Feasibility of discontinuing immunosuppression in children with idiopathic nephrotic syndrome

BACKGROUND

Despite adverse events associated with the long-term use of immunosuppressants, their long-term discontinuation remains challenging in children with idiopathic nephrotic syndrome. Relapse and resumption of immunosuppressants after discontinuation and associated risk factors were analyzed.

METHODS

This single-center retrospective cohort study included children with frequently relapsing/steroid-dependent nephrotic syndrome (FRNS/SDNS) or steroid-resistant nephrotic syndrome (SRNS) who initiated immunosuppressant treatment between 2010 and 2020. Patients treated with immunosuppressants for less than two years, those with genetic SRNS, and those with continuation of immunosuppressants were excluded.

RESULTS

Sixty-eight patients with FRNS/SDNS or SRNS discontinued immunosuppressants. Discontinuation of immunosuppressants was more frequently tried in patients with less relapse on initial immunosuppressants and less rituximab administration. Of 68 patients who discontinued immunosuppressants, 45 (66%) relapsed and 31 (46%) resumed immunosuppressants with a median follow-up of 39.8 months (IQR 24.6-71.2 months) after discontinuation. The relapse-free survival rates were 40.0%, 35.3%, and 35.3% in 1, 2, and 3 years from discontinuation of immunosuppressants, respectively. Relapse on initial immunosuppressants (HR 2.038, 95%CI 1.006-4.128, P = 0.048) and the relapse-free interval before discontinuation of immunosuppressants (HR 0.971, 95%CI 0.944-0.998, P = 0.037) were significant risk factors associated with relapse after the discontinuation of immunosuppressants, adjusting for sex, age at immunosuppressant treatment initiation, SRNS, and rituximab use.

CONCLUSIONS

Long-term discontinuation of immunosuppressants can be feasible in patients without a relapse on initial immunosuppressants, those with longer relapse-free interval before discontinuation of immunosuppressants, and those without a relapse for one year after discontinuation of immunosuppressants.

TRIAL REGISTRATION

Not applicable.

Rituximab in combination with cyclosporine and steroid pulse therapy for childhood-onset multidrug-resistant nephrotic syndrome: a multicenter single-arm clinical trial (JSKDC11 trial)

BACKGROUND

Only 80% of children with idiopathic nephrotic syndrome respond well to glucocorticoid therapy. Multidrug-resistant nephrotic syndrome (MRNS) is associated with a poor kidney prognosis. Several retrospective studies have identified rituximab as an effective treatment for MRNS; however, prospective studies are required to assess its efficacy and safety.

METHODS

We conducted a multicenter, non-blinded, single-arm trial to investigate the efficacy and safety of rituximab in patients with childhood-onset MRNS who were resistant to cyclosporine and more than three courses of steroid pulse therapy. The enrolled patients received four 375 mg/m2 doses of rituximab in combination with baseline cyclosporine and steroid pulse therapy. The primary endpoint was a > 50% reduction in the urinary protein/creatinine ratio from baseline on day 169. Complete and partial remissions were also evaluated.

RESULTS

Six patients with childhood-onset MRNS were enrolled. All patients were negative for pathogenic variants of podocyte-related genes. On day 169, five patients (83.3%) showed a > 50% reduction in the urinary protein/creatinine ratio, two patients showed partial remission, and two patients showed complete remission. No deaths occurred and severe adverse events occurred in two patients (infection in one patient and acute kidney injury in one patient). Three patients needed treatment for moderate-to-severe infection.

CONCLUSIONS

The study treatment effectively reduced the urinary protein/creatinine ratio in patients with childhood-onset MRNS. The adverse events in this study were within the expected range; however, attention should be paid to the occurrence of infections.

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.

Successful treatment of fulminant myocarditis due to COVID-19 in a 5-year-old girl

Reports of acute myocarditis are increasing due to the worldwide spread of coronavirus disease 2019 (COVID-19). We report a case of a 5-year-old girl with fulminant myocarditis caused by COVID-19, who was successfully treated with veno-arterial extracorporeal membrane oxygenation (VA-ECMO). The unvaccinated patient had developed fever 1 week before attending our hospital and was "presumptive positive" for COVID-19 based on the surrounding infectious situation. The fever resolved, but the day before the visit, abdominal pain appeared. The patient visited her previous physician with vomiting as the main complaint. She was transferred to our hospital due to impaired consciousness and bradycardia, with a heart rate of 40 beats/min. Immediately after transfer, she was diagnosed with complete atrioventricular (AV) block and was scheduled to undergo percutaneous pacing lead insertion. However, the patient had ventricular tachycardia, AV block and hypotension intraoperatively and required cardiopulmonary resuscitation. The patient was in an extremely unstable circulatory state, and VA-ECMO was urgently introduced. After multidisciplinary treatment for acute myocarditis, waiting for an improvement in AV block, and recovery of cardiac function, the patient was weaned from VA-ECMO on the eighth day after admission. The patient was discharged with no cardiac or neurologic sequelae.

Learning objective

The rapid introduction of veno-arterial extracorporeal membrane oxygenation for fulminant myocarditis caused by coronavirus disease 2019 (COVID-19) in young children is extremely effective. Vaccination may be important for preventing infection with COVID-19 and avoiding severe complications.

Renal pathology in adult and paediatric population of Japan: review of the Japan renal biopsy registry database from 2007 to 2017

BACKGROUND

The Japan Renal Biopsy Registry (J-RBR), a nationwide, web-based, registry system, started in 2007. This study aimed to summarise the epidemiology of biopsy-diagnosed kidney disease in Japan over 10 years.

METHODS

We analysed the J-RBR database, from 2007 to 2017. Patients' clinical data collected at the time of biopsy and histopathological diagnoses were used for epidemiological and clinicopathologic analyses.

RESULTS

The predominant renal biopsy diagnoses were immunoglobulin A nephropathy (39.2%), lupus nephritis (6.5%) and minimal change disease (6.0%) in younger adults (19-64 years), and membranous nephropathy (17.4%), antineutrophil cytoplasmic antibody-associated vasculitis or anti-glomerular basement membrane glomerulonephritis (13.0%), and immunoglobulin A nephropathy (12.5%) in older adults (≥ 65 years). The percentages of patients diagnosed with membranoproliferative glomerulonephritis and immunoglobulin A nephropathy decreased, whereas those with immunoglobulin A vasculitis and diabetic nephropathy increased over the decade. In paediatric patients (< 19 years), immunoglobulin A nephropathy (36.1%), minimal change disease (17.6%), and immunoglobulin A vasculitis (8.6%) were the predominant diagnoses. The percentage of patients diagnosed with immunoglobulin A vasculitis increased over the decade. Based on the sex distribution, minimal change disease and membranous nephropathy were predominant in men aged < 20 and > 40 years, respectively, whereas immunoglobulin A vasculitis and antineutrophil cytoplasmic antibody-associated vasculitis or anti-glomerular basement membrane glomerulonephritis were predominant in women in their 20s and 30s and aged < 50 years, respectively. Immunoglobulin A nephropathy was predominant in men at most ages and in women in their 20s to 40s.

CONCLUSIONS

This study describes the distribution and changes in kidney biopsy diagnoses over 10 years in Japan and paves the way for future research on kidney diseases in adults and children.

Reference blood pressure values obtained using the auscultation method for 2-year-old Japanese children: from the Japan Environment and Children's Study

BACKGROUND

Reference blood pressure (BP) values for Japanese children based on a large number of measurements by auscultation have not yet been established.

METHODS

This was a cross-sectional analysis of data from a birth-cohort study. The data from the sub-cohort study conducted for children at the age of 2 years in the Japan Environment and Children's Study from April 2015 to January 2017 were analyzed. BP was measured via auscultation using an aneroid sphygmomanometer. Each participant was measured in triplicate, and the average value of two consecutive measurements with a difference of less than 5 mmHg was recorded. The reference BP values were estimated using the lambda-mu-sigma (LMS) method and compared with those obtained via the polynomial regression model.

RESULTS

Data from 3361 participants were analyzed. Although the difference between the estimated BP values by the LMS and the polynomial regression model was small, the LMS model was more valid based on the results of the fit curve of the observed values and regression models for each model. For 2-year-old children with heights in the 50th percentile, the 50th, 90th, 95th, and 99th percentile reference values of systolic BP (mmHg) for boys were 91, 102, 106, and 112, and that for girls were 90, 101, 103, and 109, respectively, and those of diastolic BP for boys were 52, 62, 65, and 71, and that for girls were 52, 62, 65, and 71, respectively.

CONCLUSION

The reference BP values for 2-year-old Japanese children were determined based on auscultation and were made available.

