神田 善伸

The graft-versus-leukemia (GVL) effect is one of the curative mechanisms of allogeneic hematopoietic stem cell transplantation (allo-HCT). H-Y antigens, which are encoded by Y chromosome, are important targets of the GVL effect. Thus, deletion of the Y chromosome (del[Y]) might cause the GVL effect to deteriorate in a transplantation involving a female donor and male recipient, although the clinical significance of the del(Y) group remains to be elucidated. In this study, we evaluated adult male patients who underwent allo-HCT between 2010 and 2019 in Japan. There were 155 cases in the del(Y) group and 4149 cases without del(Y) who underwent female-to-male allo-HCT. Del(Y) was significantly associated with inferior overall survival (hazard ratio [HR], 1.24; 95% confidence interval [CI], 1.00-1.53; P = .049) and an increased risk of relapse (HR, 1.40; 95% CI, 1.08-1.80; P = .0098) in multivariate analyses. There was no significant difference in nonrelapse mortality between recipients with and without del(Y) (HR, 1.08; 95% CI, 0.769-1.51; P = .67). In contrast, del(Y) was not significantly associated with any clinical outcomes in the cohort of male-to-male allo-HCT. A higher incidence of relapse might have been caused by attenuation of the GVL effect resulting from a lack of H-Y antigens. Because a GVL effect resulting from sex mismatch may not be expected in men with del(Y) who undergo allo-HCT with a female donor, additional post-allo-HCT strategies might be required to prevent disease relapse.

There are limited data comparing myeloablative conditioning with fludarabine/busulfan (Flu/Bu4) and reduced-intensity conditioning with fludarabine/busulfan (Flu/Bu2) in patients with myelodysplastic syndrome (MDS) undergoing allogeneic hematopoietic stem cell transplantation (allo-HSCT). We retrospectively analyzed nationwide registry data and compared the outcomes of adult patients with MDS receiving Flu/Bu4 and Flu/Bu2 by propensity score (PS) matching. Patients who met the following criteria were eligible for enrollment: (1) age ≥16 years; (2) diagnosis of de novo MDS; (3) first allo-HSCT between 2006 and 2018; (4) related bone marrow transplantation (BMT) or peripheral blood stem cell transplantation from an HLA-matched donor, unrelated BMT from an HLA-matched or HLA-1 allele-mismatched donor, or unrelated cord blood transplantation; and (5) receiving Flu/Bu4 or Flu/Bu2 as a conditioning regimen. Flu/Bu4 comprised intravenous busulfan (total dose, 12.8 mg/kg) combined with fludarabine (total dose, 125-180 mg/m2). Flu/Bu2 comprised intravenous busulfan (total dose, 6.4 mg/kg) combined with the same dose of fludarabine. To minimize selection bias and confounding factors, we performed a propensity score (PS)-matched analysis. The primary endpoint was overall survival (OS) after allo-HSCT. A total of 3386 patients with de novo MDS underwent their first allo-HSCT between 2006 and 2018. Among them, 202 patients were assigned each to the Flu/Bu4 and Flu/Bu2 groups after PS-matched analysis. The median age was 61 (interquartile, 57-65) years. The 3-year OS rates were 44.8% (95% confidence interval [CI], 37.1-52.1%) and 46.9% (95% CI, 39.2-54.2%) in the Flu/Bu4 and Flu/Bu2 groups, respectively (P = .67). The 3-year rates of graft-versus-host disease (GVHD)-free survival, relapse-free survival (GRFS) were 28.8% (95% CI, 22.2-35.7%) and 33.0% (95% CI, 26.2-40.0%), respectively (P = .36). The 3-year cumulative incidence rates of relapse were 28.9% (95% CI, 22.6-35.6%) and 30.0% (95% CI, 23.6-36.6%), respectively (P = .47). The 3-year cumulative incidence rates of non-relapse mortality (NRM) were 28.2% (95% CI, 21.7-35.0%) and 27.1% (95% CI, 20.6-33.9%), respectively (P = .60). The 100-day cumulative incidence rate of grade II-IV acute GVHD was significantly higher in the Flu/Bu4 group than in the Flu/Bu2 group (41.7% [95% CI, 34.8%-48.4%] versus 29.3% [95% CI, 23.2%-35.7%], P = 0.012). To identify patients who had more favorable outcomes with 1 of the 2 regimens, we compared the outcomes between the 2 groups after stratifying by age, hematopoietic cell transplantation-comorbidity index, cytogenetic risk, disease status at allo-HSCT, stem cell source, and donor type. OS, GRFS, relapse, and NRM did not differ between the 2 groups in any subgroup analyses. There were no significant interactions between the choice of conditioning regimens and any other factors. There are no differences in survival between Flu/Bu4 and Flu/Bu2, although our study population was highly selected by PS matching. Data from more patients and prospective studies are needed to determine the optimal intensity of conditioning regimens in patients with MDS.

The significance of antibody-identified epitopes stimulating humoral alloimmunity is not well understood in the identification of non-permissive human leukocyte antigen (HLA) mismatching patterns in hematopoietic stem cell transplantation (HSCT). This was a retrospective study in a cohort of 9,991 patients who underwent their first HSCT for hematologic malignancies from unrelated bone marrow donors in the Transplant Registry Unified Management Program (TRUMP). HLA eplet mismatches (EMM) were quantified using HLAMatchmaker (HLAMM). The median age of patients was 48 years (range, 16 to 77). The number of EMM in recipient-donor pairs in our study population ranged from 0 to 37 in HLA class I (median, 0) and 0 to 60 in HLA class II (median, 1). In addition to the known high-risk mismatch patterns in the Japanese cohort, HLA-C EMM in the GVH direction was associated with a significantly higher risk for grade III-IV aGVHD, leading to a higher risk of non-relapse mortality and lower overall survival (compared with HLA-C matched patients, HR 1.67, 95% CI 1.44–1.95; HR 1.39, 95% CI 1.25–1.54; HR 1.20, 95% CI 1.10–1.30, respectively). HLAMM-based epitope matching might be useful for identifying patients who are at high risk for serious complications after HSCT from HLA mismatched unrelated donors.

An HLA-matched relative is the first-choice donor for patients with Philadelphia chromosome (Ph)-negative acute lymphoblastic leukemia (ALL) in first complete remission (CR1). The most promising alternative donor is thought to be an HLA-matched unrelated donor (MUD) in patients who do not have an HLA-matched related donor. Cord blood transplantation (CBT) is an alternative option. Higher rates of engraftment failure and nonrelapse mortality (NRM) are significant problems, but the ready availability of cord blood can be an advantage, because patients can immediately undergo transplantation before progression. This study was conducted to identify an appropriate alternative donor in patients with Ph-negative ALL in CR1 who do not have an HLA-matched related donor (MRD). Decision analyses using a Markov model were performed to compare immediate CBT, in which CBT was performed at 1 month after the achievement of CR1, with elective unrelated bone marrow transplantation (uBMT) from an 8/8 MUD (8/8 uBMT) or uBMT from a 7/8 MUD (7/8 uBMT), in which uBMT was performed at 4 months, in patients age 16 to 55 years with Ph-negative ALL in CR1 who did not have an MRD. We constructed a decision tree. The cycle length was set at 3 months, and analyses were performed for 19 cycles for uBMT and 20 cycles for CBT, resulting in evaluation of the 5-year life expectancy after both decisions. Transition probabilities (TPs) and utilities were estimated from prospective and retrospective Japanese studies and the registry database of Japan. Subgroup analyses were performed according to risk stratification based on WBC count and cytogenetics at diagnosis and according to age stratification, with a cutoff of 25 years. One-way sensitivity analyses for TPs and utilities were performed as well. The baseline analyses showed that 8/8 uBMT or 7/8 uBMT had superior results to CBT, with quality-adjusted life years (QALYs) of 2.86 in 8/8 uBMT, 2.84 in 7/8 uBMT, and 2.75 in CBT. One-way sensitivity analyses showed that the results of the baseline analyses were reversed if the probability of NRM in CBT improved. Subgroup analyses showed similar results in younger, older, and high-risk patients. However, QALY was worse in 8/8 uBMT compared with CBT in standard-risk patients. In one-way sensitivity analyses, the probabilities of NRM in uBMT and CBT affected the baseline results in all analyses except for comparisons between 8/8 uBMT and CBT in younger and high-risk patients. In these 2 populations, the superiority of 8/8 uBMT was consistently demonstrated throughout the one-way sensitivity analyses. For patients with Ph-negative ALL in CR1 who decide to undergo transplantation from an alternative donor, elective uBMT from either an 8/8 MUD or a 7/8 MUD is expected to yield a better outcome than immediate CBT. Nonetheless, CBT is a viable option, and improvements to reduce the risk of NRM in CBT may change these results.

