[Kidney transplantation for end-stage renal disease after third allogeneic hematopoietic stem cell transplantation for Philadelphia chromosome-positive acute lymphoblastic leukemia].

An 18-year-old man underwent allogenic bone marrow transplantation (BMT) for Philadelphia chromosome-positive acute lymphoblastic leukemia (Ph+ALL). Ph+ALL relapsed 3 months after the first BMT, and the patient underwent a second BMT. However, Ph+ALL relapsed 4 months after the second BMT, and he received a haploidentical peripheral blood stem cell transplantation (haplo-PBSCT) from his father. Molecular complete remission was confirmed 29 days after haplo-PBSCT. However, the patient needed dialysis for end-stage renal disease due to thrombotic microangiopathy 3 years and 2 months after haplo-PBSCT. He received a kidney transplantation from his father 7 years and 10 months after haplo-PBSCT, and got off dialysis after the kidney transplantation. Immunosuppressive therapy with methylprednisolone, tacrolimus, and mycophenolate mofetil was started for kidney transplantation, but the dose of immunosuppressive agents was reduced successfully without rejection soon after kidney transplantation. The patient has maintained long-term remission since the haplo-PBSCT, and his kidney function was restored by the kidney transplantation from his father.

Outcomes of allogeneic haematopoietic stem cell transplantation with intensity-modulated total body irradiation by helical tomotherapy: a 2-year prospective follow-up study.

BACKGROUND AND OBJECTIVES: Intensity-modulated radiation therapy (IMRT) helps achieve good radiation dose conformity and precise dose evaluation. We conducted a single-centre prospective study to assess the safety and feasibility of total body irradiation with IMRT (IMRT-TBI) using helical tomotherapy in allogeneic haematopoietic stem cell transplantation (allo-HSCT). PATIENTS AND METHODS: Thirty-nine adult patients with haematological malignancy (acute lymphoblastic leukaemia [n = 21], chronic myeloid leukaemia [n = 6], mixed phenotype acute leukaemia [n = 5], acute myeloid leukaemia [n = 4], and malignant lymphoma [n = 3]) who received 12 Gy IMRT-TBI were enrolled with a median follow-up of 934.5 (range, 617-1254) d. At the time of transplantation, 33 patients (85%) achieved complete remission. The conditioning regimen used IMRT-TBI (12 Gy in 6 fractions twice daily, for 3 d) and cyclophosphamide (60 mg/kg/d, for 2 d), seven patients were combined with cytarabine, and five with etoposide. We set dose constraints for the lungs, kidneys and lens as the organs at risk. RESULTS: The mean doses for the lungs and kidneys were 7.50 and 9.11 Gy, respectively. The mean maximum dose for the lens (right/left) was 5.75/5.87 Gy. The 2-year overall survival (OS), disease-free survival (DFS), cumulative incidence of relapse (CIR) and non-relapse mortality (NRM) were 69, 64, 18 and 18%, respectively. Thirty-six patients developed early adverse events (AEs) (including four patients with Grade 3/4 toxicities), most of which were reversible oral mucositis and may partially have been related to IMRT-TBI. However, the incidence of toxicity was comparable to conventional TBI-based conditioning transplantation. None of the patients developed primary graft failure, or Grade III-IV acute graft-versus-host disease (GVHD). In late complications, chronic kidney disease was observed in six patients, a lower incidence compared to conventional TBI-based conditioning transplantation. No radiation pneumonitis or cataracts were observed in any of the patients. CONCLUSIONS: IMRT-TBI is safe and feasible for haematological malignancies with acceptable clinical outcomes.KEY MESSAGESIMRT-TBI-helical tomotherapy aids in accurate dose calculation and conformity.It could be used without any considerable increase in the rate of TBI-related AEs.Allo-HSCT with IMRT-TBI may be an alternative to conventional TBI for clinical use.

Dose-finding trial of azacitidine as post-transplant maintenance for high-risk MDS: a KSGCT prospective study.

