Kazuko Kudo

Chemotherapy with cytarabine, vincristine (VCR), and prednisolone has achieved low mortality rates in pediatric patients with Langerhans cell histiocytosis (LCH). However, relapse rates remain high, making event-free survival (EFS) rates unsatisfactory. A nationwide clinical trial, LCH-12, tested a modified protocol in which the early maintenance phase was intensified with increasing dosages of VCR. Patients newly diagnosed with multifocal bone (MFB) or multisystem (MS) LCH and aged < 20 years at diagnosis were enrolled between June 2012 and November 2017. Of the 150 eligible patients, 43 with MFB were treated for 30 weeks and 107 with MS LCH were treated for 54 weeks. One patient with MS LCH died of sepsis during the induction phase. The 3-year EFS rates among patients with MFB LCH, risk organ (RO)-negative MS LCH, and RO-positive MS LCH were 66.7% (95% confidential interval [CI], 56.5-77.0%), 66.1% (95% CI 52.9-76.4%), and 51.1% (95% CI 35.8-64.5%), respectively, similar to previously observed rates. EFS rates were significantly lower in patients with disease activity scores > 6 than in those with scores ≤ 6. The strategy that included more intense treatment with VCR was not effective. Other strategies are required to improve outcomes in patients with pediatric LCH.

Central nervous system (CNS) involvement in anaplastic large cell lymphoma (ALCL) at diagnosis is rare and leads to poor prognosis with the use of the standard ALCL99 protocol alone. CNS-directed intensive chemotherapy, such as an increased dose of intravenous MTX, increased dose of dexamethasone, intensified intrathecal therapy, and high-dose cytarabine, followed by cranial irradiation, has been shown to improve survival in this population. In this paper, the authors describe a 14-year-old male with an intracranial ALCL mass at onset who received CNS-directed chemotherapy followed by 23.4 Gy of whole-brain irradiation. After the first systemic relapse, the CNS-penetrating ALK inhibitor, alectinib, was applied; it has successfully maintained remission for 18 months without any adverse events. CNS-penetrating ALK inhibitor therapy might prevent CNS relapse in pediatric ALK-positive ALCL. Next-generation ALK inhibitors could be introduced as a promising treatment option, even for primary ALCL with CNS involvement, which could lead to the omission of cranial irradiation and avoid radiation-induced sequalae. Further evidence of CNS-penetrating ALK inhibitor combined therapy for primary ALK-positive ALCL is warranted to reduce radiation-induced sequalae in future treatments.

Eczema herpeticum (EH) is a disseminated cutaneous infection with herpes simplex virus (HSV) that develops in patients with atopic dermatitis. The kinetics and clinical significance of HSV viremia in EH are poorly understood. Herein, we report HSV DNAemia in a child with EH 12 months after the completion of chemotherapy for Hodgkin lymphoma.

Langerhans cell histiocytosis (LCH) is characterized by immature dendritic cell proliferation, which is currently classified as an inflammatory myeloid neoplasm. Clinical features and outcomes vary from spontaneously regressing isolated bone disease to fatal liver, spleen, or hematopoietic system (risk organ) involvement-positive multisystem disease. LCH cells have the only mutation in the mitogen-activated protein kinase (MAPK) signaling pathway gene, represented by the BRAF V600E mutation, which is the driver mutation. The type of disease depends on the stage of hematopoietic cell differentiation at which the mutation occurs. LCH cells acquire anti-apoptosis and senescence-associated secretory phenotype by oncogene-induced senescence, with migration failure to lymph nodes. These cause LCH cell accumulation and various inflammatory cell recruitment in the lesion, resulting in severe inflammation. Tissue damage in LCH is due to this inflammation, not the LCH cell proliferation. Patients with a risk of organ involvement without the initial treatment response may be rescued by allogeneic hematopoietic stem cell transplantation after reducing the disease activity with MAPK inhibitors. Intravenous zoledronic acid and intrathecal cytarabine injections have been introduced into the ongoing clinical trial in Japan to reduce bone recurrence and prevent neurodegeneration as sequelae.

