[Discontinuation of tyrosine kinase inhibitors before epiphyseal closure leading to improved short stature in pediatric chronic myelogenous leukemia].

A 3-year-old boy was referred to our hospital with splenomegaly. Blood tests revealed hyperleukocytosis and bone marrow examination showed major BCR::ABL1 fusion, leading to the diagnosis of chronic myelogenous leukemia (CML). Due to intolerance, the tyrosine kinase inhibitor (TKI) was changed from imatinib to dasatinib to nilotinib. The patient achieved molecular remission but became markedly short in stature, measuring 129.3 cm (height standard deviation score [SDS] -3.3) at the age of 12. TKI therapy was discontinued at age 12 years and 10 months, which was 9 years and 8 months after the start of TKI and 1 year and 6 months after achievement of MR4.0, as discontinuation before epiphyseal closure would not improve short stature. At 2 years and 6 months after discontinuation, the patient's height improved to 156.1 cm (SDS-2.0) without relapse. Growth suppression by TKIs is a problem in the management of pediatric CML. This case illustrates how improvement in severe short stature can be achieved by discontinuing TKI therapy before epiphyseal closure.

Steroid-induced ocular hypertensive response in pediatric patients with acute lymphoblastic leukemia.

PURPOSE: To report the characteristics of the steroid-induced ocular hypertensive response in pediatric patients with acute lymphoblastic leukemia (ALL) treated with prednisolone (PSL) during induction therapy and with dexamethasone (DEX) during reinduction therapy. STUDY DESIGN: Retrospective. PATIENTS AND METHODS: This study included pediatric patients diagnosed with B-cell precursor ALL and treated with systemic corticosteroids sometime during the period from 2016 to 2018 at Shizuoka Children's Hospital. Data were extracted from the hematology/oncology records related to the type, dose, and duration of systemic corticosteroids as well as to the ophthalmologic examination findings, intraocular pressure (IOP) data, symptoms of high IOP, and antiglaucoma medications obtained during corticosteroid administration. The maximal IOPs of the PSL and DEX groups were compared. RESULTS: Twenty-eight patients (18 boys and 10 girls; mean age 5.5 years) were treated with systemic corticosteroids. Twelve of the 22 courses of PSL and 33 of the 44 courses of DEX were found to be associated with high IOP. The maximal IOP was higher with the use of DEX than with the use of PSL, including in those who received prophylactic therapy (PSL 25.2 mmHg, DEX 33.6 mmHg; P = 0.02). Antiglaucoma medication was given to 21 patients; 6 patients had symptoms of ocular hypertension. The maximal IOPs were 52.8 mmHg and 70.8 mmHg in the PSL and DEX groups, respectively. Both groups of patients reported severe headache. CONCLUSION: Increased IOP was frequently observed during systemic corticosteroid therapy in pediatric patients with ALL. Although most patients were asymptomatic, they occasionally presented with severe systemic symptoms. Regular ophthalmologic examinations should be included in the treatment guidelines for ALL.

Hematopoietic stem cell transplantation for infants with high-risk KMT2A gene-rearranged acute lymphoblastic leukemia.

