Role of Iron in Children With Immunoglobulin A Nephropathy and Macrohematuria-Induced Acute Kidney Injury.

Introduction: The role of iron in, and the prognosis of, pediatric Immunoglobulin A nephropathy (IgAN) with macrohematuria (MH)-induced acute kidney injury (AKI) (MH-AKI) have not been evaluated. Thirty percent of adults with MH-AKI, and especially those who are older, show progression to chronic kidney disease. Methods: We evaluated the immunohistopathologic characteristics of renal biopsy samples from pediatric patients with MH-AKI IgAN and controls, using Berlin Blue to identify iron, CD163 (a hemoglobin-scavenging receptor), and CD68 (a total macrophage marker), then compared the findings against the clinical characteristics of the patients. Results: We enrolled 44 children as follows: 19 with IgAN but no MH or AKI; 5 with IgAN and MH but no AKI (MH(+)AKI(-) IgAN); 11 with MH-AKI IgAN; and 9 with no IgAN, MH, or AKI, according to a renal biopsy. Berlin Blue staining was detected predominantly at the injured tubulointerstitium, and the areas of staining in children with MH(+)AKI(-) and MH-AKI IgAN were significantly more extensive. The areas of Berlin Blue and CD163 staining did not perfectly match; however, areas of Berlin Blue were surrounded by immunopositivity for CD163. No children with MH-AKI IgAN showed decreased renal function at their last visit. Conclusion: Children with IgAN and MH, with or without AKI, showed considerable iron deposition in their renal tubules. CD163-positive cells might scavenge hemoglobin in patients with MH-AKI IgAN, but not their roles as macrophages. The renal prognosis of pediatric MH-AKI IgAN is good.

Clinical characteristics and outcomes of immune-complex membranoproliferative glomerulonephritis and C3 glomerulopathy in Japanese children.

BACKGROUND: Membranoproliferative glomerulonephritis (MPGN) can be divided into immune-complex MPGN (IC-MPGN) and C3 glomerulopathy (C3G), which includes dense deposit disease (DDD) and C3 glomerulonephritis (C3GN). These conditions result from abnormalities in different complement pathways and may lead to different prognoses. However, there are limited studies describing the respective clinical courses. METHODS: In this study, Japanese pediatric patients diagnosed with MPGN based on kidney biopsies conducted between February 2002 and December 2022 were reclassified as having IC-MPGN or C3G (DDD or C3GN). We retrospectively analyzed the clinical characteristics and outcomes of these patients. RESULTS: Out of 25 patients with MPGN, three (12.0%) were diagnosed with DDD, 20 (80.0%) with C3GN, and two (8.0%) with IC-MPGN. There were 13 (65.0%) patients and one (33.3%) patient in remission after treatment for C3GN and DDD, respectively, and no patients with IC-MPGN achieved remission. The median follow-up period was 5.3 (2.5-8.9) years, and none of the patients in either group progressed to an estimated glomerular filtration rate < 15 ml/min/1.73 m2. Patients with C3GN presenting mild to moderate proteinuria (n = 8) received a renin-angiotensin system inhibitor (RAS-I) alone, and these patients exhibited a significant decrease in the urinary protein creatinine ratio and a notable increase in serum C3 levels at the last follow-up. CONCLUSIONS: Most patients with MPGN were diagnosed with C3GN. The remission rate for C3GN was high, and no patients developed kidney failure during the approximately 5-year follow-up. Additionally, patients with C3GN with mild to moderate proteinuria had good outcomes with RAS-I alone, but continued vigilance is necessary to determine long-term prognosis.

Isolation and identification of Wickerhamiella tropicalis from blood culture by MALDI-MS.

Wickerhamiella is a genus of budding yeast that is mainly isolated from environmental samples, and 40 species have been detected. The yeast isolated from human clinical samples usually only contain three species: W. infanticola, W. pararugosa and W. sorbophila. In this study, we isolated W. tropicalis from a blood sample of a six-year-old female with a history of B-cell precursor lymphoblastic leukemia in Japan in 2022. Though the strain was morphologically identified as Candida species by routine microbiological examinations, it was subsequently identified as W. tropicalis by sequencing the internal transcribed spacer (ITS) of ribosomal DNA (rDNA). The isolate had amino acid substitutions in ERG11 and FKS1 associated with azole and echinocandin resistance, respectively, in Candida species and showed intermediate-resistant to fluconazole and micafungin. The patient was successfully treated with micafungin. Furthermore, matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS) detected three novel peaks that are specific for W. tropicalis, indicating that MALDI-MS analysis is useful for rapid detection of Wickerhamiella species in routine microbiological examinations.

