Activation of fibroblast growth factor-inducible 14 in the early phase of childhood IgA nephropathy.

IgA nephropathy (IgAN) is the most common form of glomerulonephritis worldwide. Pediatric patients in Japan are diagnosed with IgAN at an early stage of the disease through annual urinary examinations. Tumor necrosis factor-like weak inducer of apoptosis (TWEAK) and fibroblast growth factor-inducible 14 (Fn14) have various roles, including proinflammatory effects, and modulation of several kidney diseases; however, no reports have described their roles in pediatric IgAN. In this study, we performed pathological and immunohistochemical analyses of samples from 14 pediatric IgAN patients. Additionally, gene expression arrays of glomeruli by laser-captured microdissection were performed in hemi-nephrectomized high serum IgA (HIGA) mice, a model of IgA nephropathy, to determine the role of Fn14. Glomeruli with intense Fn14 deposition were observed in 80% of mild IgAN cases; however, most severe cases showed glomeruli with little or no Fn14 deposition. Fn14 deposition was not observed in obvious mesangial proliferation or the crescent region of glomeruli, but was detected strongly in the glomerular tuft, with an intact appearance. In HIGA mice, Fn14 deposition was observed mildly beginning at 11 weeks of age, and stronger Fn14 deposition was detected at 14 weeks of age. Expression array analysis indicated that Fn14 expression was higher in HIGA mice at 6 weeks of age, increased slightly at 11 weeks, and then decreased at 26 weeks when compared with controls at equivalent ages. These findings suggest that Fn14 signaling affects early lesions but not advanced lesions in patients with IgAN. Further study of the TWEAK/Fn14 pathway will contribute to our understanding of the progression of IgAN.

Properties of Staphylococcus lugdunensis in Children.

Background. Staphylococcus lugdunensis is one of the clinically important coagulase-negative staphylococci. The purpose of this study was to elucidate the microbiological features of S. lugdunensis in hospitalized children. Methods. From January 2012 to December 2019, all isolates were retrospectively screened for S. lugdunensis. Results. Twenty-five children were eligible for study. Nineteen and six children were classified into a critical care unit group (Group A) and a general medical ward group (Group B), respectively. The prevalence of methicillin-resistant S. lugdunensis was significantly higher in Group A than in Group B (68.4% vs 0%; P < .01). Eleven children (44%) had S. lugdunensis infections, while the remaining children were colonized. Six of the 11 infected children (55%) had healthcare-associated infections. Moreover, 3 isolates exhibited the methicillin resistance. Conclusions. The bacteriological characteristics of S. lugdunensis differ depending on patient background. Selection of antibiotic treatment should in part rely on patient background data.

A Catheter-Related Bloodstream Infection by Brevibacterium casei in a Child with Acute Myeloid Leukemia: Case Report and Literature Review.

The most common organisms isolated from pediatric catheter-related bloodstream infections (CRBSIs) are Gram-positive cocci, such as coagulase-negative staphylococci and Staphylococcus aureus. There are few formal reports of Brevibacterium casei infection and even fewer reports of CRBSI due to this Gram-positive rod. Here we report the first case of CRBSI due to B. casei in an 8-year-old girl with acute myeloid leukemia in Japan. The isolate exhibited decreased susceptibility to ß-lactam antibiotics. Antimicrobial therapy with meropenem and vancomycin, in addition to the removal of central venous catheter line, consequently led to a significant clinical improvement of the patient's symptoms. A literature review found available clinical courses in 16 cases (4 pediatric cases including our case) of B. casei infection. Our case and those in literature suggested that B. casei infection often occurs in patients with indwelling central venous catheters; the literature review further suggested that removal of central venous catheters is required in most cases. Special attention should be paid to the detection of opportunistic infections due to Brevibacterium spp. in immunocompromized children who are using a central venous catheter.

Malignant Ovarian Steroid Cell Tumor, Not Otherwise Specified, Causes Virilization in a 4-Year-Old Girl: A Case Report and Literature Review.

