The extrafollicular B cell response is a hallmark of childhood idiopathic nephrotic syndrome.

The efficacy of the B cell-targeting drug rituximab (RTX) in childhood idiopathic nephrotic syndrome (INS) suggests that B cells may be implicated in disease pathogenesis. However, B cell characterization in children with INS remains limited. Here, using single-cell RNA sequencing, we demonstrate that a B cell transcriptional program poised for effector functions represents the major immune perturbation in blood samples from children with active INS.

Efficacy and safety of levamisole in childhood nephrotic syndrome: A meta-analysis.

Present evidence regarding the efficacy and safety of levamisole in childhood nephrotic syndrome (NS), particularly the steroid-sensitive NS (SSNS), is limited. We searched relevant databases such as PubMed/MEDLINE, Embase, Google Scholar, and Cochrane CENTRAL till June 30, 2020. We included 12 studies for evidence synthesis (5 were clinical trials that included 326 children).

Relapsing and refractory peritoneal dialysis peritonitis caused by Corynebacterium amycolatum.

Background: Peritonitis is an important complication and cause of morbidity in patients undergoing peritoneal dialysis (PD). Corynebacterium species, often considered skin and mucosal contaminants, are a rare cause of PD-associated peritonitis and have been acknowledged in published guidelines for the diagnosis and treatment of PD peritonitis only over the last decade.

Case-diagnosis/treatment: We present two children with difficult-to-treat episodes of PD peritonitis due to Corynebacterium amycolatum.

Rapid whole genome sequencing of critically ill pediatric patients from genetically underrepresented populations.

We describe a case series of five infants (age range: 1-90 days; 4 females and 1 male) who presented to Al Jalila Children's intensive care units (ICU) with complex multisystem disorders. Patients were Emirati, Kenyan, Jordanian, Filipino, or Pakistani. Trio rapid whole genome sequencing (rWGS) was performed on all five patients and their parents within the hospital's genomics facility.

Case Report: Guillain-Barré Syndrome as Primary Presentation of Systemic Lupus Erythematosus (SLE-GBS) in a Teenage Girl.

Peripheral nervous system involvement accounts for fewer than 10% of SLE cases with neuropsychiatric manifestations. Guillain-Barré syndrome (GBS) as the presenting, major manifestation of pediatric SLE is extremely rare, and the best treatment approach is unknown. A 14-year-old, previously healthy female teenager developed classic features of GBS with ascending bilateral muscle weakness leading to respiratory insufficiency, associated with protein-cell dissociation in cerebro-spinal fluid, nerve root enhancement by MRI and reduction in compound muscle action potential amplitude.

Making the Correct Diagnosis in Thrombotic Microangiopathy: A Narrative Review.

Purpose Of Review: Thrombotic microangiopathy (TMA) is suspected in patients presenting with thrombocytopenia and evidence of a microangiopathic hemolytic anemia. Patients with TMA can be critically ill, so rapid and accurate identification of the underlying etiology is essential. Due to better insights into pathophysiology and causes of TMA, we can now categorize TMAs as thrombotic thrombocytopenic purpura, postinfectious (mainly Shiga toxin-producing -induced) hemolytic uremic syndrome (HUS), TMA associated with a coexisting condition, or atypical HUS (aHUS).

Predicting Adverse Outcomes for Shiga Toxin-Producing Escherichia coli Infections in Emergency Departments.

Objective: To assess the performance of a hemolytic uremic syndrome (HUS) severity score among children with Shiga toxin-producing Escherichia coli (STEC) infections and HUS by stratifying them according to their risk of adverse events. The score has not been previously evaluated in a North American acute care setting.

Study Design: We reviewed medical records of children <18 years old infected with STEC and treated in 1 of 38 participating emergency departments in North America between 2011 and 2015.

Case Report: CMV-Associated Congenital Nephrotic Syndrome.

Congenital nephrotic syndrome, historically defined by the onset of large proteinuria during the first 3 months of life, is a rare clinical disorder, generally with poor outcome. It is caused by pathogenic variants in genes associated with this syndrome or by fetal infections disrupting podocyte and/or glomerular basement membrane integrity. Here we describe an infant with congenital CMV infection and nephrotic syndrome that failed to respond to targeted antiviral therapy.

Clinical Characteristics and Outcome of Canadian Patients Diagnosed With Atypical Hemolytic Uremic Syndrome.

Background: Atypical hemolytic uremic syndrome (aHUS) is an extremely rare, heterogeneous disease of uncontrolled activation of the alternative complement pathway that is difficult to diagnose. We have evaluated the Canadian patients enrolled in the Global aHUS Registry to provide a Canadian perspective regarding the diagnosis and management of aHUS and the specific challenges faced.

Objective: To evaluate Canadian patients enrolled in the Global aHUS Registry to provide a Canadian perspective regarding the diagnosis and management of aHUS and the specific challenges faced.

Predicting Hemolytic Uremic Syndrome and Renal Replacement Therapy in Shiga Toxin-producing Escherichia coli-infected Children.

Background: Shiga toxin-producing Escherichia coli (STEC) infections are leading causes of pediatric acute renal failure. Identifying hemolytic uremic syndrome (HUS) risk factors is needed to guide care.

Methods: We conducted a multicenter, historical cohort study to identify features associated with development of HUS (primary outcome) and need for renal replacement therapy (RRT) (secondary outcome) in STEC-infected children without HUS at initial presentation.

The Canadian childhood nephrotic syndrome (CHILDNEPH) study: report on mid-study feasibility, recruitment and main measures.