The role of allogeneic hematopoietic stem cell transplantation (HSCT) for infants with acute lymphoblastic leukemia (ALL) and KMT2A gene rearrangement (KMT2A-r) is controversial in terms of both its efficacy and potential for acute and late toxicities. In Japanese Pediatric Leukemia/Lymphoma Study Group trial MLL-10, by introducing intensive chemotherapy, indication of HSCT was restricted to patients with high-risk (HR) features only (KMT2A-r and either age <180 days or presence of central nervous system leukemia). Of the 56 HR patients, 49 achieved complete remission. Forty-three patients received HSCT in first remission including 38 patients receiving protocol-specified HSCT with conditioning consisting of individualized targeted doses of busulfan, etoposide, and cyclophosphamide. Three-year event-free survival (EFS) of 56.8% (95% confidence interval [CI], 42.4% to 68.8%) and overall survival of 80.2% (95% CI, 67.1% to 88.5%) were accomplished. Univariable analysis showed that Interfant-HR criteria and flow cytometric minimal residual disease (MRD; ≥0.01%), both at the end of induction and at the end of consolidation (EOC), were significantly associated with poorer EFS. In the multivariable analysis, positive MRD at EOC was solely associated with poor EFS (P < .001). Rapid pretransplant MRD clearance and tailored HSCT strategy in the MLL-10 trial resulted in a favorable outcome for infants with HR KMT2A-r ALL. However, considering the high rate of potentially life-threatening toxicities and the risk of late effects, its indication should be further restricted or even eliminated in the future by introducing more effective therapeutic modalities with minimal toxicities. This trial was registered at the University Hospital Medical Information Network Clinical Trials Registry (UMIN-CTR) as #UMIN000004801.

Fatal Progressive Meningoencephalitis Diagnosed in Two Members of a Family With X-Linked Agammaglobulinemia.

Chronic enteroviral meningoencephalitis is a well-known complication in patients with X-linked agammaglobulinemia (XLA). However, progressive neurodegenerative disorders or chronic neuroinflammatory diseases with no causative microorganisms have been recognized as rare central nervous system (CNS) complications in XLA. We herein report a family in which two of three members with XLA had developed progressive meningoencephalitis with an unknown etiology. A 15-month-old male infant presented with left-sided ptosis. Initially, the family denied any family history of inherited diseases, but later disclosed a family history of agammaglobulinemia previously diagnosed in two family members. In the early 1980s, one of the elder brothers of the index patient's mother who had been treated with intramuscular immunoglobulin [or later intravenous immunoglobulin (IVIG)] for agammaglobulinemia deceased at 10 years of age after showing progressive neurological deterioration during the last several years of his life. The index patient was diagnosed with XLA caused by Bruton tyrosine kinase deficiency (654delG; Val219Leufs*9), and chronic meningoencephalitis with an unknown infectious etiology. Magnetic resonance imaging of the brain demonstrated inflammatory changes in the basal ganglia, hypothalamus, midbrain, and pons, with multiple nodular lesions with ring enhancement, which showed impressive amelioration after the initiation of IVIG replacement therapy. Pleocytosis, which was characterized by an increase in CD4-positive and CD8-positive T cells expressing an activation marker and an elevation in inflammatory cytokines in the cerebrospinal fluid, was identified. No microorganism was identified as a cause of CNS complications. He thereafter developed brain infarction at 19 months of age and fatal status epilepticus at 5 years of age, despite regular IVIG with high trough levels and regular intraventricular immunoglobulin administration. The etiology of this rare CNS complication in XLA is currently unknown. Previous studies have suggested a possible association of IVIG, which was clearly denied in our index case because of the demonstration of his neurological disorder at presentation. In the future, extensive and unbiased molecular methods to detect causative microorganisms, as well as to investigate the possible role of autoimmunity are needed to clarify the etiology of CNS complications.

Development and characterisation of NKp44-based chimeric antigen receptors that confer T cells with NK cell-like specificity.

