An Immunological Axis Involving Interleukin 1ß 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-1ß 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-1ß signaling and neutrophilia, while particularly neutrophil stimulation with recombinant IL-1ß 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-1ß 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.

Social Deprivation Is Associated With Lower Access to Pre-emptive Kidney Transplantation and More Urgent-Start Dialysis in the Pediatric Population.

Introduction: Socioeconomic status (SES) is recognized as an important determinant of kidney health. We aimed to evaluate the association of social deprivation with different indicators at kidney replacement therapy (KRT) initiation in the French pediatric metropolitan population. Methods: All patients with end-stage kidney disease (ESKD) who started KRT before 20 years old in France between 2002 and 2015 were included. We investigated different indicators at KRT initiation, which are as follows: KRT modality (dialysis vs. pre-emptive transplantation), late referral to a nephrologist, and dialysis modality (hemodialysis [HD] vs. peritoneal dialysis [PD], urgent vs. planned start of dialysis, use of catheter vs. use of fistula for HD vascular access). An ecological index (European Deprivation Index [EDI]) was used as a proxy for social deprivation. Results: A total of 1115 patients were included (males 59%, median age at dialysis 14.4 years, glomerular/vascular diseases 36.8%). The most deprived group represented 38.7% of the patients, suggesting pediatric patients with ESKD come from a more socially deprived background. The most deprived group was more likely to initiate KRT with dialysis versus kidney transplantation. Among patients on HD, the odds of starting treatment in emergency with a catheter was >2-fold higher for the most deprived compared with the least deprived children (adjusted odds ratio [aOR] 2.35, 95% CI 1.16-4.78). Conclusion: Children from the most deprived area have lower access to pre-emptive transplantation, have lower access to PD, tend to be late referred to a nephrologist, and have more urgent initiation of HD with a catheter.

Immune-mediated thrombotic thrombocytopenic purpura in childhood treated by caplacizumab, about 3 cases.

Immune-mediated thrombotic thrombocytopenic purpura (iTTP) is a rare disease in adults and exceptional in childhood. Caplacizumab has proven its effectiveness in the treatment of iTTP in adulthood in association with standard of care. Unfortunately, this treatment is restricted to adults. We report our experience in three children who were treated successfully with caplacizumab.

Defects in KCNJ16 Cause a Novel Tubulopathy with Hypokalemia, Salt Wasting, Disturbed Acid-Base Homeostasis, and Sensorineural Deafness.

BACKGROUND: The transepithelial transport of electrolytes, solutes, and water in the kidney is a well-orchestrated process involving numerous membrane transport systems. Basolateral potassium channels in tubular cells not only mediate potassium recycling for proper Na+,K+-ATPase function but are also involved in potassium and pH sensing. Genetic defects in KCNJ10 cause EAST/SeSAME syndrome, characterized by renal salt wasting with hypokalemic alkalosis associated with epilepsy, ataxia, and sensorineural deafness. METHODS: A candidate gene approach and whole-exome sequencing determined the underlying genetic defect in eight patients with a novel disease phenotype comprising a hypokalemic tubulopathy with renal salt wasting, disturbed acid-base homeostasis, and sensorineural deafness. Electrophysiologic studies and surface expression experiments investigated the functional consequences of newly identified gene variants. RESULTS: We identified mutations in the KCNJ16 gene encoding KCNJ16, which along with KCNJ15 and KCNJ10, constitutes the major basolateral potassium channel of the proximal and distal tubules, respectively. Coexpression of mutant KCNJ16 together with KCNJ15 or KCNJ10 in Xenopus oocytes significantly reduced currents. CONCLUSIONS: Biallelic variants in KCNJ16 were identified in patients with a novel disease phenotype comprising a variable proximal and distal tubulopathy associated with deafness. Variants affect the function of heteromeric potassium channels, disturbing proximal tubular bicarbonate handling as well as distal tubular salt reabsorption.