We previously reported that risk-stratified therapy and intensive postremission chemotherapy (PRC) contributed to the improved survival of childhood acute myeloid leukemia (AML) in the AML99 study, which led us to consider a reduction in the number of PRC courses with more restrictive indications for stem cell transplantation (SCT) in the successor AML-05 study. We here report the outcome of AML patients without core-binding factor mutation (non-CBF AML) in the AML-05 study. Two-hundred eighty-nine children (age < 18 years old) with non-CBF AML were eligible. Patients with unfavorable cytogenetics and/or poor bone marrow response to the first induction course were candidates for SCT in the AML-05 study. After two courses of induction, a further three courses of PRC were given in AML-05, while four courses were given in the AML99 study. The 3-year event-free survival (EFS) rate in the AML-05 study (46.7%, 95% CI: 40.6-52.6%) was comparable to that of non-CBF AML in the AML99 study (51.5%, 95% CI: 42.7-59.6%) (P = .16). However, the 3-year overall survival (OS) rate in the AML-05 study (62.9%, 95% CI: 56.3-68.8%) was slightly lower than that in the AML99 study (71.6%, 95% CI: 63.2-78.5%) (P = .060), mainly due to decreased remission induction rate and increased nonrelapsed mortality. In conclusion, reductions in the number of PRC courses from four to three, together with repetitive cycles of high-dose cytarabine, were acceptable for non-CBF childhood AML.

BACKGROUND: Aggressive systemic mastocytosis (ASM) is a rare malignant disease characterized by disordered mast cell accumulation in various organs. We here describe a female ASM patient with a previous history of ovarian dysgerminoma. METHODS: Molecular cytogenomic analyses were performed to elucidate an etiological link between the ASM and dysgerminoma of the patient. RESULTS: This patient was affected by ovarian dysgerminoma which was treated by chemotherapy and surgical resection. Having subsequently been in complete remission for 2 years, she developed symptoms of ASM. A somatic D816A mutation in the KIT gene was detected in her bone marrow, which facilitated the diagnosis of ASM. Unexpectedly, this KIT D816A variant was also detected in the prior ovarian dysgerminoma sample. Whole-exome sequencing allowed us to identify a somatic nonsense mutation of the TP53 gene in the bone marrow, but not in the dysgerminoma. Microarray analysis of the patient's bone marrow revealed a copy-number-neutral loss of heterozygosity at the TP53 locus, suggestive of the homozygous nonsense mutation in the TP53 gene. In addition, the loss of heterozygosity at the TP53 locus was also detected in the dysgerminoma. CONCLUSIONS: These results indicated that either the mast cells causing the ASM in this case had originated from the preceding ovarian dysgerminoma as a clonal evolution of a residual tumor cell, which acquired the TP53 mutation, or that both tumors developed from a common cancer stem cell carrying the KIT D816A variation.

Varicella-zoster virus (VZV) reactivation from the enteric nervous system can cause ileus (Ogilvie's syndrome) in adult patients. Since no pediatric cases have been described, we sought to retrospectively analyze VZV reactivation in pediatric hematology-oncology patients to determine whether VZV infection including subclinical VZV reactivation can induce gastrointestinal complications such as Ogilvie's syndrome. Thirty-five patients who received chemotherapy at our institution between September 2013 and June 2018 were included. Serum samples were collected weekly during hospitalization and every 3 months during outpatient maintenance chemotherapy. A real-time polymerase chain reaction assay was used to measure VZV DNA load in serum. The clinical features of patients with VZV infection were retrospectively analyzed. Of 1165 serum samples, 7 (0.6%) were positive for VZV DNA. VZV DNA was detected in 3 of 35 patients. In patient A, VZV DNA was detected during two episodes. The first episode involved varicella-like eruptions caused by the Oka VZV vaccine strain. The second episode involved herpes zoster (HZ) caused by the same strain. Patients B and C had a clinical course that was typical for HZ caused by wild-type VZV. No gastrointestinal symptoms were observed at the time of VZV infection in these three patients. VZV DNA was not detected in any other samples. No pediatric cases with Ogilvie's syndrome caused by VZV reactivation were demonstrated in this cohort. Additionally, no subclinical VZV reactivation was found in this cohort. Further study is needed to elucidate the precise incidence of pediatric Ogilvie's syndrome caused by VZV reactivation.