Chapter 4: CKD treatment in cancer survivors, from Clinical Practice Guidelines for the Management of Kidney Injury During Anticancer Drug Therapy 2022

Chronic kidney disease (CKD) is one of the most disabling disorders with significant comorbidity and mortality. Incidence and prevalence of CKD in cancer survivors are remarkably high in both adults and pediatric patients. The reasons for this high incidence/prevalence are multifold but kidney damage by cancer itself and cancer treatment (pharmacotherapy/surgery/radiation) are the main reasons. Since cancer survivors commonly have significant comorbidities, risk of cancer recurrence, limited physical function or life expectancy, special attentions should be paid when considering the treatment of CKD and its complications. Especially, shared decision-making should be considered when selecting the renal replacement therapies with as much information/facts/evidence as possible.

CD4 + and CD8 + T-lymphocyte number as predictive marker of relapse after rituximab treatment in childhood-onset refractory nephrotic syndrome

BACKGROUND

Rituximab is a promising option for refractory idiopathic nephrotic syndrome. However, no simple predictive markers for relapse after rituximab have been established. To determine such markers, we investigated the relationship between CD4 + and CD8 + cell counts and relapse after rituximab administration.

METHODS

We retrospectively investigated patients with refractory nephrotic syndrome who received rituximab followed by immunosuppressive as maintenance therapy. Patients were divided into no relapse in 2 years after rituximab treatment or relapse group. After rituximab treatment, CD4 + /CD8 + cell counts were measured monthly, at prednisolone discontinuation, and at B-lymphocyte recovery. To predict relapse, these cell counts were analyzed using receiver operating characteristic (ROC). Additionally, relapse-free survival was reevaluated based on the result of ROC analysis for 2 years.

RESULTS

Forty-eight patients (18 in the relapse group) were enrolled. At prednisolone discontinuation (52 days after rituximab treatment), the relapse-free group showed significantly lower cell counts than the relapse group (median CD4 + cell count: 686 vs. 942 cells/µL, p = 0.006; CD8 + : 613 vs. 812 cells/µL, p = 0.005). In the ROC analysis, CD4 + cell count > 938 cell/µL and CD8 + cell count > 660 cells/µL could predict relapse in 2 years (sensitivity, 56% and 83%; specificity, 87% and 70%). The patient group with both lower CD4 + and CD8 + cell counts showed significantly longer 50% relapse-free survival (1379 vs. 615 days, p < 0.001 and 1379 vs. 640 days, p < 0.001).

CONCLUSIONS

Lower CD4 + and CD8 + cell counts in the early phase after rituximab administration may predict a lower risk of relapse.

Early predictive factors for progression to kidney failure in infants with severe congenital anomalies of the kidney and urinary tract

BACKGROUND

Severe congenital anomalies of the kidney and urinary tract (CAKUT) progress to infantile kidney failure with replacement therapy (KFRT). Although prompt and precise prediction of kidney outcomes is important, early predictive factors for its progression remain incompletely defined.

METHODS

This retrospective cohort study included patients with CAKUT treated at 12 centers between 2009 and 2020. Patients with a maximum serum creatinine level ≤ 1.0 mg/dL during the first 3 days, patients who died of respiratory failure during the neonatal period, patients who progressed to KFRT within the first 3 days, and patients lacking sufficient data were excluded.

RESULTS

Of 2187 patients with CAKUT, 92 were finally analyzed. Twenty-five patients (27%) progressed to KFRT and 24 (26%) had stage 3-5 chronic kidney disease without replacement therapy during the median observation period of 52.0 (interquartile range, 22.0-87.8) months. Among these, 22 (24%) progressed to infantile KFRT. The kidney survival rate during the infantile period was significantly lower in patients with a maximum serum creatinine level during the first 3 days (Cr-day3-max) ≥ 2.5 mg/dL (21.8%) compared with those with a Cr-day3-max < 2.5 mg/dL (95.2%) (log-rank, P < 0.001). Multivariate analysis demonstrated Cr-day3-max (P < 0.001) and oligohydramnios (P = 0.025) were associated with higher risk of infantile KFRT. Eighty-two patients (89%) were alive at the last follow-up.

CONCLUSIONS

Neonatal kidney function, including Cr-day3-max, was associated with kidney outcomes in patients with severe CAKUT. Aggressive therapy for severe CAKUT may have good long-term life outcomes through infantile dialysis and kidney transplantation. A higher resolution version of the Graphical abstract is available as Supplementary information.

Factors related to ultrafiltration volume with icodextrin dialysate use in children

BACKGROUND

Icodextrin has a lower absorption rate, and icodextrin peritoneal dialysate contributes to more water removal than glucose dialysate in patients with high peritoneal permeability. There are limited data on icodextrin dialysate use in children.

METHODS

This study included all pediatric patients who received peritoneal equilibration tests and peritoneal dialysis with icodextrin dialysate at the study center. The factors related to ultrafiltration volume with icodextrin dialysate with long dwell time were statistically analyzed. Then the ultrafiltration volume with icodextrin and medium-concentration glucose dialysate was compared in individual cycles in the same patients.

RESULTS

Thirty-six samples were included in the icodextrin group, and nine samples were used to compare the ultrafiltration volume with icodextrin and glucose dialysate. Dwell time, D/P-creatinine, D/D₀-glucose, age, height, and weight correlated significantly with the ultrafiltration volume of icodextrin dialysate (p < 0.05). A dwell volume equal to or more than 550 mL/m² was associated with a significantly higher ultrafiltration volume than a lower dwell volume (p = 0.039). Multiple regression analysis revealed that dwell time (p = 0.038) and height (p < 0.01) correlated with ultrafiltration volume significantly. In addition, the ultrafiltration volume was superior (p < 0.01), and dwell time was longer (p = 0.02), with icodextrin dialysate than with medium-concentration glucose dialysate.

CONCLUSIONS

The ultrafiltration volume with icodextrin dialysate decreases in patients with small stature. Providing sufficient dwell time and volume is important for maximal water removal even in children. Ultrafiltration volume is superior with icodextrin than medium-concentration glucose dialysate for long dwell times. A higher resolution version of the Graphical abstract is available as Supplementary information.

Changes in Patterns of Infection Associated with Pediatric Idiopathic Nephrotic Syndrome: A Single-Center Experience in Japan

OBJECTIVE

We studied infection rates and risk factors for infection in current patients with idiopathic nephrotic syndrome (INS).

STUDY DESIGN

This retrospective cohort study included the clinical data for children with diagnosed INS in our center between January 2010 and December 2020. The infection rates and risk factors were analyzed.

RESULTS

We enrolled 187 patients, including 85 cases with steroid-dependent/frequently relapsing nephrotic syndrome and 45 with steroid-resistant nephrotic syndrome. Infection was observed a total of 84 times in 55 patients (95.5 per 1000 person-years). Pneumonia was the most common infection (21 cases, 23.9 per 1000 person-years), followed by febrile neutropenia (12 cases, 13.7 per 1000 person-years), whereas peritonitis and bacteremia were observed in only 3 and 2 cases, respectively. The multivariate analyses by logistic regression showed that rituximab treatment was significantly associated with infections in pediatric INS (P = .001). The infection rate during the B-cell-depleted state with immunosuppressants (318 per 1000 person-years) was greater than that with normal B-cell count with immunosuppressants (109 per 1000 person-years) or without immunosuppressants (76 per 1000 person-years).

CONCLUSION

Common infections, such as peritonitis and bacteremia, decreased, whereas infections associated with medication (eg, rituximab) increased. The rate of infection increases during B-cell depletion after treatments with rituximab and other immunosuppressants.

Urine alpha 1-microglobulin-to-creatinine ratio and beta 2-microglobulin-to-creatinine ratio for detecting CAKUT with kidney dysfunction in children

BACKGROUND

The leading cause of advanced chronic kidney disease (CKD) in children is congenital anomalies of the kidney and urinary tract (CAKUT). However, the most appropriate parameters of biochemical urine analysis for detecting CAKUT with kidney dysfunction are not known.

METHODS

The present observational study analyzed data on children with CAKUT (stage 2-4 CKD) and the general pediatric population obtained from school urine screenings. The sensitivity and specificity of urine alpha 1-microglobulin-, beta 2-microglobulin-, protein-, and the albumin-to-creatinine ratios (AMCR, BMCR, PCR, ACR, respectively) in detecting CAKUT with kidney dysfunction were compared with those of the conventional urine dipstick, and the most appropriate of these four parameters were evaluated.

RESULTS

In total, 77 children with CAKUT and 1712 subjects in the general pediatric population fulfilled the eligibility criteria. Conventional dipstick urinalysis was insufficient due to its low sensitivity; even when the threshold of proteinuria was +/-, its sensitivity was only 29.7% for stage 2 and 44.1% for stage 3 CKD. Among the four parameters assessed, the AMCR and BMCR were adequate for detecting CAKUT in children with stage 3-4 CKD (the respective sensitivity and specificity of the AMCR for detecting CAKUT in stage 3 CKD was 79.4% and 97.5% while that of BMCR was 82.4% and 97.5%). These data were validated using national cohort data.