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

OBJECTIVE: Anakinra has been shown to be successful in preventing and treating cardiovascular lesions both in experimental murine models of Kawasaki disease (KD) and in several studies on intravenous immunoglobulin (IVIG)- and steroid-resistant patients with KD. This study was undertaken to determine the safety of blocking interleukin-1 in patients with IVIG-resistant KD. METHODS: Sixteen patients were included in the present study. Patients with KD who were not responsive to 1 or more courses of 2 mg/kg of IVIG received anakinra by subcutaneous daily injections. Starting doses were 2 mg/kg of IVIG (4 mg/kg in patients who were age <8 months and who weighed ≥5 kilograms), and the dose was increased up to 6 mg/kg every 24 hours if the patient's body temperature remained >38°C, indicative of a fever. Treatment duration was 14 days. The last visit was on day 45. Primary outcome was abatement of fever. Secondary measures included disease activity, coronary artery Z score, and C-reactive protein (CRP) levels. RESULTS: Seventy-five percent of patients in the intention-to-treat group and 87.5% in the per-protocol group became afebrile within 48 hours of the last escalation dose of anakinra. Reduction of disease activity by 50% was indicated on 93.3% (95% confidence interval [95% CI] 68.1-99.8%) of physician evaluations and on 100% (95% CI 73.5-100%) of parent evaluations. CRP values normalized by day 30. At the initial screening, 12 of 16 patients had a maximum coronary artery Z score of >2, and 10 of 16 patients had a maximum Z score of >2.5. At day 45, 5 of 10 patients (50% [95% CI 18.7-81.3%]) and 6 of 12 patients (50% [95% CI 21.1-78.9%]) had achieved coronary artery Z scores of <2.5 and <2, respectively. Five serious adverse events were observed in 3 patients, but no serious infections or deaths occurred. CONCLUSION: Anakinra was well tolerated in the study patients and may have some efficacy in reducing fever, markers of systemic inflammation, and coronary artery dilatation in individuals with IVIG-refractory KD.

Mycophenolic acid area under the concentration-time curve is associated with therapeutic response in childhood-onset lupus nephritis.

BACKGROUND: Mycophenolic acid (MPA), the active compound of mycophenolate mofetil (MMF), is widely used in lupus nephritis treatment. Therapeutic drug monitoring of adults suggests that area under the concentration-time curve (AUC) of MPA (MPA-AUC) is associated with clinical outcomes, but childhood data are scarce. METHODS: Retrospective study of 27 children with biopsy-proven lupus nephritis treated with MMF between 2008 and 2016. In 25 children, MPA-AUC was performed within 6 months after kidney biopsy and MMF initiation. Treatment response at 6 months was defined as normal or improved GFR by 25% compared with baseline, 50% reduction of proteinuria to < 0.5 g/day or 50 mg/mmol, and no hematuria. RESULTS: A total of 62 MPA-AUC were analyzed in 27 patients. Overall median was 44 mg h/L (interquartile range [IQR] 33-54). Individual dose adaptation was required in 32 cases (52%) to achieve target AUC of 30-60 mg h/L. At 6 months, 14/25 patients were defined as responders (56%, median MPA-AUC 49 mg h/L (40-59)) and 11/25 as non-responders (44%, 29 mg h/L (24-38)). Patients with MPA-AUC levels > 45, 30-45, and < 30 mg h/L had 6-month response rates of 89% (8/9), 60% (6/10), and 0% (0/6), respectively. In a logistic regression model adjusted for age, sex, lupus nephritis classification, and time since MMF initiation, an MPA-AUC > 45 mg h/L was significantly associated with therapeutic response (OR 3.6, 95% CI 2.4-9.5, p = 0.03). CONCLUSIONS: Therapeutic drug monitoring leading to individualized dosing may improve efficacy of MMF. MPA-AUC > 45 mg h/L is associated with better response rate and may be considered as a target value in pediatric lupus nephritis.

Efficacy and safety of intravenous immunoglobulin with rituximab versus rituximab alone in childhood-onset steroid-dependent and frequently relapsing nephrotic syndrome: protocol for a multicentre randomised controlled trial.