Recurrent spinal atypical teratoid/rhabdoid tumor with pulmonary metastasis.

BACKGROUND: Atypical teratoid/rhabdoid tumors (ATRT) are aggressive pediatric central nervous system malignancies that predominantly affect the brain and have poor survival outcomes. However, spinal ATRT is an uncommon subset of ATRT, and its clinical course and management are poorly understood. CASE: We describe a case of spinal ATRT in a previously healthy 5-year-old girl who initially presented with rapid-onset gait disturbance. Magnetic resonance imaging (MRI) revealed an extramedullary tumor at thoracic level 5 (T5) without bony destruction or metastasis. The patient partially recovered after surgical resection. One month was required for a definitive diagnosis, and the pathology confirmed ATRT characterized by the loss of INI-1 protein expression. Chemoradiotherapy with local irradiation and high-dose chemotherapy with autologous peripheral blood stem cell transplantation led to complete remission and functional recovery for 5 months. However, the condition exhibited progression in the cerebrospinal fluid (CSF) region, resulting in cerebellar, cerebral, and spinal tumor development. Eventually, the disease metastasized to the lungs and disseminated to the entire cerebrospinal cord and fluid. The patient died 15 months after the initial diagnosis. CONCLUSION: This case emphasizes the importance of considering ATRT as a potential diagnostic modality for pediatric spinal cord tumors, enabling prompt multidisciplinary intervention. The heterogeneous appearance of spinal ATRT may make distinguishing it from other spinal tumors difficult, resulting in delayed diagnosis and treatment. The treatment approach for ATRT remains challenging with no established standards. Local irradiation may be preferable to minimize neurodevelopmental effects, and initial craniospinal irradiation may potentially prevent recurrence. Our case emphasizes the likelihood of extracranial metastasis in ATRT, thereby highlighting the importance of a comprehensive assessment of both genetic and epigenetic profiles to identify any factors that may influence the clinical course of this disease. Prompt diagnosis and comprehensive therapeutic strategies are critical for improving outcomes in spinal ATRT patients.

Rare TCF3 variants associated with pediatric B cell acute lymphoblastic leukemia.

Germline genetic variants influence development of pediatric B cell acute lymphoblastic leukemia (B-ALL). Genome-wide association studies (GWAS) have identified several pediatric B-ALL susceptibility loci. IKZF1 and PAX5, transcription factors involved in B cell development, have been reported as susceptibility genes for B-ALL development. Therefore, we hypothesized that rare variants of genes involved in B cell development would be candidate susceptibility loci for pediatric B-ALL. Thus, we sequenced TCF3, a key transcription factor gene involving in B cell development. Saliva DNA from 527 pediatric patients with pediatric B-ALL in remission who were registered with the Tokyo Children's Cancer Study Group (TCCSG) were examined. As a TCF3 gene-based evaluation, the numbers of rare deleterious germline TCF3 sequence variants in patients with pediatric B-ALL were compared with those in cancer-free individuals using data in public databases. As a TCF3 single-variant evaluation, the frequencies of rare deleterious germline TCF3 sequence variants in patients with pediatric B-ALL were also compared with those in control data. TCF3 gene-based analysis revealed significant associations between rare deleterious variants and pediatric B-ALL development. In addition, TCF3 variant-based analysis showed particularly strong association between variant rs372168347 (three in 521 TCCSG and three in the 15780 gnomAD whole genome analysis cohort, p = 0.0006) and pediatric B-ALL development. TCF3 variants are known to influence B cell maturation and may increase the risk of preleukemic clone emergence.

Assessment of anthracycline-induced cardiotoxicity in childhood cancer survivors during long-term follow-up using strain analysis and intraventricular pressure gradient measurements.