CONCLUSION

AMCR and BMCR are superior to dipstick urinalysis, PCR, and ACR in detecting CAKUT with kidney dysfunction, particularly stage 3 CKD. However, for AMCR, external validation is required. A higher resolution version of the Graphical abstract is available as Supplementary information.

[Management of Chronic Kidney Disease in Cancer Survivors]

Chronic kidney disease(CKD)associated with cancer and its treatment affects life after cancer treatment. There is inconclusive opinion on whether CKD treatment in survivors after cancer treatment needs special care differently than in the general population with CKD. Several topics were discussed by nephrologists, urologists and medical oncologists, pediatricians, pharmaceutical specialists, and others based on the results of a literature search, and the consensus was documented in the "Clinical Practice Guidelines for the Management for Kidney Injury During Anticancer Drug Therapy, 2022". The prevalence of CKD among adult cancer survivors is reported to be 4-7%. The characteristics include(1)elderly and physically impaired patients(, 2)a high risk of cancer recurrence, and(3)frequently cancer treatment-related CKD. Although there are no cancer survivor-specific indications or contraindications in the selection of renal replacement therapy, renal transplantation is often preferred in pediatric cancer survivors. It was determined that it is not appropriate to recommend or not recommend the administration of erythropoietin stimulating agents for renal anemia in cancer survivors based on a systematic review and discussion between panelists. When used in individual cases, its application should be well examined and consideration should be given to avoiding high hemoglobin level and to monitoring for cancer development.

Acrodysostosis and pseudohypoparathyroidism (PHP): adaptation of Japanese patients with a newly proposed classification and expanding the phenotypic spectrum of variants

Objective

This study aimed to report on 15 Japanese patients with acrodysostosis and pseudohypoparathyroidism (PHP) and analyze them using the newly proposed classification of the EuroPHP network to determine whether this classification system is suitable for Japanese patients.

Design

We divided the patients into three groups based on hormone resistance, the number of fingers with short metacarpals, the existence of cone-shaped epiphyses and gene defects.

Methods

We carried out clinical, radiological and genetic evaluations of two patients in group A (iPPSD5), six patients in group B (iPPDS4) and seven patients in group C (iPPSD2).

Results

Group A consisted of two siblings without hormone resistance who had the most severe bone and physical developmental delays. PDE4D gene defects were detected in both cases. Group B consisted of six patients who showed hormone resistance without hypocalcemia. Short metacarpal bones with corn-shaped epiphyses were observed in all patients. In two cases, PRKAR1A gene defects were detected; however, their clinical and radiological features were not identical. The facial dysmorphism and developmental delay were less severe and PRKAR1A gene defects were detected in case B-3. Severe facial dysmorphism and deformity of metacarpal bones were observed, but no gene defect was detected in case B-1. Group C consisted of seven patients with PHP1a, four of whom had maternally inherited heterozygous inactivating mutations in one of the GNAS genes. The clinical and radiological features of the patients in group C were not identical either.

Conclusions

The newly proposed classification is suitable for Japanese patients; however, heterogeneities still existed within groups B and C.

Half of children with IgA vasculitis-associated nephritis with nephrotic state spontaneously recover

BACKGROUND

The clinical spectrum of Henoch-Schönlein purpura nephritis (HSPN), now known as IgA vasculitis-associated nephritis (IgAVN), ranges from isolated microscopic haematuria to nephrotic syndrome, progressive glomerulonephritis, and kidney failure. The outcome also varies, and the management of IgAVN is controversial. The presence of nephrotic state at disease onset is thought to be a risk factor of a poor prognosis. However, not all patients with nephrotic state have a poor prognosis, and it is unclear whether they need early treatment.

METHODS

We herein retrospectively examined the clinical course of paediatric IgAVN cases with nephrotic state (serum albumin [sAlb]<3.0g/dL and urine protein-creatinine ratio of >2.0 g/ gCr) without kidney injury treated at our hospital between 2010 and 2018.

RESULTS

Of the 216 patients with IgAVN identified, 17 met the inclusion criteria. The median follow-up period from disease onset to the last observation was 40.5 months (IQR:31.0-74.2). Eleven patients were male, the median age at onset was 5 years, the minimum serum Alb level was 1.9 g/dL, the maximum proteinuria value was 12.3 g/gCr, and the median minimum eGFR was 86.0 mL/min/1.73 m² in the acute phase. Eight patients (47%) achieved resolution of nephrotic state within three months and complete remission without treatment by the last observation. The patients with spontaneous resolution of nephrotic state had less severe hypoalbuminaemia (Alb<2.0g/dL) and tended to show a quick increase in the serum albumin level.

CONCLUSIONS

Our study found that half of paediatric patients with IgAVN with nephrotic state achieved spontaneous resolution without treatment and enjoyed a favorable short-term outcome. Consideration of the duration of nephrotic state and trends in the serum albumin level in children with IgAVN may allow unnecessary kidney biopsies and immunosuppressive therapy to be avoided. This article is protected by copyright. All rights reserved.

Long-term Efficacy and Safety of Repeated Rituximab to Maintain Remission in Idiopathic Childhood Nephrotic Syndrome: An International Study

Background: Long-term outcomes following multiple rituximab courses among children with frequently-relapsing, steroid-dependent nephrotic syndrome (FRSDNS) are unknown. Methods: A retrospective cohort study at 16 pediatric nephrology centers from 10 countries in Asia, Europe, and North America included children with FRSDNS who received ≥2 rituximab courses. Primary outcomes were relapse-free survival and adverse events. Results: 346 children (age 9.8 years, IQR 6.6-13.5; 73% boys) received 1149 rituximab courses. 145, 83, 50, 28, 22, and 18 children received 2, 3, 4, 5, 6 and ≥7 courses, respectively. Median follow-up was 5.9 years (IQR, 4.3-7.7). Relapse-free survival differed by treatment courses (clustered log-rank test p<0.001). Compared to the first course (10.0 months, 95% CI, 9.0-10.7), relapse-free period and relapse risk progressively improved following subsequent courses (12.0-16.0 months; HRadj, 0.03-0.13; 95% CI, 0.01-0.18; ps<0.001). B-cell depletion duration remained similar with repeated treatments (6.1 months, 95% CI, 6.0-6.3). Adverse events were mostly mild, most commonly hypogammaglobulinemia (50.9%), infection (4.5%), and neutropenia (3.7%). Side effects did not increase with more treatment courses nor higher cumulative dose. Only 78 of the 353 episodes of hypogammaglobulinemia were clinically significant. Younger age at presentation (2.8 vs 3.3 years; p=0.05) and at first rituximab (8.0 y vs 10.0 years; p=0.01) and history of steroid resistance (28% vs 18%; p=0.01) were associated with significant hypogammaglobulinemia. All 53 infective episodes resolved, except one patient with hepatitis B infection and another with EBV infection. There were 42 episodes of neutropenia, associated with history of steroid resistance (30% vs 20%, p=0.04). Upon last follow-up, 332 children (96%) had normal kidney function. Conclusion: Children receiving repeated rituximab for FRSDNS experience an improving clinical response. Side effects appear acceptable but significant complications can occur. These findings support repeated rituximab use in FRSDNS.

Risks and renal outcomes of severe acute kidney injury in children with steroid-resistant nephrotic syndrome

BACKGROUND

Risks and renal outcomes of severe acute kidney injury (AKI) in children with steroid-resistant nephrotic syndrome (SRNS), particularly those who require dialysis, have not been fully explored.

METHODS

This retrospective cohort study enrolled children who had been diagnosed with idiopathic nephrotic syndrome at the National Center for Child Health and Development between March 2002 and December 2018. Children with steroid-sensitive nephrotic syndrome or SRNS-related gene mutations were excluded.

RESULTS

Sixty-two children with SRNS (37 boys; median age, 3.6 years [interquartile range (IQR) 2.0-10.3]) were enrolled. Sixteen patients (25.8%) had severe AKI, including nine patients (14.5%) who received dialysis. The period from nephrotic syndrome (NS) onset to partial remission (median [IQR]) was not significantly influenced by dialysis status, but tended to be longer in the dialysis group (125 days [74-225] vs. 40 days [28-113]; p = 0.09); notably, no patient developed chronic kidney disease during the follow-up period. Infection and posterior reversible encephalopathy (PRES) were significantly associated with AKI. Patients with AKI tended to require dialysis in the presence of infection, undergo treatment with cyclosporine A, and have PRES. The period from onset of NS to AKI was significantly longer in the dialysis group (26 days [15.5-46.0] vs. 4 days [0.0-14.0]; p = 0.01).

