Plasma-derived factor VIIa and factor X mixture agent (MC710) prophylaxis in haemophilia B patients with inhibitors.

INTRODUCTION: Haemophilia B patients with factor IX inhibitors have particularly unmet needs for conventional therapy. AIM: Phase II/III clinical trial, multicentre, open-label, prospective, self-controlled study was conducted to assess MC710 prophylaxis in haemophilia B patients with inhibitors. METHODS: We enrolled haemophilia patients who had received episodic or prophylactic treatment with bypassing agents up to that time. The participants continued their conventional therapy for 24 weeks and then MC710 was prophylactically infused intravenously every 2 or 3 days at 60 to 120 µg as FVIIa per kilogram of body weight for 24 weeks. The primary endpoint was the annual bleeding rate (ABR) requiring bypassing agents, which was compared intraindividually between the conventional therapy period and the MC710 prophylaxis period. RESULTS: A total of 11 male haemophilia B patients were enrolled. The median ABR ratio for each participant (the prophylaxis period ABR divided by the conventional therapy period ABR) was .33 (2.1/6.5), range from .00 to 3.77. ABR ratios for 9 of the 11 patients ranged from .00 to .60, and 3 of the 9 patients had zero bleeding events during the prophylaxis period. Meanwhile, ABR ratios for the remaining two patients were 2.53 and 3.77, respectively. Although a fibrinogen decrease recovered by the dose reduction was reported for only one participant as the sole adverse drug reaction in this study, no thrombotic events or other safety concerns were reported. CONCLUSION: MC710 prophylaxis is considered to be decrease the bleeding rate in haemophilia B patients with inhibitors without safety concerns.

Impact of immunophenotypic characteristics on genetic subgrouping in childhood acute lymphoblastic leukemia: Tokyo Children's Cancer Study Group (TCCSG) study L04-16.

Immunophenotyping was performed in 1044 consecutive childhood acute lymphoblastic leukemia (ALL) patients enrolled in the Tokyo Children's Cancer Study Group L04-16 trial, revealing novel findings associated with genetic abnormalities. In addition to TCF3-PBX1 and MEF2D fusions, the CD10(+) subtype of KMT2A-MLLT3-positive ALL frequently exhibited the cytoplasmic-µ(+) pre-B ALL immunophenotype. Although ETV6-RUNX1 was significantly correlated with myeloid antigen expression, more than half of patients expressed neither CD33 nor CD13, while the CD27(+) /CD44(-) immunophenotype was maintained. Expression of CD117 and CD56 in B-cell precursor-ALL was limited to certain subtypes including ETV6-RUNX1 and KMT2A-MLLT3. Besides BCR-ABL1, CRLF2, hyperdiploidy, and hypodiploidy, CD66c was also expressed in Ph-like kinase fusion-, PAX5 fusion-, and DUX4 fusion-positive ALL, but not in MEF2D fusion-positive ALL, indicating constant selectivity of CD66c expression. In T-ALL, SIL-TAL1-positive patients were likely to exhibit a more mature immunophenotype. Expression of CD21 and CD10 was not rare in T-ALL, while lack of CD28 was an additional feature of early T-cell precursor-ALL. Considering the immunophenotype as a prognostic maker, MEF2D fusion-positive ALL with CD5 expression may be associated with a poorer prognosis in comparison with those lacking CD5 expression. In cases with characteristic marker expression, the presence of certain fusion transcripts could be predicted accurately.

X-linked agammaglobulinemia associated with B-precursor acute lymphoblastic leukemia.

X-linked agammaglobulinemia (XLA) is clinically characterized by reduced number of peripheral B cells and diminished levels of serum immunoglobulins, and caused by a mutation in the Bruton's tyrosine kinase (BTK) gene, which play a pivotal role in signal transduction of pre-B-cell receptor (BCR) and BCR. B-cell precursor acute lymphoblastic leukemia (BCP-ALL) is the most common malignancy in children, and it may be associated with gene alterations that regulate B-cell development. Here we described a first case of XLA associated BCP-ALL. The whole-exome sequencing revealed a somatic mutation in MLL2 in the sample from the onset of BCP-ALL. This study suggests that the alterations of BTK and MLL2 synergistically function as leukemogenesis.

Biotin-responsive basal ganglia disease: a case diagnosed by whole exome sequencing.