We report a case of a 4-year-old girl with an ovarian steroid cell tumor, not otherwise specified (SCT-NOS). She was admitted to the hospital with progressing virilization and Cushing's syndrome, which included abnormality of the perineum, hirsutism, hypertrichosis, flushing of face, hoarseness, and weight gain. Blood testing showed a significantly increased testosterone level and slightly increased cortisol level. Computed tomography scan revealed an 8.0 × 5.0 × 5.0 cm tumor of the right ovary. The patient underwent right salpingo-oophorectomy, and pathological examination showed malignant potential. Three courses of bleomycin, etoposide, and cisplatin were administered as postoperative chemotherapy. After tumor resection, her testosterone decreased to undetectable levels. However, during the course of the treatment, the patient suffered from adrenal insufficiency resulting in the need for hydrocortisone replacement therapy. Although SCT-NOS in childhood are typically benign, pathological findings should be carefully observed for potential malignancy. In cases of cortisol-producing SCT-NOS, serum levels should be monitored, and hydrocortisone replacement therapy should be considered before resection.

Brain Abscess Associated with Polymicrobial Infection after Intraoral Laceration: A Pediatric Case Report.

Brain abscesses, infections within the brain parenchyma, can arise as complications of various conditions including infections, trauma, and surgery. However, brain abscesses due to polymicrobial organisms have rarely been reported in children. We herein report a case of a 9-year-old girl with unresolved congenital cyanotic heart disease (CCHD) presenting with right hemiplegia who was diagnosed with brain abscess caused by Streptococcus intermedius, Parvimonas micra, and Fusobacterium nucleatum after oropharyngeal injury. She was treated with intravenous antimicrobial therapy, drainage under craniotomy, and antiedema therapy with glycerol and goreisan, which led to the improvement of right hemiplegia to baseline; she was discharged following eight weeks of intravenous antimicrobial therapy. The clinical diagnosis of the brain abscess was difficult due to the nonspecific presentation, highlighting the importance of cranial imaging without haste in patients at increased risk for brain abscesses such as those with CCHD, presenting with fever in the absence of localizing symptoms or fever, accompanied with abnormal neurological findings.

Mesenchymal Stem Cell Therapy Overcomes Steroid Resistance in Severe Gastrointestinal Acute Graft-Versus-Host Disease.

The authors describe the high effectiveness of human mesenchymal stem cell (hMSC) therapy to treat steroid-refractory gastrointestinal acute graft-versus-host Disease (aGVHD) in a 15-year-old boy with acute lymphoblastic leukemia (ALL). He received allogeneic hematopoietic stem cell transplantation due to high-risk hypodiploid ALL. Around the time of engraftment, he developed severe diarrhea following high-grade fever and erythema. Although methylprednisolone pulse therapy was added to tacrolimus and mycophenolate mofetil, diarrhea progressed up to 5000~6000 ml/day and brought about hypocalcemia, hypoalbuminemia, and edema. Daily fresh frozen plasma (FFP), albumin, and calcium replacements were required to maintain blood circulation. After aGVHD was confirmed by colonoscopic biopsy, MSC therapy was administered. The patient received 8 biweekly intravenous infusions of 2×106 hMSCs/kg for 4 weeks, after which additional 4 weekly infusions were performed. A few weeks after initiation, diarrhea gradually resolved, and at the eighth dose of hMSC, lab data improved without replacements. MSC therapy successfully treated steroid-refractory gastrointestinal GVHD without complications. Despite life-threatening diarrhea, the regeneration potential of children and adolescents undergoing SMC therapy successfully supports restoration of gastrointestinal damage. Even with its high treatment costs, SMC therapy should be proactively considered in cases where young patients suffer from severe gastrointestinal GVHD.

Early detection of the PAX3-FOXO1 fusion gene in circulating tumor-derived DNA in a case of alveolar rhabdomyosarcoma.

Cell-free DNA (cfDNA), which are small DNA fragments in blood derived from dead cells including tumor cells, could serve as useful biomarkers and provide valuable genetic information about the tumors. cfDNA is now used for the genetic analysis of several types of cancers, as a surrogate for tumor biopsy, designated as "liquid biopsy." Rhabdomyosarcoma (RMS), the most frequent soft tissue tumor in childhood, can arise in any part of the body, and radiological imaging is the only available method for estimating the tumor burden, because no useful specific biological markers are present in the blood. Because tumor volume is one of the determinants of treatment response and outcome, early detection at diagnosis as well as relapse is essential for improving the treatment outcome. A 15-year-old male patient was diagnosed with alveolar RMS of prostate origin with bone marrow invasion. The PAX3-FOXO1 fusion was identified in the tumor cells in the bone marrow. After the diagnosis, cfDNA was serially collected to detect the PAX3-FOXO1 fusion sequence as a tumor marker. cfDNA could be an appropriate source for detecting the fusion gene; assays using cfDNA have proved to be useful for the early detection of tumor progression/recurrence. Additionally, the fusion gene dosage estimated by quantitative polymerase chain reaction reflected the tumor volume during the course of the treatment. We suggest that for fusion gene-positive RMSs, and other soft tissue tumors, the fusion sequence should be used for monitoring the tumor burden in the body to determine the diagnosis and treatment options for the patients.

