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Importance: Cell therapy is a promising treatment approach for stroke and other diseases. However, it is unknown whether MultiStem (HLCM051), a bone marrow-derived, allogeneic, multipotent adult progenitor cell product, has the potential to treat ischemic stroke., Objective: To assess the efficacy and safety of MultiStem when administered within 18 to 36 hours of ischemic stroke onset., Design, Setting, and Participants: The Treatment Evaluation of Acute Stroke Using Regenerative Cells (TREASURE) multicenter, double-blind, parallel-group, placebo-controlled phase 2/3 randomized clinical trial was conducted at 44 academic and clinical centers in Japan between November 15, 2017, and March 29, 2022. Inclusion criteria were age 20 years or older, presence of acute ischemic stroke (National Institutes of Health Stroke Scale [NIHSS] score of 8-20 at baseline), confirmed acute infarction involving the cerebral cortex and measuring more than 2 cm on the major axis (determined with diffusion-weighted magnetic resonance imaging), and a modified Rankin Scale (mRS) score of 0 or 1 before stroke onset. Data analysis was performed between May 9 and August 15, 2022., Exposure: Patients were randomly assigned to either intravenous MultiStem in 1 single unit of 1.2 billion cells or intravenous placebo within 18 to 36 hours of ischemic stroke onset., Main Outcomes and Measures: The primary end points were safety and excellent outcome at day 90, measured as a composite of a modified Rankin Scale (mRS) score of 1 or less, a NIHSS score of 1 or less, and a Barthel index score of 95 or greater. The secondary end points were excellent outcome at day 365, mRS score distribution at days 90 and 365, and mRS score of 0 to 1 and 0 to 2 at day 90. Statistical analysis of efficacy was performed using the Cochran-Mantel-Haenszel test., Results: This study included 206 patients (104 received MultiStem and 102 received placebo). Their mean age was 76.5 (range, 35-95) years, and more than half of patients were men (112 [54.4%]). There were no between-group differences in primary and secondary end points. The proportion of excellent outcomes at day 90 did not differ significantly between the MultiStem and placebo groups (12 [11.5%] vs 10 [9.8%], P = .90; adjusted risk difference, 0.5% [95% CI, -7.3% to 8.3%]). The frequency of adverse events was similar between treatment groups., Conclusions and Relevance: In this randomized clinical trial, intravenous administration of allogeneic cell therapy within 18 to 36 hours of ischemic stroke onset was safe but did not improve short-term outcomes. Further research is needed to determine whether MultiStem therapy for ischemic stroke has a beneficial effect in patients who meet specific criteria, as indicated by the exploratory analyses in this study., Trial Registration: ClinicalTrials.gov Identifier: NCT02961504.

Allogeneic hematopoietic stem cell transplantation (HSCT) is the only curative therapy for the hematologic manifestations of Diamond-Blackfan anemia (DBA). However, data regarding the optimal conditioning regimen for DBA patients are limited. We retrospectively compared the outcomes of DBA patients who underwent HSCT using either myeloablative conditioning (MAC) or reduced-intensity conditioning (RIC) regimens. The patients belonged to a cohort treated at our hospitals between 2000 and 2018. HSCT was performed in 27 of 165 patients (16.4%). The median age at the time of HSCT was 3.6 years. Stem cell sources included bone marrow for 25 patients (HLA-matched sibling donors, n = 5; HLA-mismatched related donors, n = 2; HLA-matched/mismatched unrelated donors, n = 18) or cord blood for 2 patients. MAC or RIC regimens were used in 12 and 15 patients, respectively. Engraftment was successful in all 27 patients who underwent HSCT. Three patients who underwent HSCT using MAC regimens developed sinusoidal obstruction syndrome. The 3-year overall survival (OS) and failure-free survival rates (FFS) post-transplantations were 95.2% and 88.4%, respectively, with no significant differences between MAC and RIC regimens. Our data suggest that HSCTs using RIC regimens are effective and obtain engraftment with excellent OS and FFS for young DBA patients.

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., (© 2020 Wiley Periodicals, Inc.)

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., (© 2019 Wiley Periodicals, Inc.)

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. 54.5%, respectively, p = 0.040). Disease state at the time of HSCT was the most important prognostic factor.

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., (Copyright © 2019 Elsevier Ltd. All rights reserved.)

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.

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.