Using whole exome sequencing, we confirmed a diagnosis of biotin-responsive basal ganglia disease (BBGD) accompanied by possible Kawasaki Disease. BBGD is an autosomal-recessive disease arising from a mutation of the SLC19A3 gene encoding the human thiamine transporter 2 protein, and usually manifests as subacute to acute encephalopathy. In this case, compound heterozygous mutations of SLC19A3, including a de novo mutation in one allele, was the cause of disease. Although a large number of genetic neural diseases have no efficient therapy, there are several treatable genetic diseases, including BBGD. However, to achieve better outcome and accurate diagnosis, therapeutic analysis and examination for disease confirmation should be done simultaneously. We encountered a case of possible Kawasaki disease, which had progressed to BBGD caused by an extremely rare genetic condition. Although the prevalence of BBGD is low, early recognition of this disease is important because effective improvement can be achieved by early biotin and thiamine supplementation.

Meralgia Paresthetica as a Presentation of Acute Appendicitis in a Girl With Acute Lymphoblastic Leukemia.

A 7-year-old girl with Philadelphia chromosome-positive acute lymphoblastic leukemia developed recurrent fever and meralgia paresthetica (MP) during chemotherapy, which resolved after administration of antibiotics. Five months after the onset of these symptoms, enhanced computed tomography showed a periappendiceal abscess extending into the psoas muscle. The cause of her fever and MP was thought to be appendicitis, which probably developed during induction chemotherapy but did not result in typical abdominal pain. Patients with recurrent fever and MP should be evaluated by imaging examinations including computed tomography to search for appendicitis.

Paroxysmal sympathetic hyperactivity and the later development of epilepsy in a chemotherapy-associated brain damage.

BACKGROUND: Chemotherapy in childhood leukemia potentially induces brain lesions and neurological sequelae. Paroxysmal sympathetic hyperactivity (PSH) is known as a treatment-associated complication; however, the full clinical spectra of PSH remain to be elusive. CASE REPORT: A 5-year-old girl was diagnosed of acute myeloid leukemia (AML) M5. After the intensification therapy, she developed recurrent symptoms of episodic tachycardia, hypertension and perspiration lasting for several hours per day. The low-frequency-high-frequency ratio on Holter electrocardiography was rapidly increased from 0.84 to 2.24 at the onset of the paroxysmal event, whereas the video-monitoring electroencephalography (EEG) never identified ictal patterns of epileptiform discharges during the episodes. Thus, the diagnosis of PSH was given at 7 years of age. Myoclonic and generalized tonic-clonic seizures frequently appeared from 10 years of age, which poorly responded to anticonvulsants. EEG showed diffuse slow-wave bursts with multifocal spikes. Serial head magnetic resonance imaging (MRI) revealed diffuse cerebral and hippocampal atrophy, but not inflammatory lesions in the limbic system. CONCLUSION: We first demonstrate a pediatric case with PSH who developed drug-resistant epilepsy 3 years after the onset of PSH. Our data suggest the pathophysiological link of persistent PSH with chemotherapy-associated brain damage.

Efficacy and safety of intravenous thiamylal in pediatric procedural sedation for magnetic resonance imaging.

OBJECTIVE: To evaluate the efficacy and safety of intravenous (i.v.) thiamylal in pediatric magnetic resonance imaging (MRI) sedation. METHODS: Infants and children from 1 month up to 8 years of age who underwent MRI in our hospital between April 2017 and March 2019 were included in this prospective observational study. Initial dose of 2 mg/kg thiamylal was given intravenously; however, additional doses were administered as needed. MRI was performed after adequate sedation was achieved. The primary endpoint was the success rate of MRI, while secondary endpoints were adverse events related to sedation, time to sedate, recovery time, and the dose of thiamylal. RESULTS: A total of 118 patients were included in the analysis with median age and weight of 31.5 months (14.0-56.8 months) and 12.6 kg (9.5-15.7 kg), respectively. The success rate of MRI was 96.6% (114/118), and the median dose of thiamylal per body weight was 3.6 (2.8-4.0) mg/kg. The median time from the first dose of thiamylal to MRI was 7 min (4-10 min) and that from the end of MRI scanning to the confirmation of emergence was 8 min (5-25 min). Adverse events encountered included respiratory arrests (n = 3) and reduction in oxygen saturation (SpO2; n = 9). There were no significant differences in the age, dose of thiamylal, sex, body weight, the American Society of Anesthesiologists physical status, and neurological abnormalities between the groups with and without respiratory complications. CONCLUSION: This study demonstrated an adequate efficacy and safety of i.v. thiamylal, with rapid sedation and patient recovery.