Prolonged adrenal insufficiency after high-dose glucocorticoid in infants with leukemia.

Although outcomes for infant leukemia have improved recently, transient adrenal insufficiency is commonly observed during treatment, especially after glucocorticoid administration. We identified three infants with acute leukemia who suffered from prolonged adrenal insufficiency requiring long-term (from 15 to 66 months) hydrocortisone replacement. All infants showed life-threatening symptoms associated with adrenal crisis after viral infections or other stress. Severe and prolonged damage of hypothalamo-pituitary-adrenal (HPA) axis is likely to occur in early infants with leukemia, therefore routine tolerance testing to evaluate HPA axis and hydrocortisone replacement therapy are recommended for infants with leukemia to avoid life-threatening complications caused by adrenal crisis.

Usefulness of positron emission tomography-CT for diagnosis of primary bone marrow lymphoma in children.

Primary bone marrow lymphoma (PBML) is hard to diagnose in children, due to the difficult identification of malignant cells in bone marrow. The first case, a 5-year-old boy, showed knee swelling with an intermittent fever. The second case, a 12-year-old girl, showed fever of unknown origin without lymphadenopathy or hepatosplenomegaly. In both cases, the diagnosis was not confirmed despite the repeated bone marrow aspirations. Finally, bone marrow aspiration and biopsy at the positive site by positron emission tomography (PET)-CT contributed to definitive diagnosis of PBML. The PET-CT is useful for the accurate diagnosis of PBML in children with non-specific symptoms.

Histological characterisation of visceral changes in a patient with type 2 Gaucher disease treated with enzyme replacement therapy.

Gaucher disease is a lysosomal storage disease caused by deficiency of glucocerebrosidase and accumulation of glucocerebroside. Three major sub-types have been described, type 2 is an acute neurological form that exhibits serious general symptoms and poor prognosis, compared with the other types. This case was a girl diagnosed with type 2 Gaucher disease at 12months of age who presented with poor weight gain from infancy, stridor, hypertonia, hepatosplenomegaly, trismus and an eye movement disorder. Enzyme replacement therapy (ERT) was administered, but she had frequent myoclonus and developmental regression. She needed artificial ventilation because of respiratory failure. She died at 11years of age. An autopsy demonstrated infiltrating CD68-positive large cells containing abundant lipids in alveoli, while in the liver, kidney and bone marrow CD68-positive cells were small and round. In the bone marrow, myelodysplastic changes were present without Gaucher cells. The infiltration of Gaucher cells in alveoli was marked, suggesting that ERT was relatively ineffective in pulmonary involvement, particularly intra-alveolar. Additional treatments are necessary to improve the neurological and pulmonary prognosis of type 2Gaucher disease.

Manifestation of recessive combined D-2-, L-2-hydroxyglutaric aciduria in combination with 22q11.2 deletion syndrome.

22q11.2 deletion syndrome is one of the most common human microdeletion syndromes. The clinical phenotype of 22q11.2 deletion syndrome is variable, ranging from mild to life-threatening symptoms, depending mainly on the extent of the deleted region. Brain malformations described in association with 22q11.2 deletion syndrome include polymicrogyria, cerebellar hypoplasia, megacisterna magna, and agenesis of the corpus callosum (ACC), although these are rare. We report here for the first time a patient who manifested combined D-2- and L-2-hydroxyglutaric aciduria as a result of a hemizygous mutation in SLC25A1 in combination with 22q11.2 deletion. The girl was diagnosed to have ACC shortly after birth and a deletion of 22q11.2 was identified by genetic analysis. Although the patient showed cardiac anomalies, which is one of the typical symptoms of 22q11.2 deletion syndrome, her rather severe phenotype and atypical face prompted us to search for additional pathogenic mutations. Three genes present in the deleted 22q11.2 region, SLC25A1, TUBA8, and SNAP29, which have been reported to be associated with brain malformation, were analyzed for the presence of pathogenic mutations. A frameshift mutation, c.18_24dup (p.Ala9Profs*82), was identified in the first exon of the remaining SLC25A1 allele, resulting in the complete loss of normal SLC25A1 function in the patient's cells. Our results support the notion that the existence of another genetic abnormality involving the retained allele on 22q11.2 should be considered when atypical or rare phenotypes are observed.