Background: Indications for hematopoietic stem cell transplantation (HSCT) have decreased with the improvement in chemotherapy for pediatric acute myeloid leukemia (AML) in the last decade. We conducted reevaluation of autologous HSCT (AHSCT) to compare myeloablative conditioning (MAC) regimens for pediatric AML without the need for consideration of toxicities caused by allogeneic immune reactions., Procedure: This retrospective study analyzed the clinical outcomes of 220 children with AML who underwent consecutive AHSCT between 1989 and 2002 in Japan by the national prospective registry. The transplantation outcomes of various conditioning regimens were compared., Results: The median follow-up period of the survivors was 160 months. The clinical outcomes of busulfan + cyclophosphamide ± etoposide or busulfan + melphalan regimens were significantly superior compared with other busulfan-based and total body irradiation-based regimens (leukemia-free survival [LFS]: 68% vs 42% and 55%, P = 0.001; overall survival [OS]: 74% vs 49% and 61%, P < 0.001). Multivariate analysis showed that busulfan + cyclophosphamide ± etoposide and busulfan + melphalan regimens were independent favorable factors for LFS (hazard ratio: 0.46; P < 0.001) and OS (hazard ratio: 0.40; P < 0.001) compared with the other busulfan-based regimen, and both age 2 years or older and advanced stage at AHSCT were independent poor predictors for LFS and OS, simultaneously., Conclusion: Busulfan + cyclophosphamide ± etoposide and busulfan + melphalan regimens exhibited superior antileukemic effects compared with other BU-based myeloablative regimens., (© 2018 Wiley Periodicals, Inc.)

Background: We sought to determine whether late-phase human herpesvirus 6B (HHV-6B) infection in hematopoietic stem cell transplant (HSCT) recipients was associated with serious outcomes and mortality., Methods: The occurrence and course of HHV-6B infection was monitored for at least 60 days after transplant using virus isolation and real-time polymerase chain reaction. Risk factors for late-phase HHV-6B infection were examined, and the propensity score was calculated with significant risk factors. The inverse probability-weighted multivariable logistic regression analysis was performed to estimate odds ratios (ORs) and the 95% confidence intervals (95% CI) for mortality., Results: Late-phase HHV-6B infection was observed in 12/89 (13.5%) of the HSCT recipients. Older age (OR: 10.3, 95% CI: 2.1/72.9, P = .0027), hematologic malignancy (OR: 10.3, 95% CI: 1.8/97.1, P = .0063), unrelated donor transplantation (OR: 5.3, 95% CI: 1.1/36.0, P = .0345), and sex-mismatched donor transplantation (OR: 6.3, 95% CI: 1.4/39.5, P = .0149) were identified as risk factors for late-phase HHV-6B infection. Fifteen subjects died (17%). Inverse probability-weighted multivariable logistic model analysis revealed that late-phase HHV-6B infection was an independent risk factor for mortality (OR: 4.2, 95% CI: 1.7/11.0, P = .0012). Among 5 of the fatal cases of late-phase HHV-6B infection, viral infection might be associated with severe clinical manifestations., Conclusion: Late-phase HHV-6B infection in HSCT recipients was associated with worse outcomes. The full spectrum of clinical features of the infection has not been fully elucidated, and therefore, recipients with high-risk factors for late-phase HHV-6B infection should be carefully monitored., (© 2018 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.)

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 <.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 HSCT 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., (Copyright © 2017 The American Society for Blood and Marrow Transplantation. Published by Elsevier Inc. All rights reserved.)

Background: In children with acute myeloid leukemia (AML), hematopoietic stem cell transplantation (HSCT) in first remission is indicated for patients with a relatively high risk of relapse. Second HSCT is a curative option; however, few reports have been published about a second HSCT in children for AML with posttransplantation relapse., Procedure: Using the database provided by the Japanese Society of Hematopoietic Cell Transplantation, we analyzed 46 children with AML who underwent a second allogeneic HSCT after achieving a second remission., Results: The median duration from the first to second HSCT was 20 months, and the source of the second HSCT was related bone marrow (BM) in 22, related peripheral blood in 6, unrelated BM in 14, and unrelated cord blood in 4 patients. Twenty-five children eventually died of the following causes: progressive disease in 14 and transplant-related toxicities in 9. The 5-year overall survival rate was 41.7 ± 7.7%. An interval of less than 24 months between the first and second HSCT was a significant poor prognostic factor., Conclusions: Children with AML who experience a relapse after HSCT in first remission have a good chance of survival with a second HSCT if a second remission is achieved., (© 2015 Wiley Periodicals, Inc.)

Pediatric patients with acute myeloid leukemia (AML) mainly receive myeloablative conditioning regimens based on busulfan (BU) or total body irradiation (TBI) before allogeneic hematopoietic cell transplantation (allo-HCT); however, the optimal conditioning regimen remains unclear. To identify which of these regimens is better for pediatric patients, we performed a retrospective analysis of nationwide registration data collected in Japan between 2006 and 2011 to assess the outcomes of patients receiving these regimens before a first allo-HCT. Myeloablative conditioning regimens based on i.v. BU (i.v. BU-MAC) (n = 69) or TBI (TBI-MAC) (n = 151) were compared in pediatric AML patients in first or second complete remission (CR1/CR2). The incidences of sinusoid obstruction syndrome, acute and chronic graft-versus-host disease, and early nonrelapse mortality (NRM) before day 100 were similar for both conditioning groups; however, the incidence of bacterial infection during the acute period was higher in the TBI-MAC group (P = .008). Both groups showed a similar incidence of NRM, and there was no significant difference in the incidence of relapse between the groups. Univariate and multivariate analyses revealed no significant differences in the 2-year relapse-free survival rates for the i.v. BU-MAC and TBI-MAC groups in the CR1/CR2 setting (71% versus 67%, P = .36; hazard ratio, .73; 95% CI, .43 to 1.24, respectively). TBI-MAC was no better than i.v. BU-MAC for pediatric AML patients in remission. Although this retrospective registry-based analysis has several limitations, i.v. BU-MAC warrants further evaluation in a prospective trial., (Copyright © 2015 American Society for Blood and Marrow Transplantation. Published by Elsevier Inc. All rights reserved.)