CONCLUSION

Dialysis was commonly required among children with SRNS who exhibited severe AKI. The period from onset of NS to partial remission tended to be longer in patients receiving dialysis, whereas renal prognosis was satisfactory during subsequent follow-up.

Interventions for Shiga toxin-producing Escherichia coli gastroenteritis and risk of hemolytic uremic syndrome: A population-based matched case control study

Background

The role of antibiotics in the treatment of Shiga toxin-producing Escherichia coli (STEC) infection is controversial.

Objectives

To evaluate the association between treatment (antibiotics, antidiarrheal agents, and probiotics) for STEC infection and hemolytic uremic syndrome (HUS) development.

Patients and methods

We performed a population-based matched case-control study using the data from the National Epidemiological Surveillance of Infectious Diseases (NESID) between January 1, 2017 and December 31, 2018. We identified all patients with STEC infection and HUS as cases and matched patients with STEC infection without HUS as controls, with a case-control a ratio of 1:5. Further medical information was obtained by a standardized questionnaire. Multivariable conditional logistic regression model was used.

Results

7760 patients with STEC infection were registered in the NESID. 182 patients with HUS and 910 matched controls without HUS were selected. 90 patients with HUS (68 children and 22 adults) and 371 patients without HUS (266 children and 105 adults) were included in the main analysis. The matched ORs of any antibiotics and fosfomycin for HUS in children were 0.56 (95% CI 0.32–0.98), 0.58 (0.34–1.01). The matched ORs for HUS were 2.07 (1.07–4.03), 0.86 (0.46−1.61) in all ages treated with antidiarrheal agent and probiotics.

Conclusions

Antibiotics, especially fosfomycin, may prevent the development of HUS in children, while use of antidiarrheal agents should be avoided.

Mycophenolate Mofetil after Rituximab for Childhood-Onset Complicated Frequently-Relapsing or Steroid-Dependent Nephrotic Syndrome

BACKGROUND

Rituximab is the standard therapy for childhood-onset complicated frequently relapsing or steroid-dependent nephrotic syndrome (FRNS/SDNS). However, most patients redevelop FRNS/SDNS after peripheral B cell recovery.

METHODS

We conducted a multicenter, randomized, double-blind, placebo-controlled trial to examine whether mycophenolate mofetil (MMF) administration after rituximab can prevent treatment failure (FRNS, SDNS, steroid resistance, or use of immunosuppressive agents or rituximab). In total, 39 patients (per group) were treated with rituximab, followed by either MMF or placebo until day 505 (treatment period). The primary outcome was time to treatment failure (TTF) throughout the treatment and follow-up periods (until day 505 for the last enrolled patient).

RESULTS

TTFs were clinically but not statistically significantly longer among patients given MMF after rituximab than among patients receiving rituximab monotherapy (median, 784.0 versus 472.5 days, hazard ratio [HR], 0.59; 95% confidence interval [95% CI], 0.34 to 1.05, log-rank test: P=0.07). Because most patients in the MMF group presented with treatment failure after MMF discontinuation, we performed a post-hoc analysis limited to the treatment period and found that MMF after rituximab prolonged the TTF and decreased the risk of treatment failure by 80% (HR, 0.20; 95% CI, 0.08 to 0.50). Moreover, MMF after rituximab reduced the relapse rate and daily steroid dose during the treatment period by 74% and 57%, respectively. The frequency and severity of adverse events were similar in both groups.

CONCLUSIONS

Administration of MMF after rituximab may sufficiently prevent the development of treatment failure and is well tolerated, although the relapse-preventing effect disappears after MMF discontinuation.

Validation of the estimated glomerular filtration rate equation for Japanese children younger than 2 years

BACKGROUND

We have developed a simple and easy method of estimating the glomerular filtration rate (eGFR) of serum creatinine in Japanese children (eGFR_Uemura). The eGFR equation is for children aged 2-18 years. Therefore Uemura et al. developed an equation for children younger than 2 years (eGFR_{under 2}). The aim of the present study was to validate this new equation.

METHODS

We collected the data of 13 patients from previous studies and compared the results of eGFR_{under 2}, eGFR_Uemura, and updated eGFR developed by Schwartz (eGFR_Schwartz) with measured GFR using mean error (ME), root mean square error (RMSE), P₃₀ and Bland-Altman analysis.

RESULTS

The ME of eGFR_{under 2}, eGFR_Uemura and eGFR_Schwartz were 2.3 ± 15.9, 7.7 ± 14.5, and 16.0 ± 18.2 ml/min/1.73m², respectively. The RMSEs were 15.5, 15.9, and 49.6, respectively. The P₃₀ values were 76.9%, 76.9%, and 53.8%, respectively. The graph of Bland-Altman bias analysis showed fan-shape. The eGFR_{under 2} equation was the most accurate in the three equations.

CONCLUSION

The eGFR_{under 2} equation was useful for Japanese children younger than 2 years.

Tocilizumab for Juvenile Takayasu Arteritis Complicated with Acute Heart Failure at Onset

Chronic heart failure caused by aortic valve regurgitation is a common complication of Takayasu arteritis (TA). However, fewer patients develop acute heart failure (AHF), and no specific treatment for AHF in TA has been established. We encountered a 12-year-old girl with TA who developed AHF at onset. We successfully treated her with intravenous methylprednisolone and tocilizumab. She developed palpitations and shortness of breath three weeks before admission. Her symptoms exacerbated rapidly and she finally entered the intensive care unit due to respiratory distress and tachycardia. Blood pressure measurements on the left arm and bilateral legs were paradoxically lower than that on the right arm. Chest X-ray revealed a severely enlarged heart. Contrast computed tomography showed an expanded aorta, aortic aneurysm, meandering, and irregular diameter of the aorta. The left ventricular ejection fraction (LVEF) was 20% on cardiac ultrasound. Her medical condition was finally diagnosed as TA with AHF. Along with inotropes and diuretics, methylprednisolone pulse therapy was administered on hospital days 2-4 and hospital days 12-14, followed by oral prednisolone. However, cardiac function was not notably improved. As intravenous cyclophosphamide therapy requires hydration and may exacerbate AHF, we initiated weekly subcutaneous tocilizumab treatment (162 mg/week) from hospital day 20. Inotropes were discontinued on hospital day 51 and her LVEF had gradually improved to 37.5% at discharge (day 63). As AHF in TA is presumed to be due to inflammation of the myocardium, tocilizumab could be a treatment option for TA with AHF.

Influenza virus vaccination in pediatric nephrotic syndrome significantly reduces rate of relapse and influenza virus infection as assessed in a nationwide survey

Although vaccination may precipitate relapses of nephrotic syndrome (NS) in children with idiopathic NS, no data are available regarding NS activity regarding influenza (flu) virus infections and NS relapses after receiving inactivated flu vaccines. We conducted a nationwide study of children aged 6 months to 15 years with idiopathic NS to assess the relationship between NS relapse, flu vaccination, and flu infections. We used a multivariate Poisson regression model (MPRM) to calculate the risk ratio (RR) for flu infection and for NS relapse in children with and without flu vaccination. Data of 306 children were assessed. The MPRM in all 306 children showed a significantly lower RR for flu infection (RR: 0.21, 95% confidence interval CI 0.11-0.38) and for NS relapse (RR: 0.22, 95% CI 0.14-0.35) in children receiving flu vaccination compared with unvaccinated children. In an additional MPRM only among 102 children receiving flu vaccination, they had a significantly lower risk for NS relapse during the post-vaccination period (RR: 0.31. 95% CI 017-0.56) compared with the pre-vaccination period. Although our study was observational, based on the favorable results of flu vaccinations regarding flu infections and NS relapse, the vaccine may be recommended for children with NS.

Risk factors for post-nephrectomy hypotension in pediatric patients

BACKGROUND

Although hypotension is a life-threatening complication of nephrectomy in children, risk factors for its development remain unknown. We evaluated the incidence, clinical course, and associated risk factors of pediatric post-nephrectomy hypotension in an observational study.

METHODS

This retrospective observational study included the clinical data of children who underwent nephrectomy in our center between 2002 and 2020. Patients undergoing nephrectomy at kidney transplantation and those who developed hypotension before nephrectomy were excluded.

RESULTS

The study included 55 nephrectomies in 51 patients, including 42 unilateral, 4 two-stage bilateral, and 5 simultaneous bilateral nephrectomies. The diagnoses were isolated Wilms tumor, neuroblastoma, congenital nephrotic syndrome, Denys-Drash syndrome, WAGR (Wilms tumor, aniridia, genitourinary malformations, and mental retardation) syndrome, and autosomal recessive polycystic kidney disease in 24, 10, 9, 6, 1, and 1 patient, respectively. Post-nephrectomy hypotension developed in 11 (20%) patients. Two patients (3.6%) had persistent hypotension; both had their kidneys resected, and one patient (1.8%) died. Male sex, kidney disease, resection of both kidneys, low estimated glomerular filtration rate, increased left ventricular posterior wall thickness in diastole, hypertension before nephrectomy, antihypertensive use, hyperreninemia, and hyperaldosteronism were significantly associated with post-nephrectomy hypotension. Multivariate logistic regression analysis revealed that hypertension before nephrectomy was the only significant risk factor for post-nephrectomy hypotension (P = 0.04).

