A multi-institutional study found a possible role of anti-nephrin antibodies in post-transplant focal segmental glomerulosclerosis recurrence

Possible roles of anti-nephrin antibodies in post-transplant recurrent focal segmental glomerulosclerosis (FSGS) have been reported recently. To confirm these preliminary results, we performed a multi-institutional study of 22 Japanese pediatric kidney transplant recipients with FSGS including eight genetic FSGS and 14 non-genetic (presumed primary) FSGS. Eleven of the 14 non-genetic FSGS patients had post-transplant recurrent FSGS. Median (interquartile range) plasma levels of anti-nephrin antibodies in post-transplant recurrent FSGS measured using ELISA were markedly high at 899 (831, 1292) U/mL (cutoff 231 U/mL) before transplantation or during recurrence. Graft biopsies during recurrence showed punctate IgG deposition co-localized with nephrin that had altered localization with increased nephrin tyrosine phosphorylation and Src homology and collagen homology A expressions. Graft biopsies after remission showed no signals for IgG and a normal expression pattern of nephrin. Anti-nephrin antibody levels decreased to 155 (53, 367) U/mL in five patients with samples available after remission. In patients with genetic FSGS as in those with non-genetic FSGS without recurrence, anti-nephrin antibody levels were comparable to those of 30 control individuals, and graft biopsies had no signals for IgG and a normal expression pattern of nephrin. Thus, our results suggest that circulating anti-nephrin antibodies are a possible candidate for circulating factors involved in the pathogenesis of post-transplant recurrent FSGS and that this may be mediated by nephrin phosphorylation. Larger studies including other ethnicities are required to confirm this finding.

En bloc kidney transplantation from pediatric donors to teenage recipients: Two case reports

Introduction

Since the implementation of the new selection criteria in 2018, kidney donations from pediatric patients have been prioritized for pediatric recipients and kidney donations from pediatric donors have increased in Japan. Herein, we present two cases of en bloc kidney transplantation.

Case presentation

Case 1: A 19-year-old male patient who had been on hemodialysis for 5 years due to end-stage renal disease. After brain death, a graft from a 5-year-old boy was transplanted into the right iliac fossa. Case 2: A 19-year-old male patient, who had previously undergone a living kidney transplantation at the age of 3, received a secondary cadaveric kidney transplantation in the left iliac fossa. The graft was procured from a 17-month-old girl following cardiac death.

Conclusion

This report will help surgeons perform en bloc kidney transplantation in the growing number of pediatric kidney donations, such as those in Japan.

A nationwide survey of MYH9-related disease in Japan

BACKGROUND

MYH9-related disease (MYH9-RD) is characterized by congenital macrothrombocytopenia, Döhle body-like granulocyte inclusions, and nephropathy, which may progress to end-stage kidney disease (ESKD). However, information on the effects of renin-angiotensin system (RAS) inhibitors on kidney survival is currently lacking and the outcomes of kidney replacement therapy (KRT) in MYH9-RD are largely unknown.

METHODS

We conducted a cross-sectional nationwide survey by sending questionnaires to 145 institutions in Japan and analyzed data for 49 patients.

RESULTS

The median patient age was 27 years. Genetic analysis was performed in 37 (76%) patients. Twenty-four patients (65%) had MYH9 variants affecting the motor domain of non-muscle myosin heavy chain-IIA, and these patients had poorer kidney survival than those with variants affecting the tail domain (P = 0.02). There was no significant difference in kidney survival between patients treated with and without RAS inhibitors. Hemodialysis and peritoneal dialysis were performed in 16 and 7 patients, respectively. There were no major bleeding complications during the perioperative period or during follow-up, except for one patient. Most of the 11 patients who underwent kidney transplantation required perioperative red cell concentrate transfusions, but there was no graft loss during the median posttransplant observational period of 2.0 (interquartile range, 1.3-6.8) years.

CONCLUSION

Our study demonstrated no beneficial effect of RAS inhibitors on kidney function in patients with MYH9-RD, indicating the need for further studies with more patients. All modalities of KRT are feasible options for MYH9-RD patients who progress to ESKD, with adequate attention to bleeding complications.

Case Report: Guanfacine and methylphenidate improved chronic lower back pain in autosomal dominant polycystic kidney disease with comorbid attention deficit hyperactivity disorder and autism spectrum disorder

Autosomal dominant polycystic kidney disease (ADPKD) is an inherited renal disease characterized by the bilateral development of multiple cysts in the kidneys. Pain management is a clinically important issue, especially because approximately 60% of patients with ADPKD experience chronic pain related to hemorrhage from renal cysts, which significantly reduces their daily life. The cystic fibrosis transmembrane conductance regulator, the molecule responsible for cyst formation in ADPKD, is also the cause of cystic fibrosis. Since attention deficit hyperactivity disorder (ADHD) is known to occur frequently in conjunction with cystic fibrosis, ADPKD may be associated with ADHD. However, to our knowledge, no study has investigated 1) ADHD or autism spectrum disorder (ASD) as comorbidities with ADPKD, 2) the effects of ADHD medications on chronic pain in ADPKD, or 3) cerebral blood flow corresponding to guanfacine (GF) or methylphenidate (MP) treatment for chronic pain. We report the case of a 15-year-old girl with ADPKD, who had chronic back pain associated with ADPKD and had to withdraw from high school because the pain interfered with her daily life. Although she took antihypertensive medications to prevent bleeding, they did not provide adequate blood pressure control. The patient was referred to a child psychiatrist and diagnosed with ASD; however, the pain did not improve. Subsequently, she was referred to our pain center. The diagnosis of ADHD was confirmed and treatment with ADHD medications was initiated. Monotherapy with MP, atomoxetine, and GF resulted in hypertension and hypotension as side effects; however, a combination of MP 18 mg and GF 4 mg provided pain relief and moderate blood pressure control, and the patient was able to go on to college. During the course of treatment, there was an improvement in the distribution of cerebral blood flow in the prefrontal and insular cortices. Confirmation of an ADHD diagnosis comorbid with ASD enabled the use of ADHD medications. The combination of MP and GF improved chronic back pain and high blood pressure due to ADPKD and cerebral blood flow. Screening for ADHD is important in the treatment of ADPKD.

Successful administration of eltrombopag in preparation for peritoneal dialysis catheter placement in a girl with MYH9-related disease

MYH9-related disease is an autosomal dominant disorder characterized by macrothrombocytopenia, nephropathy, inclusion bodies in leukocytes, sensorineural hearing loss, and cataract. Severe cases require kidney replacement therapy in the patient's second decade of life; thrombocytopenia constitutes a major risk factor for hemorrhagic complications during dialysis initiation or kidney transplantation. Prophylactic platelet transfusion prior to surgery is commonly administered to affected patients in these cases. However, transfusion in such patients has limitations other than the general risk of allergic reactions and blood-borne infections; it may also trigger alloimmunization, leading to platelet transfusion resistance or the development of anti-donor antibodies in potential kidney transplant recipients. Here, we describe prophylactic administration of eltrombopag, an oral thrombopoietin receptor agonist, prior to laparoscopic peritoneal dialysis catheter placement in a 15-year-old girl with MYH9-related disease. Her platelet count was approximately 30 × 103/μL at baseline; it increased to 61 × 103/μL on the day before surgery, thereby avoiding the need for platelet transfusions. There were no major bleeding or adverse events associated with eltrombopag administration. Thus, eltrombopag may be a safe and effective alternative to prophylactic platelet transfusions in patients with MYH9-related disease.