Fludarabine/cyclophosphamide-based conditioning regimens are standard in bone marrow transplantation (BMT) for acquired bone marrow failure in children, however, graft failure may occur. Using the data from a nationwide transplantation registry, we compared the outcomes of children aged <16 years with acquired aplastic anemia and refractory cytopenia of childhood who underwent allogeneic BMT with either fludarabine/melphalan (n = 71) or fludarabine/cyclophosphamide (n = 296) between 2000 and 2016. The fludarabine/melphalan regimen provided excellent outcomes, with 3-year overall survival and failure-free survival rates of 98% and 97%, respectively. The 83% 3-year failure-free survival in the fludarabine/cyclophosphamide group was significantly inferior (P = 0.002), whereas the overall survival did not differ between the two groups. Late graft failure was the most common cause of treatment failure in the fludarabine/cyclophosphamide group, which experienced a significantly higher incidence of late graft failure than the fludarabine/melphalan group (11% vs. 3%; P = 0.035). Multivariate analyses showed that the fludarabine/melphalan regimen was associated with a better failure-free survival (hazard ratio [HR] 0.12; P = 0.005) and lower risk of late graft failure (HR 0.16; P = 0.037). Fludarabine/melphalan-based conditioning regimen can be a promising option for children with acquired bone marrow failure receiving BMT.

BACKGROUND: The number of hematopoietic stem cell transplantation (HSCT) procedures performed for pediatric acute promyelocytic leukemia (APL) has decreased in the all-trans retinoic acid (ATRA) era. Although HSCT is still widely adopted as part of salvage therapy for relapsed patients, there is no general consensus about the optimal transplant type (autologous [auto-HSCT] or allogeneic HSCT [allo-HSCT]). PROCEDURES: We retrospectively reviewed the clinical data of 95 childhood APL patients who underwent their first HSCT between 1990 and 2014. Of the 95 patients, 40 (42%), 41 (43%), and 3 (3%) underwent HSCT procedures after achieving their first complete remission (CR1), CR2, and CR3, respectively, and 11 (12%) underwent HSCT while in a non-CR state. RESULTS: The non-CR group exhibited significantly worse five-year overall survival (5yOS) and disease-free survival (5yDFS) (5yOS: 46%; 5yDFS: 46%) than the CR1 (5yOS: 80%; 5yDFS: 78%) and CR2 + CR3 groups (5yOS: 81%; 5yDFS: 76%) (P = 0.013 and P < 0.01, respectively). Of the patients treated in CR2, no significant differences in 5yOS or the five-year cumulative incidence of relapse (5yRI) were detected between the auto-HSCT and allo-HSCT groups (5yOS: 85%, vs 78%, P = 0.648; 5yRI: 9%, vs 11%, P = 0.828). Among the patients who underwent allo-HSCT in CR2, those with matched sibling donors displayed a significantly higher 5yRI (33%) than those with other types of donors (0%, P = 0.015). CONCLUSIONS: Even after relapsing, childhood APL can be cured with HSCT if CR is achieved. These findings demonstrate that achieving CR followed by HSCT is the preferred strategy for treating children with relapsed or refractory APL.

BACKGROUND: Human herpesvirus-6B (HHV-6B) infection after allogenic hematopoietic stem cell transplantation (allo-HSCT) is known to be associated with post-transplant limbic encephalitis in adults. Meanwhile, the association between HHV-6B infection and central nervous system complications remains unclear in pediatric allo-HSCT patients. METHODS: In this study, HHV-6B infection was monitored for more than 50 days after HSCT using virus isolation and real-time PCR. Clinical information such as patient background and encephalitis status was collected retrospectively from medical records. Risk factors for HHV-6B infection were determined by the Cox proportional hazards model, and the clinical features of HHV-6B encephalitis in pediatric allo-HSCT patients were elucidated. RESULTS: Human herpesvirus-6B infection was observed in 74 (33.8%) of 219 patients at 3-47 days (median 18, interquartile range 13-20). Risk factors identified in multivariable analysis were hematological malignancy (hazards ratio [HR], 5.0; 95% confidence interval [CI], 2.3/12.5; P < .0001), solid tumor (HR, 4.8; CI, 1.5/16.3; P = .0104), unrelated donor (HR, 2.1; CI, 1.0/4.6; P = .0378), and sex-mismatched donor (HR 1.8; CI, 1.1/3.0; P = .0257). HHV-6B encephalitis occurred in only one of the 219 patients (0.46%); this patient demonstrated the typical clinical course of posterior reversible encephalopathy syndrome. CONCLUSION: Hematological malignancy, solid tumor, unrelated donor, and sex-mismatched donor were significant risk factors for HHV-6B infection after pediatric allo-HSCT. In pediatric allo-HSCT patients, the incidence of HHV-6B encephalitis was low and the clinical features differed from those in adult patients.