BACKGROUND: It has been reported that prolonged neutropenia during post-remission chemotherapy is associated with a reduced risk of disease relapse in pediatric acute myeloid leukemia (AML) patients. METHODS: We retrospectively reviewed the charts of adult AML patients in first complete remission (CR1) who underwent consolidation chemotherapy with high-dose cytarabine. Those receiving allogeneic hematopoietic cell transplantation in CR1 were excluded. We calculated the D-index, which is an area-based neutropenia index. The patients were divided into 2 groups using the median value of the D-index during the first cycle of consolidation chemotherapy (C#1). RESULTS: Fifty-six patients were included. The 2-year cumulative incidence of relapse was 54.8% (95% confidence interval (CI): 37.5-73.8) in patients with a D-index < 5,118 and 62.0% (95%CI: 42.7-81.4) in those with a D-index ≥ 5,118 (P = 0.56). In a multivariate analysis, intermediate / adverse cytogenetic risk (HR 2.76), performance status ≥ 2 (HR 5.55) and 2 cycles of induction chemotherapy required to achieve CR1 (HR 4.29) were identified as significant factors associated with relapse. The D-index at C#1 did not have a significant impact. CONCLUSIONS: In contrast to pediatric patients, the severity of neutropenia is not associated with a risk of disease relapse in adult AML patients.

Cytomegalovirus reactivation is still a critical concern following allogeneic hematopoietic cell transplantation, and cellular immune reconstitution of cytomegalovirus-specific cytotoxic T-cells is necessary for the long-term control of cytomegalovirus reactivation after allogeneic hematopoietic cell transplantation. Here we show the features of repertoire diversity and the gene expression profile of HLA-A24 cytomegalovirus-specific cytotoxic T-cells in actual recipients according to the cytomegalovirus reactivation pattern. A skewed preference for BV7 genes and sequential "G" amino acids motif is observed in complementarity-determining region-3 of T cell receptor-β. Increased binding scores are observed in T-cell clones with complementarity-determining region-3 of T cell receptor-β with a "(G)GG" motif. Single-cell RNA-sequence analyses demonstrate the homogenous distribution of the gene expression profile in individual cytomegalovirus-specific cytotoxic T-cells within each recipient. On the other hand, bulk RNA-sequence analyses reveal that gene expression profiles among patients are different according to the cytomegalovirus reactivation pattern, and are associated with cytokine production or cell division. These methods and results can help us to better understand immune reconstitution following hematopoietic cell transplantation, leading to future studies on the clinical application of adoptive T-cell therapies.

BACKGROUND: We assessed the kinetics of cytomegalovirus (CMV) reactivation using the area under the curve (AUC), which simultaneously reflects both the viral load at each time point and the duration of CMV antigenemia (CMV-AG). METHODS: We performed a single-institute retrospective analysis in patients who received allogeneic hematopoietic stem cell transplantation (HSCT) between 2007 and 2017 and survived more than 100 days after HSCT. The AUC of CMV-AG (CMV-AUC) was calculated by a trapezoidal method using the number of CMV-AG tested by the C10/C11 method after logarithmic transformation, and plotted weekly up to day 100. RESULTS: CMV reactivation was observed in 195 cases and the median CMV-AUC for CMV-reactivated patients was 8.7 (range 0.5-30.7). Older age, corticosteroid administration, CMV-seropositive transplant recipients, HSCT from an unrelated donor, and underlying diseases were independent predictive factors for higher CMV-AUC. Higher CMV-AUC was associated with poor overall survival (OS) with borderline significance in a univariate analysis (p = .07), but was not significant in a multivariate analysis. Older age, high-risk disease status, and female gender were identified as significant factors associated with poor OS in this study. On the other hand, CMV-AUC (hazard ratio: no reactivation reference, low 0.98, high 2.49, p < .01), older age, HCT-CI ≥3, and corticosteroid administration were identified as significant factors associated with increased incidence of non-relapse mortality (NRM). CONCLUSIONS: The kinetics of CMV reactivation in terms of CMV-AUC reflect both the severity and duration of CMV reactivation. High CMV-AUC was associated with an increased incidence of NRM in survivors over 100 days.

Myeloablative conditioning with fludarabine/busulfan (Flu/Bu4) prior to allogeneic hematopoietic stem cell transplantation (allo-HSCT) is effective for acute myeloid leukemia. However, the effectiveness of Flu/Bu4 for myelodysplastic syndrome (MDS) remains poorly understood. Therefore, we retrospectively analyzed nationwide registry data in Japan from 2006 to 2018 and compared transplant outcomes of adult MDS patients receiving Flu/Bu4 and busulfan/cyclophosphamide (Bu4/Cy) using propensity score (PS) matching. The primary endpoint was overall survival (OS). Among 2,482 MDS patients, 153 patients were assigned each to the Flu/Bu4 and Bu4/Cy groups. The 3-year OS rates were 52.7% (95% confidence interval [CI], 43.8-60.8%) and 49.5% (95% CI, 40.8-57.6%) in the Flu/Bu4 and Bu4/Cy group, respectively (P = 0.548). The 3-year progression-free survival (P = 0.858), the cumulative incidence of relapse (P = 0.536), and cumulative incidence of non-relapse mortality (P = 0.684) were not significantly different between the two groups. According to the findings of subgroup analyses, no patient had a favorable OS when using either of the two regimens. In conclusion, although our PS-matched cohort mainly comprised older patients who had a low hematopoietic cell transplantation-comorbidity index and low-risk disease status, Flu/Bu4 could be an alternative to Bu4/Cy for MDS patients prior to allo-HSCT.

PURPOSE: The anti-leukemic activity of allogeneic hematopoietic cell transplantation (HCT) depends on both the intensity of conditioning regimen and the strength of the graft-versus-leukemia (GVL) effect. However, it is unclear whether the sensitivity of the GVL effects differs between donor type and graft source. EXPERIMENTAL DESIGN: We retrospectively evaluated the effect of acute and chronic graft-versus-host disease (GVHD) on transplant outcomes for adults with acute leukemia (n = 6,548) between 2007 and 2017 using a Japanese database. In all analyses, we separately evaluated three distinct cohorts based on donor type [(8/8 allele-matched sibling donor, 8/8 allele-matched unrelated donor, and unrelated single-cord blood (UCB)]. RESULTS: The multivariate analysis, in which the development of GVHD was treated as a time-dependent covariate, showed a reductive effect of grade I-II acute GVHD on treatment failure (defined as 1-leukemia-free survival; P < 0.001), overall mortality (OM; P < 0.001), relapse (P < 0.001), and non-relapse mortality (NRM; P < 0.001) in patients receiving from UCB. A reductive effect of limited chronic GVHD on treatment failure (P < 0.001), OM (P < 0.001), and NRM (P < 0.001) was also shown in patients receiving from UCB. However, these effects were not always shown in patients receiving from other donors. The beneficial effects of mild acute and chronic GVHD after UCB transplantation on treatment failure were noted relatively in subgroups of patients with acute myelogenous leukemia and a non-remission status. CONCLUSIONS: These data suggested that the development of mild GVHD could improve survival after UCB transplantation for acute leukemia.