Characterization of cytoskeletal and structural effects of INF2 variants causing glomerulopathy and neuropathy

Focal segmental glomerulosclerosis (FSGS) is a common glomerular injury leading to end-stage renal disease. Monogenic FSGS is primarily ascribed to decreased podocyte integrity. Variants between residues 184 and 245 of INF2, an actin assembly factor, produce the monogenic FSGS phenotype. Meanwhile, variants between residues 57 and 184 cause a dual-faceted disease involving peripheral neurons and podocytes (Charcot-Marie-Tooth CMT/FSGS). To understand the molecular basis for INF2 disorders, we compared structural and cytoskeletal effects of INF2 variants classified into two subgroups: One (G73D, V108D) causes the CMT/FSGS phenotype, and the other (T161N, N202S) produces monogenic FSGS. Molecular dynamics analysis revealed that all INF2 variants show distinct flexibility compared to the wild-type INF2 and could affect stability of an intramolecular interaction between their N- and C-terminal segments. Immunocytochemistry of cells expressing INF2 variants showed fewer actin stress fibers, and disorganization of cytoplasmic microtubule arrays. Notably, CMT/FSGS variants caused more prominent changes in mitochondrial distribution and fragmentation than FSGS variants and these changes correlated with the severity of cytoskeletal disruption. Our results indicate that CMT/FSGS variants are associated with more severe global cellular defects caused by disrupted cytoskeleton-organelle interactions than are FSGS variants. Further study is needed to clarify tissue-specific pathways and/or cellular functions implicated in FSGS and CMT phenotypes.

Pioglitazone enhances proteinuria reduction in complicated pediatric nephrotic syndrome

BACKGROUND

Nephrotic syndrome (NS) is a common pediatric kidney disease, yet current treatments for complicated NS are only partially effective and have significant toxicity. There is no Food and Drug Administration (FDA)- or European Medicines Agency (EMA)-approved safe and effective treatment for NS. Thiazolidinediones (TZDs) have been shown to reduce proteinuria in both diabetic and non-diabetic kidney disease and in preclinical studies to directly protect podocytes from injury and reduce proteinuria. Here, we report on the potential utility of the addition of the TZD pioglitazone (PIO) to enhance proteinuria reduction in 8 children and young adults with steroid dependent NS and steroid resistant NS.

METHODS

Clinical data were analyzed in comparable time periods before and after the addition of PIO to their medical regimens. Eight NS patients with minimal change NS (n = 2), focal segmental glomerulosclerosis (FSGS) (n = 4), or collapsing FSGS (n = 2) were evaluated.

RESULTS

Prior to PIO initiation, all children and young adults had already received multiple immunosuppressive medications (mean = 3.75). Five of eight patients (63%; "Responders") had notable proteinuria reduction within 1 month of PIO initiation (62% reduction; P = 0.04) and normalization within 6 months (97% reduction; P = 0.04). PIO-related benefits among the responders included notable increases in serum albumin (2.5 to 3.7 g/dl; P = 0.08), dramatic reductions in hospitalizations for IV albumin infusions and diuresis (11 to 0; P < 0.01), and considerable reduction in total immunosuppression (43% reduction; P > 0.1). Importantly, no patients experienced any adverse events attributable to PIO during a total of 136 patient-months of treatment.

CONCLUSIONS

While confirmatory safety and efficacy studies are needed, these findings suggest pioglitazone (a non-immunosuppressive drug) may be useful to enhance proteinuria reduction in some children and young adults with complicated NS. A higher resolution version of the Graphical abstract is available as Supplementary information.

Global survival trends for brain tumors, by histology: analysis of individual records for 556,237 adults diagnosed in 59 countries during 2000-2014 (CONCORD-3)

BACKGROUND

Survival is a key metric of the effectiveness of a health system in managing cancer. We set out to provide a comprehensive examination of worldwide variation and trends in survival from brain tumors in adults, by histology.

METHODS

We analyzed individual data for adults (15-99 years) diagnosed with a brain tumor (ICD-O-3 topography code C71) during 2000-2014, regardless of tumor behavior. Data underwent a 3-phase quality control as part of CONCORD-3. We estimated net survival for 11 histology groups, using the unbiased nonparametric Pohar Perme estimator.

RESULTS

The study included 556,237 adults. In 2010-2014, the global range in age-standardized 5-year net survival for the most common sub-types was broad: in the range 20%-38% for diffuse and anaplastic astrocytoma, from 4% to 17% for glioblastoma, and between 32% and 69% for oligodendroglioma. For patients with glioblastoma, the largest gains in survival occurred between 2000-2004 and 2005-2009. These improvements were more noticeable among adults diagnosed aged 40-70 years than among younger adults.

CONCLUSIONS

To the best of our knowledge, this study provides the largest account to date of global trends in population-based survival for brain tumors by histology in adults. We have highlighted remarkable gains in 5-year survival from glioblastoma since 2005, providing large-scale empirical evidence on the uptake of chemoradiation at population level. Worldwide, survival improvements have been extensive, but some countries still lag behind. Our findings may help clinicians involved in national and international tumor pathway boards to promote initiatives aimed at more extensive implementation of clinical guidelines.

Survival analysis among pediatric patients receiving kidney replacement therapy: a Japanese nationwide cohort study

BACKGROUND

Limited data are available on the survival and causes of death in pediatric patients with chronic kidney disease (CKD) stage 5 receiving kidney replacement therapy (KRT) in Asia.

METHODS

Data were obtained from the Japanese nationwide cross-sectional CKD stage 5 survey on pediatric patients (<20 years of age) who started KRT from 2006 to 2013. The cohort was divided into three groups according to age at the start of KRT: <1, 1-5, and 6-19 years.

RESULTS

Among the 701 children who were included, 59.3% were boys. Peritoneal dialysis was the most common initial modality of KRT (60.3%). Median age at KRT initiation was 10.2 years. Infants (<1 year old) accounted for 16.0% of the total cohort. Overall survival at 1 and 5 years was 97.2% and 92.5%, respectively. Infants had significantly lower survival rates than the other groups (hazard ratio, 5.35; 95% CI, 2.60-11.03; P < 0.001). In contrast, after the age of 1 year, the survival rate improved and did not differ from that of other age groups. The most common causes of death were infection (35.9%) and sudden death (15.4%).

CONCLUSIONS

The overall survival rate of pediatric patients with CKD stage 5 in Japan is like that in other high-income countries. Age at initiation of KRT is an important factor affecting survival since the poorest survival rate was observed in infants. Further improvement in infant dialysis therapy is still needed to improve survival of the youngest children. A higher resolution version of the Graphical abstract is available as Supplementary information.

Response to steroid and immunosuppressive therapies may predict post-transplant recurrence of steroid-resistant nephrotic syndrome

BACKGROUND

Recurrence of SRNS is a major challenge in KT. Several clinical factors, including initial steroid sensitivity, have been associated with increased post-transplant SRNS recurrence risk. However, conflicting data have been reported, possibly due to the heterogeneous pathophysiology of SRNS and the lack of genetic testing of SRNS patients. Furthermore, the response to immunosuppressive therapies has not been evaluated.

METHODS

Seventy patients aged 1-15 years at SRNS onset who underwent KT between 2002 and 2018 were enrolled. Patients with secondary, familial, syndromic, and genetic forms of SRNS and those who were not treated with steroid were excluded. This study aimed to assess the risk factors for post-transplant recurrence, including treatment responses to initial steroid therapy and additional therapies with immunosuppressive agents, rituximab, plasmapheresis, and/or LDL-A.