INTRODUCTION: Guidelines for the treatment of steroid-dependent nephrotic syndrome (SDNS) and frequently relapsing nephrotic syndrome (FRNS) are lacking. Given the substantial impact of SDNS/FRNS on quality of life, strategies aiming to provide long-term remission while minimising treatment side effects are needed. Several studies confirm that rituximab is effective in preventing early relapses in SDNS/FRNS; however, the long-term relapse rate remains high (~70% at 2 years). This trial will assess the association of intravenous immunoglobulins (IVIgs) to rituximab in patients with SDNS/FRNS and inform clinicians on whether IVIg's immunomodulatory properties can alter the course of the disease and reduce the use of immunosuppressive drugs and their side effects. METHODS AND ANALYSIS: We conduct an open-label multicentre, randomised, parallel group in a 1:1 ratio, controlled, superiority trial to assess the safety and efficacy of a single infusion of rituximab followed by IVIg compared with rituximab alone in childhood-onset FRNS/SDNS. The primary outcome is the occurrence of first relapse within 24 months. Patients are allocated to receive either rituximab alone (375 mg/m²) or rituximab followed by IVIg, which includes an initial Ig dose of 2 g/kg, followed by 1.5 g/kg injections once a month for the following 5 months (maximum dose: 100 g). ETHICS AND DISSEMINATION: The study has been approved by the ethics committee (Comité de Protection des Personnes) of Ouest I and authorised by the French drug regulatory agency (Agence Nationale de Sécurité du Médicament et des Produits de Santé). Results of the primary study and the secondary aims will be disseminated through peer-reviewed publications. TRIAL REGISTRATION NUMBER: NCT03560011.

[Vaccine recommendations for children with idiopathic nephrotic syndrome]. / Recommandations vaccinales pour les enfants avec un syndrome néphrotique idiopathique.

The specific treatment of idiopathic nephrotic syndrome is based on corticosteroid therapy and/or steroid-sparing immunosuppressive agents in children who are steroid-dependant or frequent relapsers (60-70 %). Patients have an increased infectious risk not only related to the disease during relapses (hypogammaglobulinemia and urinary leakage of opsonins) but also to treatments (corticosteroids or immunosuppressive agents) in period of remission. Vaccination is therefore particularly recommended in these patients. Potential vaccine risks are ineffectiveness, induction of vaccine disease and relapse of idiopathic nephrotic syndrome. Only live vaccines expose to the risk of vaccine disease: they are in general contra-indicated under immunosuppressive treatment. The immunogenicity of inactivated vaccines is reduced but persists. The immunogenic stimulus of vaccination may in theory trigger a relapse of the nephrotic syndrome. Nevertheless, this risk is low in the literature, and even absent in some studies. The benefit-risk ratio is therefore in favor of vaccination with respect to the vaccination schedule for inactivated vaccines, with wide vaccination against pneumococcus and influenza annually. Depending on the context and after expert advice, immunization with live vaccines could be discussed if residual doses/levels of immunosuppressive treatments are moderate and immunity preserved.

Defining the risk of first intravenous immunoglobulin unresponsiveness in non-Asian patients with Kawasaki disease.

About 10-20% of patients with Kawasaki disease (KD) are unresponsive to intravenous immunoglobulin (IVIg) and are at increased risk of coronary artery abnormalities (CAAs). Early identification is critical to initiate aggressive therapies, but available scoring systems lack sensitivity in non-Japanese populations. We investigated the accuracy of 3 Japanese scoring systems and studied factors associated with IVIg unresponsiveness in a large multiethnic French population of children with KD to build a new scoring system. Children admitted for KD between 2011-2014 in 65 centers were enrolled. Factors associated with second line-treatment; i.e. unresponsiveness to initial IVIg treatment, were analyzed by multivariate regression analysis. The performance of our score and the Kobayashi, Egami and Sano scores were compared in our population and in ethnic subgroups. Overall, 465 children were reported by 84 physicians; 425 were classified with KD (55% European Caucasian, 12% North African/Middle Eastern, 10% African/Afro-Caribbean, 3% Asian and 11% mixed). Eighty patients (23%) needed second-line treatment. Japanese scores had poor performance in our whole population (sensitivity 14-61%). On multivariate regression analysis, predictors of secondary treatment after initial IVIG were hepatomegaly, ALT level ≥30 IU/L, lymphocyte count <2400/mm3 and time to treatment <5 days. The best sensitivity (77%) and specificity (60%) of this model was with 1 point per variable and cut-off ≥2 points. The sensitivity remained good in our 3 main ethnic subgroups (74-88%). We identified predictors of IVIg resistance and built a new score with good sensitivity and acceptable specificity in a non-Asian population.