OBJECTIVES: One of the reasons as to why chimeric antigen receptors (CAR)-T cell therapy for malignancies other than CD19- or BCMA-positive tumors has yet to produce remarkable progress is the paucity of targetable antigens. NKp44 is only expressed by activated natural killer cells and detects a variety of transformed cells, while it reportedly does not react with normal tissues. The aim of this study is to develop CAR-T cell that can target multiple types of tumor cells. METHODS: We created a series of novel CAR constructs in first-generation (1G) and second-generation (2G) CAR format with the extracellular immunoglobulin-like domain of NKp44 (NKp44-CAR). RESULTS: Transduction of the best 1G construct into human primary T cells led to specific cytotoxic effects and cytokine secretion upon encountering multiple types of neoplastic cells including AML, T-ALL and childhood solid tumors. Replacement of the extracellular hinge domain of NKp44 with that of CD8α resulted in diminished CAR function. The 1G NKp44-CAR-T cells exhibited significantly better tumor control in long-term co-culture assays compared with activated NK cells, as well as with NK cells transduced with identical NKp44-CAR. T cells transduced with the best 2G-CAR construct with 4-1BB co-stimulatory domain proliferated at significantly higher levels upon single antigen exposure and showed significantly better tumor control compared with the 1G-CAR and 2G-CAR with CD28 co-stimulatory domain. CONCLUSIONS: NKp44-based CAR endows T cells with NK cell-like anti-tumor specificity. The CAR gene created in this study will be useful for the development of novel gene-modified T-cell immunotherapy.

Effects of cryotherapy on high-dose melphalan-induced oral mucositis in pediatric patients undergoing autologous stem cell transplantation.

Cryotherapy is a conventional method for preventing melphalan-induced oral mucositis (OM) in adult patients. We retrospectively examined the clinical benefits of cryotherapy in 41 pediatric patients undergoing autologous stem cell transplantation using a melphalan-etoposide-carboplatin regimen. Twenty-two patients received cryotherapy. The cumulative incidence of grade 3-4 OM was significantly lower in the cryotherapy group (57.1%) than in the noncryotherapy group (89.5%; P = .041). Multivariate analyses identified cryotherapy and the melphalan dose as independent factors for the lower occurrence of OM. The present study demonstrates the clinically significant efficacy of cryotherapy for preventing melphalan-induced OM in pediatric patients.

Personalized pharmacokinetic targeting with busulfan in allogeneic hematopoietic stem cell transplantation in infants with acute lymphoblastic leukemia.

Individual busulfan (BU) dosing based on pharmacokinetic (PK) data is preferable for hematopoietic stem cell transplantation (HSCT) conditioning, but information on BU PK in infants is scarce. We report BU PK data on HSCT conditioning for infants with KMT2A-gene-rearrangement-positive acute lymphoblastic leukemia (MLL-r ALL). Infants showed wide variation in BU PK indices, such as clearance (CL) and volume of distribution (Vd) value, which are distributed more widely among those who received oral, rather than intravenous (IV), BU. Because the steady state concentration (Css) fluctuates readily in infants, dose re-adjustment based on PK at the initial administration was important even if the initial dose was determined by a PK test. HSCT can be performed safely within the Css range of 600-900 ng/mL per dose, although it was difficult to fit within the therapeutic index of BU. The clinical outcome of engraftment, graft-versus-host disease, adverse events, including sinusoidal obstruction syndrome, and survival did not correlate with the BU PK data, which paradoxically suggests that remaining within this Css range helped minimize transplant-related toxicities, while securing engraftment in infants with MLL-r ALL.

Successful treatment of histiocytic sarcoma with cladribine and high-dose cytosine arabinoside in a child.

Histiocytic sarcoma, a rare hematopoietic neoplasm with evidence of histiocytic differentiation, is often refractory to conventional chemotherapy and radiotherapy, and its prognosis is generally dismal. The optimal management of this malignancy has not been established. We report a case of 8-year-old girl with histiocytic sarcoma involving the left femur. The tumor rapidly responded to a combination of cladribine and high-dose cytosine arabinoside, an aggressive salvage regimen for refractory Langerhans cell histiocytosis, and became impalpable during the first cycle. The patient has remained in complete remission more than 7 years from diagnosis.

Human T-cell leukemia virus type 1 (HTLV-1) Tax1 oncoprotein but not HTLV-2 Tax2 induces the expression of OX40 ligand by interacting with p52/p100 and RelB.