RESULTS

Data from 36 kidney transplant recipients were analyzed. Twenty-two (61%) patients experienced post-transplant SRNS recurrence, while 14 patients did not. The proportion of patients who achieved complete or partial remission with initial steroid therapy and/or additional therapies with immunosuppressive agents, rituximab, plasmapheresis, and/or LDL-A was significantly higher in the SRNS recurrence group (19/22, 86%) than in the group without SRNS recurrence (6/14, 43%; p = .01).

CONCLUSION

This study suggests that the response to steroid treatment, other immunosuppressive agents, rituximab, plasmapheresis, and/or LDL-A may predict post-transplant SRNS recurrence.

Urinary extracellular vesicles signature for diagnosis of kidney disease

Congenital disorders characterized by the quantitative and qualitative reduction in the number of functional nephrons are the primary cause of chronic kidney disease (CKD) in children. We aimed to describe the alteration of urinary extracellular vesicles (uEVs) associated with decreased renal function during childhood. By nanoparticle tracking analysis and quantitative proteomics, we identified differentially expressed proteins in uEVs in bilateral renal hypoplasia, which is characterized by a congenitally reduced number of nephrons. This expression signature of uEVs reflected decreased renal function in CKD patients by congenital anomalies of the kidney and urinary tract or ciliopathy. As a proof-of-concept, we constructed a prototype ELISA system that enabled the isolation of uEVs and quantitation of expression of molecules representing the signature. The system identified decreased renal function even in its early stage. The uEVs signature could pave the way for non-invasive methods that can complement existing testing methods for diagnosing kidney diseases.

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Urinary extracellular vesicles (uEVs) are altered in chronic kidney disease (CKD)

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Characteristic expression signatures associated with childhood CKD are identified

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An ELISA utilizing the signature detected decreased renal function

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uEVs signature has potential in diagnosing kidney diseases

Overexpression of Plasmalemmal Vesicle-Associated Protein-1 Reflects Glomerular Endothelial Injury in Cases of Proliferative Glomerulonephritis with Monoclonal IgG Deposits

Introduction

Proliferative glomerulonephritis with monoclonal IgG deposits (PGNMID) occasionally presents refractory nephrotic syndrome resulting in poor renal prognosis, but its etiology is not fully elucidated. Given that glomerular endothelial cell (GEC) stress or damage may lead to podocytopathy and subsequent proteinuria, as in thrombotic microangiopathy (TMA), diabetic kidney disease, and focal segmental glomerulosclerosis, we investigated the evidence of glomerular endothelial injury by evaluating the expression of plasmalemmal vesicle-associated protein-1 (PV-1), a component of caveolae in the cases of PGNMID.

Methods

We measured the immunofluorescent PV-1 intensities of 23 PGNMID cases and compared with those of primary membranoproliferative glomerulonephritis (MPGN) (n = 5) and IgA nephropathy (IgAN) (n = 54) cases. PV-1 localization was evaluated with Caveolin-1, and CD31 staining, and the ultrastructural analysis was performed using a low-vacuum scanning electron microscope (LVSEM). To check the association of podocyte injury, we also conducted 8-oxoguanine and Wilms tumor 1 (WT1) double stain. We then evaluated PV-1 expression in other glomerulitis and glomerulopathy such as lupus nephritis and minimal change disease.

Results

The intensity of glomerular PV-1 expression in PGNMID is significantly higher than that in the other glomerular diseases, although the intensity is not associated with clinical outcomes such as urinary protein levels or renal prognosis. Immunostaining and LVSEM analysis revealed that glomerular PV-1 expression is localized in GECs in PGNMID. 8-oxoguanine accumulation was detected in WT1-positive podocytes but not in PV-1-expressing GECs, suggesting GEC-derived podocyte injury in PGNMID.

Conclusion

PV-1 overexpression reflects glomerular endothelial injury, which could be associated with podocyte oxidative stress in PGNMID cases.

Serum sodium level is inversely correlated with body temperature in children

BACKGROUND

Several studies have demonstrated that non-osmotic antidiuretic hormone activity contributes to the development of hyponatremia in children with common febrile diseases. However, the relationship between hyponatremia and body temperature has remained unclear. We therefore examined this relationship in children with common diseases.

METHODS

In this retrospective case study based on a chart review, 1,973 children presenting with acute illnesses at Hirakata City Hospital between November 2008 and October 2009, and for whom blood test data were available, were enrolled. The median age of this cohort was 2.7 years and the mean serum sodium concentration was 136.4 mEq/L; 454 patients showed hyponatremia (<135 mEq/L). The patients were classified into four groups on the basis of body temperature, <37 °C, 37 °C (37.0-37.9 °C), 38 °C (38.0-38.9 °C) and ≥39 °C, and their serum sodium concentration was compared.

RESULTS

The mean sodium level was significantly lower in febrile (135.9 mEq/L) than in non-febrile (138.5 mEq/L) patients. The mean serum sodium levels in the four temperature groups were, in ascending order, 138.5 mEq/L (95% CI, 138.3-138.8 mEq/L), 137.3 mEq/L (137.1-137.5 mEq/L), 136.1 mEq/L (135.8-136.3 mEq/L) and 134.6 mEq/L (134.4-134.9 mEq/L), respectively. The serum sodium level in each individual temperature range became significantly lower as body temperature increased (P < 0.001).

CONCLUSIONS

There is a clear inverse correlation between serum sodium level and body temperature in children with common febrile diseases, and fever may play an important role in this relationship.

A novel de novo truncating TRIM8 variant associated with childhood-onset focal segmental glomerulosclerosis without epileptic encephalopathy: a case report

BACKGROUND

Heterozygous truncating variants in the Tripartite motif containing 8 (TRIM8) gene have been reported to cause epileptic encephalopathy, both with and without proteinuria. A recent study showed a lack of TRIM8 protein expression, with suppressor of cytokine signaling 1 (SOCS1) overexpression, in podocytes and tubules from a patient with a TRIM8 variant, who presented with epileptic encephalopathy and focal segmental glomerulosclerosis (FSGS). To date, no patients with TRIM8 variants who presented with nephrotic syndrome but without neurological manifestations have been described.

CASE PRESENTATION

An 8-year-old girl presented with nephrotic syndrome, without epilepsy or developmental delay. Her kidney biopsy specimens showed FSGS and cystic dilatations of the distal tubules. Whole-exome sequencing identified a novel de novo heterozygous variant in the C-terminal encoding portion of TRIM8 (c.1461C > A), resulting in a premature stop codon (p.Tyr487*). Reverse transcription-polymerase chain reaction using peripheral blood mononuclear cells identified the mRNA sequence of the mutant allele, which confirmed an escape from nonsense-mediated mRNA decay. Immunofluorescence studies showed a lack of TRIM8 expression in glomerular and tubular cells and cystic dilatation of distal tubules. Immunohistochemical studies showed overexpression of SOCS1 in glomerular and tubular cells.

CONCLUSIONS

We reported a patient with FSGS, associated with a de novo heterozygous TRIM8 variant, without any neurological manifestations. Our results expanded the clinical phenotypic spectrum of TRIM8 variants.