CONCLUSIONS

Hypertension before nephrectomy is a significant risk factor for pediatric post-nephrectomy hypotension. Life-threatening hypotension, which might occur after bilateral nephrectomy in infants, should be considered, especially in children with higher risks.

Ultrasonography as a Diagnostic Support Tool for Childhood Takayasu Arteritis Referred to as Fever of Unknown Origin: Case Series and Literature Review

Introduction

Childhood Takayasu arteritis (c-TA) often shows nonspecific symptoms, such as fever of unknown origin (FUO). Delay of diagnosis may result in organ dysfunction by arterial occlusion; therefore, early diagnosis is very important. Although ultrasonography is the first-line screening tool for children with FUO, its diagnostic efficacy of evaluation of systemic arteries in c-TA that presents as FUO remains unclear. We evaluated the suitability of ultrasonography evaluation that included systemic vessels for the early diagnosis of c-TA initially presenting as FUO.

Methods

We review five patients who received a diagnosis of c-TA in our institution and also performed a literature review regarding TA cases with FUO and diagnosed on the basis of initial ultrasonography.

Results

As in our cases, the median period from onset to diagnosis was 25 days (interquartile range [IQR], 21-35). Comparing the initial ultrasonography findings with later contrast-enhanced computed tomography (CECT) findings in the abdominal aorta, celiac artery, superior mesenteric artery, bilateral renal arteries, and bilateral common carotid arteries, the concordance rate between ultrasonography and CECT was moderate (Kappa coefficient was 0.50). All the patients were successfully treated without severe vascular damage. The literature review revealed 12 articles; although 9 of the 13 patients did not show the characteristic features (such as blood pressure discrepancy, bruit, or pulse deficiency), the median time to diagnosis was still 5 months (IQR, 3-12).

Conclusions

During initial screening for patients with FUO, ultrasonography including evaluation of systemic vessels could contribute to earlier diagnosis of c-TA.

Incidence of malignancy after pediatric kidney transplantation: a single-center experience over the past three decades in Japan

BACKGROUND

Malignancy after kidney transplantation (KT) is one of the most serious post-transplant complications. This study aimed to investigate the incidence, type, and outcomes of malignancy after pediatric KT.

METHODS

We performed a retrospective cohort study on pediatric kidney transplant recipients aged 18 years or younger who received their first transplant between 1975 and 2009.

RESULTS

Among the 375 children who underwent KT, 212 were male (56.5%) and 163 were female (43.5%) (median age at KT, 9.6 years [interquartile range {IQR}] 5.8-12.9 years). The incidence of malignancy was 5.6% (n = 21). The cumulative incidences of cancer were 0.8%, 2.5%, 2.8%, 4.2%, 5.5%, and 15.6% at 1, 5, 10, 15, 20, and 30 years post-transplantation, respectively. Of 375 patients, 12 (3.2%) had solid cancer and nine (2.4%) had lymphoproliferative malignancy. The median age at the first malignancy was 21.3 years (IQR 11.5-33.3 years). The median times from transplant to diagnosis were 22.3 years (IQR 12.3-26.6 years) for solid cancer and 2.2 years (IQR 0.6-2.8) for lymphoproliferative malignancies. During follow-up, five recipients died due to malignancy. The causes of death were hepatocellular carcinoma in one patient, squamous cell carcinoma in the transplanted kidney in one patient, malignant schwannoma in one patient, and Epstein-Barr virus-related lymphoma in two patients. The mortality rate was 0.79 per 1000 person-years (95% confidence interval 0.38, 1.85).

CONCLUSIONS

Early diagnosis and treatment of malignancies in transplant recipients is an important challenge. Therefore, enhanced surveillance and continued vigilance for malignancy following KT are necessary.

Contradiction between genetic analysis and diuretic loading test in type I Bartter syndrome: a case report

BACKGROUND

In typical cases of Bartter syndrome (BS), assessing response to diuretics (furosemide and thiazide), hereinafter referred to as diuretic loading test, may be used to diagnose the type by detecting which part of the kidney tubule is not functioning correctly. However, the diuretic loading test may not always agree with the results of genetic analyses.

CASE PRESENTATION

A 5-year-old boy was admitted due to lower extremity weakness and abnormal gait. He had a recurrent episode of muscle weakness and laboratory results showed severe hypokalemia. The direct genomic sequencing of the case revealed a new mutation in the SLC12A1 gene, which is associated with type I Bartter syndrome. Because there was the difference between the phenotype and genotype, we conducted a diuretic loading test to confirm the diagnosis. However, the results showed a clear increase in urine excretion of Na and Cl. These results were not consistent with typical type I BS, but consistent with the patient's phenotype.

CONCLUSION

The diuretic loading test has limited utility for diagnosis especially in atypical cases. On the other hand, this test, which allows assessment of channel function, is useful for better understanding of the genotype-phenotype correlation.

Whole-Genome Sequencing of Shiga Toxin-Producing Escherichia coli OX18 from a Fatal Hemolytic Uremic Syndrome Case

We report a fatal case of hemolytic uremic syndrome with urinary tract infection in Japan caused by Shiga toxin–producing Escherichia coli. We genotypically identified the isolate as OX18:H2. Whole-genome sequencing revealed 3 potentially pathogenic lineages (OX18:H2, H19, and H34) that have been continuously isolated in Japan.

Mean of creatinine clearance and urea clearance examined over 1 h estimates glomerular filtration rate accurately and precisely in children

AIM

Accurate and precise estimation of glomerular filtration rate (GFR) is essential in kidney disease. We evaluated the usefulness of the mean of creatinine clearance (C_Cr ) and urea clearance (C_UN ) examined over a 1-h urine collection period (1-h (C_Cr  + C_UN )/2) in a retrospective, cross-sectional study across two centres, as a relatively simple method for estimating GFR in children.

METHODS

Children aged ≤18 years who underwent inulin clearance (C_In ) tests were eligible. Two clearance values were obtained during a 2-h test consisting of two periods of 1 h each. The mean clearance in two periods was defined as 1-h clearance. 1-h (C_Cr  + C_UN )/2, 1-h C_Cr , 1-h C_UN and GFR estimated by Cr-based and cystatin C (CysC)-based formulas for Japanese children were compared with C_In . Bland-Altman plots were used to evaluate correlations. The primary outcome measure was the correlation between 1-h (C_Cr  + C_UN )/2 and C_In .

RESULTS

Fifty-three children were analysed. Their median age was 10.9 (interquartile range [IQR] 5.3-14.2) years, and median C_In and 1-h (C_Cr  + C_UN )/2 were 77.0 (IQR: 51.5-95.1) and 81.0 (IQR: 64.1-97.7) ml/min/1.73 m² , respectively. Percentage difference of C_In and 1-h (C_Cr  + C_UN )/2 in the Bland-Altman plot was -11.2% (95% confidence interval - 15.3% - -7.1%), with 95% lower and upper limits of agreement of -40.3% and 18.0%, respectively. Thus, 1-h (C_Cr  + C_UN )/2 was 1.12 times C_In .

CONCLUSION

1 h (C_Cr  + C_UN )/2 was almost concordant with C_In . 1-h (C_Cr  + C_UN )/2 can estimate GFR accurately and precisely, making it a simple and speedy test for use in clinical practice.

Live attenuated vaccines under immunosuppressive agents or biological agents: survey and clinical data from Japan

Live attenuated vaccines are contraindicated for patients on immunosuppressive agents or biological agent, except for live attenuated varicella vaccine, although previous reports showed their effectiveness and safety. This study is the nationwide cross-sectional research about the current utilization of live attenuated vaccines for patients on immunosuppressive agents or biological agents in Japan. We sent questionnaires to pediatric centers and examined whether each institution offered live attenuated vaccines to patients with immunosuppressive agents or biological agents (institutional research). We also examined adverse events associated with live attenuated vaccines between 2013 and 2017 (patient research). In the institutional research, 46 out of 334 institutions (13.8%) administered live attenuated vaccines to patients receiving immunosuppressive agents. In contrast, only six out of 270 institutions (2.2%) administered live attenuated vaccines to patients receiving biological agents. However, 66.3% of physicians answered that patients receiving immunosuppressive agents should be immunized with live attenuated vaccines, and only 7.0% disagreed with them. In the patient research, data for 781 patients were collected. Vaccine-associated infections were observed in only two patients (0.3%), both of whom had varicella, although they recovered promptly. No life-threatening adverse events were noted.