The outcome of 55 children with severe aplastic anemia (SAA) who received a second hematopoietic stem cell transplantation (HSCT) was retrospectively analyzed using the registration data of the Japanese Society for Hematopoietic Cell Transplantation. The 5-year overall survival (OS) and failure-free survival (FFS) after the second transplantation were 82.9% (95% confidence interval (CI), 69.7-90.8)) and 81.2% (95% CI, 67.8-89.4), respectively. FFS was significantly better when the interval between the first and second transplantation was >60 days (88.9%; 95% CI, 73.0-95.7) than when it was ⩽60 days (61.4%; 95% CI, 33.3-80.5; P=0.026). All 12 patients who were conditioned with regimens containing fludarabine and melphalan were alive with hematopoietic recovery. These findings justify the recommendation of a second HSCT for children with SAA who have experienced graft failure after first HSCT.

We analyzed 3 hematopoietic stem cell transplant (HSCT) recipients with inherited chromosomally integrated human herpesvirus-6 (inherited CIHHV-6). Cases 1 (inherited CIHHV-6A) and 2 (inherited CIHHV-6B) were inherited CIHHV-6 recipients. Case 3 received bone marrow from a donor with inherited CIHHV-6B. Following HSCT, HHV-6B was isolated from Case 1. HHV-6A and -6B messenger RNAs were detected in Cases 1 and 3., (© 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.)

Background: The relative efficacy of allogeneic hematopoietic cell transplantation (allo-HCT) after reduced toxicity conditioning (RTC) compared with standard myeloablative conditioning (MAC) in pediatric patients with acute myeloid leukemia (AML) has not been studied extensively. To address whether RTC is a feasible approach for pediatric patients with AML in remission, we performed a retrospective investigation of the outcomes of the first transplant in patients who had received an allo-HCT after RTC or standard MAC, using nationwide registration data collected between 2000 and 2011 in Japan., Procedure: We compared a fludarabine (Flu) and melphalan (Mel)-based regimen (RTC; n = 34) with total body irradiation (TBI) and/or busulfan (Bu)-based conditioning (MAC; n = 102) in demographic- and disease-criteria-matched childhood and adolescent patients with AML in first or second complete remission (CR1/CR2)., Results: The incidence of engraftment, early complications, grade II-IV acute graft-versus-host disease (GVHD), and chronic GVHD were similar in each conditioning group. The risk of relapse (25% vs. 26%) and non-relapse mortality (13% vs. 11%) after 3 years did not differ between these groups, and univariate and multivariate analyses demonstrated that the 3-year overall survival (OS) rates after Flu/Mel-RTC and MAC were comparable (mean, 72% [range, 51-85%] and 68% [range, 58-77%], respectively)., Conclusions: The results suggest that the Flu/Mel-RTC regimen is a clinically acceptable conditioning strategy for childhood and adolescent patients with AML in remission. Although this retrospective, registry-based analysis has several limitations, RTC deserves to be further investigated in prospective trials., (© 2014 Wiley Periodicals, Inc.)

Incorporation of imatinib into chemotherapeutic regimens has improved the prognosis of children with Philadelphia chromosome-positive acute lymphoblastic leukemia (Ph(+) ALL). We investigated a role of imatinib immediately before hematopoietic stem cell transplantation (HSCT). Children with Ph(+) ALL were enrolled on JPLSG Ph(+) ALL 04 Study within 1 week of initiation of treatment for ALL. Treatment regimen consisted of Induction phase, Consolidation phase, Reinduction phase, 2 weeks of imatinib monotherapy phase, and HSCT phase (Etoposide+CY+TBI conditioning). Minimal residual disease (MRD), the amount of BCR-ABL transcripts, was measured with the real-time PCR method. The study was registered in UMIN-CTR: UMIN ID C000000290. Forty-two patients were registered and 36 patients (86%) achieved complete remission (CR). Eight of 17 patients (47%) who had detectable MRD at the beginning of imatinib monotherapy phase showed disappearance or decrease in MRD after imatinib treatment. Consequently, 26 patients received HSCT in the first CR and all the patients had engraftment and no patients died because of complications of HSCT. The 4-year event-free survival rates and overall survival rates among all the 42 patients were 54.1 ± 7.8% and 78.1 ± 6.5%, respectively. Four of six patients who did achieve CR and three of six who relapsed before HSCT were salvaged with imatinib-containing chemotherapy and subsequently treated with HSCT. The survival rate was excellent in this study although all patients received HSCT. A longer use of imatinib concurrently with chemotherapy should eliminate HSCT in a subset of patients with a rapid clearance of the disease., (© 2015 The Authors. Cancer Medicine published by John Wiley & Sons Ltd.)