The efficacy of and indications for hematopoietic stem cell transplantation (HSCT) in pediatric Langerhans cell histiocytosis (LCH) remain undetermined. This retrospective study analyzed 30 children with refractory LCH who underwent HSCT in Japan between 1996 and 2014. Eleven patients received a myeloablative conditioning (MAC) regimen, while 19 patients received a reduced-intensity conditioning (RIC) regimen. Among the 26 patients with complete data, 23 patients had risk organ (RO) involvement during clinical course. Disease status at HSCT was no active disease (NAD) (4), active disease-regression (AD-r) (2), active disease-stable (AD-s) (4), and active disease-progressive (AD-p) (16). Seventeen of the 30 patients (57%) were alive with a median follow-up of 433 days (range 9-5307) after HSCT. Death occurred within 3 months after HSCT in eight of 13 patients. RIC and MAC patients were similar in both overall survival (OS) (56.8% vs. 63.6%, respectively, p = 0.789) and failure-free survival (56.8% vs. 54.6%, respectively, p = 0.938). Regarding disease status at HSCT, the six patients with NAD/AD-r experienced better outcomes than the 20 with AD-s/AD-p (5-year OS, 100% vs. 5

OBJECTIVE: Pediatric acute myeloid leukemia (AML) with KMT2A rearrangement is detected in 15-20% of all pediatric AML patients and is associated with adverse outcomes even after allogeneic hematopoietic stem cell transplantation (HSCT). To investigate outcomes and prognostic factors, we investigated 90 pediatric AML patients with KMT2A rearrangement after allogeneic HSCT. METHODS: We retrospectively analyzed Japanese registration data for patients who had received allogeneic HSCT between 1988 and 2011. Median age was 3 years (range, 0-15 years), and no gender difference was evident. Median observation period was 119 months. RESULTS: The 3-year overall survival (OS) rate of KMT2A-rearranged AML was 52.1% (95% confidence interval (CI), 42.4-64%, n = 90), and the 3-year disease-free survival (DFS) rate was 46.7% (95%CI, 36.8-58.2%). The 3-year DFS of KMT2A-rearranged AML was not significantly poorer than that of other AML (P = 0.09), and no significant difference was also seen in 3-year OS rate (P = 0.21). Multivariate analysis showed disease status (complete remission) at HSCT was associated with better outcomes. A significant difference in treatment-related mortality (TRM) was apparent between HSCT from a HLA full-matched related donor and that from a haploidentical donor (P = 0.001). DISCUSSION: HSCT is a curative option for pediatric AML with KMT2A rearrangement. Pretransplant status was the most significant prognostic indicator for relapse and survival. Enhancing supportive therapy to reduce TRM will further improve treatment outcomes of KMT2A-rearranged pediatric AML.

Myeloid leukemia associated with Down syndrome (ML-DS) is characterized by a predominance of acute megakaryoblastic leukemia, the presence of GATA1 mutations and a favorable outcome. Because DS children can also develop conventional acute myeloid leukemia with unfavorable outcome, detection of GATA1 mutations is important for diagnosis of ML-DS. However, myelofibrosis and the significant frequency of dry taps have hampered practical screening of GATA1 mutations using bone marrow (BM) samples. In response to those problems, 82 patients were enrolled in the Japanese Pediatric Leukemia/Lymphoma Study Group AML-D11 study. GATA1 mutations were analyzed by Sanger sequencing (SS) using genomic DNA (gDNA) from BM and cDNA from peripheral blood (PB) followed by targeted next-generation sequencing (NGS) using pooled diagnostic samples. BM and PB samples were obtained from 71 (87%) and 82 (100%) patients, respectively. GATA1 mutations were detected in 46 (56%) and 58 (71%) patients by SS using BM gDNA and PB cDNA, respectively. Collectively, GATA1 mutations were identified in 73/82 (89%) patients by SS. Targeted NGS detected GATA1 mutations in 74/82 (90%) patients. Finally, combining the results of SS with those of targeted NGS, GATA1 mutations were identified in 80/82 (98%) patients. These results indicate that SS using BM gDNA and PB cDNA is a rapid and useful method for screening for GATA1 mutations in ML-DS patients. Thus, a combination of SS and targeted NGS is a sensitive and useful method to evaluate the actual incidence and clinical significance of GATA1 mutations in ML-DS patients.