BACKGROUND: Cardiac dysfunction due to cardiotoxicity from anthracycline chemotherapy is a leading cause of morbidity and mortality in childhood cancer survivors (CCS), and the cumulative incidence of cardiac events has continued to increase. This study identifies an adequate indicator of cardiac dysfunction during long-term follow-up. PROCEDURE: In total, 116 patients (median age: 15.5 [range: 4.7-40.2] years) with childhood cancer who were treated with anthracycline were divided into three age groups for analysis (C1: 4-12 years of age, C2: 13-18 years of age, C3: 19-40 years of age), and 116 control patients of similar ages were divided into three corresponding groups (N1, N2, and N3). Layer-specific strains were assessed for longitudinal strain (LS) and circumferential strain (CS). The total and segmental intraventricular pressure gradients (IVPG) were also calculated based on Doppler imaging of the mitral inflow using Euler's equation. RESULTS: Conventional echocardiographic parameters were not significantly different between the patients and controls. All layers of the LS and inner and middle layers of the basal and papillary CS in all ages and all IVPGs in C2 and C3 decreased compared to those of corresponding age groups. Interestingly, basal CS and basal IVPG in CCS showed moderate correlation and both tended to rapidly decrease with aging. Furthermore, basal IVPG and anthracycline dose showed significant correlations. CONCLUSIONS: Basal CS and total and basal IVPGs may be particularly useful indicators of cardiotoxicity in long-term follow-up.

Clinical Usefulness of T-Cell Receptor Vß Repertoire Analysis for Differentiating Multisystem Inflammatory Syndrome in Japanese Children From Toxic Shock Syndrome and Kawasaki Disease.

The specific expansion of T-cell receptor ß chain variable region (TCR-Vß21.3 + ) CD4 + and CD8 + T cells was observed in Japanese patients with multisystem inflammatory syndrome in children. In contrast, these findings were not observed in patients with toxic shock syndrome and Kawasaki disease. T-cell receptor ß chain variable region repertoire analysis to detect specific expansion of Vß21.3 + T cells might be useful for differentiating multisystem inflammatory syndrome in children from toxic shock syndrome and Kawasaki disease.

Long-term outcome of combination therapy with corticosteroids, mizoribine and RAS inhibitors as initial therapy for severe childhood IgA vasculitis with nephritis.

BACKGROUND: Patients with severe IgA vasculitis with nephritis (IgAVN) typically receive aggressive therapy as an initial approach. We have consistently performed combination therapy including corticosteroids and immunosuppressants as initial therapy for severe IgAVN over a 20-year-plus period, with only minor changes to the treatment protocol. This study seeks to reveal the efficacy of combination therapy for severe IgAVN. METHODS: We retrospectively studied 50 Japanese children diagnosed between 1996 and 2019 with clinicopathologically severe IgAVN who were defined as ISKDC classification grade IIIb-V and/or serum albumin < 2.5 g/dL. RESULTS: The median age at the onset of IgAVN was 8.0 years (IQR: 6.0-10.0). At biopsy, 44% of patients had nephrotic syndrome and 14% had kidney dysfunction. All patients were treated with combination therapy after biopsy. Abnormal proteinuria resolved after initial therapy in all 50 patients. However, eight patients (16%) had recurrence of proteinuria. Abnormal proteinuria was again resolved in three of these patients with additional treatment. At the last follow-up (median 59.5 months; IQR, 26.2-84.2), the median urine protein-to-creatine ratio was 0.08 g/gCr (IQR, 0.05-0.15), and only one patient had kidney dysfunction. CONCLUSIONS: Combination therapy provided good kidney outcomes for Japanese children with severe IgAVN. Even including recurrent cases, the degree of proteinuria was slight, and kidney function was good at the last follow-up. A higher resolution version of the Graphical abstract is available as Supplementary information.

Clinical significance of serum cytokine profiles for differentiating between Kawasaki disease and its mimickers.

OBJECTIVES: To investigate the clinical significance of serum cytokine profiles for differentiating between Kawasaki disease (KD) and its mimickers. METHODS: Patients with KD, including complete KD, KD shock syndrome (KDSS), and KD with macrophage activation syndrome (KD-MAS), and its mimickers, including multisystem inflammatory syndrome in children, toxic shock syndrome, and Yersinia pseudotuberculosis infection, were enrolled. Serum levels of interleukin (IL)-6, soluble tumor necrosis factor receptor type II (sTNF-RII), IL-10, IL-18, and chemokine (C-X-C motif) ligand 9 (CXCL9) were measured using enzyme-linked immunosorbent assay and compared them with clinical manifestations. RESULTS: Serum IL-6, sTNF-RII, and IL-10 levels were significantly elevated in patients with KDSS. Serum IL-18 levels were substantially elevated in patients with KD-MAS. Patients with KD-MAS and KD mimickers had significantly elevated serum CXCL9 levels compared with those with complete KD. Area under the receiver operating characteristic curve analysis showed that serum IL-6 was the most useful for differentiating KDSS from the others, IL-18 and CXCL9 for KD-MAS from complete KD, and CXCL9 for KD mimickers from complete KD and KD-MAS. CONCLUSION: Serum cytokine profiles may be useful for differentiating between KD and its mimickers.