Molecular relapse after allogeneic hematopoietic cell transplantation (allo-HCT) has been thought to predict clinical relapse in patients with Philadelphia chromosome-positive acute lymphoblastic leukemia (PhALL). Tyrosine kinase inhibitor (TKI) administration after allo-HCT may dynamically change the status from molecular relapse to molecular remission, but these state changes cannot be accurately represented by conventional survival indicators such as relapse-free survival, where events are usually considered irreversible. We aimed to develop novel indicators of transplant outcomes for allo-HCT recipients with PhALL and to visualize current molecular-relapse-free survival (CMRFS) and current on-TKI status (CTKI), treating molecular relapse or TKI administration after allo-HCT as a reversible event. We retrospectively analyzed 286 patients with PhALL who received allo-HCT between 2000 and 2016 in order to develop the indicators. CMRFS was defined as the probability of molecular remission without clinical relapse or death at any time after allo-HCT. Similarly, CTKI was defined as the probability of TKI administration without clinical relapse or death at any time after allo-HCT. The 1- and 5-year CMRFS rates were 67% and 59%, respectively, whereas the 1- and 5-year conventional molecular relapse-free survival rates were 42% and 37%. The 1- and 5-year CTKI rates were 14% and 8%, respectively. In a post hoc analysis focusing on patients who had achieved a molecular complete remission within 6 weeks (n = 201), the 5-year CMRFS rate (71%) was similar to the 5-year conventional molecular relapse-free survival (molRFS) rate (70%) in the non-TKI group. On the other hand, the 5-year CMRFS rate in the TKI group was 61%, whereas the 5-year conventional molRFS rate was only 38%. CMRFS and CTKI might become useful indicators of transplant success in terms of survival, leukemia-free status, and treatment-free status at any time point. Future extension of these survival models to other clinical situations is warranted.

Mutations of CCAAT/enhancer binding protein alpha (CEBPAmu) are found in 10-15% of de novo acute myeloid leukemia (AML) cases. Double-mutated CEBPA (CEBPAdm) is associated with a favorable prognosis; however, single-mutated CEBPA (CEBPAsm) does not appear to improve prognosis. We investigated the CEBPAmu for prognosis in 1028 AML patients, registered in the Multi-center Collaborative Program for Gene Sequencing of Japanese AML. It was found that CEBPAmu in the basic leucine zipper domain (bZIP) was strongly associated with a favorable prognosis, but CEBPAmu out of the bZIP domain was not. The presence of CEBPAmu in bZIP was a strong indicator of a higher chance of achieving complete remission (p<0.001), better overall survival (OS; p<0.001) and a lower risk of relapse (p<0.001). The prognostic significance of CEBPAmu in bZIP was also observed in the subgroup with CEBPAsm (all patients, OS: p=0.008; the cumulative incidence of relapse (CIR): p=0.063. patients aged ≤70 years and with intermediate-risk karyotype, OS: p=0.008; CIR: p=0.026). Multivariate analysis of 744 patients aged ≤70 years showed that CEBPAmu in bZIP was the most potent predictor of OS (hazard ratio: 0.3287; p<0.001). CEBPAdm was validated as a cofounding factor, which was overlapping with CEBPAmu in bZIP. In summary, these findings indicate that CEBPAmu in bZIP is a potent marker for AML prognosis. It holds potential in the refinement of treatment stratification and the development of targeted therapeutic approaches in CEBPA mutated AML.

Recipient cytomegalovirus (CMV) seropositivity is known to be a risk factor for CMV reactivation after allogeneic hematopoietic stem cell transplantation (allo-HCT). We explored the association of CMV-IgG titer of recipients with CMV reactivation after allo-HCT and developed a model for predicting CMV reactivation for the purpose of identifying a high-risk group. In addition, we evaluated the impact of CMV-IgG titer on survival outcomes and acute graft-versus-host disease (GVHD). We retrospectively analyzed 309 patients who achieved neutrophil engraftment after allo-HCT and evaluated whether pretransplantation recipient CMV-IgG titer was associated with transplantation outcomes, including CMV reactivation. Using the best cutoff value determined by a receiver operating characteristic curve analysis, we divided the study cohort into 3 groups: high-titer, low-titer, and negative. CMV reactivation occurred most frequently in the high-titer group, followed by the low-titer and negative groups (81%, 37%, and 16%, respectively, at 180 days after allo-HCT; P < .01). In a multivariate analysis, recipient CMV-IgG titer was significantly associated with subsequent CMV reactivation (hazard ratio [HR], 9.31 in the high-titer group [P < .01] and 2.91 in the low-titer group [P = .023]). CMV diseases were observed exclusively in the high-titer group. Overall survival (OS) was lower in the high-titer group compared with the other 2 groups (2-year OS, 56%, 60%, and 80%, respectively; P = .075), whereas the cumulative incidences of grade II-IV acute GVHD, nonrelapse mortality (NRM), and relapse were not significantly different among the 3 groups. In multivariate analyses, CMV-IgG titer was not associated with increased risks of these outcomes, although CMV reactivation itself was identified as a risk factor for NRM (HR, 3.05; P = .002). Our data demonstrate that a higher titer of recipient CMV-IgG is predictive of CMV reactivation after allo-HCT. Further investigation is needed to determine how to apply these results to prophylactic or preemptive strategies against CMV, considering recipient CMV-IgG titer for effective risk stratification.

Minimal residual disease (MRD) monitoring by quantitative real-time reverse transcription PCR (qRT-PCR) is the standard of care in Philadelphia chromosome-positive acute lymphoblastic leukemia (Ph-positive ALL). We evaluated the impact of MRD status at hematopoietic cell transplantation (HCT) on relapse, as measured by a unified protocol at a central laboratory. Only patients with Ph-positive ALL who had minor transcripts (e1a2) and who underwent allogeneic HCT in first complete remission between 2008 and 2017 were included. First, patients with negative-MRD (n = 196) and positive-MRD (n = 61) at HCT were analyzed. As expected, MRD positivity at HCT was significantly associated with an increased risk of hematological relapse (hazard ratio [HR], 2.91; 95% CI 1.67-5.08; P < 0.001) in the multivariate analysis. Next, patients with positive-MRD were divided into low-MRD (n = 39) and high-MRD (n = 22) groups. In the multivariate analysis, high-MRD at HCT was not significantly associated with an increased risk of hematological relapse compared to the low-MRD group (HR 1.10; 95% CI 0.54-2.83; P = 0.620). These results indicate that the therapeutic decisions should be made based on MRD positivity, rather than on the MRD level, at HCT.