Exon skipping in CYBB mRNA and skewed inactivation of X chromosome cause late-onset chronic granulomatous disease.

Chronic granulomatous disease (CGD) is a hereditary immunodeficiency syndrome caused by a defect in the NADPH oxidase complex, which is essential for bactericidal function of phagocytes. Approximately 70% of patients with CGD have a mutation in the CYBB gene on the X chromosome, resulting in defective expression of gp91phox, one of the membrane-bound subunits of NADPH oxidase. Although most patients with X-linked CGD are males, owing to transmission of this disease as an X-linked recessive trait, there are female patients with X-linked CGD. Here, we report the case of a teenage girl with X-linked CGD associated with a heterozygous mutation in exon 5 of the CYBB gene (c.389G > C; R130P), which causes skipping of exon 5, resulting in a premature stop codon in exon 6 of CYBB. Accurate pro-mRNA splicing for mature mRNA formation is regulated by several splicing mechanisms that are essential for appropriate recognition of exonic sequences. The c.389G > C mutation disrupts exonic-splicing regulator sequences, thereby resulting in the aberrant skipping of exon 5 in the CYBB transcript of the patient. The patient showed an extremely skewed (≥96%) X inactivation pattern of the HUMARA locus; this inactivation is thought to be responsible for the development of CGD not only in neutrophils but also in monocytic, T-cell, and B-cell lineages and in CD34-positive immature hematopoietic cells. Our case and other reports indicate that the onset of X-linked CGD in female patients tends to occur later in life, and that the symptoms tend to be milder as compared to male patients.

Reemergence of translocation t(11;19)(q23;p13.1) in the absence of clinically overt leukemia.

We report the case of a 10-year-old female with acute myeloid leukemia (AML) FAB M0 carrying a novel t(11;19)(q23;p13.1) MLL-ELL variant, in which intron 8 of MLL is fused to exon 6 of ELL. Complete remission, judged by morphology and cytogenetic analysis, was achieved after the conventional chemotherapy. Eight months after completion of therapy, the level of WT-1 in peripheral blood and the number of cells with the MLL-ELL fusion transcript resurged. However, the patient remained overtly healthy and the morphology in the bone-marrow smear was innocuous, with no sign of relapse or secondary leukemia. Without any evidence of relapse, the patient has been closely observed without any therapeutic intervention. For approximately 2 years after the completion of therapy, despite clonal proliferation of pre-leukemic cells with an MLL-ELL fusion gene, she has maintained complete remission. In this case, the rare variant form of MLL-ELL fusion that has been identified may be related to diminished leukemogenic capacity, resulting in the persistence of pre-leukemic status; an additional genetic abnormality may thus be necessary for full transformation of pre-leukemic cells.

[Leukemia].

Leukemia is derived from hematopoietic stem/progenitor cells that have acquired genetic abnormalities, leading to malignant transformation. The basis of therapyfor leukemia is a combination of anti-cancer drugs based on risk stratification. The overall 5-year survival rate in leukemia patients of all ages is still 40%, although it has improved in pediatric patients. Leuke- mia itself is a heterogeneous disease that includes various entities/subtypes with different pathogenic gene aberrations. Selection of the treatment strategylargelydepends on risk stratification, and this in turn is mainlybased on specific recurrent chromosome aberrations. However, in acute myeloid leukemia(AML), a significant proportion of patients present with a normal karyotype according to conventional cytogenetic analysis and are classified into an intermediate-risk group, which actuallyconsists of various subtypes with different prognoses. In addition, leukemic cells usuallyharbor one or more driver mutations among their various genetic aberrations, and these driver mutations could affect prognosis. The discoveryof additional mutations in genes such as NPM1, CEBPA and FLT3, which are frequent in AML patients with a normal karyotype, have improved the precision of risk stratification in AML. In this regard, array-based gene expression analysis and whole exome/ transcriptome sequencing could be useful tools for identifying the whole spectrum of genetic aberrations, or for compiling a complete list of mutated genes within leukemic cells. Genetic profiling information obtained using these newlydeveloped methods could provide more accurate information for molecular subtyping and risk stratification in leukemia.