The Japanese Society for Apheresis clinical practice guideline for therapeutic apheresis

Most of the diseases for which apheresis therapy is indicated are intractable and rare, and each patient has a different background and treatment course prior to apheresis therapy initiation. Therefore, it is difficult to conduct large-scale randomized controlled trials to secure high-quality evidence. Under such circumstances, the American Society for Apheresis (ASFA) issued its guidelines in 2007, which were repeatedly revised until the latest edition in 2019. The ASFA guidelines are comprehensive. However, in the United States, a centrifugal separation method is mainly used for apheresis, whereas the mainstream procedure in Japan is the membrane separation method. The target diseases and their backgrounds are different from those in Japan. Due to these differences, the direct adoption of the ASFA guidelines in Japanese practice creates various problems. One of the features of apheresis in Japan is the development of treatment methods using hollow-fiber devices such as double filtration plasmapheresis (DFPP) and selective plasma exchange and adsorption-type devices such as polymyxin B-immobilized endotoxin adsorption columns. Specialists in emergency medicine, hematology, collagen diseases/rheumatology, respiratory medicine, cardiovascular medicine, gastroenterology, neurology, nephrology, and dermatology who are familiar with apheresis therapy gathered for this guideline, which covers 86 diseases. In addition, since apheresis therapy involves not only physicians but also clinical engineers, nurses, dieticians, and many other medical professionals, this guideline was prepared in the form of a worksheet so that it can be easily understood at the bedside. Moreover, to the clinical purposes, this guideline is designed to summarize apheresis therapy in Japan and to disseminate and further develop Japanese apheresis technology to the world. As diagnostic and therapeutic techniques are constantly advancing, the guidelines need to be revised every few years. In order to ensure the high quality of apheresis therapy in Japan, both the Japanese Society for Apheresis Registry and the guidelines will be inseparable.

Shared decision making for the initiation and continuation of dialysis: a proposal from the Japanese Society for Dialysis Therapy

Background

In Japan, forgoing life-sustaining treatment to respect the will of patients at the terminal stage is not stipulated by law. According to the Guidelines for the Decision-Making Process in Terminal-Stage Healthcare published by the Ministry of Health, Labor and Welfare in 2007, the Japanese Society for Dialysis Therapy (JSDT) developed a proposal that was limited to patients at the terminal stage and did not explicitly cover patients with dementia. This proposal for the shared decision-making process regarding the initiation and continuation of maintenance hemodialysis was published in 2014.

Methods and results

In response to changes in social conditions, the JSDT revised the proposal in 2020 to provide guidance for the process by which the healthcare team can provide the best healthcare management and care with respect to the patient's will through advance care planning and shared decision making. For all patients with end-stage kidney disease, including those at the nonterminal stage and those with dementia, the decision-making process includes conservative kidney management.

Conclusions

The proposal is based on consensus rather than evidence-based clinical practice guidelines. The healthcare team is therefore not guaranteed to be legally exempt if the patient dies after the policies in the proposal are implemented and must respond appropriately at the discretion of each institution.

Material survey for a millimeter-wave absorber using a 3D-printed mold

Radio absorptive materials (RAMs) are key elements for receivers in the millimeter-wave range. We previously established a method for production of RAM by using a 3D-printed mold. An advantage of this method is a wide range of choices for absorptive materials to be used. To take advantage of this flexibility, we added a range of absorptive materials to a base epoxy resin, STYCAST-2850FT, and examined the optical performance of the resultant RAM across a wide frequency range under cryogenic conditions. We found that adding a particular type of carbon fiber produced the best performance with a reflectance at 77 K estimated as 0.01%-3% over a frequency range of 20-300 GHz.

Analysis of water and electrolyte imbalance in a patient with adipsic hypernatremia associated with subfornical organ-targeting antibody

Patients with adipsic hypernatremia present with chronic hypernatremia because of defects in thirst sensation and dysregulated salt appetite, without demonstrable hypothalamic structural lesions. The involvement of autoantibodies directed against the sodium channel, Na_x in the subfornical organ (SFO) has recently been reported. However, the pathophysiology of water and electrolyte imbalance underlying the disease has yet to be elucidated. We describe the case of a 5-year-old boy who complained of headaches and vomiting that gradually worsened. Brain magnetic resonance imaging detected no abnormal lesions. Blood laboratory testing revealed a serum sodium (Na) concentration of 152 mmol/L and a serum osmolarity of 312 mOsm/L. His body weight had slightly decreased, and his thirst sensation was absent. His plasma vasopressin concentration was 0.9 pg/mL, despite the high serum osmolarity. He was encouraged to drink water, and oral 1-deamino-8-D-arginine-vasopressin was administered. When serum sodium concentrations were normalized, plasma vasopressin concentrations were apparently normal and ranged from 0.8 to 2.0 pg/mL. He did not present with polyuria at any time. Immunohistochemical study using mouse brain sections and the patient's serum revealed the deposition of human immunoglobulin G (IgG) antibody in the mouse SFO. In conclusion, our observations suggested that water and electrolyte imbalance in adipsic hypernatremia is characterized by a certain amount of vasopressin release regardless of serum sodium concentrations with no response to hyperosmolarity.

Peritoneal Dialysis Guidelines 2019 Part 1 (Position paper of the Japanese Society for Dialysis Therapy)

Approximately 10 years have passed since the Peritoneal Dialysis Guidelines were formulated in 2009. Much evidence has been reported during the succeeding years, which were not taken into consideration in the previous guidelines, e.g., the next peritoneal dialysis PD trial of encapsulating peritoneal sclerosis (EPS) in Japan, the significance of angiotensin-converting enzyme inhibitors (ACEIs) and angiotensin receptor blockers (ARBs), the effects of icodextrin solution, new developments in peritoneal pathology, and a new international recommendation on a proposal for exit-site management. It is essential to incorporate these new developments into the new clinical practice guidelines. Meanwhile, the process of creating such guidelines has changed dramatically worldwide and differs from the process of creating what were “clinical practice guides.” For this revision, we not only conducted systematic reviews using global standard methods but also decided to adopt a two-part structure to create a reference tool, which could be used widely by the society’s members attending a variety of patients. Through a working group consensus, it was decided that Part 1 would present conventional descriptions and Part 2 would pose clinical questions (CQs) in a systematic review format. Thus, Part 1 vastly covers PD that would satisfy the requirements of the members of the Japanese Society for Dialysis Therapy (JSDT). This article is the duplicated publication from the Japanese version of the guidelines and has been reproduced with permission from the JSDT.

A case of IgA vasculitis with necrotizing arteritis in a 13-year-old girl

IgA vasculitis (IgAV) is the most frequent form of vasculitis in childhood which classically presents with purpura of the lower extremities, joint pain or swelling and abdominal pain. Though it is a self-limiting disease, and its prognosis is generally good, glomerulonephritis is one of the most important complications. IgAV is classified as a small vessel vasculitis, and though glomerulonephritis develops in IgAV, necrotizing arteritis is rarely seen. Here, we present a case of a 13-year-old girl with IgAV, glomerulonephritis, and necrotizing arteritis in the small renal arteries. There have been only a few reports of adult cases of IgAV with necrotizing arteritis in the kidneys, but there have been no pediatric cases. Some previous reports showed a high mortality rate and implied the possibility of overlap with other vasculitides. In the current report, a rare case of IgAV is described which exhibited necrotizing arteritis rather than overlap with another vasculitis, with a relatively typical clinical course for IgAV and laboratory tests.

Favorable therapeutic efficacy of low-density lipoprotein apheresis for nephrotic syndrome with impaired renal function

Many reports have shown the therapeutic efficacy of LDL apheresis (LDL-A) in drug-resistant nephrotic syndrome (NS) for improvement of heavy proteinuria and severely impaired renal function. To obtain comprehensive results in a large number of cases, a post hoc analysis of the Prospective Observational survey on the Long-Term Effects of the LDL-Apheresis on the Drug Resistant Nephrotic Syndrome (POLARIS) study was performed by stratifying enrolled cases according to the pretreatment estimated glomerular filtration rate (eGFR) levels indicating normal (N) (≥60 ml/min/1.73 m² ), moderately impaired (M) (≥30 to <60 ml/min/1.73 m² ), and severely impaired (S) (<30 ml/min/1.73 m² ) renal function. Significant improvements of proteinuria and renal function were found in Group N and, most interestingly, in Group M. A tendency for improvement in proteinuria was found in Group S. Most cases in all groups had not entered end-stage renal disease at 2 years after LDL-A treatment. These results suggest that LDL-A has therapeutic efficacy even in cases in which renal function has declined to 30 ml/min/1.73 m² .