Impact of donor age considering HLA disparity on hematopoietic cell transplantation (HCT) outcomes has not been fully evaluated. We evaluated 8486 patients who received unrelated bone marrow transplantation (UR-BMT) from 8/8 or 7/8 HLA-matched donors. Compared to 8/8 HLA-matched younger donors (<40 years), 8/8 HLA-matched older donors (subdistribution hazard ratio [SHR], 1.16; 95% CI, 0.97-1.38) and 7/8 HLA-matched younger donors (SHR, 1.33; 95% CI, 1.11-1.58) were associated with increased risk of grade III-IV acute graft-versus-host disease (aGVHD). 7/8 HLA-matched older donors had further increased risk (SHR, 2.00; 95% CI, 1.68-2.38) due to interaction between donor age and HLA disparity (p for interaction = 0.038). Progression-free survival (PFS) after UR-BMT with 8/8 HLA-matched younger donors was comparable to that after UR-BMT with 8/8 HLA-matched older donors, whereas UR-BMT with 7/8 HLA-matched younger or older donors was significantly associated with lower PFS than UR-BMT with 8/8 HLA-matched younger donors (younger donor; HR, 1.12; 95% CI, 1.04-1.21, older donor; HR, 1.28; 95% CI, 1.17-1.40; p for interaction = 0.079). In conclusion, adverse effect of increased donor age requires attention, especially in HLA-mismatched UR-BMT due to interaction between donor age and HLA disparity. Intensive aGVHD prophylaxis may be required to improve outcomes after HCT with mismatched older donors.

Allogeneic hematopoietic cell transplantation (HCT) is a potentially curative post-remission therapy for adult patients with acute myeloid leukemia (AML) in complete remission (CR). The availability of alternative human leukocyte antigen (HLA)-mismatched donors, such as cord blood and haploidentical related donors, could allow patients to receive allogeneic HCT who are without an HLA-matched sibling or unrelated donor. The use of these alternative donors is preferable for patients with advanced disease due to the rapid availability. However, comparative data for cord blood transplantation (CBT) and haploidentical related donor transplantation (haplo-HCT) are limited for adult patients with AML in CR. We sought to compare overall survival (OS); leukemia-free survival (LFS); graft-versus-host disease (GVHD)-free, relapse-free survival (GRFS); and chronic GVHD-free, relapse-free survival (CRFS) between single-unit CBT (SCBT) and haplo-HCT recipients for adult patients with intermediate- or poor-risk AML in CR. We retrospectively analyzed and compared the results of allogeneic hematopoietic cell transplantation in 1313 adult patients with intermediate- or poor-risk AML in CR who received either SCBT (n = 1102) or unmanipulated haplo-HCT (n = 211) between 2007 and 2018 in Japan. Among the whole cohort, the cumulative incidences of neutrophil and platelet recovery were significantly lower in SCBT recipients compared with those in haplo-HCT recipients (P < .001 for neutrophil, P < .001 for platelet). SCBT was significantly associated with a higher incidence of grade II to IV acute GVHD and lower incidence of extensive chronic GVHD compared to haplo-HCT (P = .013 for grades II to IV acute GVHD; P = .006 for extensive chronic GVHD). Haplo-HCT recipients developed a higher incidence of cytomegalovirus (CMV) antigenemia compared to SCBT recipients (P = .004). In the multivariate analysis, there were no significant differences for grades III or IV acute GVHD (hazard ratio [HR], 1.17; 95% confidence interval [CI], .88 to 1.57; P = .26), relapse incidence (HR, 1.09; 95% CI, .76 to 1.58; P = .61), non-relapse mortality (HR, .83; 95% CI, .58 to 1.18; P = .32), OS (HR, .92; 95% CI, .70 to 1.20; P = .56), LFS (HR, .94; 95% CI, .73 to 1.21; P = .67), GRFS (HR, 1.12; 95% CI, .90 to 1.40; P = .27), or CRFS (HR, 1.15; 95% CI, .92 to 1.44; P = .19) between the two donor types. In the propensity score matching analysis, which identified 180 patients in each cohort, there were no significant differences in transplant outcomes between the two donor types, except for delayed neutrophil (P < .001) and platelet recovery (P < .001) and a higher incidence of grades II to IV acute GVHD (P = .052) in SCBT. SCBT and unmanipulated haplo-HCT had similar survival outcomes for adult patients with AML in CR despite the lower hematopoietic recovery and higher grade II to IV acute GVHD in SCBT recipients and the higher CMV antigenemia in haplo-HCT recipients.

Most acute leukemia patients receive consecutive intensive chemotherapy, which usually takes several months before allogeneic hematopoietic stem cell transplantation (allo-HCT). Intensive chemotherapy often induces gastrointestinal adverse events. These adverse events leave patients in a state of malnutrition, leading to a reduction in body weight. In this study, we analyzed the impact of body weight loss before allo-HCT on survival outcomes of acute leukemia patients (acute myeloid leukemia, acute lymphoid leukemia and mixed phenotype acute leukemia). A loss of body weight (LBW), which was a reduction of body weight from diagnosis or relapse to transplantation, was calculated in 182 acute leukemia patients who received first allo-HCT at our center between June 2006 and September 2019. A receiver operating characteristics curve for nonrelapse mortality (NRM) was plotted for defining the cut-off value of LBW. The cutoff value of LBW was defined as 13.2%. A higher LBW was significantly associated with inferior NRM and overall survival (OS) (2-year [2y] NRM 36.1% versus 11.5%, P = .0025; 2y-OS 39.9% versus 65.8%, P = .020). The adverse impact of LBW was also confirmed in multivariate analyses for NRM and OS (HR of NRM 2.74 [1.25-6.03], P = .0012; HR of OS 2.06 [1.00-3.07], P = .0049). The main cause of death included disease progression (n = 34) and infection (n = 35). Death cause by infection was more frequently observed in the high-LBW group (15 cases [35.7%] versus 20 cases [14.3%]; P = .0035). In addition, subgroup analyses based on a combination of the body mass index at diagnosis and LBW were performed. When the non-overweight-low LBW group (body mass index [BMI] ≤25 and LBW ≤13.2%) was used as a reference in multivariate analysis, the overweight-high LBW group (BMI >25 and LBW >13.2%) showed an increased risk of poor survival outcomes (HR of NRM 4.27 [95% confidence interval {CI}, 1.82-10.0], P < .001; HR of OS 1.93 [95%, CI 1.00-3.71], P = .050). High LBW was significantly associated with inferior survival outcomes, and the adverse effect of malnutrition might be greater than the favorable effect of the reduction in overweight.

Mesenchymal stromal cells (MSCs) have been shown to inhibit aerobic glycolysis in activated T cells, leading to increased autophagy. Although tryptophan depletion induced by indoleamine 2,3-dioxygenase (IDO) generated by MSCs has been suggested as a potential mechanism, we found that this inhibition was completely abolished when T cells were physically separated from MSCs using the Transwell system. Instead, in the current study, we demonstrate that programmed cell death 1 receptor (PD-1) and its ligand PD-L1, the expression of which is induced on activated T cells and MSCs, respectively, in response to IFN-γ are involved in this inhibition. Blockade of PD-1/PD-L1 interaction by blocking antibodies significantly restored glucose uptake, glycolytic activity, and cluster formation of activated T cells, whereas a specific inhibitor of IDO, 1-methyl-DL-tryptophan, had no effect. Neither surface nor cytoplasmic glucose transporter-1 expression on T cells was changed by MSCs. In addition, glycolytic gene expression in activated T cells was not inhibited despite the presence of MSCs. However, we found that hexokinase II (HK2) protein expression was markedly decreased in activated T cells that had been cocultured with MSCs. PD-1 blocking antibody restored HK2 expression. Taken together, our findings indicate that the PD-1/PD-L1 axis is involved in the MSC-mediated suppression of T cell glycolysis by negatively regulating HK2 activity at the protein level, but not at the mRNA level.