International cohort of 382 children with lupus nephritis - presentation, treatment and outcome at 24 months.

BACKGROUND: Children with lupus have a higher chance of nephritis and worse kidney outcome than adult patients. METHODS: We retrospectively analyzed clinical presentation, treatment and 24-month kidney outcome in a cohort of 382 patients (≤ 18 years old) with lupus nephritis (LN) class ≥ III diagnosed and treated in the last 10 years in 23 international centers. RESULTS: The mean age at onset was 11 years 9 months and 72.8% were females. Fifty-seven percent and 34% achieved complete and partial remission at 24-month follow-up, respectively. Patients with LN class III achieved complete remission more often than those with classes IV or V (mixed and pure). Only 89 of 351 patients maintained stable complete kidney remission from the 6th to 24th months of follow-up. eGFR ≥ 90 ml/min/1.73 m2 at diagnosis and biopsy class III were predictive of stable kidney remission. The youngest and the oldest age quartiles (2y-9y, 5m) (14y, 2m-18y,2m) showed lower rates of stable remission (17% and 20.7%, respectively) compared to the two other age groups (29.9% and 33.7%), while there was no difference in gender. No difference in achieving stable remission was found between children who received mycophenolate or cyclophosphamide as induction treatment. CONCLUSION: Our data show that the rate of complete remission in patients with LN is still not high enough. Severe kidney involvement at diagnosis was the most important risk factor for not achieving stable remission while different induction treatments did not impact outcome. Randomized treatment trials involving children and adolescents with LN are needed to improve outcome for these children. A higher resolution version of the Graphical abstract is available as Supplementary information.

Successful all robotic-assisted excision of highly malignant mediastinal neuroblastoma in a toddler: A case report.

An otherwise well 28-month-old girl presented with fever/left thigh pain. Computed tomography identified a 7 cm right posterior mediastinal tumor extending to the paravertebral and intercostal spaces with multiple bone and bone marrow metastases on bone scintigraphy. Thoracoscopic biopsy diagnosed MYCN non-amplified neuroblastoma. Chemotherapy shrank the tumor to 5 cm by 35 months of age. Robotic-assisted resection was chosen because the patient was large enough and public health insurance coverage was available. At surgery, the tumor was well-demarcated by chemotherapy and dissection posteriorly from the ribs/intercostal spaces and medially from the paravertebral space and azygos vein was facilitated by superior visualization/instrument articulation. The capsule of the resected specimen was intact on histopathology, confirming complete tumor resection. Despite minimum distance specifications between arms, trocars, and target sites with robotic assistance, excision was safe without instrument collisions. Robotic assistance should be actively considered for pediatric malignant mediastinal tumor provided the thorax is of adequate size.

The dynamics of laboratory markers reflecting cytokine overproduction in macrophage activation syndrome complicated with systemic juvenile idiopathic arthritis.

OBJECTIVES: To validate the correlation between laboratory markers reflecting disease activity of macrophage activation syndrome (MAS) and serum cytokine levels and identify the valuable laboratory markers that change over time for a prompt MAS diagnosis. METHODS: Serum cytokine levels were determined by enzyme-linked immunosorbent assay and compared with laboratory markers reflecting MAS disease activity.The changes in values were evaluated from the acute phase of systemic juvenile idiopathic arthritis (s-JIA) to MAS diagnosis. RESULTS: CXCL9 was significantly correlated with aspartate aminotransferase (AST), lactate dehydrogenase (LDH), D dimer, and urine ß2 microglobulin levels. sTNF-RII was significantly correlated with platelet counts, AST, LDH, D dimer, and ferritin levels. Significant changes in platelet count, LDH, and D dimer levels were observed. Decreased platelet counts were the most valuable indicator for MAS diagnosis. CONCLUSION: Monitoring the laboratory markers that change over time, particularly decreased platelet counts, was valuable for the prompt MAS diagnosis in s-JIA.

Is influenza vaccination associated with nephrotic syndrome relapse in children? A multicenter prospective study.