CONCLUSION

In pediatric centers, the demand for live attenuated vaccines in patients receiving immunosuppressive agents was high and most physicians think they should be immunized. Immunization with live attenuated vaccines appeared safe in patients receiving immunosuppressive agents, although further studies are needed for patients receiving biological agents What is known: • Live attenuated vaccines (LAV) are generally contraindicated for patients on immunosuppressive agents (IS) or biological agents (BA), except for live attenuated varicella vaccine, as immunocompromised patients are at greater risk for serious viral infection from the vaccine strains. • Viral infections, such as measles and varicella, cause serious complications in children receiving IS. • Several previous reports showed that LAV is relatively effective and safe for patients receiving IS. What is new: • In Japan, the demand for LAV in patients receiving IS was high, and most physicians hoped they should be immunized. • Vaccine-associated infection is rarely observed in patients with IS after LAV administration. • Immunization with LAV appeared safe in patients receiving IS.

TRIAL REGISTRATION

University Hospital Medical Information Network (UMIN).

TRIAL REGISTRATION NUMBER

UMIN000029176.Date of registration: 2017/09/19.

Prognosis and acute complications at the first onset of idiopathic nephrotic syndrome in children: a nationwide survey in Japan (JP-SHINE study)

BACKGROUND

Information on the epidemiology of idiopathic nephrotic syndrome (INS) in children, complications of INS and the side effects of steroid therapy is scarce.

METHODS

The Japanese Pediatric Survey Holding Information of Nephrotic Syndrome, a nationwide cohort study, was conducted by the Japanese Study Group of Renal Disease in Children and enrolled 2099 children with newly diagnosed INS between 1 January 2010 and 31 December 2012. We conducted a follow-up study of the complications during the first onset and the patients' prognosis in this cohort.

RESULTS

We obtained follow-up data on 999 children (672 males) with a median age at onset of 4.5 years [interquartile range (IQR) 2.8-9.4] and a median follow-up period of 4.1 years (IQR 2.5-5.1). At the first onset, 24% of patients experienced severe acute kidney injury (AKI), defined as a serum creatinine increase to a level two or more times the baseline. On logistic regression analysis, age, hematuria, severe hypoalbuminemia (serum albumin <1.0 g/dL) and severe bacterial infection were not independent factors, but female sex {hazard ratio [HR] 1.5 [95% confidence interval (CI) 1.1-1.7]} and hypertension [HR 4.0 (95% CI 2.6-6.0)] were significantly related to AKI. During the observation period, ocular hypertension requiring treatment occurred in 17.4% of patients, among which 0.4% received surgical treatment. Progression to frequently relapsing nephrotic syndrome/steroid-dependent nephrotic syndrome in 3 years was seen in 44.2% of the patients and was shown by the Cox regression analysis to be significantly related to younger age and days until remission at the first episode, but not to sex, hematuria, the minimum serum albumin level or AKI. Two patients died during the observation period. One patient showed progression to end-stage kidney disease.

CONCLUSION

Based on the results of a multicenter questionnaire survey, the overall survival and renal survival rates were found to be excellent. However, proper management of complications, particularly in AKI and ocular hypertension, is mandatory.

Prophylactic rituximab administration in children with complicated nephrotic syndrome

BACKGROUND

Rituximab is effective for maintaining remission in patients with complicated nephrotic syndrome, although a history of steroid-resistant nephrotic syndrome (SRNS) is a risk factor for early relapse. We investigated the efficacy of prophylactic rituximab treatment for maintaining remission after B cell recovery.

METHODS

Patients with complicated steroid-dependent or frequently relapsing nephrotic syndrome with history of SRNS who received a single dose of rituximab (375 mg/m²) and continued immunosuppressive agents were enrolled in this retrospective study. Patients were divided into two groups: a prophylaxis group, which received additional rituximab treatment at B cell recovery and a non-prophylaxis group. The relapse-free period from the last rituximab infusion (the second treatment in prophylaxis group and the first treatment in non-prophylaxis group) was compared between two groups using the Kaplan-Meier method, and risk factors for early relapse were calculated using multivariate analysis by Cox proportional hazards model.

RESULTS

Sixteen patients in the prophylaxis group and 45 in the non-prophylaxis group were enrolled. Fifty-percent relapse-free survival after the last rituximab treatment was 667 days in the former and 335 days in the latter (p = 0.001). Multivariate analysis showed that additional rituximab treatment was the only significant negative factor for early relapse, with a hazard ratio of 0.40 (p = 0.02). Fifty-percent relapse-free survival after B cell recovery was much longer in the prophylaxis group (954 vs. 205.5 days, p = 0.003).

CONCLUSIONS

Additional rituximab treatment at B cell recovery can maintain prolonged remission even after B cell recovery in patients with complicated nephrotic syndrome with history of SRNS.

Perinatal factors contributing to chronic kidney disease in a cohort of Japanese children with very low birth weight

BACKGROUND

Developmental programming of chronic kidney disease (CKD) in young adults is linked to preterm birth and intrauterine growth restriction (IUGR). Which confers a higher risk of progression to chronic kidney damage in children with very low birth weight (VLBW; born weighing < 1500 g): prematurity or IUGR?

METHODS

This is a national historical cohort study of children with VLBW cared for in perinatal medical centers in Japan. Predictive factors included three latent variables (prematurity, IUGR, stress during neonatal period) and eight observed variables (gestational age, birth weight Z-score, maternal age, duration of treatment with antibiotics and diuretics, maternal smoking, late-onset circulatory collapse, kidney dysfunction) during the perinatal period. The primary endpoint was estimated glomerular filtration rate (eGFR) at age ≥ 3 years. A structural equation model was used to examine the pathologic constitution.

RESULTS

The 446 children with VLBW included 253 boys and 193 girls, of mean age 5.8 ± 2.6 years and mean eGFR 111.7 ml/min/1.73 m² at last encounter. Pathway analyses showed intrauterine malnutrition (β = 0.85) contributed more to chronic kidney damage than stress during the neonatal period (β = - 0.19) and prematurity (β = 0.12), and kidney dysfunction and late-onset circulatory collapse were important observed variables in stress during the neonatal period.

CONCLUSIONS

IUGR was more harmful to future kidneys of VLBW neonates. Neonatal kidney dysfunction and late-onset circulatory collapse were important risk factors for subsequent CKD development. This emphasizes the need for obstetricians to monitor for fetal growth restriction and neonatologists to minimize neonatal stress to prevent CKD in later life.

Prospective study of live attenuated vaccines for patients receiving immunosuppressive agents

Patients receiving immunosuppressive agents are at risk of life-threatening infections. However, live vaccines are generally contraindicated in them. We conducted a prospective study regarding live attenuated vaccines for them. Patients elder than one year of age with immunosuppressive agents who showed negative or borderline antibody titers (virus-specific IgG levels < 4.0) against one or more of measles, rubella, varicella, and mumps and fulfilled the criteria (CD4 cell counts ≥ 500/mm3, stimulation index of lymphocyte blast transformation by PHA ≥ 101.6, serum IgG level ≥ 300 mg/dl, no steroid use or prednisolone < 1 mg/kg/day or < 2 mg/kg/2 days, trough levels of tacrolimus or cyclosporine were < 10 ng/ml or < 100 ng/ml and under good control of primary disease) were enrolled. Sixty-four vaccinations were administered to 32 patients. The seroconversion rates for measles, rubella, varicella, and mumps were 80.0%, 100.0%, 59.1%, and 69.2%, respectively. No life-threatening adverse events were observed, although one patient suffered from vaccine-strain varicella who showed cellular and humoral immunodeficiency (CD4 cell counts = 511/mm3, stimulation index of lymphocyte blast transformation by PHA = 91.1, serum IgG level = 208 mg/dl). This girl was immunized before we established the criteria for vaccination. Immunization with live attenuated vaccines for patients receiving immunosuppressive agents might be effective and safe if their cellular and humoral immunological parameters are within normal levels. However, determining the criteria for vaccination by immunological parameters should be established to guarantee the safety of live vaccines in the future. Clinical Trial Registration: UMIN Clinical Trials Registry (UMIN-CTR) UMIN000007710. The date of registration: 2012/4/13.