BACKGROUND: We retrospectively compared the impact of the areas over and under the lymphocyte curve (L_AOC vs L_AUC) on cytomegalovirus (CMV) reactivation after allogeneic hematopoietic stem cell transplantation (HSCT). METHODS: Among 394 consecutive patients who underwent their first allogeneic HSCT at our center between 2007 and 2018, 301 patients met the inclusion criteria. L_AOC was calculated as the area over the lymphocyte curve during lymphopenia (absolute lymphocyte count [ALC] <700/μL). We calculated L_AOC and L_AUC from day 0 to day 15 (L_AOC15, L_AUC15) and from day 0 to day 30 (L_AOC30, L_AUC30). RESULTS: CMV antigenemia was defined as more than 3 cells/2 slides by the C10/11 method and detected in 204 cases (CMV reactivation) at a median of 39 days after HSCT. Although there were significant differences in L_AOC15, L_AOC30, L_AUC15, and L_AUC30 between patients with and without CMV reactivation, there was no difference in accuracy for predicting CMV reactivation between L_AOC and L_AUC. In a multivariate analysis, L_AOC15 and L_AUC15 were each identified as independent predictive factors for CMV reactivation, along with advanced age and CMV serostatus. However, ALC at day 14 or day 21 was as accurate as area-based indexes such as L_AOC15 and L_AUC15. L_AOC15 and L_AUC15 were significantly associated with longer duration of anti-CMV antiviral therapy while ALC was not. CONCLUSIONS: L_AOC15 and L_AUC15 had similar impacts on CMV reactivation. Although these area-based indexes were not superior to ALC for predicting CMV reactivation, they might predict patients who need longer duration of antiviral therapy more accurately.

Although measurable residual disease (MRD) at the time of allogeneic hematopoietic cell transplantation (allo-HCT) has been reported to be an important prognostic factor for Philadelphia chromosome (Ph)-positive acute lymphoblastic leukemia (ALL) during first complete remission (CR1), the prognostic impact of MRD is unclear during second CR (CR2). To clarify the impact of MRD for both CR1 and CR2, we analyzed data from a registry database including 1625 adult patients with Ph+ ALL who underwent first allo-HCT during either CR1 or CR2 between 2002 and 2017. Adjusted overall and leukemia-free survival rates at 4 years were 71% and 64%, respectively, for patients undergoing allo-HCT during CR1 with MRD-, 55% and 43% during CR1 with MRD+, 51% and 49% during CR2 with MRD-, and 38% and 29% during CR2 with MRD+. Although survival rates were significantly better among patients with CR1 MRD- than among patients with CR2 MRD-, no significant difference was observed in survival rate between patients with CR1 MRD+ and CR2 MRD-. Relapse rates after 4 years were 16% in patients with CR1 MRD-, 29% in CR1 MRD+, 21% in patients with CR2 MRD-, and 46% in patients with CR2 MRD+. No significant difference was identified in relapse rate between patients with CR1 MRD- and CR2 MRD-. CR2 MRD- was not a significant risk factor for relapse in multivariate analysis (hazard ratio, 1.26; 95% confidence interval, 0.69-2.29; P = .45 vs CR1 MRD-). MRD at time of allo-HCT was an important risk factor in patients with Ph+ ALL during both CR1 and CR2.

A multicenter retrospective study was conducted to evaluate the clinical significance of preconditioning intervention (PCI) before allogeneic hematopoietic cell transplantation (HCT) in patients with acute myelogenous leukemia (AML) not in remission. The study cohort consisted of 519 patients classified according to the intensity (intensive/moderate) of PCI and their response to PCI. The group treated with PCI had higher blast counts in the peripheral blood (PB) and had a lower overall survival (OS) rate (P < .001) and higher nonrelapse mortality (NRM) rate (P = .035) compared with those without PCI (no PCI group). Approximately 40% of the patients (68 of 236) achieved a good response to PCI (good PCI group), and those patients had lower blast counts in the PB compared with the group with poor response to PCI (poor PCI group). OS in the good PCI group was comparable to that in the no PCI group and significantly better than that in the poor PCI group (hazard ratio, .54; 95% confidence interval, .39 to .77; P < .001). However, OS was significantly lower in patients with intensive/moderate PCI compared with the no PCI group. These results suggest that PCI increases NRM without decreasing the post-transplantation relapse rate, but may be beneficial for patients with lower blast counts in PB irrespective of its intensity.

Graft-versus-host disease is a major complication after allogeneic hematopoietic stem cell transplantation for hematological malignancies. Immunosuppressive drugs, such as anti-thymocyte globulin, alemtuzumab, and post-transplant cyclophosphamide, have been used to prevent graft-versus-host disease in HLA-mismatched haploidentical hematopoietic stem cell transplantation. Here, we investigated whether these drugs could ameliorate graft-versus-host disease without diminishing the graft-versus-leukemia effect by using a xenogeneic transplanted graft-versus-host disease/graft-versus-leukemia model. Anti-thymocyte globulin treatment diminished graft-versus-host disease symptoms, completely depleted the infiltration of inflammatory cells in the liver and intestine, and led to prolonged survival. By contrast, improvement after post-transplant cyclophosphamide treatment remained minimal. Alemtuzumab treatment modestly prolonged survival despite an apparent decrease of Tregs. In the graft-versus-leukemia model, 1.5 to 2.0 mg/kg of anti-thymocyte globulin and 0.6 to 0.9 mg/kg of alemtuzumab reduced graft-versus-host disease with minimal loss of graft-versus-leukemia effect. Mice treated with 400 mg/kg of post-transplant cyclophosphamide did not develop graft-versus-host disease or leukemia, but it was difficult to evaluate the graft-versus-leukemia effect due to the sensitivity of A20 cells to cyclophosphamide. Although the current settings provide narrow optimal therapeutic windows, further studies are warranted to maximize the benefits of each immunosuppressant.

BACKGROUND: Despite a strong association between acute graft-versus-host disease (GVHD) and cytomegalovirus reactivation (CMVR), the joint effect of acute GVHD and CMVR on nonrelapse mortality (NRM) has not been well studied. METHODS: We evaluated the impact of CMVR on NRM stratified according to the development of acute GVHD using a landmark method. This study included 6078 patients who received their first allogeneic hematopoietic cell transplantation (HCT) with a pre-emptive strategy for CMVR between 2008 and 2017. RESULTS: The cumulative incidences of grade II-IV acute GVHD (G24GVHD), CMVR by day 100, and CMV disease by day 365 were 37.3%, 52.1%, and 2.9%, respectively. Patients with G24GVHD were associated with the subsequent development of CMVR, and the presence of CMVR also increased the risk of G24GVHD. In a landmark analysis at day 65, the cumulative incidence of NRM at 1 year was 5.4%, 10.0%, 13.9%, and 19.7% in patients with G24GVHD-/CMVR-, G24GVHD-/CMVR+, G24GVHD+/CMVR-, and G24GVHD+/CMVR+, respectively. In a multivariate analysis, CMVR was respectively associated with an increased risk of NRM by day 365 in patients without G24GVHD (HR [hazard ratio], 1.59, 95% CI, 1.24-2.05, P < 0.001) and with G24GVHD (HR, 1.34, 95% CI, 1.06-1.70, P = 0.014), but the interaction between G24GVHD and CMVR was not significant (P = 0.326). Subgroup analyses suggested that the joint effect of acute GVHD and CMVR might vary according to the baseline characteristics. CONCLUSIONS: These data regarding the close relationship between acute GVHD and CMVR should provide important implications for the treatment strategy after HCT.