We report the outcomes of 30 patients with juvenile myelomonocytic leukemia (JMML) who received unmanipulated hematopoietic stem cell transplantation (HSCT) with oral or intravenous busulfan, fludarabine, and melphalan between 2001 and 2011. Mutations in PTPN11 were detected in 15 patients. Six patients received human leukocyte antigen (HLA)-matched HSCT from related donors, and 24 patients received HSCT from alternative donors, including 13 HLA-mismatched donors. Primary engraftment failed in five patients, all of whom had received allografts from HLA-mismatched donors. HLA-mismatched HSCT resulted in poorer event-free survival than HLA-matched HSCT (28.8 vs. 70.6 %). Three patients died of transplantation-related causes, and eight patients experienced hematological relapse (including five patients who died due to disease progression). Eight patients received a second HSCT, and four of these patients have survived. The 5-year estimated overall survival for all patients was 72.4: 88.9 % for the patients without a mutation in PTPN11 (n = 10) and 58.3 % for the patients with a mutation in PTPN11 (n = 15) (P = 0.092). The conditioning regimen reported in the present study achieved hematological and clinical remission in >50 % of patients with JMML who received HSCT from alternative donors, and may also be effective for JMML patients with PTPN11 mutation.

Background: Cyclosporine A (CsA) is used widely for graft-versus-host disease (GVHD) prophylaxis in hematopoietic stem cell transplantation (HSCT); however, the optimal schedule of its administration has not been established. Although comparative studies of adult patients undergoing HSCT have demonstrated enhanced efficacy and safety of twice-daily infusion (TD) compared with continuous infusion (CIF) of CsA, to our knowledge, similar studies have not yet been performed in pediatric groups., Procedure: A self-administered questionnaire was used to retrospectively compare the clinical outcome and incidence of CsA-associated adverse events of 70 pediatric acute myelogenous leukemia patients who were receiving CsA by TD (n = 36) or CIF (n = 34) as GVHD prophylaxis for their first allogeneic HSCT., Results: The cumulative incidences of grade II-IV acute GVHD and chronic GVHD, as well as the overall survival and event-free survival rates, did not differ significantly between the TD and CIF groups; however, the incidence of severe hypertension was significantly higher in the CIF group than the TD group., Conclusions: The analysis presented here indicates that TD and CIF administration of CsA have similar prophylactic effect on pediatric GVHD and suggest that TD is associated with a lower rate of toxicity than CIF in pediatric patients undergoing HSCT. Pediatr Blood Cancer 2015;62:291-298. © 2014 Wiley Periodicals, Inc., (© 2014 Wiley Periodicals, Inc.)

Background: Allogeneic hematopoietic stem cell transplantation (HSCT) is the only curable approach for myelodysplastic syndrome (MDS) and myeloproliferative neoplasms (MPN); however, the event-free survival rate of patients with pediatric MDS and MPN is still only approximately 60%. Although salvage HSCT is the only curative approach for patients with the failure of previous HSCT, its safety and efficacy have yet to be determined., Procedures: We retrospectively analyzed 51 pediatric MDS or MPN who received salvage HSCT for relapse or graft failure following HSCT using registry data of the Japan Society for Hematopoietic Cell Transplantation. The indications used for salvage HSCT were relapse in 22 patients and graft failure in 29 patients., Results: The overall survival (OS) rate for salvage HSCT in relapsed patients was 49.0 ± 10.8% at 3 years. The cumulative incidence of relapse following salvage HSCT was 29.8 ± 10.7% at 3 years, whereas the incidence of non-relapse mortality (NRM) was 28.6 ± 10.2%. No significant differences were observed in the OS after salvage HSCT between disease types. Twenty-four of 29 patients who received salvage HSCT for graft failure achieved engraftment, resulting in an engraftment probability of 81.5 ± 8.0% on day 100. The OS rate after salvage HSCT for graft failure was 56.8 ± 9.6% at 3 years., Conclusions: Second HSCT should be considered as a valuable option for the patients with relapse and graft failure in patients with pediatric MDS or MPN after HSCT, but high NRM is an important issue that needs to be addressed., (© 2014 Wiley Periodicals, Inc.)