Installation of multiple automated external defibrillators to prevent sudden death in school-aged children.

BACKGROUND: Recently, a student died of idiopathic ventricular fibrillation in a school where an automated external defibrillator (AED) had been installed. The tragedy could not be prevented because the only AED in the school was installed in the teachers' office, far from the school ground where the accident took place. This prompted establishment of a multiple AED system in schools. The aim of this study was to analyze the efficacy of the multiple AED system to prevent sudden death in school-aged children. METHODS: Assumed accident sites consisted of the school ground, gymnasium, Judo and Kendo hall, swimming pool, and classrooms on the first and the fourth floor. Multiple AED were installed in the teachers' office, gymnasium, some classrooms, and also provided as a portable AED in a rucksack. The time from the accident site to the teachers' office for single AED, and from the accident site to the nearest AED for multiple AED, was calculated. RESULTS: The AED retrieval time was significantly shorter in 55 elementary schools and in 29 junior high schools when multiple AED were installed compared with single AED. Except for the classroom on the fourth floor, the number of people who took >120 s to bring the AED to the accident site was lower when multiple AED were installed compared with the single AED. CONCLUSION: Multiple AED provided in appropriate sites can reduce the time to reach the casualty and hence prevent sudden death in school-aged children.

[Recent progress in leukemic stem cell research for childhood leukemia].

Leukemic stem cells (LSCs) were originally identified in acute myeloid leukemia (AML) cases by using xenograft models, as a distinct cell population that can initiate leukemia in immunodeficient mice. Since then, many efforts have been made to clarify the identities of LSCs and other cancer stem cells in various cancer types, to both understand their biology and determine the most suitable targets for anti-cancer therapies. LSCs were identified as existing in the immature CD34+CD38- leukemic population in most AML cases, and these cells were found to share some features with normal hematopoietic stem cells. On the other hand, recent studies have shown that in childhood acute lymphoblastic leukemia (ALL), LSCs exist among B-lineage-committed progenitors expressing CD19. In contrast to AML, in which LSCs generate leukemic cells in a hierarchical order with LSCs at the top, leukemia propagation in childhood ALL is better explained by a stochastic model. In B-precursor ALL, LSCs form via acquisition of additional genetic change(s) in CD19+ B-lineage progenitor cells with self-renewing capacity. These LSCs possess a growth advantage and the capacity to produce progeny with the same ability as the LSCs. Identification of genetic and cellular targets in leukemic transformation is necessary to develop improved anti-cancer therapies.

HMGA2 as a potential molecular target in KMT2A-AFF1-positive infant acute lymphoblastic leukaemia.

Acute lymphoblastic leukaemia (ALL) in infants is an intractable cancer in childhood. Although recent intensive chemotherapy progress has considerably improved ALL treatment outcome, disease cure is often accompanied by undesirable long-term side effects, and efficient, less toxic molecular targeting therapies have been anticipated. In infant ALL cells with KMT2A (MLL) fusion, the microRNA let-7b (MIRLET7B) is significantly downregulated by DNA hypermethylation of its promoter region. We show here that the expression of HMGA2, one of the oncogenes repressed by MIRLET7B, is reversely upregulated in infant ALL leukaemic cells, particularly in KMT2A-AFF1 (MLL-AF4) positive ALL. In addition to the suppression of MIRLET7B, KMT2A fusion proteins positively regulate the expression of HMGA2. HMGA2 is one of the negative regulators of CDKN2A gene, which encodes the cyclin-dependent kinase inhibitor p16(INK4A) . The HMGA2 inhibitor netropsin, when combined with demethylating agent 5-azacytidine, upregulated and sustained the expression of CDKN2A, which resulted in growth suppression of KMT2A-AFF1-expressing cell lines. This effect was more apparent compared to treatment with 5-azacytidine alone. These results indicate that the MIRLET7B-HMGA2-CDKN2A axis plays an important role in cell proliferation of leukaemic cells and could be a possible molecular target for the therapy of infant ALL with KMT2A-AFF1.