This study aimed to analyze the factors associated with outcomes of bone marrow transplantation (UR-BMT) or cord blood stem cell transplantation from unrelated donors (UR-CBT). We assessed the time from diagnosis to transplantation among acute myeloid leukemia (AML) patients with intermediate- or poor-risk cytogenetics to identify the potential clinical efficacy of transplantation. We retrospectively analyzed 5331 patients who received UR-BMT or UR-CBT between 2008 and 2017. Patients were divided into four groups according to time from diagnosis to transplantation: (1) UR-BMT and > 5 months (n = 2353), (2) UR-BMT and ≤ 5 months (n = 379), (3) UR-CBT and > 5 months (n = 1494), and (4) UR-CBT and ≤ 5 months (n = 1106). There was no difference in overall survival (OS) for transplantation at ≤5 months and > 5 months in patients with first complete remission for both UR-BMT and UR-CBT, but OS in patients with primary induction failure (PIF) and transplantation at ≤ 5 months was significantly higher in the UR-CBT group compared with that at >5 months (P < 0.001). Multivariate Cox regression analysis also showed that transplantation at >5 months in patients with PIF was an independent predictor of poorer OS. Therefore, UR-CBT at ≤ 5 months after diagnosis is an alternative option for AML patients with PIF.

BACKGROUND: We retrospectively evaluated the association between the D-index, which reflects both the depth and duration of neutropenia, and proven/probable invasive fungal disease (IFD) early after allogeneic hematopoietic stem cell transplantation (HSCT) at our center (n = 394). METHODS: The D-index was defined as the area over the neutrophil curve during neutropenia. The cumulative D-index from the start of neutropenia until the development of infection (c-D-index) was also evaluated as a real-time assessment of neutropenia. RESULTS: There were 19 cases of early proven/probable IFD before and within 1 week after engraftment. Fifteen cases (78.9%) were seen as breakthrough infection while on empiric (n = 7), preemptive (n = 4) or prophylactic (n = 4) antifungal administration with mold-active agents. The c-D-index and lower performance status were identified as independent significant predictive factors for IFD. A receiver operating characteristic (ROC) curve analysis showed that the D-index and c-D-index were more accurate than the simple duration of neutropenia and as accurate as the duration of profound neutropenia for predicting IFD. The sensitivity, specificity, and positive and negative predictive values of the c-D-index using an appropriate cutoff (CO) value (10 644) determined by ROC curve analysis were 73.1%, 63.2%, 9.1%, and 97.9%, respectively. The advantage of the c-D-index to cumulative days of neutropenia in terms of positive and negative predictive values seemed to be small. CONCLUSIONS: The appropriate CO value for the c-D-index for predicting IFD was as high as 10 644 in allogeneic HSCT with a more frequent use of empiric antifungal therapy. The c-D-index is useful for assessing the risk of breakthrough IFD.

The pulmonary function test (PFT) is an important test for risk stratification before allogeneic transplantation (allo-HCT). However, it might be preferable to avoid PFT as much as possible in the recent era of coronavirus disease 2019 (COVID-19), because PFT requires forced expirations and might produce aerosols, increasing the risk of COVID-19 transmission. Therefore, we tried to predict normal PFT results before allo-HCT based on computed tomography (CT) findings. This study included 390 allo-HCT recipients at our center for whom lung CT images and PFT results before allo-HCT were available. Abnormal CT findings were less likely to be observed in the normal PFT group (47.0% versus 67.4%, P = .015), with a high negative predictive value of 92.9%. In a multivariate analysis, normal CT was significantly associated with normal PFT (odds ratio, 2.47; 95% confidence interval, 1.22 to 4.97; P = .012). A model for predicting normal PFT was constructed based on the results of a multivariate analysis, and the area under the curve of the receiver operating characteristic analysis was 0.656, which gave a sensitivity of 45.5% and a specificity of 86.0%. The relatively high specificity of the model suggested that PFT can be omitted in patients with normal CT findings before allo-HCT.

Graft failure (GF) is a life-threatening complication after allogeneic stem cell transplantation (SCT). Although salvage SCTs can be performed with haploidentical donor (HID) or cord blood (CB), no study has compared the performances of these two sources. Using nationwide registration data, we compared the transplant outcomes of patients who developed GF and underwent salvage transplantation from HID (n = 129) and CB (n = 570) from 2007 to 2016. The HID group demonstrated better neutrophil recovery (79.7 vs. 52.5% at 30 days, P < 0.001). With a median follow-up of 3 years, both groups demonstrated similar overall survival (OS) and nonrelapse mortality (NRM; 1-year OS, 33.1 vs. 34.6% and 1-year NRM, 45.1 vs. 49.8% for the HID and CB groups). After adjustments for other covariates, OS did not differ in both groups. However, HID was associated with a lower NRM (hazard ratio, 0.71; P = 0.038) than CB. The incidence of acute graft-versus-host disease (GVHD)-related deaths was significantly higher in the HID group, although infection-related deaths were observed more frequently in the CB group. HID may be a promising salvage SCT option after GF due to its faster engraftment and low NRM.

The major limitation of cord blood transplantation (CBT) for adults remains the delayed hematopoietic recovery and higher incidence of graft failure, which result in a higher risk of early mortality in CBT. We evaluated early overall survival (OS), non-relapse mortality (NRM), neutrophil engraftment, acute graft-vs-host disease, and cause of early death among 9678 adult patients who received single-unit CBT in Japan between 1998 and 2017. The probability of OS at 100 days was 64.4%, 71.7%, and 78.9% for the periods 1998 to 2007, 2008 to 2012, and 2013 to 2017, respectively (P < .001). The cumulative incidences of NRM at 100 days during the same period were 28.3%, 20.8%, and 14.6%, respectively (P < .001). The cumulative incidences of neutrophil engraftment were also improved during the same period (P < .001). The most common cause of death within 100 days after CBT was bacterial infection in 1998 to 2007 and primary disease in the latter two time periods. Across the three time periods, the proportions of deaths from bacterial and fungal infection, graft failure, hemorrhage, sinusoidal obstructive syndrome, and organ failure decreased in a stepwise fashion. Landmark analysis of OS and NRM after 100 days showed that OS did not change over time in the multivariate analysis. Our registry-based data demonstrated a significant improvement of early OS after CBT for adults over the past 20 years. The landmark analysis suggested that improvement of early mortality could lead to an improvement of long-term OS after CBT.

Pulmonary complications are fatal adverse events after allogeneic hematopoietic cell transplantation (allo-HCT). On the other hand, smoking is a well-known risk factor for various pulmonary diseases and also increases the incidence of pulmonary complications and overall mortality in allo-HCT recipients. In this study, we retrospectively assessed the impact of smoking intensity on survival outcomes. This study included consecutive allo-HCT recipients at our center between June 2007 and May 2019 whose smoking profiles were available (n = 408); they were divided into high (pack-years >10, n = 171) and low (pack-years ≤10, n = 231) pack-years groups. In univariate analyses, nonrelapse mortality (NRM) and overall survival (OS) were significantly inferior in the high pack-years group (1-year NRM 26.6% versus 13.9%, P < .001; 1-year OS 58.4% versus 70.1%, P = .0067). However, this association was not observed in multivariate analyses. In subgroup analyses according to sex, the survival outcomes in the high pack-years group were significantly inferior in males (NRM hazard ratio [HR], 2.24 [95% confidence interval (CI), 1.23 to 4.07], P = .0082; OS HR, 1.54 [95% CI, 1.04 to 2.28], P = .031), but not in females (NRM HR, 0.587 [95% CI, 0.241 to 1.43], P = .24; OS HR, 0.689 [95% CI, 0.400 to 1.19], P = .18). In summary, high pack-years were associated with inferior survival of allo-HCT recipients, especially in males.