Sinusoidal obstruction syndrome (SOS) is a lethal complication after hematopoietic stem cell transplantation (HSCT). Defibrotide (DF) is the only drug internationally recommended for SOS treatment in Western countries. Recombinant human soluble thrombomodulin (rhTM), which is promising for the treatment of patients with disseminated intravascular coagulation, is also reported to be potentially effective for SOS. To clarify the safety and efficacy of DF and rhTM, we conducted a retrospective survey of these agents in Japan. Data from 65 patients who underwent allogeneic HSCT and received DF (n  =  24) or rhTM (n  =  41) for SOS treatment were collected. The complete response rates for SOS on day 100 were 50% and 54% in the DF and rhTM groups, respectively. The 100-day overall survival rates were 50% in the DF group, and 48% in the rhTM group. Several severe hemorrhagic adverse events were observed in one patient in the DF group and five patients in the rhTM group. The main causes of death were SOS-related death, and no patient died of direct adverse events of DF or rhTM. Our results suggest that rhTM, as well as DF, can be effective as a novel treatment option for SOS.

Allogeneic hematopoietic stem cell transplantation (HSCT) can be used to treat children with refractory acute myeloid leukemia (AML). This retrospective analysis aimed to describe the outcomes and risk factors in such children. Data were collected through the nation-wide registry program in Japan. A total of 417 AML (median age: 13 years) patients 20 years or younger at HSCT, between January 2001 and December 2015, were included. A total of 314 patients died, and the median follow-up duration of the survivors was 1052 days. The most frequent cause of death was leukemia progression (58%). The 3-year overall survival (OS) rate was 23% (95% confidence interval [CI]: 19-28%). Chronic GVHD was associated with improved 3-year OS (47%, 95% CI, 36-57%, hazard ratio: 0.603, p = 0.001). Low performance status, presence of more than 25% of marrow blasts, presence of blasts in the blood at transplantation, FAB (other than M1 or M2), male donors, and number of transplantations ≥ 2 were adverse pre-HSCT variables. Patients with 0, 1-2, 3-4, 5, and 6-7 pre-HSCT variables had 3-year OS rates of 52%, 32%, 19%, 8, and 0%, respectively. Our findings may help experts decide if HSCT should be performed in such cases.

BACKGROUNDS: Multidisciplinary therapy has increased the risk of subsequent late effects, but detailed analyses on secondary cancers in childhood cancer survivors (CCSs) are limited in Asian countries. METHODS: This was a retrospective cohort study comprising 10,069 CCSs who were diagnosed between 1980 and 2009 across 15 Japanese hospitals. We conducted secondary analyses to estimate the incidence of secondary cancer according to each primary malignancy and to elucidate the association between primary and secondary cancers. We also explored the risk factors for the development of secondary cancer in each independent primary malignancy. RESULTS: The cumulative incidence of secondary cancer at 20 years varied among primary cancers: hematological malignancy, 3.1% (95% CI 2.2-4.3); retinoblastoma, 6.6% (95% CI 1.5-16.8); pediatric solid tumor, 2.5% (95% CI 1.3-4.2); brain tumors, 5.2% (95% CI 1.7-11.8) bone/soft tissue sarcoma, 5.2% (95% CI 2.3-10.1); and others, 3.3% (95% CI 1.6-6.0) (p = 0.015). The cumulative incidence of secondary cancers is highest in those with osteosarcoma (13.1%) followed by those with hepatoblastoma (8.4%) and retinoblastoma (6.6%). Close association between the primary and secondary cancer diagnoses was found. The risk factors for secondary cancer development depended on the primary cancer, but autologous/allogeneic stem cell transplantation was a relatively common risk factor. CONCLUSION: The cumulative incidence of secondary cancer varied among primary cancers. The primary cancer was closely associated with the secondary cancer but stem cell transplantation was a common risk factor for secondary cancers among CCSs.

Graft-versus-host disease (GVHD) occasionally leads to morbidity and mortality but is thought to reduce the risk of relapses in patients with a hematological malignancy. However, information on the effect of GVHD in pediatric leukemia is limited. Using a nationwide registry, we retrospectively analyzed 1526 children who underwent allogeneic stem cell transplantation for leukemia. Grades 0-I acute GVHD were associated with a higher relapse rate at three years after transplantation, at 25.4 and 24.3%, respectively, than grades II, III, or IV acute GVHD at 18.9%, 21.2%, and 2.6%, respectively. In contrast, the overall survival curve of the grades 0 and I GVHD groups (79.0% and 79.5%, respectively) approximated that of the grade II GVHD group (76.3%), and the probability of survival was worst in the severe GVHD groups (66.9% for grade III and 42.5% for grade IV). Chronic GVHD also reduced the relapse risk but conferred no survival advantage. Acute lymphoblastic leukemia was more sensitive to acute GVHD than acute myeloid leukemia (AML) while AML was more sensitive to chronic GVHD. Our study reproduced the preventive effects of GVHD against pediatric leukemia relapses but failed to demonstrate a significant survival advantage.