The outcomes of children with relapsed acute myeloid leukemia (AML) are known to be poor, but remain obscure. We retrospectively analyzed 71 patients who had relapsed following first-line treatment under the AML99 protocol. We investigated the time and site of recurrence, response to re-induction therapy, and performance of hematopoietic stem cell transplantation (HSCT) in relapsed cases, and performed a multivariate analysis to identify prognostic factors. The 5-year overall-survival (OS) rate after relapse was 37 %. Of 71 patients, three died without any anti-leukemic therapy and two underwent allogeneic HSCT. The remaining 66 patients received re-induction chemotherapy, and 33 (50 %) achieved second CR (CR2). Twenty-two of 25 (88 %) late relapse patients and 11 of 41 (27 %) early relapse patients achieved CR2 (P < 0.001). Twenty-nine CR2 cases and 35 non-CR2 cases underwent allogeneic HSCT. The 5-year OS rate was significantly higher in patients who underwent HSCT in CR2 than those in non-CR2 (66 vs. 17 %, P < 0.000001). Multivariate analysis indicated that early relapse (P < 0.05) and the positivity of the FMS-like tyrosine kinase 3--internal tandem duplication (P < 0.05) were adverse prognostic factors for survival. In conclusion, the etiology of relapsed pediatric AML needs to be elucidated and effective chemotherapy should be administered to obtain CR2.

Bloodstream infection (BSI) is the most common infectious complication of hematopoietic stem cell transplantation (HSCT) and can cause substantial morbidity and mortality. Identification of risk factors for BSI might be helpful in efforts to reduce transplantation-related death. This study analyzed the incidence of BSI and risk factors for BSI after HSCT in pediatric patients with aplastic anemia (AA). BSI occurred in 39 of the 351 patients with AA (11.1%). Onset of BSI occurred at a median of 8 days after HSCT (range, 0 to 92 days). The 5-year overall survival rate was lower in patients with BSI than in patients without BSI (63.32% ± 7.90% versus 93.35% ± 1.44%; P < .0001). Univariate analysis identified the following variables as associated with BSI: history of immunosuppressive therapy with antithymocyte globulin (ATG), transplantation from an unrelated donor, frequent blood transfusion before transplantation, major or major plus minor ABO type mismatch, graft-versus-host disease prophylaxis with tacrolimus and without cyclosporine, and long interval from diagnosis to transplantation. Among these factors, long interval from diagnosis to transplantation was the sole statistically significant risk factor for BSI on multivariate analysis. In patients who underwent HSCT from a related donor, age ≥14 years at transplantation was risk factor for BSI. In contrast, history of immunosuppressive therapy with ATG, frequent blood transfusion before HSCT, graft failure, and major or major plus minor ABO type mismatch were risk factors for BSI in patients who underwent HSCT from an unrelated donor. Because the overall 5-year survival rate without BSI was >90%, even in patients who were received a transplant from an unrelated donor, control of BSI is very important for successful HSCT in pediatric patients with AA., (Copyright © 2014 American Society for Blood and Marrow Transplantation. Published by Elsevier Inc. All rights reserved.)

Allogeneic hematopoietic stem cell transplantation (HSCT) has not been widely used in patients with acute myeloid leukemia (AML) and Down syndrome (DS) due to fear of transplantation-related toxicity. A retrospective analysis of the outcome of allogeneic HSCT was conducted in 15 patients with AML and DS. The five patients transplanted with the reduced intensity conditioning (4 in complete remission (CR) and 1 in non-CR) had a significantly better survival rate than 10 patients transplanted with a conventional conditioning (4 in CR and 6 in non-CR) (3-year EFS (95% confidence interval): 80.0% (20.4-96.9%) vs. 10.0% (0.6%-35.8%), P = 0.039)., (© 2013 Wiley Periodicals, Inc.)

Recent reports revealed that intravenous (iv) busulfan (BU) may not only reduce early nonrelapse mortality (NRM) but also improve overall survival (OS) probability in adults. Therefore, we retrospectively compared outcomes for 460 children with acute leukemia who underwent hematopoietic stem cell transplantation with either iv-BU (n = 198) or oral busulfan (oral-BU) (n = 262) myeloablative conditioning. OS at 3 years was 53.4% ± 3.7% with iv-BU and 55.1% ± 3.1% with oral-BU; the difference was not statistically significant (P = .77). OS at 3 years in 241 acute lymphoblastic leukemia and 219 acute myeloid leukemia patients was 56.4% ± 5.5% with iv-BU and 54.6% ± 4.1 with oral-BU (P = .51) and 51.0% ± 5.0% with iv-BU and 55.8% ± 4.8% with oral-BU (P = .83), respectively. Cumulative incidence of relapse at 3 years with iv-BU was similar to that with oral-BU (39.0% ± 3.6% and 36.4% ± 3.1%, respectively; P = .67). Cumulative incidence of NRM at 3 years was 16.6% ± 2.7% with iv-BU and 18.3% ± 2.5% with oral-BU (P = .51). Furthermore, multivariate analysis showed no significant survival advantage with iv-BU. In conclusion, iv-BU failed to show a significant survival advantage in children with acute leukemia., (Copyright © 2013 American Society for Blood and Marrow Transplantation. Published by Elsevier Inc. All rights reserved.)

