacterial infection were classified as bacterial (sensitivity, 100% [95% CI, 100%-100%]) and 27 of 28 patients with definite viral infection were classified as viral (specificity, 96.4% [95% CI, 89.3%-100%]). When applied to additional validation datasets from patients with meningococcal and inflammatory diseases, bacterial infection was identified with a sensitivity of 91.7% (95% CI, 79.2%-100%) and 90.0% (95% CI, 70.0%-100%), respectively, and with specificity of 96.0% (95% CI, 88.0%-100%) and 95.8% (95% CI, 89.6%-100%). Of the children in the indeterminate groups, 46.3% (63/136) were classified as having bacterial infection, although 94.9% (129/136) received antibiotic treatment. CONCLUSIONS AND RELEVANCE This study provides preliminary data regarding test accuracy of a 2-transcript host RNA signature discriminating bacterial from viral infection in febrile children. Further studies are needed in diverse groups of patients to assess accuracy and clinical utility of this test in different clinical settings.

Seasonality of Kawasaki Disease: A Global Perspective

Background Understanding global seasonal patterns of Kawasaki disease (KD) may provide insight into the etiology of this vasculitis that is now the most common cause of acquired heart disease in children in developed countries worldwide. Methods Data from 1970-2012 from 25 countries distributed over the globe were analyzed for seasonality. The number of KD cases from each location was normalized to minimize the influence of greater numbers from certain locations. The presence of seasonal variation of KD at the individual locations was evaluated using three different tests: time series modeling, spectral analysis, and a Monte Carlo technique. Results A defined seasonal structure emerged demonstrating broad coherence in fluctuations in KD cases across the Northern Hemisphere extra-tropical latitudes. In the extra-tropical latitudes of the Northern Hemisphere, KD case numbers were highest in January through March and approximately 40% higher than in the months of lowest case numbers from August through October. Datasets were much sparser in the tropics and the Southern Hemisphere extra-tropics and statistical significance of the seasonality tests was weak, but suggested a maximum in May through June, with approximately 30% higher number of cases than in the least active months of February, March and October. The seasonal pattern in the Northern Hemisphere extra-tropics was consistent across the first and second halves of the sample period. Conclusion Using the first global KD time series, analysis of sites located in the Northern Hemisphere extra-tropics revealed statistically significant and consistent seasonal fluctuations in KD case numbers with high numbers in winter and low numbers in late summer and fall. Neither the tropics nor the Southern Hemisphere extra-tropics registered a statistically significant aggregate seasonal cycle. These data suggest a seasonal exposure to a KD agent that operates over large geographic regions and is concentrated during winter months in the Northern Hemisphere extra-tropics.

Transcript abundance patterns in Kawasaki disease patients with intravenous immunoglobulin resistance

Intravenous immunoglobulin (IVIG)-resistant Kawasaki disease (KD) patients comprise at least 20% of treated patients and are at high risk for coronary artery abnormalities. If identified early in the course of the disease, such patients may benefit from additional anti-inflammatory therapy. The aim of this study was to compare the transcript abundance between IVIG resistant and -responsive KD patients, to identify biomarkers that might differentiate between these two groups and to generate new targets for therapies in IVIG resistant KD patients. We compared the transcript abundance profiles of whole-blood RNA on Agilent arrays from acute and convalescent KD subjects and age-similar, healthy controls. KD subjects were stratified as IVIG resistant or -responsive based on response to initial IVIG therapy. Transcript abundance was higher for IL-1 pathway genes (IL-1 receptor, interleukin receptor associated kinase, p38 mitogen-activated protein kinase), and MMP-8. These findings point to candidate biomarkers that may predict IVIG resistance in acute KD patients. The results also underscore the importance of the IL-1 pathway as a mediator of inflammation in KD and suggest that IL-1 or its receptor may be reasonable targets for therapy, particularly for IVIG resistant patients.

Differential Expression of miR-145 in Children with Kawasaki Disease

Background Kawasaki disease is an acute, self-limited vasculitis of childhood that can result in structural damage to the coronary arteries. Previous studies have implicated the TGF-β pathway in disease pathogenesis and generation of myofibroblasts in the arterial wall. microRNAs are small non-coding RNAs that modulate gene expression at the post-transcriptional level and can be transported between cells in extracellular vesicles. To understand the role that microRNAs play in modifying gene expression in Kawasaki disease, we studied microRNAs from whole blood during the acute and convalescent stages of the illness. Methodology/Principal Findings RNA isolated from the matched whole blood of 12 patients with acute and convalescent Kawasaki disease were analyzed by sequencing of small RNA. This analysis revealed six microRNAs (miRs-143, -199b-5p, -618, -223, -145 and -145* (complementary strand)) whose levels were significantly elevated during the acute phase of Kawasaki disease. The result was validated using targeted qRT-PCR using an independent cohort (n = 16). miR-145, which plays a critical role in the differentiation of neutrophils and vascular smooth muscle cells, was expressed at high levels in blood samples from acute Kawasaki disease but not adenovirus-infected control patients (p = 0.005). miR-145 was also detected in small extracellular vesicles isolated from acute Kawasaki disease plasma samples. Pathway analysis of the predicted targets of the 6 differentially expressed microRNAs identified the TGF-β pathway as the top pathway regulated by microRNAs in Kawasaki disease. Conclusion Sequencing of small RNA species allowed discovery of microRNAs that may participate in Kawasaki disease pathogenesis. miR-145 may participate, along with other differentially expressed microRNAs, in regulating expression of genes in the TGF-β pathway during the acute illness. If the predicted target genes are confirmed, our findings suggest a model of Kawasaki disease pathogenesis whereby miR-145 modulates TGF-β signaling in the arterial wall.