Human T-cell leukemia virus type 1 (HTLV-1) is a causative retrovirus of adult T-cell leukemia and HTLV-1-associated myelopathy. Unlike HTLV-1, the same group of retrovirus HTLV-2 has not been found to be associated with these diseases. HTLV-1 and HTLV-2 encode transforming proteins Tax1 and Tax2, and a few distinct activities of Tax1 from those of Tax2 have been proposed to contribute to the HTLV-1-specific pathogenesis of disease. One significant difference of Tax1 from Tax2 is the activation of transcription factor NF-κB2/p100/p52. We found that Tax1 but not Tax2 induces the expression of OX40 ligand (OX40L) in a human T-cell line. To induce the OX40L expression, Tax1 but not Tax2 was observed to interact with NF-κB2/p100/p52 and RelB and the distinct interaction activity was mediated by the Tax1 amino acid region of 225-232. In addition, Tax1 but not Tax2 or Tax1/225-232 interacted with p65, p50, and c-Rel; however, the interactions were much less than those noted with NF-κB2/p100/p52 and RelB. OX40L is a T-cell costimulatory molecule of the tumor necrosis factor family, and its signal plays a critical role in establishing adaptive immunity by inducing the polarized differentiation of T-cells to cells such as T helper type 2 and T follicular helper cells. Therefore, the present findings suggest that Tax1 might alter the immune response to HTLV-1 and/or differentiation of HTLV-1-infected T-cells via OX40L induction, thereby acting as a factor mediating the distinct phenotypes and pathogenesis of HTLV-1 from that of HTLV-2.

Human T-cell leukemia virus type 1 Tax oncoprotein represses the expression of the BCL11B tumor suppressor in T-cells.

Human T-cell leukemia virus type 1 (HTLV-1) is the etiological agent of adult T cell leukemia (ATL), which is an aggressive form of T-cell malignancy. HTLV-1 oncoproteins, Tax and HBZ, play crucial roles in the immortalization of T-cells and/or leukemogenesis by dysregulating the cellular functions in the host. Recent studies show that HTLV-1-infected T-cells have reduced expression of the BCL11B tumor suppressor protein. In the present study, we explored whether Tax and/or HBZ play a role in downregulating BCL11B in HTLV-1-infected T-cells. Lentiviral transduction of Tax in a human T-cell line repressed the expression of BCL11B at both the protein and mRNA levels, whereas the transduction of HBZ had little effect on the expression. Tax mutants with a decreased activity for the NF-κB, CREB or PDZ protein pathways still showed a reduced expression of the BCL11B protein, thereby implicating a different function of Tax in BCL11B downregulation. In addition, the HTLV-2 Tax2 protein reduced the BCL11B protein expression in T-cells. Seven HTLV-1-infected T-cell lines, including three ATL-derived cell lines, showed reduced BCL11B mRNA and protein expression relative to an uninfected T-cell line, and the greatest reductions were in the cells expressing Tax. Collectively, these results indicate that Tax is responsible for suppressing BCL11B protein expression in HTLV-1-infected T-cells; Tax-mediated repression of BCL11B is another mechanism that Tax uses to promote oncogenesis of HTLV-1-infected T-cells.

Alveolar rhabdomyosarcoma after treatment of osteosarcoma.

Secondary rhabdomyosarcoma (RMS) after treatment of osteosarcoma (OS) is rare. Reported here is the case of a metachronous RMS in the nasal cavity, developing 12 years after successful treatment of non-metastatic OS. The patient was diagnosed as having OS of the femur at 2 years of age. Chemotherapy for OS included doxorubicin (cumulative dose, 488 mg/m(2) ). No radiotherapy was given. There was no family history suggestive of cancer predisposition syndrome. At 14 years of age, alveolar RMS was diagnosed on histopathology. PAX3-FKHR fusion transcripts were detected on reverse transcription-polymerase chain reaction. Germline TP53 mutation was not seen on standard DNA sequencing. The occurrence of secondary sarcomas, in the Children's Cancer Survivor study conducted in North America, has been associated with high cumulative doses of anthracyclines, which may also have played a role in the development of RMS in the present case. In the future, novel molecular technologies might uncover genetic cancer predisposition in patients with metachronous cancers.