We report long-term outcomes of 329 childhood severe aplastic anemia (SAA) patients who underwent hematopoietic SCT (HSCT) from an HLA-matched sibling donor in the Japanese Hematopoietic Cell Transplantation Registry. OS and EFS at 10 years were as high as 89.7+/-1.7% and 85.5+/-2.0%, respectively. Five cases of late malignancies (LM) were identified (malignant peripheral nerve sheath tumor, thyroid carcinoma, colon carcinoma, MDS and hepatoblastoma). Cumulative incidence of LM was 0.8% at 10 years and 2.5% at 20 years, respectively, which was lower than that in previous reports. This low incidence is in keeping with the low occurrence of skin cancer in Japanese population and of acute GVHD in our study group. Radiation-containing conditioning was not significantly associated with the incidence of LM after HSCT probably because of absolute low patient number who developed LM in our series. In terms of LM development after HSCT, low-dose TBI in HSCT for SAA to avoid graft rejection, which is commonly used in Japan, might be tolerable in the Japanese population because of its low incidence.

Myeloid leukemia in Down syndrome (ML-DS) is associated with good response to chemotherapy and favorable prognosis. Because little research has been focused on refractory/relapsed (R/R) cases, we conducted a retrospective analysis for R/R ML-DS. Among ML-DS patients diagnosed between 2000 and 2010 in Japan, 26 relapsed (25 in the BM and 1 in the skin), and 3 refractory patients were enrolled. The male/female ratio was 18/11. The median age at initial diagnosis of ML-DS was 2 years, and the median time to relapse was 8.6 months. Each patient initially had been treated with ML-DS-specific protocols. Thirteen of the 26 patients achieved complete remission with various kinds of reinduction chemotherapies; 2 of 8 survived without further recurrence after receiving allogeneic hematopoietic stem cell transplantation, and 4 of 5 maintained complete remissions with chemotherapy alone. Treatment failures mostly were associated with disease progression rather than treatment-related toxicities. The 3-year OS rate was 25.9% ± 8.5%. A longer duration from initial diagnosis to relapse was a significant favorable prognostic factor (P < .0001). We conclude that clinical outcome for patients with R/R ML-DS generally are unfavorable, even in those receiving hematopoietic stem cell transplantation. Novel methods to identify poor prognostic factors for ML-DS are necessary.

Background: Hemophagocytic lymphohistiocytosis (HLH) is associated with hypercytokinemia in children. Although HLH can be also observed after hematopoietic stem cell transplantation (HSCT), the incidence and clinical features of HLH after HSCT remain obscure., Procedure: The clinical features of HLH after HSCT (post-HSCT HLH) were investigated in children with malignancies, immune deficiencies, or aplastic anemia. The HLH/Langerhans Cell Histiocytosis (LCH) Committee of the Japanese Society of Pediatric Hematology (JSPH) sent questionnaires to hospitals with JPSH members asking for details of cases in which HLH occurred after HSCT between 1998 and 2008., Results: Among 42 children who were diagnosed with post-HSCT HLH between 1998 and 2008 in Japan, 37 fulfilled our inclusion criteria; of these, 26 were classified as early-onset (onset <30 days after HSCT) and 11 were classified as late-onset (onset >30 days after HSCT). In the early-onset group, the presence of respiratory symptoms, high levels of total bilirubin, and triglycerides at onset and the lack of control of GVHD with tacrolimus were significantly associated with non-resolution of HLH (P < 0.05). The survival rate was significantly higher in patients with resolution of HLH than in those without resolution (59% vs. 14%, P < 0.05)., Conclusions: These findings suggest that early-onset post-HSCT HLH is a specific entity of HLH, and appropriate diagnosis and prompt management need to be established., (Copyright © 2011 Wiley Periodicals, Inc.)

Background: Idiopathic pneumonia syndrome (IPS) is a severe complication that can occur after hematopoietic stem cell transplantation (HSCT) and is often associated with a fatal outcome despite intensive supportive care., Procedure: To assess the incidence and risk factors of IPS, we reviewed 251 consecutive patients (median age, 7.0 years) who received HSCT at the Department of Pediatrics, Nagoya University Hospital, between January 1990 and July 2009., Results: Twenty of 251 (cumulative incidence of IPS at 2 years after HSCT, 8.0%; 95% confidence interval (CI), 5.1-12.4%) patients developed IPS. The median duration from HSCT to diagnosis of IPS was 67 days (range, 12-486 days). Patients with IPS had significantly higher 5-year transplant-related mortality compared to patients without IPS (52% (95% CI, 19-77%) vs. 13% (95% CI, 5-25%), P < 0.001), and the probability of 5-year overall survival was significantly worse for patients with IPS (42% (95% CI, 25-64%) vs. 68% (95% CI, 59-76%), P = 0.01). By multivariate analysis, high risk in underlying disease (HR, 2.5; 95% CI, 1.0-6.7; P = 0.05) and a busulfan-containing regimen (HR, 3.5; 95% CI, 1.3-9.9; P < 0.01) were identified as the independent risk factors for developing IPS., Conclusion: The prophylactic strategies for IPS in patients with these risk factors were warranted., (Copyright © 2011 Wiley Periodicals, Inc.)