Evaluation of Various Sources of Viral Infection in Strawberry Fields of Quebec, Canada.

The decline of cultivated strawberry (Fragaria × ananassa Duchesne ex Rozier; Rosaceae) observed in the province of Quebec, Canada, between 2012 and 2014 was mostly caused by persistent viruses: strawberry mild yellow edge virus (SMYEV) (Potexvirus; Alphaflexiviridae) and strawberry crinkle virus (SCV) (Cytorhabdovirus; Rhabdoviridae); and semi-persistent viruses: strawberry mottle virus (SmoV) (Secoviridae), strawberry vein banding virus (SVBV) (Caulimovirus; Caulimoviridae), and strawberry pallidosis virus (SPaV) (Crinivirus: Closteroviridae) transmitted by insect vectors. The objective of this study was to determine the sources of viral contamination in commercial strawberry fields in Quebec. Specifically, we wished to 1) determine the prevalence of persistent viruses in winged strawberry aphid Chaetosiphon fragaefolii (Cockerell) (Hemiptera: Aphididae) specimens captured; 2) determine the prevalence of all viruses in wild strawberry Fragaria virginiana Miller plants near commercial plantings; and 3) evaluate the viral contamination of strawberry transplants obtained from nurseries and tested before and after planting in commercial strawberry fields. Results indicated high percentage (38%) of the aphids (n = 205) and high percentage (67%) of F. virginiana patches (n = 12) were infected by strawberry viruses. Ultimately, our results showed a low percentage (5%) of the plants from various nurseries (n = 56) were infected before planting, whereas a third (29%) of the healthy exposed plants in the fields (n = 96) became rapidly infected by insect vectors within a year of having been planted. This study provides significant insights on the relative importance of the various sources of contamination in Quebec strawberry fields: C. fragaefolii versus F. virginiana versus nurseries versus post-nursery infections through exposure to virus-carrying insects.

Eculizumab treatment in severe pediatric STEC-HUS: a multicenter retrospective study.

BACKGROUND: Hemolytic uremic syndrome related to Shiga-toxin-secreting Escherichia coli infection (STEC-HUS) remains a common cause of acute kidney injury in young children. No specific treatment has been validated for this severe disease. Recently, experimental studies highlight the potential role of complement in STEC-HUS pathophysiology. Eculizumab (EC), a monoclonal antibody against terminal complement complex, has been used in severe STEC-HUS patients, mostly during the 2011 German outbreak, with conflicting results. METHODS: On behalf of the French Society of Pediatric Nephrology, we retrospectively studied 33 children from 15 centers treated with EC for severe STEC-HUS. Indication for EC was neurologic involvement in 20 patients, cardiac and neurologic involvement in 8, cardiac involvement in 2, and digestive involvement in 3. Based on medical status at last follow-up, patients were divided into two groups: favorable (n = 15) and unfavorable outcomes (n = 18). RESULTS: Among patients with favorable outcome, 11/14 patients (79%) displayed persistent blockade of complement activity before each EC reinjection. Conversely, in patients with unfavorable outcome, only 9/15 (53%) had persistent blockade (p = n.s.). Among 28 patients presenting neurological symptoms, 19 had favorable neurological outcome including 17 with prompt recovery following first EC injection. Only two adverse effects potentially related to EC treatment were reported. CONCLUSIONS: Taken together, these results may support EC use in severe STEC-HUS patients, especially those presenting severe neurological symptoms. The study, however, is limited by absence of a control group and use of multiple therapeutic interventions in treatment groups. Thus, prospective, controlled trials should be undertaken.

A capillary electrophoresis coupled to mass spectrometry pipeline for long term comparable assessment of the urinary metabolome.