Langerhans cell histiocytosis (LCH) with single-system (SS) multifocal bone (MFB) lesions is rarely fatal, but patients may experience relapses and develop LCH-associated sequelae. To evaluate effect on outcomes of pediatric multifocal LCH, we tested a treatment protocol modified from the Japan Langerhans Cell Histiocytosis Study Group (JLSG)-96 study. We assessed the outcomes of all consecutive newly diagnosed pediatric patients with LCH with SS-MFB lesions who were treated with JLSG-02 protocol in 2002-2009. JLSG-02 was modified from JLSG-96 as follows: increased prednisolone dosage at the induction phase and extension of maintenance therapy duration from 24 to 48 weeks. In total, 82 patients with a median follow-up duration of 8.0 years were eligible for analysis. At 6 weeks, 92.7% responded to induction; however, 27.6% of responders experienced relapses. In total, 4.8% developed central nervous system-related sequelae, including central diabetes insipidus and neurodegeneration, which were associated with relapse. None of the patients died. The 5-year event-free survival rates were not different between JLSG-02 and -96 cohort (66.7 vs. 65.1%; p = 0.697). Modification of previous treatment protocol did not contribute to improvement of outcomes in LCH with SS-MFB lesions.

Background: Respiratory syncytial virus (RSV) infection is common and may be severe among patients with preexisting cardiac anomalies, but direct involvement of myocardial damage is not common in those patients. Additionally, myocardial involvement has been rarely described among immune compromised children. Case presentation: A 4-year-old girl with acute lymphoblastic leukemia who received maintenance chemotherapy in an outpatient clinic developed systemic inflammatory response syndrome. RSV infection was confirmed by a positive rapid antigen test and serological assay. Subsequently, she was diagnosed with severe myocarditis caused by RSV infection, which was diagnosed by abnormal findings of cardiac echography and ECG and elevated biomarkers for myocardial damage. Then, she was treated in the intensive care unit for 13days. High amounts of RSV type B RNA was detected in tracheal aspirates and serum sample. Conclusion: This case report emphasizes that RSV infection may be associated with myocarditis in immunocompromised children receiving maintenance chemotherapy.

Few reports have focused on adolescent and young adult (AYA) patients with acute myeloid leukemia (AML) treated with hematopoietic stem cell transplantation (HSCT). We performed a retrospective analysis based on data obtained from a Japanese nationwide registration database to compare HSCT outcomes in AYA patients with AML with those in children with AML. An analysis of the 2973 patients with de novo AML who received allogeneic HSCT from 1990 to 2013 showed inferior 5-year overall survival (OS) (54% versus 58%, P&lt;.01) and increased treatment-related mortality (TRM) (16% versus 13%, P=.02) in AYA patients. Multivariate analysis for both OS and TRM showed a significant negative impact on AYAs. However, the negative impact of older age lost its significance in an additional analysis focusing on 1407 recent transplant recipients with high-resolution HLA typing (2000 to 2013). Finally, we analyzed the impact of transplantation center type on HSCI' outcomes in 317 adolescent patients (15 to 18 years old) and found no difference in outcomes between patients treated at a pediatric or an adult hospital. Higher age was a strong predictive factor for inferior OS resulting from increased TRM, which can be eliminated with better donor selection using high-resolution HLA typing. (C) 2017 American Society for Blood and Marrow Transplantation.

Background: Currently, the standard management of moderate aplastic anemia (MAA) has not been well described, although the superiority of the combination of antithymocyte globulin (ATG) and cyclosporine (CyA) over CyA alone has been demonstrated in terms of hematological responses and failure-free survival (FFS). Procedure: We adopted this therapeutic strategy and treated 95 children with MAA who were enrolled in two consecutive prospective studies between October 1992 and August 2009. Results: For these patients, the 6-month response rate was 54.7% (complete response, 13.7%; partial response, 41.1%). There were no statistically significant differences in the overall response rates between the transfusion-dependent (48.8%, n = 41) and transfusion-independent groups (59.3%, n = 54; P = 0.4). Treatment failure was defined as the requirement of salvage treatment, and was observed in 52 patients. The 10-year FFS was 44.0% (95% confidence interval [CI], 32.9%-54.6%). Of the 22 patients who underwent a second immunosuppressive therapy (IST), 12 responded. Forty patients underwent hematopoietic stem cell transplantation as second-or third-line therapy and three died of complications. Consequently, the 10-year overall survival rate was 96.0% (95% CI, 88.0%-98.7%) with a median follow-up period of 103 months (range, 29-221 months). Conclusions: Although current guidelines recommend only observation for patients with transfusion-independent MAA, the results of our study justify early intervention with ATG and CyA in those patients. A prospective randomized trial is warranted to clarify the risks and benefits of early intervention with IST and observation alone until progression to severe AA in patients with MAA.