Refractory infantile spasms associated with mosaic variegated aneuploidy syndrome.

BACKGROUND: Mosaic variegated aneuploidy syndrome (Online Mendelian Inheritance in Man 257300), or premature chromatid separation syndrome, is a rare cancer-prone disorder associated with an autosomal recessive trait related to BUB1B gene mutations. The risk of malignancy is high, with rhabdomyosarcoma, Wilms tumor, and leukemia reported in several cases. Clinical features also include prenatal-onset growth retardation, microcephaly, mild dysmorphism, feeding difficulty, hypotonia, seizures, and developmental delay. PATIENT: A boy patient exhibited severe developmental delay, microcephaly, hypotonia, intractable seizures including infantile spasms with hypsarrhythmia at 6 months old, and Dandy-Walker malformation on magnetic resonance imaging. Seizures were refractory to conventional antiepileptics and treatment with adrenocorticotropic hormone. Wilms tumor and an unidentified intraorbital tumor also developed at 22 months old. RESULTS: Chromosomal analysis showed multiple aneuploid cells, and premature chromatid separation was found in all chromosomes in 59.5% of 119 cells, indicating mosaic variegated aneuploidy syndrome. CONCLUSIONS: The present case report demonstrates that mosaic variegated aneuploidy syndrome can be associated with developmental brain anomalies that lead to early-onset epileptic encephalopathy. Awareness of this disorder is important not only for proper diagnosis but also for genetic counseling of the family.

Disseminated BCG infection mimicking metastatic nasopharyngeal carcinoma in an immunodeficient child with a novel hypomorphic NEMO mutation.

BACKGROUND: Nuclear factor-κB essential modulator (NEMO) deficiency is a developmental and immunological disorder. The genetic and phenotypic correlation has been described. METHODS: We report a unique clinical presentation and the identification of a novel missense mutation in the NEMO gene in a 3-year-old boy with bacillus Calmette-Guerin (BCG) infection. RESULTS: The patient presented with fever, cervical lymphadenopathy, and abnormal anti-Epstein-Barr virus (EBV) antibody titers, suggestive of EBV-related diseases including chronic active EBV infection, X-linked lymphoproliferative syndrome, or nasopharyngeal carcinoma. Although the biopsy specimen from a nasopharyngeal lesion was initially diagnosed as squamous cell carcinoma, this was changed to disseminated BCG infection involving the nasopharynx, multiple systemic lymph nodes, and brain. A novel mutation (designated D311E) in the NEMO gene, located in the NEMO ubiquitin-binding (NUB) domain, was identified as the underlying cause of the immunodeficiency. Impaired immune responses which are characteristic of patients with NEMO deficiency were demonstrated. The patient underwent successful unrelated bone marrow transplantation at 4.9 years of age. CONCLUSION: This study suggests the importance of the NUB domain in host defense against mycobacteria. The unique presenting features in our patient indicate that a hypomorphic NEMO mutation can be associated with atypical pathological findings of the epithelial tissues in patients with BCG infection.

Reactive tonsillar enlargement with strong 18F-FDG uptake after chemotherapy for tonsillar diffuse large B-cell lymphoma.

We describe a 14-year-old boy who exhibited left palatine tonsillar enlargement after 6 cycles of aggressive chemotherapy for diffuse large B-cell lymphoma of the right palatine tonsil. The cervical computed tomography scan at 4 months after completion of chemotherapy revealed enlargement of the left palatine tonsil in addition to the thymus without any clinical symptoms. The F-fluorodeoxyglucose positron emission tomography indicated focal areas of strong F-fluorodeoxyglucose uptake in the left palatine tonsil. Histologic examination confirmed tonsillar hyperplasia with no evidence of recurrence. Reactive tonsillar hyperplasia after chemotherapy is rarely reported.