Hepatoblastoma with multiple tumors in a school-aged child.

Clinicians need to consider hepatoblastoma in the differential even in school-aged children or adolescents presenting with multiple liver tumors.

Functional analysis of JAK3 mutations in transient myeloproliferative disorder and acute megakaryoblastic leukaemia accompanying Down syndrome.

JAK3 mutations have been reported in transient myeloproliferative disorder (TMD) as well as in acute megakaryoblastic leukaemia of Down syndrome (DS-AMKL). However, functional consequences of the JAK3 mutations in TMD patients remain undetermined. To further understand how JAK3 mutations are involved in the development and/or progression of leukaemia in Down syndrome, additional TMD patients and the DS-AMKL cell line MGS were screened for JAK3 mutations, and we examined whether each JAK3 mutation is an activating mutation. JAK3 mutations were not detected in 10 TMD samples that had not previously been studied. Together with our previous report we detected JAK3 mutations in one in 11 TMD patients. Furthermore, this study showed for the first time that a TMD patient-derived JAK3 mutation (JAK3(I87T)), as well as two novel JAK3 mutations (JAK3(Q501H) and JAK3(R657Q)) identified in an MGS cell line, were activating mutations. Treatment of MGS cells and Ba/F3 cells expressing the JAK3 mutants with JAK3 inhibitors significantly decreased their growth and viability. These results suggest that the JAK3 activating mutation is an early event during leukaemogenesis in Down syndrome, and they provide proof-of-principle evidence that JAK3 inhibitors would have therapeutic effects on TMD and DS-AMKL patients carrying activating JAK3 mutations.

Characterization of a patient with atypical amegakaryocytic thrombocytopenia.

We report a 6-year-old girl with amegakaryocytic thrombocytopenia, the first case of this rare congenital disorder not to have an MPL gene mutation. Although no mutations were identified in MPL, Mpl protein was absent in the platelets and TPO induced phosphorylation of the Janus tyrosine kinase 2 (Jak2) was not detected. In addition to the defect of Mpl, the patient demonstrated markedly reduced expression of glycoprotein VI (GPVI) in contrast to normal expression of other platelet-specific proteins GPIb alpha, GPIb beta, and GPIIb. To explore the causes for the absence of Mpl, the entire coding region of Jak2 and AML1 were sequenced and no mutations were identified. To our knowledge, this is the first report that describes a case of amegakaryocytic thrombocytopenia that is not caused by a mutation in MPL and demonstrates the severe impairment of GPVI expression on platelets.

Recurrent RARB Translocations in Acute Promyelocytic Leukemia Lacking RARA Translocation.

Translocations of retinoic acid receptor-α (RARA), typically PML-RARA, are a genetic hallmark of acute promyelocytic leukemia (APL). However, because a small fraction of APL lack translocations of RARA, we focused here on APL cases without RARA translocation to elucidate the molecular etiology of RARA-negative APL. We performed whole-genome sequencing, PCR, and FISH for five APL cases without RARA translocations. Four of five RARA-negative APL cases had translocations involving retinoic acid receptor-ß (RARB) translocations, and TBL1XR1-RARB was identified as an in-frame fusion in three cases; one case had an RARB rearrangement detected by FISH, although the partner gene could not be identified. When transduced in cell lines, TBL1XR1-RARB homodimerized and diminished transcriptional activity for the retinoic acid receptor pathway in a dominant-negative manner. TBL1XR1-RARB enhanced the replating capacity of mouse bone marrow cells and inhibited myeloid maturation of human cord blood cells as PML-RARA did. However, the response of APL with RARB translocation to retinoids was attenuated compared with that of PML-RARA, an observation in line with the clinical resistance of RARB-positive APL to ATRA. Our results demonstrate that the majority of RARA-negative APL have RARB translocations, thereby forming a novel, distinct subgroup of APL. TBL1XR1-RARB as an oncogenic protein exerts effects similar to those of PML-RARA, underpinning the importance of retinoic acid pathway alterations in the pathogenesis of APL.Significance: These findings report a novel and distinct genetic subtype of acute promyelocytic leukemia (APL) by illustrating that the majority of APL without RARA translocations harbor RARB translocations. Cancer Res; 78(16); 4452-8. ©2018 AACR.