We report two patients with chronic granulomatous disease (CGD). The first patient presented with granulomatous colitis and pulmonary aspergillosis, and the second patient with liver abscess and restrictive pulmonary disorder. Both patients underwent allogeneic hematopoietic stem cell transplantation, the first from an HLA-matched sibling donor, and the second from an HLA-matched unrelated donor, after preconditioning with fludarabine, anti-thymocyte globulin, cyclophosphamide, and total-body irradiation of 3 Gy. The engraftment was prompt and the regimen-related toxicity was mild. The patients are able to return to their daily lives with full donor chimerism, although the second patient underwent a living-related-donor orthotopic liver transplantation from his mother for chronic liver graft-versus-host disease. The conditioning regimen we used was feasible and applicable to patients with CGD accompanied by inflammatory disease and severe infection.

We present the case of a 15-year-old adolescent boy with recurrent precursor B-cell acute lymphoblastic leukemia, which appeared 9 years and 7 months after a first unrelated allogeneic hematopoietic stem cell transplantation (HSCT). The patient received chemotherapy and a subsequent second unrelated allogeneic HSCT, and was free of the disease 3 years after the second HSCT. A molecular study revealed the same rearrangement pattern at IGK@ in both the first relapse and the later relapse, confirming the common origin of the leukemic blasts at different time points. However, a new Vδ2-Dδ3 rearrangement of TRD@ emerged at the later relapse. A subsequent, more sensitive examination revealed a minor subpopulation with rearrangements at both IGK@ and TRD@, even during the first relapse. This finding suggests that the minor clone, related to the major clone, was present at the first relapse, leading to the later recurrence, even though the major clone at the first relapse had been eradicated by the first allogeneic HSCT. Although a later relapse after allogeneic HSCT is a rare phenomenon, clinicians should keep in mind that later relapses can occur, even after allogeneic HSCT.

Langerhans cell histiocytosis (LCH) that is refractory to conventional chemotherapy has a poor outcome. Hematopoietic stem cell transplantation (SCT) is a promising approach for refractory LCH because of its immunomodulatory effect. In this study, the outcomes of children with refractory LCH undergoing SCT in Japan were analyzed. Between November 1995 and March 2007, 15 children younger than 15 years (9 males, 6 females) with refractory LCH underwent SCT. The patients' median age at diagnosis was 8 months (range, 28 days to 28 months), and all had failed conventional chemotherapy. The median age at SCT was 23 months (range, 13-178 months). Nine had risk organ involvement at diagnosis, including liver (n=6), spleen (n=5), lung (n=5), and/or hematopoietic system (n=4). For SCT, a myeloablative regimen was used for 10 patients, and a reduced-intensity conditioning regimen (RIC) was used for five. The donor source varied among the patients, but allogeneic cord blood was primarily used (n=10). Subsequently, 11 of 15 patients have survived with no evidence of disease, with a 10-year overall survival (OS) rate (median+/-standard error) of 73.3+/-11.4%. The 10-year OS rate of nine patients with risk organ involvement at diagnosis was 55.6+/-16.6%, whereas six without risk organ involvement have all survived with no evidence of disease (P=0.07). These results indicate that SCT is promising as a salvage approach for children with refractory LCH.

Background: Post-transplant outcomes of hemophagocytic lymphohistiocytosis (HLH) patients were analyzed in Japan where Epstein-Barr virus (EBV)-associated severe forms are problematic., Methods: Fifty-seven patients (43 familial HLH [12 FHL2, 11 FHL3, 20 undefined], 14 EBV-HLH) who underwent stem cell transplantation (SCT) between 1995 and 2005 were enrolled based on the nationwide registration., Results: Fifty-seven patients underwent 61 SCTs, including 4 consecutive SCTs. SCTs were employed using allogeneic donors in 93% of cases (allo 53, twin 1, auto 3). Unrelated donor cord blood transplantation (UCBT) was employed in half of cases (21 FHL, 7 EBV-HLH). Reduced intensity conditioning was used in 26% of cases. The 10-year overall survival rates (median +/- SE%) were 65.0 +/- 7.9% in FHL and 85.7 +/- 9.4% in EBV-HLH patients, respectively. The survival of UCBT recipients was >65% in both FHL and EBV-HLH patients. Three out of four patients were alive with successful engraftment after second UCBT. FHL patients showed a poorer outcome due to early treatment-related deaths (<100 days, seven patients) and a higher incidence of sequelae than EBV-HLH patients (P = 0.02). The risk of death for FHL patients having received an unrelated donor bone marrow transplant was marginally higher than that for a related donor SCT (P = 0.05) and that for UCBT (P = 0.07)., Conclusions: EBV-HLH patients had a better prognosis after SCT than FHL patients. FHL patients showed either an equal or better outcome even after UCBT compared with the recent reports. UCB might therefore be acceptable as an alternate SCT source for HLH patients, although the optimal conditioning remains to be determined., ((c) 2009 Wiley-Liss, Inc.)