DGCR6 at the proximal part of the DiGeorge critical region is involved in conotruncal heart defects.

Cardiac anomaly is one of the hallmarks of DiGeorge syndrome (DGS), observed in approximately 80% of patients. It often shows a characteristic morphology, termed as conotruncal heart defects. In many cases showing only the conotruncal heart defect, deletion of 22q11.2 region cannot be detected by fluorescence in situ hybridization (FISH), which is used to detect deletion in DGS. We investigated the presence of genomic aberrations in six patients with congenital conotruncal heart defects, who show no deletion at 22q11.2 in an initial screening by FISH. In these patients, no abnormalities were identified in the coding region of the TBX1 gene, one of the key genes responsible for the phenotype of DGS. However, when copy number alteration was analyzed by high-resolution array analysis, a small deletion or duplication in the proximal end of DiGeorge critical region was detected in two patients. The affected region contains the DGCR6 and PRODH genes. DGCR6 has been reported to affect the expression of the TBX1 gene. Our results suggest that altered dosage of gene(s) other than TBX1, possibly DGCR6, may also be responsible for the development of conotruncal heart defects observed in patients with DGS and, in particular, in those with stand-alone conotruncal heart defects.

Identification of CD34+ and CD34- leukemia-initiating cells in MLL-rearranged human acute lymphoblastic leukemia.

Translocation of the mixed-lineage leukemia (MLL) gene with AF4, AF9, or ENL results in acute leukemia with both lymphoid and myeloid involvement. We characterized leukemia-initiating cells (LICs) in primary infant MLL-rearranged leukemia using a xenotransplantation model. In MLL-AF4 patients, CD34(+)CD38(+)CD19(+) and CD34(-)CD19(+) cells initiated leukemia, and in MLL-AF9 patients, CD34(-)CD19(+) cells were LICs. In MLL-ENL patients, either CD34(+) or CD34(-) cells were LICs, depending on the pattern of CD34 expression. In contrast, in patients with these MLL translocations, CD34(+)CD38(-)CD19(-)CD33(-) cells were enriched for normal hematopoietic stem cells (HSCs) with in vivo long-term multilineage hematopoietic repopulation capacity. Although LICs developed leukemic cells with clonal immunoglobulin heavy-chain (IGH) rearrangement in vivo, CD34(+)CD38(-)CD19(-)CD33(-) cells repopulated recipient bone marrow and spleen with B cells, showing broad polyclonal IGH rearrangement and recipient thymus with CD4(+) single positive (SP), CD8(+) SP, and CD4(+)CD8(+) double-positive (DP) T cells. Global gene expression profiling revealed that CD9, CD32, and CD24 were over-represented in MLL-AF4, MLL-AF9, and MLL-ENL LICs compared with normal HSCs. In patient samples, these molecules were expressed in CD34(+)CD38(+) and CD34(-) LICs but not in CD34(+)CD38(-)CD19(-)CD33(-) HSCs. Identification of LICs and LIC-specific molecules in primary human MLL-rearranged acute lymphoblastic leukemia may lead to improved therapeutic strategies for MLL-rearranged leukemia.

Lineage-dependent skewing of loss of heterozygosity (LOH) of KRAS gene in a case of juvenile myelomonocytic leukemia.

Juvenile myelomonocytic leukemia (JMML) is a clonal disease arising from abnormal hematopoietic stem cells, although the involvement of lymphoid lineage differs among reported cases. Here, we present a case of JMML with a KRAS G13D mutation. The mutation was detected in various hematopoietic lineages, including T and B lymphocytes and also in lineage(-) CD34(+) CD38(-) hematopoietic stem cells, showing a different percentage of affected cells in each lineage. Single cell-based analysis of hematopoietic cells revealed the loss of wild-type KRAS in a significant proportion of G13D-harboring cells. The percentage of loss of heterozygosity (LOH)/non-LOH cells showed lineage-dependent skewing in hematopoietic cells. The loss of the wild-type KRAS allele may be a common secondary genetic change in KRAS-related JMML and may affect the differentiation behavior of early JMML progenitors.