Acute myeloid leukaemia (AML) is a molecularly and clinically heterogeneous disease. Targeted sequencing efforts have identified several mutations with diagnostic and prognostic values in KIT, NPM1, CEBPA and FLT3 in both adult and paediatric AML. In addition, massively parallel sequencing enabled the discovery of recurrent mutations (i.e. IDH1/2 and DNMT3A) in adult AML. In this study, whole-exome sequencing (WES) of 22 paediatric AML patients revealed mutations in components of the cohesin complex (RAD21 and SMC3), BCORL1 and ASXL2 in addition to previously known gene mutations. We also revealed intratumoural heterogeneities in many patients, implicating multiple clonal evolution events in the development of AML. Furthermore, targeted deep sequencing in 182 paediatric AML patients identified three major categories of recurrently mutated genes: cohesion complex genes [STAG2, RAD21 and SMC3 in 17 patients (8·3%)], epigenetic regulators [ASXL1/ASXL2 in 17 patients (8·3%), BCOR/BCORL1 in 7 patients (3·4%)] and signalling molecules. We also performed WES in four patients with relapsed AML. Relapsed AML evolved from one of the subclones at the initial phase and was accompanied by many additional mutations, including common driver mutations that were absent or existed only with lower allele frequency in the diagnostic samples, indicating a multistep process causing leukaemia recurrence.

Background: Hemophagocytic lymphohistiocytosis (HLH) is a life threatening hematological disorder associated with severe systemic inflammation caused by an uncontrolled and ineffective immune response resulting in cytokine storm. Epstein-Barr virus (EBV) is the most common infectious agent in patients with the viral-associated HLH. Limited numbers of cases with cardiac complication have been demonstrated in other viral-associated HLH patients. Herein, we report a pediatric case of severe EBV-associated HLH with cardiac complications. Case presentation: A previously healthy 4-year-old Japanese female was admitted to a local hospital with a four day history of fever. Despite antibiotic treatment, her fever persisted to day 7 of the illness. Finally, the diagnosis of HLH was confirmed by fulfilling diagnostic criteria for HLH and pathological analysis of bone marrow aspiration. Real-time PCR detected a high copy number of EBV DNA in the peripheral blood mononuclear cells (PBMCs) at the time of hospital admission. During treatment according to HLH-2004 protocol, sudden cardiopulmonary arrest (CPA) occurred on day 30 of the illness and immediate resuscitation was successful. Acute myocarditis was considered the cause of the CPA. Although the treatment regimen was completed on day 88 of the illness, a remarkably high copy number of EBV DNA was still detected in her PBMCs. Based on our flow cytometric in situ hybridization analysis that revealed EBV infection of only B lymphocytes, we decided to administer rituximab to control the abnormal EBV infection. Afterwards the amount of EBV DNA decreased gradually to undetectable level on day 130 of the illness. Unfortunately, a coronary artery aneurysm was discovered at the left main coronary artery on day 180 of the illness. Finally, the patient was discharged from the hospital on day 203 of the illness without sequelae except for a coronary aneurysm. Conclusions: In this case report, EBV-HLH was complicated with cardiac symptoms such as myocarditis and coronary artery aneurysm. Although remarkably high copy number of EBV DNA was detected in PBMCs after completion of the HLH-2004 protocol, rituximab treatment resulted in a dramatic decrease of EBV DNA to undetectable levels. Rituximab treatment might have been beneficial for the patient's survival.