Clinical and histological features in pediatric and adolescent/young adult patients with renal disease: a cross-sectional analysis of the Japan Renal Biopsy Registry (J-RBR)

BACKGROUND

Only a few studies have investigated epidemiological and clinicopathological information regarding pediatric and adolescent and young adult (AYA) patients with renal disease. The purpose of this study was to clarify the differences and relationship of clinicopathological findings between pediatric and AYA patients using the Japan Renal Biopsy Registry (J-RBR).

METHODS

This cross-sectional study analyzed data from patients registered in the J-RBR between 2007 and 2017. Clinicopathological findings at diagnosis were analyzed for 3,463 pediatric (age < 15 years) and 6,532 AYA (age 15-30 years) patients.

RESULTS

Although chronic nephritic syndrome was the most common clinical diagnosis at age > 5 years, nephrotic syndrome was the most frequent diagnosis at age < 4 years. The most common pathological diagnosis as classified by pathogenesis in pediatric patients was primary glomerular disease (except IgA nephropathy), whereas IgA nephropathy was increased in AYA patients. Mesangial proliferative glomerulonephritis was the most common pathological diagnosis as classified by histopathology in both pediatric and AYA patients. Minor glomerular abnormalities were the most frequent histopathologic diagnoses of nephrotic syndrome in childhood, but their frequency decreased with age.

CONCLUSION

To the best of our knowledge, this is the first report of clinicopathological features of pediatric and AYA patients in a large nationwide registry of renal biopsy. There were differences of clinical, pathological and histopathologic findings between pediatric and AYA patients.

Monoclonal and polyclonal immunoglobulin G deposits on tubular basement membranes of native and pretransplant kidneys: A retrospective study

Monoclonal tubular basement membrane immune deposits (TBMID) are associated with progression of interstitial injury in renal allograft. However, the significance of monoclonal and polyclonal TBMID in the native kidney remains unclear. We retrospectively analyzed 1894 native kidney biopsies and 1724 zero-hour biopsies performed between 2008 and 2018 in our institution. The rate of immunoglobulin G (IgG) TBMID was found to be 8.4% among native kidney biopsies and 0.4% among zero-hour biopsies. Polyclonal TBMID is common in IgG4-related tubulointerstitial nephritis (37.5%), diabetic nephropathy (31.3%) and lupus nephritis (25.5%). Monoclonal IgG TBMID was identified in seven cases, including three zero-hour biopsies. The combination of IgG1κ was observed in two cases, IgG1λ in three, and IgG2κ in two. Electron microscopy revealed powdery electron-dense deposits in all cases. Monoclonal gammopathy of undetermined significance was diagnosed in one case. Although one patient with focal segmental glomerulosclerosis developed renal failure, all others exhibited stable renal function. Monoclonal IgG TBMID in the native kidney is not associated with renal prognosis. However, this may be an interesting immunopathological finding that would help clarify the pathogenesis of TBM immune deposits. Further study for both monoclonal and polyclonal TBMID is required in the future.

Morphologic Analysis of Urinary Podocytes in Focal Segmental Glomerulosclerosis

BACKGROUND

The development of glomerulosclerosis in FSGS is associated with a reduction in podocyte number in the glomerular capillary tufts. Although it has been reported that the number of urinary podocytes in FSGS exceeds that of minimal-change nephrotic syndrome, the nature of events that promote podocyte detachment in FSGS remains elusive.

METHODS

In this study, we provide detailed, morphologic analysis of the urinary podocytes found in FSGS by examining the size of the urinary podocytes from patients with FSGS, minimal-change nephrotic syndrome, and GN. In addition, in urinary podocytes from patients with FSGS and minimal-change nephrotic syndrome, we analyzed podocyte hypertrophy and mitotic catastrophe using immunostaining of p21 and phospho-ribosomal protein S6.

RESULTS

The size of the urinary podocytes was strikingly larger in samples obtained from patients with FSGS compared with those with minimal-change nephrotic syndrome and GN (P=0.008). Urinary podocytes from patients with FSGS had a higher frequency of positive immunostaining for p21 (P<0.001) and phospho-ribosomal protein S6 (P=0.02) than those from patients with minimal-change nephrotic syndrome. Characteristic features of mitotic catastrophe were more commonly observed in FSGS than in minimal-change nephrotic syndrome urinary samples (P=0.001).

CONCLUSIONS

We posit that the significant increase in the size of urinary podocytes in FSGS, compared with those in minimal-change nephrotic syndrome, may be explained by hypertrophy and mitotic catastrophe.

Laminin β2 variants associated with isolated nephropathy that impact matrix regulation

Mutations in LAMB2, encoding laminin β₂, cause Pierson syndrome and occasionally milder nephropathy without extrarenal abnormalities. The most deleterious missense mutations that have been identified affect primarily the N-terminus of laminin β₂. On the other hand, those associated with isolated nephropathy are distributed across the entire molecule, and variants in the β₂ LEa-LF-LEb domains are exclusively found in cases with isolated nephropathy. Here we report the clinical features of mild isolated nephropathy associated with 3 LAMB2 variants in the LEa-LF-LEb domains (p.R469Q, p.G699R, and p.R1078C) and their biochemical characterization. Although Pierson syndrome missense mutations often inhibit laminin β₂ secretion, the 3 recombinant variants were secreted as efficiently as WT. However, the β₂ variants lost pH dependency for heparin binding, resulting in aberrant binding under physiologic conditions. This suggests that the binding of laminin β₂ to negatively charged molecules is involved in glomerular basement membrane (GBM) permselectivity. Moreover, the excessive binding of the β₂ variants to other laminins appears to lead to their increased deposition in the GBM. Laminin β₂ also serves as a potentially novel cell-adhesive ligand for integrin α₄β₁. Our findings define biochemical functions of laminin β₂ variants influencing glomerular filtration that may underlie the pathogenesis of isolated nephropathy caused by LAMB2 abnormalities.

Valganciclovir prophylaxis for cytomegalovirus infection in pediatric kidney transplant recipients: a single-center experience

BACKGROUND

There are two approaches for treating cytomegalovirus (CMV) infection occurring after kidney transplantation (KTx). One is preemptive therapy in which treatment is started after confirming positive CMV antigenemia using periodic antigenemia assay. The other approach is prophylactic therapy in which oral valganciclovir (VGCV) is started within 10 days after KTx and continued for 200 days. The Transplantation Society guidelines recommend prophylactic therapy for high-risk (donor's CMV-IgG antibody positive and recipient's negative) pediatric recipients. However, the adequate dose and side effects of VGCV are not clear in children, and there is no sufficient information about prophylaxis for Japanese pediatric recipients.

METHODS

A single-center retrospective analysis was conducted on case series of high-risk pediatric patients who underwent KTx and received oral VGCV prophylaxis at the Department of Pediatric Nephrology, Tokyo Women's Medical University, between August 2018 and March 2019. Data were collected using medical records.

RESULTS

The dose of administration was 450 mg in all the study patients (n = 5). Reduction or discontinuation was required in four of five patients due to adverse events, which included neutropenia in one patient, anemia in two patients, and neutropenia and digestive symptoms in one patient. Late-onset CMV disease occurred in all patients. No seroconversion was observed during prophylaxis.