Natural killer (NK) cells expressing killer cell immunoglobulin-like receptors (KIRs) can recognize specific HLA class I molecules as their ligands. By studying a large Japanese transplant registry, we compared transplant outcomes between patients heterozygous for HLA-CAsn80/CLys80 (HLA-C1/C2) and those homozygous for HLA-C1 (HLA-C1/C1) among patients who had undergone HLA-matched hematopoietic stem cell transplantation (HSCT). A high frequency of KIR2DL1 with strong HLA-C2 binding capacity and a low frequency of HLA-C2 and KIR haplotype B are characteristic of the Japanese population. In our previous report, HLA-C1/C1 patients with myeloid leukemia were less likely to relapse than HLA-C1/C2 patients. We newly assessed 2884 patients with acute lymphoblastic leukemia (ALL) who received HLA-matched allogeneic HSCT and analyzed their leukemia relapses by using adjusted competing-risk methods. HLA-C1/C1 patients with ALL experienced significantly higher relapse rates than HLA-C1/C2 patients (hazard ratio [HR] = 1.55, P = .003), contrary to our results in patients with myeloid leukemia. We allocated patients with ALL to several subgroups and found a higher frequency of relapse (HR >1.8) in the HLA-C1/C1 group than in the HLA-C1/C2 group among patients with Ph-negative ALL, those who had no cytomegalovirus reactivation, those who received transplants from donors who were aged 41 years or older, and those who experienced acute graft-versus-host disease, especially if it required systemic treatment. One interpretation of our results is that KIR2DL1-positive NK cells disrupt T cells, antigen-presenting cells, or both from working efficiently in transplant immunity in HLA-C1/C1 patients with ALL. Another is that KIR2DS1-positive NK cells directly attack HLA-C2-positive ALL blasts in HLA-C1/C2 patients. Whether HLA-C2 can cause recurrence to decrease or increase in patients depending on the disease (ALL or myeloid leukemia) will be a very important finding. We hope that our results will provide clues to the real mechanisms behind relapse after transplantation in patients with different HLA profiles.

Some studies support the hypothesis that HLA genes and haplotypes evolved by natural selection through their protective abilities against specific infectious pathogens. However, very little is known regarding the impact of high-frequency HLA haplotypes on the risk of relevant infectious diseases among a given ethnic group. We evaluated the impact of high-frequency HLA haplotypes on cytomegalovirus (CMV) reactivation and infection in allogeneic hematopoietic stem cell transplantation (allo-HSCT) in a Japanese population as a model of infectious disease that has coexisted with humans. A total of 21,127 donor-patient pairs were analyzed. HLA-A-B-DRB1 haplotypes were estimated using the maximum probability algorithm. Seven haplotypes with >1% frequency were defined as high-frequency haplotypes (HfHPs). Homozygotes of HfHP and heterozygotes had significantly lower risk of CMV reactivation and infection (hazard ratio [HR] = 0.88, P = .009 and HR = 0.93, P = .003, respectively) than homozygotes of low-frequency HLA haplotypes (LfHPs). In subgroup analyses of a different donor source, these associations were statistically significant in unrelated donor transplants. Finally, CMV risk for homozygotes and heterozygotes of each HfHP was compared with that of homozygotes of LfHPs. The 2 most predominant HfHP groups (A*24:02-B*52:01-DRB1*15:02 group and A*24:02-B*07:02-DRB1*01:01 group) had a significantly lower risk of CMV reactivation and infection (HR = 0.86, P < .001 and HR = 0.91, P = .033, respectively). Our findings suggest that HfHPs may be protective against CMV reactivation and infection and that increased care regarding CMV reactivation and infection may be necessary for patients with LfHP after allo-HSCT.

The prognostic significance of FLT3-tyrosine kinase domain (TKD) mutations remains unknown. To investigate the prognostic impact of FLT3-TKD, 676 de novo acute myeloid leukemia (AML), we retrospectively analyzed cases and conducted a review of the literature. Of the 676 de novo AML cases, 34 (5.0%) were FLT3-TKD-positive; both FLT3-TKD and FLT3-ITD were noted in only two cases (0.3%). Although no significant differences in relapse-free survival (RFS) were noted, FLT3-TKD-positive cases showed better prognoses than FLT3-ITD-positive cases (FLT3-TKD versus FLT3-ITD, p = 0.152). For overall survival (OS), although FLT3-TKD-positive cases showed prognoses similar to those for FLT3-WT cases, their prognoses were significantly better than those of FLT3-ITD-positive cases (FLT3-TKD versus FLT3-ITD, p = 0.032). Moreover, the 5-year OS for FLT3-TKD-positive cases was 46.1%, indicating that this as an intermediate prognosis group. Although no reports from Asia have indicated a frequency of FLT3-TKD-positive cases > 10%, several reports from Europe and the United States have indicated frequencies > 10%. This suggests the possibility that FLT3-TKD-positive cases are less common in Asia than in Europe and the United States. We anticipate that in the future, the appearance of targeting agents, such as FLT3 inhibitors, will improve the prognosis of FLT3-TKD-positive AML relative to that of FLT3-WT AML.

To investigate optimal unit selection for umbilical cord blood transplantation (UCBT), we conducted a registry-based study of 1355 adults with acute myeloid leukemia in first or second complete remission who underwent single-unit UCBT. To be eligible for analysis, UCB units had to contain a total nucleated cell (TNC) dose of 2.0 × 107/kg or higher and present at least a 4/6-match for HLA-A, -B, and -DR antigens in line with clinical practice in Japan, both of which are less stringent criteria than those used in Western countries. Neither TNC dose nor the degree of HLA matching affected survival (P = 0.138 and P = 0.696, respectively). As for HLA-A, -B antigens and -DRB1 allele, better HLA matching was associated with lower non-relapse mortality (P = 0.011) but higher relapse (P = 0.046), resulting in no improvement in survival (P = 0.680). Taking the allele level for each HLA-A, -B, and -DRB1 into consideration was less useful for predicting non-relapse mortality (P = 0.198). These findings suggest that the less stringent criteria for UCB unit selection are acceptable for Japanese patient population and perhaps even more beneficial in terms of providing a better chance to find a suitable UCB unit.

We compared the effect of HLA single-antigen and single-allele mismatched unrelated bone marrow transplantation (UBMT) without in vivo/ex vivo T cell depletion. Becasue a single DRB1 mismatch is preferred among 1-allele or 1-antigen mismatched donors, we performed mismatched allele- or antigen-specific analyses with a single DRB1 mismatch as the reference. In adjusted comparison by multivariate analyses, an HLA-DRB1 single-allele mismatch resulted in a decreased risk of nonrelapse mortality (NRM; relative risk [RR], 1.33; 95% confidence interval [CI], 1.08 to 1.63, P = .006) compared with an HLA-DR single-antigen mismatch and conferred a decreased risk of NRM (RR, 1.25; 95% CI, 1.01 to 1.57; P = .025) and overall mortality (RR, 1.16; 95% CI, 1.00 to 1.37; P = .046) compared with an HLA-C single-antigen mismatch. Relative to an HLA-DRB1 single-allele mismatch, 2-mismatch transplants, including those with 1 or more antigen mismatches, resulted in a significantly increased risk of NRM (1-antigen/1-allele mismatch: RR, 1.68; 95% CI, 1.03 to 2.05; P < .001; 2-antigen mismatch: RR, 1.58; 95% CI, 1.04 to 2.02; P = .001) and overall mortality (1-antigen/1-allele mismatch: RR, 1.27; 95% CI, 1.09 to 1.47; P = .002; 2-antigen mismatch: RR, 1.27; 95% CI, 1.03 to 1.57; P = .02). NRM correlated with the combined number of mismatches and allele or antigen mismatches, with rates of 22%, 27%, 32%, 31%, and 38% at 4years for full match, single-allele mismatch, single-antigen mismatch, 2-allele mismatch, and 2 mismatches that included an antigen mismatch, respectively. Our results support the preference for an allele mismatch rather than an antigen mismatch in unrelated bone marrow donors with 1 DR mismatch or 2 mismatches for T cell-replete UBMT.