Purpose Acute lymphoblastic leukemia (ALL) makes up a significant proportion of all pediatric cancers, and relapsed ALL is a leading cause of cancer-associated deaths in children. Identification of risk factors and druggable molecular targets in ALL can lead to a better stratification of treatments and subsequent improvement in prognosis. Patients and Methods We enrolled 59 children with relapsed or primary refractory ALL who were treated in our institutions. We primarily performed RNA sequencing (RNA-seq) using patients' leukemic cells to comprehensively detect gene fusions and analyze gene expression profiles. On the basis of results obtained by RNA-seq, we performed genetic validation, functional analysis, and in vitro drug sensitivity testing using patients' samples and an exogenous expression model. Results We identified a total of 26 gene fusions in 22 patients by RNA-seq. Among these, 19 were nonrandom gene fusions already described in ALL, and four of the remaining seven involved identical combination of MEF2D and BCL9. All MEF2D-BCL9-positive patients had B-cell precursor immunophenotype and were characterized as being older in age, being resistant to chemotherapy, having very early relapse, and having leukemic blasts that mimic morphologically mature B-cell leukemia with markedly high expression of HDAC9. Exogenous expression of MEF2D-BCL9 in a B-cell precursor ALL cell line promoted cell growth, increased HDAC9 expression, and induced resistance to dexamethasone. Using a primary culture of leukemic blasts from a patient, we identified several molecular targeted drugs that conferred inhibitory effects in vitro. Conclusion A novel MEF2D-BCL9 fusion we identified characterizes a novel subset of pediatric ALL, predicts poor prognosis, and may be a candidate for novel molecular targeting. (C) 2016 by American Society of Clinical Oncology

A phase 1 study was conducted to evaluate the safety, pharmacokinetics (PK), efficacy and pharmacogenetic characteristics of clofarabine in seven Japanese pediatric patients with relapsed/refractory acute lymphoblastic leukemia (ALL). Patients in Cohort 1 received clofarabine 30 mg/m(2)/day for 5 days, followed by 52 mg/m(2)/day for 5 days in subsequent cycles. Cohort 2 patients were consistently treated with 52 mg/m(2)/day for 5 days. No more than six cycles were performed. Every patient had at least one ≥Grade 3 adverse event (AE). AEs (≥Grade 3) related to clofarabine were anaemia, neutropenia, febrile neutropenia, thrombocytopenia, alanine aminotransferase increased, aspartate aminotransferase increased, haemoglobin decreased, and platelet (PLT) count decreased. C max and AUC of clofarabine increased in a dose-dependent fashion, but its elimination half-life (T 1/2) did not appear to be dependent on dose or duration of treatment. Clofarabine at 52 mg/m(2)/day shows similarly tolerable safety and PK profiles compared to those in previous studies. No complete remission (CR), CR without PLT recovery, or partial remission was observed. Since clofarabine is already used as a key drug for relapsed/refractory ALL patients in many countries, the efficacy of clofarabine in Japanese pediatric patients should be evaluated in larger study including more patients, such as by post-marketing surveillance.

We evaluated the efficacy of treatment using reduced cumulative doses of anthracyclines in children with acute promyelocytic leukaemia (APL) in the Japanese Paediatric Leukaemia/Lymphoma Study Group AML-P05 study. All patients received two and three subsequent courses of induction and consolidation chemotherapy respectively, consisting of all-trans retinoic acid (ATRA), cytarabine and anthracyclines, followed by maintenance therapy with ATRA. Notably, a single administration of anthracyclines was introduced in the second induction and all consolidation therapies to minimize total doses of anthracycline. The 3-year event-free (EFS) and overall survival rates for 43 eligible children were 83·6% [95% confidence interval (CI): 68·6–91·8%] and 90·7% (95% CI: 77·1–96·4%), respectively. Although two patients died of intracranial haemorrhage or infection during induction phases, no cardiac adverse events or treatment-related deaths were observed during subsequent phases. Patients not displaying M1 marrow after the first induction therapy, or those under 5 years of age at diagnosis, showed inferior outcomes (3-year EFS rate; 33·3% (95% CI: 19·3–67·6%) and 54·6% (95% CI: 22·9–78·0%), respectively). In conclusion, a single administration of anthracycline during each consolidation phase was sufficient for treating childhood APL. In younger children, however, conventional ATRA and chemotherapy may be insufficient so that alternative therapies should be considered.

Idiopathic aplastic anemia (AA) is a rare hematological complication of Down syndrome (DS). The safety and efficacy of immunosuppressive therapy (IST) in individuals with DS remain unknown. We used a standard regimen of IST, comprising antithymocyte globulin and cyclosporine A, to treat three children with DS and idiopathic acquired AA. Two patients achieved a hematological (complete or partial) response and became transfusion independent at the final follow-up. The third patient failed to respond to IST and underwent bone marrow transplantation from a human leukocyte antigen (HLA)-mismatched unrelated donor. None of the patients experienced severe or unexpected adverse events during IST. Our experience suggests that IST is a safe and reasonable treatment, even in individuals with DS who suffer from AA and lack an HLAmatched sibling donor.