CONCLUSIONS

Our preliminary study suggests that the dosage endorsed by The Transplantation Society may be an overdose for Japanese pediatric recipients. Further studies are required to examine the safety and efficacy of VGCV prophylaxis in Japanese pediatric recipients.

Glomerular Neovascularization in Nondiabetic Renal Allograft Is Associated with Calcineurin Inhibitor Toxicity

INTRODUCTION

Extra efferent arterioles, also known as polar vasculosis (PV), are often observed in the glomerular vascular pole and are associated with glomerular hypertrophy, indicating early recurrent diabetic kidney disease (DKD) in renal allografts. However, its significance in patients without diabetes remains uncertain.

METHODS

A total of 9,004 renal allograft biopsy specimens obtained between January 2007 and December 2017 at Tokyo Women's Medical University were retrospectively analyzed to examine the clinical and pathological significance of PV in renal allografts. PV was identified in 186 biopsy specimens obtained from 165 patients. The PV group comprised 46 patients; 35 patients without DKD and 11 patients with DKD as the initial cause of ESRD, whose clinical information was available and treated with the calcineurin inhibitor (CNI) tacrolimus. The non-PV group comprising patients with renal allografts matched for age and postoperative day included 93 patients without DKD and 16 patients with DKD as the initial cause of ESRD.

RESULTS

In patients with nondiabetic renal allografts, systolic blood pressure was significantly higher in the PV group than in the non-PV group. The trough tacrolimus levels during the overall study period and at 2 weeks, 1 month, and 2 years after transplantation were significantly higher in the PV group compared with the non-PV group. Glomerulomegaly was significantly more common. Moreover, ah and aah scores in Banff score were significantly higher in the PV group than in the non-PV group. In those with diabetic renal allografts, although the clinical parameters and tacrolimus trough levels in all time periods were not significantly different between the PV and non-PV groups, the ah score was significantly higher in the PV group.

CONCLUSION

PV was associated with CNI toxicity in nondiabetic but not in diabetic renal allografts. The pathogenesis of PV in renal allografts is considered to be multifactorial.

Chronic Active Antibody-Mediated Rejection with Linear IgG Deposition on Glomerular Capillaries in a Kidney Transplant Recipient

Glomerular IgG deposition is rarely observed in antibody-mediated rejection. Here, we report chronic active antibody-mediated rejection with linear IgG deposition on glomerular capillary walls in a pediatric kidney transplant recipient. A 6-year-old boy with bilateral renal hypoplasia underwent preemptive deceased-donor kidney transplantation. Five years after the transplantation, an allograft biopsy revealed chronic active antibody-mediated rejection with diffuse linear IgG deposition on glomerular capillaries. Anti-glomerular basement membrane antibody, donor-specific anti-human leukocyte antigen (HLA) antibodies, and anti-angiotensin II type 1 receptor antibody were negative. A multiplex antibody assay identified anti-major histocompatibility complex class I chain-related molecule A antibody. Additionally, a single-antigen bead assay identified autoantibodies to 12 non-HLA antigens, including vimentin and glutathione S-transferase theta-1. To investigate whether IgG autoantibodies in the patient's serum bind to antigens on glomerular capillaries, we incubated the patient's serum with 0-h biopsy specimens of tissue donated to the patient and a control subject, both obtained immediately after nephrectomy from respective donors. IgG signals were observed in neither patient nor control samples. Nevertheless, linear IgG deposition may be explained by the binding of autoantibodies to non-HLA antigens that are usually hidden and only exposed via severe endothelial cell injury. Further studies are needed to confirm the significance of non-HLA antibodies in glomerular IgG deposition.

Left coronary cusp ablation to eliminate epicardial substrates – a novel strategy for left ventricular summit ventricular tachycardia ablation

Background

Catheter ablation of LV summit VT can be challenging due to possible subepicardial or intramural site of origin and its close proximity to the major coronary vessels.

Objective

Local electrograms monitoring inside LV summit communicating vein potentially defines arrhythmogenic substrates and facilitates ablation from the adjacent anatomical structures.

Results

We experienced two cases of LV summit VT with epicardial local abnormal ventricular activities (Epi-LAVA) recorded from distal bipolar electrode of the 2F microcatheter in communicating vein close to the superior portion of LV summit. During sinus rhythm, Epi-LAVA displayed isolated late fractionated potentials in the first case but had initial fractionated potentials fused with terminal portion of far-field ventricular signals and late isolated potentials exhibiting 2:1 conduction in the second case. Epi-LAVA represented earliest ventricular signals during VT in both cases. Pace mapping at Epi-LAVA sites yielded single QRS morphology with excellent pacemap score and induced VT. Our strategy was to perform ablation at the facing site of Epi-LAVA aiming to eliminate the potentials transmurally. Radiofrequency (RF) energy was applied above and under the left coronary cusp opposite to Epi-LAVA sites using 3.5-mm tip open-irrigation catheter with a power of 30–35 W for 60 seconds under real-time intracardiac echocardiograhic guidance. VT was slowed and terminated in 1 second. Repeat ablation delayed and completely abolished Epi-LAVA followed by noninducibility of VT. Anatomical proximity of the left coronary cusp semilunar insertion and subepicardial or intramural site of origin possibly dictates successful ablation. Epi-LAVA from coronary vein mapping serve as a new landmark of the ablation target with a measurable procedural endpoint.

Conclusion

Elimination of epicardial substrates with RF energy application at the left coronary cusp can be a novel strategy for LV summit VT ablation.

Funding Acknowledgement

Type of funding source: None

Rapid progression to end-stage renal disease in a child with IgA-dominant infection-related glomerulonephritis associated with parvovirus B19

Parvovirus B19 (PVB19) has been known to cause acute glomerulonephritis and nephrotic syndrome with various renal histologic patterns, such as endocapillary glomerulonephritis and collapsing glomerulopathy. Remission is achieved spontaneously or by treatment with steroid and/or immunosuppressants in most patients, except those with sickle cell anemia or two APOL1 risk alleles. In this study, we report the case of a previously healthy 5-year-old boy with infection-related glomerulonephritis (IRGN) associated with PVB19 that progressed to end-stage renal disease (ESRD). He presented with macrohematuria, nephrotic-range proteinuria, and progressive renal dysfunction despite treatment with methylprednisolone pulse therapy, plasmapheresis, and intravenous immunoglobulin. The kidney biopsy specimens exhibited endocapillary infiltration and mesangiolysis with cellular crescent formation. Immunofluorescence analysis revealed that IgA was dominantly positive in the glomeruli, with some co-localized with KM55, which is a specific monoclonal antibody for galactose-deficient IgA1 (Gd-IgA1). The intensity of the KM55 signal in the present patient was weaker than that in patients with IgA nephropathy. To our knowledge, this is the first report of IRGN associated with PVB19 that progressed to ESRD without any underlying diseases. Further investigations are needed to determine the significance of IgA and Gd-IgA1 deposition in IRGN associated with PVB19.