Refractory Hypertension in Infantile-Onset Denys-Drash Syndrome

Denys-Drash syndrome is characterized by progressive nephropathy, gonadal dysgenesis, and Wilms tumor caused by a WT1 gene mutation. Infants with Denys-Drash syndrome frequently experience severe hypertension, but detailed clinical manifestations have yet to be clarified. Cases of infantile-onset Denys-Drash syndrome with severe hypertension at our hospital were retrospectively analyzed and the pathogenesis of hypertension was investigated. Six infants who received the diagnosis of Denys-Drash syndrome at the median age of 10 days (range: 2-182 days) were enrolled. Five infants had the complication of severe hypertension within a few days of diagnosis. All the patients showed rapid progression to end-stage renal disease and urgently required dialysis due to anuria/oliguria and hypervolemia with a median duration of 7.5 days (range: 0-17 days) on the day after diagnosis. Even under dialysis, all the patients continued to need antihypertensive treatment. Five patients underwent a preventive nephrectomy for Wilms tumor, and one patient underwent a nephrectomy due to progression to Wilms tumor. Two patients developed hypotension after a nephrectomy. The main causes of hypertension were hypervolemia in the predialysis stage, renin-associated hypertension in the dialysis stage, and multiple factors, including increased plasma catecholamine-associated hypertension in the postnephrectomy dialysis stage. At last the follow-up after bilateral nephrectomy, four of the five patients required antihypertensive treatment. Not all the patients showed target organ complications caused by hypertension. Severe hypertension is a common complication of infantile-onset Denys-Drash syndrome. The possibility of hypotension after nephrectomy should be considered in patients with Denys-Drash syndrome.

A cross-sectional nationwide survey of congenital and infantile nephrotic syndrome in Japan

BACKGROUND

Congenital nephrotic syndrome (CNS) and infantile nephrotic syndrome (INS) cause substantial morbidity and mortality. In Japan, there is a lack of knowledge regarding the characteristics of CNS and INS. This study aimed to clarify the characteristics of CNS and INS in Japan.

METHODS

This cross-sectional nationwide survey obtained data from 44 institutions in Japan managing 92 patients with CNS or INS, by means of two survey questionnaires sent by postal mail. Patients aged < 16 years by 1 April 2015, with a diagnosis of CNS or INS, were included in this study. The primary outcome was end-stage kidney disease.

RESULTS

A total of 83 patients with CNS or INS were analyzed. The most frequent disease type was non-Finnish (60.2%); 33 patients (39.8%) had Finnish type. Among those with non-Finnish-type disease, 26 had no syndrome and 24 had a syndrome, of which the most frequent was Denys-Drash syndrome (70.8%). Patients with non-Finnish-type disease with syndrome showed the earliest progression to end-stage kidney disease compared with the other two groups, whereas patients with non-Finnish-type disease without syndrome progressed more slowly compared with the other two groups. In the Finnish-type group, the disease was diagnosed the earliest; a large placenta was reported more frequently; genetic testing was more frequently performed (93.8%); mental retardation was the most frequent extra-renal symptom (21.2%); and thrombosis and infection were more frequent compared with the other groups. Patients with non-Finnish-type disease with syndrome had a higher frequency of positive extra-renal symptoms (79.2%), the most common being urogenital symptoms (54.2%). Treatment with steroids and immunosuppressants was more frequent among patients with non-Finnish-type disease without syndrome. Two patients with non-Finnish-type disease without syndrome achieved complete remission. In all groups, unilateral nephrectomy was performed more often than bilateral nephrectomy and peritoneal dialysis was the most common renal replacement therapy.

CONCLUSIONS

The present epidemiological survey sheds light on the characteristics of children with CNS and INS in Japan. A high proportion of patients underwent genetic examination, and patient management was in accord with current treatment recommendations and practices.

TRIAL REGISTRATION

Not applicable.

A girl with MIRAGE syndrome who developed steroid-resistant nephrotic syndrome: a case report

BACKGROUND

MIRAGE syndrome is a recently discovered rare genetic disease characterized by myelodysplasia (M), infection (I), growth restriction (R), adrenal hypoplasia (A), genital phenotypes (G), and enteropathy (E), caused by a gain-of-function mutation in the SAMD9 gene. We encountered a girl with molecularly-confirmed MIRAGE syndrome who developed steroid-resistant nephrotic syndrome.

CASE PRESENTATION

She was born at 33 weeks gestational age with a birth weight of 1064 g. She showed growth failure, mild developmental delays, intractable enteropathy and recurrent pneumonia. She was diagnosed as MIRAGE syndrome by whole exome sequencing and a novel SAMD9 variant (c.4615 T > A, p.Leu1539Ile) was identified at age four. Biopsied skin fibroblast cells showed changes in the endosome system that are characteristic of MIRAGE syndrome, supporting the genetic diagnosis. Proteinuria was noted at age one, following nephrotic syndrome at age five. A renal biopsy showed focal segmental glomerulosclerosis (FSGS) with immune deposits. Steroid treatment was ineffective. Because we speculated that her nephrosis was a result of genetic FSGS, we decided not to introduce immunosuppressive agents and instead started enalapril to reduce proteinuria. Although her proteinuria persisted, her renal function was normal at age eight.

CONCLUSIONS

This is the first detailed report of a MIRAGE syndrome patient with nephrotic syndrome. Because patients with MIRAGE syndrome have structural abnormalities in the endosomal system, we speculate that dysfunction of endocytosis in podocytes might be a possible mechanism for proteinuria.

Two cases of idiopathic steroid-resistant nephrotic syndrome complicated with thrombotic microangiopathy

Background

Thrombotic microangiopathy (TMA) is a histopathological entity associated with microangiopathic hemolytic anemia, thrombocytopenia, and end-organ ischemic damage. Although TMA is caused by various diseases, there have been few reports regarding children with idiopathic nephrotic syndrome (NS) and TMA. Here we report two 1-year-old infants with steroid-resistant NS (SRNS) who presented with severe hypertension, acute kidney injury (AKI), and TMA.

Case presentation

The diagnosis of NS was complicated with anemia, AKI, and hypertension. Maximum blood pressure was 150/70 mmHg in Case 1 and 136/86 mmHg in Case 2. There was no thrombocytopenia during their clinical course in both cases. Renal biopsy showed the features of TMA, including endothelial cell swelling, capillarectasia or marked mesangiolysis, along with mesangial proliferation in Case 1 and TMA with minor glomerular abnormalities in Case 2. Hemolytic uremic syndrome, thrombotic thrombocytopenic purpura, and secondary TMA other than that caused by hypertension were excluded. Oral prednisolone therapy, frequent infusion of albumin and diuretics, and multiple anti-hypertensive drugs were initiated. Blood pressure was controlled after 6 and 7 days from initiation of multiple anti-hypertensive drugs and lisinopril was added due to persistent mild proteinuria and mild hypertension after improvement of renal function in both cases. Proteinuria resolved completely 4 months after admission with daily oral prednisolone for 4 weeks followed by alternative daily oral prednisolone for 4 weeks in Case 1. Proteinuria resolved completely 10 months after admission with initial prednisolone treatment for 4 weeks followed by cyclosporine A and intravenous methylprednisolone pulse therapy in Case 2. The follow-up biopsy showed no TMA findings in both patients. Because the patient in Case 1 subsequently developed frequent relapsing NS, cyclosporine A was commenced after the second biopsy and he did not have any flares for 2 years. Renal function was normal in Case 1 and mildly decreased in Case 2 at last follow-up (creatinine-eGFR of 136.2 mL/min/cm² in Case 1 and 79.5 mL/min/cm² in Case 2).

Conclusion

Severe hypertension and AKI can be signs of TMA in patients with SRNS. Strict anti-hypertensive therapy might improve renal outcomes.

A simple, refined approach to diagnosing renovascular hypertension in children: A 10-year study

BACKGROUND

Despite advances in non-invasive vascular imaging, detection of renal artery stenosis via catheter angiography is the criterion standard for the diagnosis of renovascular hypertension (RVH). However, because of lack of evidence, the utility of various blood tests and imaging modalities remains unclear.

METHODS

We retrospectively analyzed the utility of blood tests (plasma renin activity [PRA], aldosterone, and renal vein renin [RVR] values) and imaging studies (computed tomography angiography [CTA], kidney ultrasonography [US]) by comparing them with catheter angiography. Ten pediatric patients with RVH at two institutions from January 2008 to December 2017 were recruited. The sensitivities for diagnosing RVH via imaging and blood tests (kidney [US], PRA, and aldosterone) were derived by examining patient records. Furthermore, the sensitivity and specificity of CT angiography were calculated by considering both the affected and non-affected renal arteries of the patients.

RESULTS

A high sensitivity for diagnosing RVH via kidney US (89%) and PRA (80%) was observed. The sensitivity and specificity of CTA were 100%, each. RVR sampling did not aid in the diagnosis of RVH; only two of six patients with unilateral RVH showed significant laterality of RVR boundary ratios. Renal scintigraphy facilitated detection of a non-functional kidney (split renal function <5%).

CONCLUSIONS

RVH in children could be diagnosed utilizing non-invasive blood and imaging tests, without catheter angiography. We recommend kidney length measurement along with measurement of PRA level, as a simple and highly useful screening test, followed by CTA as a diagnostic test.