Although capillary electrophoresis coupled to mass spectrometry (CE-MS) has potential application in the field of metabolite profiling, very few studies actually used CE-MS to identify clinically useful body fluid metabolites. Here we present an optimized CE-MS setup and analysis pipeline to reproducibly explore the metabolite content of urine. We show that the use of a beveled tip capillary improves the sensitivity of detection over a flat tip. We also present a novel normalization procedure based on the use of endogenous stable urinary metabolites identified in the combined metabolome of 75 different urine samples from healthy and diseased individuals. This method allows a highly reproducible comparison of the same sample analyzed nearly 130 times over a range of 4 years. To demonstrate the use of this pipeline in clinical research we compared the urinary metabolome of 34 newborns with ureteropelvic junction (UPJ) obstruction and 15 healthy newborns. We identified 32 features with differential urinary abundance. Combination of the 32 compounds in a SVM classifier predicted with 76% sensitivity and 86% specificity UPJ obstruction in a separate validation cohort of 24 individuals. Thus, this study demonstrates the feasibility to use CE-MS as a tool for the identification of clinically relevant urinary metabolites.

Mycophenolic Acid Pharmacokinetics and Relapse in Children with Steroid-Dependent Idiopathic Nephrotic Syndrome.

BACKGROUND AND OBJECTIVES: Therapeutic drug monitoring of mycophenolic acid can improve clinical outcome in organ transplantation and lupus, but data are scarce in idiopathic nephrotic syndrome. The aim of our study was to investigate whether mycophenolic acid pharmacokinetics are associated with disease control in children receiving mycophenolate mofetil for the treatment of steroid-dependent nephrotic syndrome. DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS: This was a retrospective multicenter study including 95 children with steroid-dependent nephrotic syndrome treated with mycophenolate mofetil with or without steroids. Area under the concentration-time curve of mycophenolic acid was determined in all children on the basis of sampling times at 20, 60, and 180 minutes postdose, using Bayesian estimation. The association between a threshold value of the area under the concentration-time curve of mycophenolic acid and the relapse rate was assessed using a negative binomial model. RESULTS: In total, 140 areas under the concentration-time curve of mycophenolic acid were analyzed. The findings indicate individual dose adaptation in 53 patients (38%) to achieve an area under the concentration-time curve target of 30-60 mg·h/L. In a multivariable negative binomial model including sex, age at disease onset, time to start of mycophenolate mofetil, previous immunomodulatory treatment, and concomitant prednisone dose, a level of area under the concentration-time curve of mycophenolic acid >45 mg·h/L was significantly associated with a lower relapse rate (rate ratio, 0.65; 95% confidence interval, 0.46 to 0.89; P=0.01). CONCLUSIONS: Therapeutic drug monitoring leading to individualized dosing may improve the efficacy of mycophenolate mofetil in steroid-dependent nephrotic syndrome. Additional prospective studies are warranted to determine the optimal target for area under the concentration-time curve of mycophenolic acid in this population.

Long-term outcome of children treated with rituximab for idiopathic nephrotic syndrome.

BACKGROUND: Rituximab (RTX) has recently showed promising results in the treatment of steroid-dependent idiopathic nephrotic syndrome (SDNS). METHODS: This was a retrospective multicenter study of 18 children treated with RTX for SDNS, with a mean follow-up of 3.2 years. RTX was introduced because of side effects or relapses during therapy with immunosuppressive agents. The children received one to four infusions of RTX during the first course of treatment, and subsequent infusions were given due to CD19-cell recovery (CD19 >1 %; 54 % of children) or relapse (41 %), as well as systematically (5 %). RESULTS: Treatment with RTX maintained sustained remission without relapse in 22 % of patients and increased the duration of remission in all other patients. The time between two successive relapses was 9 months in the absence of re-treatment and 24.5 months when infusions were performed at the time of CD19-cell recovery. At the last follow-up, 44.5 % of patients were free of oral drug therapy. Of those still receiving oral drugs, all doses had been decreased. No serious adverse events occurred. CONCLUSION: The results of this retrospective study confirm the efficacy and very good safety of RTX in the treatment of SDNS. The optimal therapeutic protocol seems to be a repeated single infusion at the time of CD19-cell recovery.