Clinical and genetic characterization of nephropathy in patients with nail-patella syndrome

Nail-patella syndrome (NPS) is a multi-system disorder characterized by hypoplastic nails, hypoplastic patella, skeletal deformities, and iliac horns, which is caused by heterozygous variants of LMX1B. Nephropathy ranging from mild urinary abnormality to end-stage renal disease occurs in some individuals with NPS. Because of the low prevalence of NPS and the lack of longitudinal studies of its kidney involvement, the clinical, pathological, and genetic features characterizing severe nephropathy remain unclear. We conducted a Japanese survey of NPS with nephropathy, and analyzed their clinical course, pathological features, and factors associated with severe renal phenotype. LMX1B gene analysis and luciferase reporter assay were also performed. Among 13 NPS nephropathy cases with genetic validation, 5 patients who had moderate-to-massive proteinuria progressed to advanced chronic kidney disease or end-stage renal disease. Pathological findings in the early phase did not necessarily correlate with renal prognosis. Variants associated with deteriorated renal function including a novel variants were confined to the N-terminal region of the LIM domain and a short sequence in the LMX1B homeodomain, which were distinct from reported variants found in isolated nephropathy without extrarenal manifestation (LMX1B-associated nephropathy). Luciferase reporter analysis demonstrated that variants in patients with severe renal phenotype caused haploinsufficiency, but no dominant-negative effects on promoter activation. A distinct proportion of NPS nephropathy patients progressed to end-stage renal disease in adolescence or young adulthood. Patients with moderate or severe proteinuria, especially those with variants in specific regions of LMX1B, should be monitored for potential deterioration of renal function.

Renal hypoplasia can be the cause of membranous nephropathy-like lesions

BACKGROUND

Renal hypoplasia (RH) is the most common cause of chronic kidney disease in children. In cases of RH, proteinuria is often induced by glomerular hypertrophy and hyperfiltration that is commonly associated with focal segmental glomerulosclerosis. This study reports the first case series of a possible association between RH and membranous nephropathy (MN).

METHODS

Of the 168 children with RH who visited our department between 1999 and 2017, five with overt proteinuria (≥ 1 g/gCr) underwent renal biopsy. We retrospectively reviewed the medical charts and analyzed biopsy specimens using light microscopy (LM), immunofluorescence (IF), and electron microscopy.

RESULTS

The five children (four boys and one girl) had a median age of 5.5 years at the time of renal biopsy. The median proteinuria was 4.23 g/gCr (range 1.46-14.25), median serum albumin, 2.9 g/dL (range 2.3-3.7), and median estimated glomerular filtration rate, 59.7 mL/min/1.73 m² (range 36.7-103.6). LM showed segmental spike formation and mesangial hypercellularity and IF study showed segmental granular immunoglobulin G (IgG) staining (IgG1 and IgG3 dominant) along the capillary loops in all five patients. Electron-dense deposits were observed in the subepithelial and mesangial areas. Thus, the pathological studies showed MN-like lesions in all patients.

CONCLUSION

Our study suggests that RH can be the cause of MN-like lesions.

Individualized concept for the treatment of autosomal recessive polycystic kidney disease with end-stage renal disease

Management of children with autosomal recessive polycystic kidney disease (ARPKD) who develop end-stage renal disease (ESRD) remains challenging because of concomitant liver disease. Patients with recurrent cholangitis are candidates for liver-kidney transplantation, while the treatment for patients with splenomegaly and pancytopenia due to portal hypertension is controversial. Herein, we report 7 children who were treated using an individualized treatment strategy stratified by liver disease. Two patients with recurrent cholangitis underwent sequential liver-kidney transplantation, while 4 patients with splenomegaly and pancytopenia but without recurrent cholangitis underwent splenectomy followed by isolated kidney transplantation. The remaining patient, who did not have cholangitis and pancytopenia, underwent isolated kidney transplantation. Blood cell counts were normalized after splenectomy was performed at the median age of 8.7 (range, 7.4-11.7) years. Kidney transplantation was performed at the median age of 8.8 (range, 1.9-14.7) years in all patients. Overwhelming post-splenectomy infections and cholangitis did not occur during the median follow-up period of 6.3 (range, 1.0-13.2) years. The estimated glomerular filtration rate at the last follow-up was 53 (range, 35-107) mL/min/1.73 m² . No graft loss occurred. Our individualized treatment strategy stratified by recurrent cholangitis and pancytopenia can be a feasible strategy for children with ARPKD who develop ESRD and warrants further evaluation.

Bardet-Biedl syndrome in two unrelated patients with identical compound heterozygous SCLT1 mutations

Bardet-Biedl syndrome (BBS) is a rare autosomal recessive ciliopathy characterized by retinitis pigmentosa (RP), truncal obesity, cognitive impairment, hypogonadism in men, polydactyly, and renal abnormalities with severe renal dysfunction. Twenty-two causative genes have already been reported for this disorder. In this study, we identified two unrelated Japanese patients with clinical diagnoses of BBS associated with compound heterozygous SCLT1 mutation. Patient 1 was a 10-year-old girl, and patient 2 was a 22-year-old man. Both the patients showed severe renal dysfunction in childhood, RP, mild intellectual disability, short stature, and truncal obesity, without oral aberrations and polydactyly. Patient 2 also had hypogonadism. We identified two missense variants in SCLT1, c.[1218G > A] and [1631A > G], in both the patients by next-generation sequencing. Subsequent cDNA analysis revealed that c.1218G > A affected exon 14 skipping in SCLT1. To date, SCLT1 has been reported as the causative gene of oral-facial-digital syndrome type IX, and Senior-Løken syndrome. The phenotypes of both the present patients were compatible with BBS. These results highlight SCLT1 as an additional candidate for BBS phenotype in an autosomal recessive manner.

Pediatric congenital hydronephrosis (ureteropelvic junction obstruction): Medical management guide

The prevalence of asymptomatic hydronephrosis, now detected by ultrasonography, has increased. However, definitive management guidelines for the management of congenital hydronephrosis have not been established. The Japanese Society of Pediatric Urology created a "medical management guide" based on new findings for physicians practicing pediatric urology. We developed a medical management guide focused on congenital hydronephrosis caused by ureteropelvic junction obstruction. This medical management guide consists of the definition, pathophysiology, epidemiology, diagnosis, classification, treatment using a clinical management algorithm of hydronephrosis and the long-term course of the disease. The aim of hydronephrosis management is to determine whether surgery should be carried out to avoid renal dysfunction, as there is a possibility for improvement without intervention. Ultrasonography is essential to make treatment decisions. Management is determined by a comprehensive assessment, including the degree of hydronephrosis, anterior-posterior diameter of the renal pelvis and, if necessary, a nuclear medicine evaluation of the status of urine drainage and renal function.

Long-term outcome of renal transplantation in childhood-onset anti-neutrophil cytoplasmic antibody-associated vasculitis

BACKGROUND

There have been a few reports of RTx for AAV in children; however, post-transplant recurrence rate and long-term prognosis remain unclear. Here, we describe the long-term outcomes of RTx in childhood-onset AAV.

METHODS

We conducted a retrospective study of children who underwent RTx for AAV between 1999 and 2017 and had a follow-up period of >2 years.

RESULTS

Seven patients consisting of three children with MPA and four with RLV were analyzed. Age at Dx was 5.9 (median; range, 4.1-14.5) years. PD was instituted in all patients, and median time on dialysis was 26 (range, 14-63) months. Age at RTx was 12.8 (median; range, 8.7-16.3) years. There were no recurrences of AAV noted during the median follow-up period of 7.0 (range, 2.7-18.8) years after RTx. Graft loss occurred in one patient due to non-adherence. Estimated glomerular filtration rate of the remaining patients at the last follow-up was 73.0 (median; range, 50.7-93.9) mL/min/1.73 m² . No malignancies and deaths occurred during the observational period.

CONCLUSIONS

Our study suggests that RTx for AAV with ESRD is a potentially safe and effective treatment choice for children with AAV.