Background: To assess reasons for continuing practice variation in the management of childhood nephrotic syndrome despite expert reviews and guidelines, we are conducting a longitudinal cohort study in children with glucocorticoid sensitive nephrotic syndrome. Objectives of this mid-study report are to describe patient and physician recruitment characteristics, glucocorticoid prescriptions, use of second line agents, biopsy practices, and adherence to study protocol.

Methods: Children with new onset nephrotic syndrome and providers are being recruited from all 12 pediatric nephrology centres across Canada with > 2½ years follow-up.

Theophylline and aminophylline for prevention of acute kidney injury in neonates and children: a systematic review.

Objective: To compare the efficacy and safety of theophylline or aminophylline for prevention of acute kidney injury (AKI) in neonates and children.

Design: Systematic review and meta-analysis with application of Grading of Recommendations, Assessment, Development and Evaluation system.

Data Sources: PubMed/MEDLINE, Embase, Google Scholar and Cochrane renal group were searched from 1970 to May 2018.

Hypophosphatemic Rickets.

Hypophosphatemic rickets, mostly of the X-linked dominant form caused by pathogenic variants of the PHEX gene, poses therapeutic challenges with consequences for growth and bone development and portends a high risk of fractions and poor bone healing, dental problems and nephrolithiasis/nephrocalcinosis. Conventional treatment consists of PO4 supplements and calcitriol requiring monitoring for treatment-emergent adverse effects. FGF23 measurement, where available, has implications for the differential diagnosis of hypophosphatemia syndromes and, potentially, treatment monitoring.

Complement depletion and Coombs positivity in pneumococcal hemolytic uremic syndrome (pnHUS). Case series and plea to revisit an old pathogenetic concept.

Hemolytic uremic syndrome is a rare complication of invasive pneumococcal infection (pnHUS). Its pathogenesis is poorly understood, and treatment remains controversial. The emerging role of complement in various forms of HUS warrants a new look at this "old" disease.

Renal tubular dysgenesis and microcolon, a novel association. Report of three cases.

Renal tubular dysgenesis (RTD) is a developmental abnormality of the nephron characterized by fetal anuria, oligohydramnios, and severe postnatal hypotension. Genetic forms have an autosomal recessive inheritance and are caused by mutations in genes encoding key components of the renin-angiotensin pathway. We report three patients from two unrelated families with RTD due to pathogenic variants of the angiotensin-converting enzyme (ACE) gene, in whom RTD was associated with microcolon.

Use of genomic and functional analysis to characterize patients with steroid-resistant nephrotic syndrome.

Background: Children with genetic causes of steroid-resistant nephrotic syndrome (SRNS) usually do well after renal transplantation, while some with idiopathic SRNS show recurrence due to a putative podocyte-toxic factor. Distinguishing different forms of SRNS based on clinical criteria has been difficult. The aim of our study was to test a novel approach that allows categorization of patients into clinically useful subgroups.

Acquired thrombotic thrombocytopenic purpura with isolated CFHR3/1 deletion-rapid remission following complement blockade.

Background: Thrombotic thrombocytopenic purpura (TTP) is caused by the abundance of uncleaved ultralarge von Willebrand factor multimers (ULvWF) due to acquired (autoantibody-mediated) or congenital vWF protease ADAMTS13 deficiency. Current treatment recommendations include plasma exchange therapy and immunosuppression for the acquired form and (fresh) frozen plasma for congenital TTP.

Case-diagnosis/treatment: A previously healthy, 3-year-old boy presented with acute microangiopathic hemolytic anemia, thrombocytopenia, erythrocyturia and mild proteinuria, but normal renal function, and elevated circulating sC5b-9 levels indicating complement activation.

Influenza-associated thrombotic microangiopathies.

Thrombotic microangiopathy (TMA) refers to phenotypically similar disorders, including hemolytic uremic syndromes (HUS) and thrombotic thrombocytopenic purpura (TTP). This review explores the role of the influenza virus as trigger of HUS or TTP. We conducted a literature survey in PubMed and Google Scholar using HUS, TTP, TMA, and influenza as keywords, and extracted and analyzed reported epidemiological and clinical data.

Rituximab in Minimal Change Disease: Mechanisms of Action and Hypotheses for Future Studies.

Treatment with rituximab, a monoclonal antibody against the B-lymphocyte surface protein CD20, leads to the depletion of B cells. Recently, rituximab was reported to effectively prevent relapses of glucocorticoid-dependent or frequently relapsing minimal change disease (MCD). MCD is thought to be T-cell mediated; how rituximab controls MCD is not understood.

Setting New Directions for Research in Childhood Nephrotic Syndrome: Results From a National Workshop.

Background: We report on the proceedings of a national workshop held in Canada with the aims to identify priorities for research in childhood nephrotic syndrome and to develop a national strategy to address these priorities.

Methods: A diverse group of participants attended the meeting, including patients, family members, researchers, and health care providers. We used small group discussions to explore priorities as perceived by patients and families and by health care providers and researchers.

Novel unbiased assay for circulating podocyte-toxic factors associated with recurrent focal segmental glomerulosclerosis.

Focal segmental glomerular sclerosis (FSGS) is an irreversible renal pathology characterized by podocyte detachment from the glomerular basement membrane, hyalinosis, and sclerosis. Clinically, it manifests with proteinuria and progressive loss of glomerular filtration. Primary idiopathic FSGS can occur in isolation and frequently progresses to end-stage renal disease, requiring dialysis or kidney transplantation.