ES is a complication that occurs immediately before or at the timing of neutrophil engraftment following autologous or allogeneic SCT. It is characterized by fever, skin rash, and non-cardiac pulmonary infiltrates. We evaluated the incidence, risk factors, and outcomes of ES following allogeneic SCT in children. Of 100 pediatric patients, 20 (20%) developed ES occurring at a median of 14 days (range 8-27 days) post-transplant. Patients presented with fever (100%), skin rash (100%), diffuse pulmonary infiltration (25%), and body weight gain (85%). On multivariate analysis, significant risk factors for ES included younger age (<8 yr old) and human leukocyte antigen disparity between donors and recipients. Univariate analysis showed that patients with ES had a higher incidence of developing chronic graft-versus-host disease and ES was not associated with other complications. Event-free survival did not significantly differ between patients with and without ES regardless of the presence of malignant or non-malignant diseases.

Late-onset non-infectious pulmonary complications (LONIPCs) that arise beyond 3 months after allogeneic hematopoietic SCT include bronchiolitis obliterans (BO), bronchiolitis obliterans with organizing pneumonia (BOOP) and idiopathic pneumonia syndrome (IPS). We retrospectively analyzed the incidence and outcome of LONIPCs among pediatric hematopoietic SCT recipients. We included 97 patients who survived for more than 3 months among the 114 who underwent allogeneic hematopoietic SCT between April 1997 and May 2007. Of the 97 enrolled patients, 10 (10.3%) developed LONIPCs at a median of 187 days after hematopoietic SCT (range, 123-826 days). Of the 10 patients with LONIPCs, eight had BO and two had IPS. Multivariate analysis showed that the onset of LONIPCs was associated with high-risk underlying disease and extensive chronic GVHD (hazard ratio, 5.42 (95% confidence interval, 1.36-21.7) and hazard ratio, 11.7 (95% confidence interval, 2.40-57.1), respectively). Only two patients responded to therapy with steroids and six of the 10 patients died. The 5-year OS rate was significantly lower among patients with, than without LONIPCs (28.0 vs 87.2%, P=0.000). Considering that we are lacking optimal therapies for LONIPCs, strategies aimed at the prevention of LONIPCs should be attempted.

Several lines of evidence indicate the clonal nature of juvenile myelomonocytic leukaemia (JMML), involving myeloid, erythroid, megakaryocyte and B-lymphoid lineages. However, it is unclear whether the T-lymphocyte lineage is involved. We demonstrated that cells from six patients with JMML repopulated in non-obese diabetic/severe combined immunodeficient/gammac(null) mice and differentiated into granulocytes, monocytes, erythrocytes, B lymphocytes, T lymphocytes and natural killer cells. The percentage of human CD45 antigen-positive cells ranged from 41% to 73% in the murine bone marrow 12 weeks after transplantation. To examine the involvement of lymphocyte subpopulations, we purified human CD3(+), CD19(+) and CD56(+) cells from murine bone marrow cells transplanted from a patient with monosomy 7. Fluorescence in situ hybridization (FISH) showed the clonal marker in 96-100% of purified CD3(+), CD19(+) and CD56(+) subpopulations. These findings support the concept that JMML originates in transplantable multilineage haematopoietic stem cells. This novel murine xenotransplant model should be useful for investigating the nature of stem cells and testing new therapies for patients with JMML.

Epstein-Barr virus (EBV)-related lymphoproliferative disorder (LPD) is a serious complication of haematopoietic stem cell transplantation (HSCT). To clarify the frequency, natural course and risk factors for LPD, we prospectively monitored 38 allogeneic (allo)-HSCT patients, focusing on the use of anti-thymocyte globulin (ATG). We used a recently developed real-time polymerase chain reaction assay to monitor EBV genome load. The subjects consisted of 19 patients given ATG for conditioning and 19 patients not given ATG. Of the 19 patients given ATG, 47.4% (nine patients) had a significant increase in EBV genome load (10(2.5) copies/microg DNA). Of these nine patients, two developed LPD. Therefore, 10.5% of the patients receiving allo-HSCT with ATG developed LPD. In contrast, none of the 19 patients without ATG had a significantly increased EBV load. The increases in viral load were observed in the second or third month after HSCT. We found that the peak viral loads of LPD patients were > 10(4.0 ) copies/microg DNA. On the other hand, the viral loads of most patients with no symptoms were < 10(2.5) copies/microg DNA. In conclusion, routine monitoring of EBV load during the second and third months after transplantation may benefit patients undergoing HSCT with ATG. We propose that an EBV load > 10(2.5) copies/microg DNA is the reactivation of EBV, and that an EBV load > 10(4.0) copies/microg DNA is indicative of developing LPD.