Nonosmotic secretion of arginine vasopressin and salt loss in hyponatremia in Kawasaki disease

BACKGROUND

The precise mechanism of hyponatremia in Kawasaki disease (KD) remains elusive because assessment of volume status based on serial changes in body weight is lacking in previous reports.

METHODS

Seventeen patients who were diagnosed with KD and hyponatremia (serum sodium levels <135 mmol/L) were analyzed. Volume status was assessed based on serial changes in body weight. Plasma arginine vasopressin (ADH), urine electrolytes, and serum cytokine levels were measured on diagnosis of hyponatremia. An increase in body weight by >3% was defined as hypervolemia and a decrease in body weight by >3% was defined as hypovolemia.

RESULTS

The volume status was hypervolemic in three patients (18%), euvolemic in 14 (82%), and hypovolemic in none (0%). Five (29%) patients were diagnosed with "syndrome of inappropriate secretion of antidiuretic hormone" (SIADH) and no patients were diagnosed with hypotonic dehydration. The contribution of decreased total exchangeable cations (salt loss) to hyponatremia (5.9% [interquartile range, 4.3%, 6.7%]) was significantly larger than that of increased total body water (-0.7% [-1.8%, 3.1%]) (P = 0.004). Serum interleukin-6 levels were elevated in all of the nine patients who were evaluated. Among the 12 (71%) patients who did not meet the criteria of SIADH and hypotonic dehydration, plasma ADH levels were inappropriately high in ten patients. These patients were also characterized by euvolemic or hypervolemic hyponatremia and salt loss, which might be compatible with a diagnosis of SIADH.

CONCLUSIONS

Our study shows that hyponatremia in KD is euvolemic or hypervolemic and is associated with nonosmotic secretion of ADH and salt loss in the majority of patients.

Validation of the Japanese Transition Readiness Assessment Questionnaire

BACKGROUND

For patients with childhood-onset chronic illnesses, the transition to adult care requires an understanding of transition readiness and the effectiveness of evaluation methods. However, no such psychometrically verified scales exist in Japan. This study aimed to develop a Japanese version of the Transition Readiness Assessment Questionnaire (TRAQ) and verify its validity and reliability.

METHODS

The Japanese TRAQ was developed in accordance with international guidelines, followed by a preliminary survey to verify face validity among six participants who fulfilled the inclusion criteria. For the main survey 107 patients who fulfilled the same inclusion criteria were asked to complete the questionnaire and provide basic information. After descriptive statistics analysis, the construct validity of the Japanese TRAQ was tested using the t-test and Pearson's correlation coefficients. Cronbach's alpha coefficients were calculated to assess reliability.

RESULTS

In the main survey, 76 participants with no missing data were included in the complete data analysis (40 males 36 females; mean age, 17.8 and 18.2 years, respectively). The mean total Japanese TRAQ score was 3.9. Cronbach's alpha coefficients were 0.94 overall and 0.8-0.96 for each of the four domains. The known-groups analysis revealed that older participants (r = 0.23, P = 0.044), those having knowledge of the disease name (yes [4.0] vs no [3.4]; P < 0.001), and making unaccompanied hospital visits (with parent/others [3.7] vs alone [4.4]; P < 0.001) had significantly higher total TRAQ scores.

CONCLUSION

We confirmed preliminarily the validity and reliability of the Japanese TRAQ.

Monoclonal immunoglobulin G deposits on tubular basement membrane in renal allograft: is this significant for chronic allograft injury?

Background

Tubular basement membrane immune deposits (TBMID) has rarely been observed in renal allografts. It is usually found in BK virus nephropathy and immune complex glomerulonephritis; however, its significance is not well understood. We conducted a retrospective clinicopathological study on monoclonal immunoglobulin G (IgG) TBMID.

Methods

We studied 7177 renal allograft biopsy specimens obtained from Tokyo Women’s Medical University from 2007 to 2015 and performed light microscopic, electron microscopic and immunofluorescence studies.

Results

Tubular basement membrane (TBM) deposits of IgG were found in 73 biopsies from 61 patients and the IgG subclass was obtained in 31 biopsies. There were no cases of monoclonal IgA or IgM TBMID. In total, 13 biopsies from 10 patients showed monoclonal IgG TBMID. Of these, seven showed monoclonal IgG1κ TBMID and one each showed monoclonal IgG2κ, IgG2λ and IgG3κ TBMID. Conversely, eight patients showed polyclonal IgG TBMID. In electron microscopy, large granular electron-dense deposits (EDDs) in the TBM were detected in all patients with monoclonal IgG1κ TBMID. EDDs were absent in TBM in patients with monoclonal IgG2κ, IgG2λ or IgG3κ TBMID. Progression of interstitial fibrosis and tubular atrophy (IFTA) was significantly higher in patients with monoclonal IgG1κ TBMID than in those with polyclonal IgG TBMID (P < 0.05). There were no significant differences in the other clinical parameters between monoclonal IgG1κ and polyclonal IgG TBMID.

Conclusions

This is the first study of patients with monoclonal IgG TBMID in renal allografts. We found that monoclonal IgG1κ TBMID was associated with EDD formation in TBM and IFTA progression.

Bardet-Biedl Syndrome Caused by Skipping of SCLT1 Complicated by Microvesicular Steatohepatitis

We treated the case of a 22-year-old male patient with liver dysfunction. At 1 year of age, hepatic fibrosis was suspected. In addition, due to the presence of retinitis pigmentosa, renal failure, obesity, mental retardation, and hypogonadism, he was diagnosed with Bardet-Biedl syndrome (BBS). Skipping of exons 14 and 17 in the sodium channel and clathrin linker 1 (SCLT1) gene was observed. At 22 years of age, the liver enzyme levels were further elevated and a diagnosis of microvesicular steatohepatitis was made. Insulin resistance, a reduction of muscle mass, an impairment of the fatty acid metabolism, and hyperleptinemia in this syndrome may cause steatohepatitis.

Deletion in the Cobalamin Synthetase W Domain-Containing Protein 1 Gene Is associated with Congenital Anomalies of the Kidney and Urinary Tract

BACKGROUND

Researchers have identified about 40 genes with mutations that result in the most common cause of CKD in children, congenital anomalies of the kidney and urinary tract (CAKUT), but approximately 85% of patients with CAKUT lack mutations in these genes. The anomalies that comprise CAKUT are clinically heterogenous, and thought to be caused by disturbances at different points in kidney development. However, identification of novel CAKUT-causing genes remains difficult because of their variable expressivity, incomplete penetrance, and heterogeneity.

METHODS

We investigated two generations of a family that included two siblings with CAKUT. Although the parents and another child were healthy, the two affected siblings presented the same manifestations, unilateral renal agenesis and contralateral renal hypoplasia. To search for a novel causative gene of CAKUT, we performed whole-exome and whole-genome sequencing of DNA from the family members. We also generated two lines of genetically modified mice with a gene deletion present only in the affected siblings, and performed immunohistochemical and phenotypic analyses of these mice.

RESULTS

We found that the affected siblings, but not healthy family members, had a homozygous deletion in the Cobalamin Synthetase W Domain-Containing Protein 1 (CBWD1) gene. Whole-genome sequencing uncovered genomic breakpoints, which involved exon 1 of CBWD1, harboring the initiating codon. Immunohistochemical analysis revealed high expression of Cbwd1 in the nuclei of the ureteric bud cells in the developing kidneys. Cbwd1-deficient mice showed CAKUT phenotypes, including hydronephrosis, hydroureters, and duplicated ureters.

CONCLUSIONS

The identification of a deletion in CBWD1 gene in two siblings with CAKUT implies a role for CBWD1 in the etiology of some cases of CAKUT.