BACKGROUND: Prospective research of children receiving heterogeneous vaccines has shown that immunization is not associated with pediatric idiopathic nephrotic syndrome (NS) relapses. However, prospective data concentrating only on influenza (flu) virus vaccines are not available. METHODS: This multicenter prospective study was conducted in children with NS who received inactivated flu vaccines from June 2017 to July 2018. The day of flu vaccination was defined as day 0, and the period between prevaccination and postvaccination days was defined as - X to + Y (period from day - 180 to 0 as the precontrolled period). The primary outcome was the NS relapse rate from day 0 to + 30 as a direct association with vaccination compared with those in the precontrolled period. Exacerbation was defined as children experiencing more NS relapses after vaccination compared with those in the precontrolled period, or children starting any new immunosuppressants due to NS relapse after vaccination. RESULTS: Sixty-three children were included. Relapse rates were not significantly different between the precontrolled period and 0 to + 30 periods (0.38 vs. 0.19 times/person-year, p = 0.95). Although the exacerbation rate during the 0 to + 180 period in children without NS relapse in the precontrolled period was very low (4/54 [7.4 %]), children with at least one NS relapse in the precontrolled period showed a remarkable increase in the rate (4/9 [44.4%]; p = 0.01). CONCLUSIONS: Flu vaccination did not significantly precipitate the direct relapse of NS in children. However, it might increase the disease activity in children with at least one NS relapse within a half year before vaccination. A higher resolution version of the Graphical abstract is available as Supplementary information.

Serum interleukin-18 level as a possible early diagnostic marker of systemic juvenile idiopathic arthritis.

Early diagnosis of systemic juvenile idiopathic arthritis (s-JIA) is a prerequisite for therapeutic efficacy. However, it is often challenging because most patients with s-JIA do not show arthritis at disease onset and are simply diagnosed with fever of unknown origin. Serum ferritin levels have commonly been used to diagnose s-JIA because they increase in patients with this condition by more than 5 times their normal value. However, there are no definite biomarkers for s-JIA, which makes the clinical diagnosis of s-JIA difficult. We report a case of s-JIA in which interleukin (IL)-18 elevation was observed before ferritin elevation at the early phase of s-JIA. We propose serum IL-18 levels as a more useful biomarker for the early diagnosis of s-JIA compared to serum ferritin levels.

First phase 1 clinical study of olaparib in pediatric patients with refractory solid tumors.

BACKGROUND: The survival of patients with high-risk, refractory, relapsed, or metastatic solid tumors remains dismal. A poly(ADP-ribose) polymerase (PARP) inhibitor could be effective for the treatment of pediatric solid tumors with defective homologous recombination. METHODS: This open-label, multicenter phase 1 clinical trial evaluated the safety, tolerability, and efficacy of olaparib, a PARP inhibitor, in pediatric patients with refractory solid tumors to recommend a dose for Phase 2 trials. Olaparib (62.5, 125, and 187.5 mg/m2 twice daily) was administered orally every day (1 cycle = 28 days) using a standard 3 + 3 dose-escalation design. Patients aged 3-18 years with recurrent pediatric solid tumors were eligible. Pharmacokinetic and pharmacodynamic analyses were performed. RESULTS: Fifteen patients were enrolled and received olaparib monotherapy, which was well tolerated. The recommended phase 2 dose for daily administration was 187.5 mg/m2 twice daily. Pharmacokinetics were dose proportional. The area under the concentration-time curve from 0 to 12 h and the peak plasma concentration for 187.5 mg/m2 twice daily in children were comparable to previous data obtained in a 200-mg, twice-daily cohort and lower than those in the 300-mg twice-daily cohort in adults. Pharmacodynamic studies demonstrated substantial inhibition of PARP activity. Two partial responses were observed in patients with Wilms tumor and neuroblastoma. CONCLUSIONS: This report is the first clinical trial to describe the use of a PARP inhibitor as monotherapy in children. Olaparib was well tolerated, with preliminary antitumor responses observed in DNA damage response-defective pediatric tumors. LAY SUMMARY: This Phase 1 trial evaluated the efficacy and safety of olaparib in patients with refractory childhood solid tumors. Olaparib was well tolerated, achieving objective response in 2/15 patients. The DNA damage response was attenuated in nearly one-half of advanced neuroblastoma patients, demonstrating the utility of the PARP inhibitor. The results support further investigation of olaparib as a new treatment for DNA damage-response or repair-defective pediatric cancers.