Antithymocyte globulin (ATG) is widely used to reduce acute graft-versus-host disease (aGVHD) and chronic GVHD (cGVHD). To clarify the different impacts of ATG for conditioning across different donor types, we retrospectively analyzed patients with acute leukemia (n = 6617) who underwent hematopoietic stem cell transplantation between 2008 and 2015 with ATG (n = 279) or without ATG (n = 6338). Because thymoglobulin is the only ATG drug approved for GVHD prophylaxis in Japan since September 2008, we included thymoglobulin alone in the present analysis. The survivors' median follow-up time was 1081 days. Patients were categorized into 5 groups: cord blood (CB; n = 1915), matched related donor (n = 1772), 1-antigen mismatched related donor (1-MMRD; n = 225), matched unrelated donor (MUD; n = 1742), and 1-allele mismatched unrelated donor (1-MMUD; n = 963). In multivariate analysis, ATG decreased overall survival (hazard ratio [HR], 1.403; P = .054) and GVHD-free/relapse-free survival (GRFS) (HR, 1.458; P = .053) in association with increased nonrelapse mortality (NRM) (HR, 1.608; P =03) with CB, whereas it improved GRFS (HR, 0.515; P < .01) and decreased grades II to IV aGVHD (HR, 0.576; P < .01), extensive cGVHD (HR, 0.460; P = .02), and NRM (HR, 0.545; P = .03) with 1-MMUD. ATG did not impact survival with 1-MMRD and MUD. The use of ATG in conditioning is beneficial due to the reduction in acute/chronic GVHD without increasing NRM or disease relapse only in 1-MMUD transplantation. On the other hand, ATG is not recommended for CB transplantation.

Blastic plasmacytoid dendritic cell neoplasm (BPDCN) is a rare skin-tropic hematological malignancy of uncertain pathogenesis and poor prognosis. We examined 118 BPDCN cases for cytomorphology, MYC locus rearrangement, and MYC expression. Sixty-two (53%) and 41 (35%) cases showed the classic and immunoblastoid cytomorphology, respectively. Forty-one (38%) MYC+BPDCN (positive for rearrangement and expression) and 59 (54%) MYC-BPDCN (both negative) cases were identified. Immunoblastoid cytomorphology was significantly associated with MYC+BPDCN. All examined MYC+BPDCNs were negative for MYB/MYBL1 rearrangement (0/36). Clinically, MYC+BPDCN showed older onset, poorer outcome, and localized skin tumors more commonly than MYC-BPDCN. MYC was demonstrated by expression profiling as one of the clearest discriminators between CAL-1 (MYC+BPDCN) and PMDC05 (MYC-BPDCN) cell lines, and its shRNA knockdown suppressed CAL-1 viability. Inhibitors for bromodomain and extra-terminal protein (BETis), and aurora kinases (AKis) inhibited CAL-1 growth more effectively than PMDC05. We further showed that a BCL2 inhibitor was effective in both CAL-1 and PMDC05, indicating that this inhibitor can be used to treat MYC-BPDCN, to which BETis and AKis are probably less effective. Our data will provide a rationale for the development of new treatment strategies for patients with BPDCN, in accordance with precision medicine.

In the opinion of the European LeukemiaNet (ELN), nucleophosmin member 1 gene mutation (NPM1 mut)-positive acute myeloid leukemia (AML) with an fms-like kinase 3-internal tandem duplication (FLT3-ITD) allele ratio (AR) <0.5 (low AR) has a favorable prognosis, and allogeneic hematopoietic stem cell transplant (allo-HSCT) in the first complete remission (CR1) period is not actively recommended. We studied 147 patients with FLT3-ITD gene mutation-positive AML, dividing them into those with low AR and those with AR of ≥0.5 (high AR), and examined the prognostic impact according to allo-HSCT in CR1. Although FLT3-ITD AR and NPM1 mut are used in the prognostic stratification, we found that NPM1 mut-positive AML with FLT3-ITD low AR was not associated with favorable outcome (overall survival [OS], 41.3%). Moreover, patients in this group who underwent allo-HSCT in CR1 had a significantly more favorable outcome than those who did not (relapse-free survival [RFS] P = .013; OS P = .003). Multivariate analysis identified allo-HSCT in CR1 as the sole favorable prognostic factor (RFS P < .001; OS P < .001). The present study found that prognosis was unfavorable in NPM1 mut-positive AML with FLT3-ITD low AR when allo-HSCT was not carried out in CR1.

High-dose melphalan followed by autologous hematopoietic stem cell transplantation (ASCT) is a standard treatment for younger myeloma patients. However, the correlation between its toxicity and renal impairment is not clear. We analyzed this relationship, focusing on estimated glomerular filtration rate (eGFR) as an index of renal function. We evaluated 78 multiple myeloma patients who underwent ASCT following high-dose melphalan at our center. Patients were divided into a higher eGFR group (eGFR ≥ 60) and a lower eGFR group (eGFR < 60). Multivariate analyses revealed that lower eGFR was independently associated with alkaline phosphatase elevation (OR 10.2, P = 0.038), mucositis (OR 10.5, P = 0.032), grade 2-4 co-elevation of both aspartate aminotransferase and alanine aminotransferase (OR 21.3, P = 0.016), delay of reticulocyte engraftment (HR 0.524, P = 0.034), and delay of platelet engraftment (HR 0.535, P = 0.0016). However, lower eGFR was not correlated with overall survival or time-to-next treatment. In summary, renal dysfunction secondary to administration of high-dose melphalan was associated with increased hepatic and mucosal toxicity and delay of hematological recovery, but did not affect survival outcomes.

The optimal treatment strategy for gastrointestinal graft-versus-host disease (GI-GVHD) after allogeneic hematopoietic cell transplantation remains to be established. We retrospectively analyzed 68 cases of GI-GVHD at our institution between 2007 and 2017. The survival outcomes were significantly inferior in patients who did not respond to the first-line treatment (1-year overall survival 27.3 vs 69.2%, P = 0.0017; non-relapse mortality 50.0 vs 18.6%, P = 0.026). After subsequent treatments, 18 patients were refractory to all steroid-based treatments such as steroid pulse therapy and oral beclomethasone dipropionate (BDP). However, these steroid-refractory cases showed a gradual increase in the response rate after the initial diagnosis of steroid refractoriness. This result may be explained by the problem of evaluating the response based solely on the volume of diarrhea, i.e., severe mucosal damage due to refractory GI-GVHD may require a long recovery and sometimes be complicated with other diseases. In conclusion, patients with GI-GVHD who failed to respond to the first-line treatment had inferior survival. However, later improvement may be observed without additional immunosuppressant other than steroid among patients who initially do not respond to steroid therapy. It is important to repeat colonoscopy in patients with refractory GI-GVHD to monitor the activity of GVHD.