Common risk variants in NPHS1 and TNFSF15 are associated with childhood steroid-sensitive nephrotic syndrome

To understand the genetics of steroid-sensitive nephrotic syndrome (SSNS), we conducted a genome-wide association study in 987 childhood SSNS patients and 3,206 healthy controls with Japanese ancestry. Beyond known associations in the HLA-DR/DQ region, common variants in NPHS1-KIRREL2 (rs56117924, P=4.94E-20, odds ratio (OR) =1.90) and TNFSF15 (rs6478109, P=2.54E-8, OR=0.72) regions achieved genome-wide significance and were replicated in Korean, South Asian and African populations. Trans-ethnic meta-analyses including Japanese, Korean, South Asian, African, European, Hispanic and Maghrebian populations confirmed the significant associations of variants in NPHS1-KIRREL2 (P_meta=6.71E-28, OR=1.88) and TNFSF15 (P_meta=5.40E-11, OR=1.33) loci. Analysis of the NPHS1 risk alleles with glomerular NPHS1 mRNA expression from the same person revealed allele specific expression with significantly lower expression of the transcript derived from the risk haplotype (Wilcox test p=9.3E-4). Because rare pathogenic variants in NPHS1 cause congenital nephrotic syndrome of the Finnish type (CNSF), the present study provides further evidence that variation along the allele frequency spectrum in the same gene can cause or contribute to both a rare monogenic disease (CNSF) and a more complex, polygenic disease (SSNS).

Primary causes of kidney disease and mortality in dialysis-dependent children

BACKGROUND

Congenital anomalies of the kidney and urinary tract (CAKUT) is associated with a slower progression to end-stage renal disease (ESRD) in pre-dialysis patients. However, little is known about the associated mortality risks after transitioning to dialysis.

METHODS

This retrospective cohort study included 0-21 year-old incident dialysis patients from the United States Renal Data System starting dialysis between 1995 and 2016. We examined the association of CAKUT vs. non-CAKUT with all-cause mortality, using Cox regression adjusted for case mix variables. We also examined the mortality risk associated with 14 non-CAKUT vs. CAKUT ESRD etiologies and under stratification by estimated glomerular filtration rate (eGFR).

RESULTS

Among 25,761 patients, the median (interquartile range) age was 17 (11-19) years, and 4780 (19%) had CAKUT. CAKUT was associated with lower mortality, with an adjusted hazard ratio (aHR) of 0.72 (95%CI, 0.64-0.81) (reference: non-CAKUT). In age-stratified analyses, CAKUT vs. non-CAKUT aHRs (95%CI) were 0.66 (0.54-0.80), 0.56 (0.39-0.80), 0.66 (0.50-0.86), and 0.97 (0.80-1.18) among patients < 6, 6-< 13, 13-< 18, and ≥ 18 years at dialysis initiation, respectively. Among non-CAKUT ESRD etiologies, the risk of mortality associated with primary glomerulonephritis (aHR, 0.93; 95%CI 0.80-1.09) and focal segmental glomerulosclerosis (aHR, 0.89; 95%CI, 0.75-1.04) were comparable or slightly lower compared to CAKUT, whereas most other primary causes were associated with higher mortality risk. While the CAKUT group had lower mortality risk compared to the non-CAKUT group patients with eGFR ≥5 mL/min/1.73m², CAKUT was associated with higher mortality in patients with eGFR < 5 mL/min/1.73 m².

CONCLUSIONS

CAKUT is associated with lower mortality among children < 18 years old, but showed comparable mortality with non-CAKUT among patients ≥ 18 years old. ESRD etiology should be considered in risk assessment for children initiating dialysis.

Inherited salt-losing tubulopathy: An old condition but a new category of tubulopathy

Bartter syndrome (BS) and Gitelman syndrome (GS) are syndromes associated with congenital tubular dysfunction, characterized by hypokalemia and metabolic alkalosis. Clinically, BS is classified into two types: the severe antenatal/neonatal type, which develops during the fetal period with polyhydramnios and preterm delivery; and the relatively mild classic type, which is usually found during infancy with failure to thrive. GS can be clinically differentiated from BS by its age at onset, usually after school age, or laboratory findings of hypomagnesemia and hypocalciuria. Recent advances in molecular biology have shown that these diseases can be genetically classified into type 1 to 5 BS and GS. As a result, it has become clear that the clinical classification of antenatal/neonatal BS, classic BS, and GS does not always correspond to the clinical symptoms associated with the genotypes in a one-to-one manner; and there is clinically no clear differential border between type 3 BS and GS. This has caused confusion among clinicians in the diagnosis of these diseases. It has been proposed that the disease name "inherited salt-losing tubulopathy" can be used for cases of tubulopathies accompanied by hypokalemia and metabolic alkalosis. It is reasonable to use this term prior to genetic typing into type 1-5 BS or GS, to avoid confusion in a clinical setting. In this article, we review causative genes and phenotypic correlations, diagnosis, and treatment strategies for salt-losing tubulopathy as well as the clinical characteristics of pseudo-BS/GS, which can also be called a "salt-losing disorder".

Cholesterol Ester Transfer Protein in Children on Peritoneal Dialysis

Objectives

To examine whether cholesterol ester transfer protein (CETP) activity and mass contribute to dyslipidemia in children on peritoneal dialysis (PD), and to determine whether CETP activity or mass is responsible for severer hyperlipidemia in smaller (younger) patients.

Study Design

27 patients (18 males, 9 females; mean age 11.8 ± 6.1 years) were enrolled. Each patient had been receiving PD for more than 6 months. Fasting blood samples were drawn and CETP activity, CETP mass, total cholesterol, triglyceride, β-lipoprotein profiles, lipoprotein lipid profiles (cholesterol and triglyceride in lipoproteins), apoprotein profile, and serum albumin levels were measured. The results were then compared, using Student's t-test, with those for a control group. In the patient group, the relationships between CETP activity and each factor were examined using simple and multiple regression analyses.

Results

Total cholesterol, triglyceride, low-density lipoprotein (LDL), very low-density lipoprotein (VLDL), chylomicron, and ApoB levels were significantly higher in the patient group. Mean CETP activity levels were 106% ± 24% in the patient group and 111% ± 21% in the control group. No significant difference in CETP activity was seen between the two groups, but CETP mass was lower in the patient group than in the control group (2.2 ± 0.6 μL/dL for the patient group vs 2.8 ± 0.9 μL/dL for the control group, p = 0.01). As a result, specific CETP activity (activity/protein mass ratio) was significantly higher in the patient group ( p < 0.0001). CETP activity was positively related to LDL and other atherogenic factors and negatively related to serum albumin level. No relationship between CETP activity and patient body weight was seen.

Conclusion

Specific CETP activity was higher in the patient group compared with that in the control group, and strong correlations were found between CETP activity and atherogenic factors in the patient group. Therefore, CETP seems to be associated with lipid abnormalities in children on PD but is not responsible for the severer hyperlipidemia seen in smaller children.

Intranasal Mupirocin does not Prevent Exit-Site Infections in Children Receiving Peritoneal Dialysis

← Objective

Exit-site infections (ESI) in patients receiving peritoneal dialysis (PD) often progress to tunnel infections and peritonitis, sometimes requiring PD catheter removal. Staphylococcus aureus (SA) is the commonest cause of ESI. In this study, we evaluated the efficacy of mupirocin nasal ointment in preventing ESI in children receiving PD.

← Design

A single-center study.

← Setting

Tokyo Metropolitan Kiyose Children's Hospital.

← Patients

47 outpatients [33 males; age 11.7 ± 4.9 years (mean ± SD)] participated in this study between April 1998 and March 1999 at Tokyo Metropolitan Kiyose Children's Hospital. The total study period comprised 399 patient-months. Nasal cultures were performed every month. Nasal carriers of SA applied intranasal mupirocin ointment twice per day for 7 days. We compared the incidence of ESI in the intervention group to 77 historical controls (48 males; age 7.6± 5.1 years); the total control period comprised 2802 patient-months.

← Results

32 patients were identified as SA nasal carriers on one or two occasions (32/47 or 68%). The total period of SA nasal carriage was 95 patient-months (95/399 or 24%). The incidence of ESI caused by SA among all ESI cases was 20/28 (71%) in the study group and 115/151 (76%) in the control. There was no significant difference. The incidence of peritonitis caused by SA among all peritonitis cases was 3/6 (50%) in the study group and 17/42 (40%) in the control group, showing no significant difference. There was no significant difference in the overall incidence of ESI, peritonitis, or replacement of PD catheters between the study group and the control group.

← Conclusion

Intranasal mupirocin ointment did not prevent ESI. Further study is needed to develop an effective method of preventing ESI in pediatric PD patients.