This 3+3 dose-escalation phase I multicenter study investigated the optimal dose of azacitidine (AZA) for post-hematopoietic stem cell transplantation (HSCT) maintenance, which remains unknown in Japan. Recipients of a first HSCT for high-risk myelodysplastic syndromes (MDS, n = 12) or acute myeloid leukemia (AML) with antecedent MDS (n = 3) received post-HSCT AZA maintenance in 2015-2019. The optimal AZA dose was defined as the dose at which 50-70% of patients can complete four cycles without dose-limiting toxicity (DLT). The initial dose level 1 was set as 30 mg/m2 for 5 days per 28-day cycle, and dose levels 0, 2, and 3 were set as 20, 40, and 50 mg/m2. DLT was defined as any grade 3 non-hematological or grade 4 hematological toxicity. The 15 evaluable patients were 55 (37-64) years old. The median observation of the post-HSCT survivors was 935 (493-1915) days. The median number of days post-HSCT to the start of AZA was 101 (59-176). In the first, second, and third cohorts, five of nine patients completed four cycles at dose level 1. In the final cohort, five of six additional patients completed at the same dose. In total, 10 (67%) patients tolerated AZA 30 mg/m2, which was determined as optimal. DLT occurred in five cases: grade 3 hepatotoxicity, pneumonia, enterocolitis, and grade 4 thrombocytopenia and neutropenia. The 2-year overall survival and disease-free survival rates post-HSCT were 77.0% and 73.3%. Post-HSCT AZA maintenance was well-tolerated and merits further evaluation for patients with MDS or AML with antecedent MDS. Trial registration: UMIN000018791.

Weight-adjusted urinary creatinine excretion predicts transplant outcomes in adult patients with acute myeloid leukemia in complete remission.

Sarcopenia is a prognostic factor for cancer. Because creatinine is formed from creatine phosphate in muscle tissue, urinary creatinine excretion (UCE) serves as an index of muscle volume. However, as of yet, there are no studies assessing the clinical impact of UCE or weight- adjusted urinary creatinine excretion (WA-UCE) on allogeneic hematopoietic stem cell transplantation (allo-HSCT) recipients. We analyzed the association between pre-transplant WA-UCE and transplant outcomes among 164 adult patients with acute myeloid leukemia in complete remission who underwent their first allo-HSCT at our center. The patients were classified into a high (n = 106) and a low WA-UCE group (n = 58) for predicting overall survival (OS) based on the receiver operating characteristics curve. On multivariate analysis, low WA-UCE was associated with poor OS, progression-free survival and a high incidence of non-relapse mortality. WA-UCE has the potential to be an objective biomarker for predicting transplant outcomes, especially the incidence of infection-related death.

Central nervous system mucormycosis in a patient with hematological malignancy: A case report and review of the literature.

Invasive mucormycosis is a refractory fungal infection. Central nervous system (CNS) mucormycosis is a rare complication caused by infiltration from the paranasal sinuses or hematogenous dissemination. Here, we present a case of a brain abscess, due to mucormycosis, diagnosed using burr craniotomy. A 25-year-old Japanese woman with relapsed-refractory acute lymphoblastic leukemia underwent cord blood transplantation (CBT). The patient experienced prolonged and profound neutropenia, and oral voriconazole was administered as primary antifungal prophylaxis. The patient received a conditioning regimen on day -11 and complained of aphasia and right hemiparesis on day -6. Magnetic resonance imaging (MRI) revealed a T2-weighted high-intensity area in the left frontal cortex. A brain abscess was suspected, and liposomal amphotericin B (L-AMB) administration was started. The patient underwent CBT as scheduled and underwent neutrophil engraftment on day 14. Although the patient achieved complete remission on day 28, her consciousness level gradually deteriorated. MRI revealed an enlarged brain lesion with a midline shift sign, suggesting brain herniation. Craniotomy was performed to relieve intracranial pressure and drain the abscess on day 38, and a diagnosis of cerebral mucormycosis was confirmed. The L-AMB dose was increased to 10 mg/kg on day 43. Although the patient's consciousness level improved, she died of hemorrhagic cystitis and aspiration pneumonia. Cerebral mucormycosis should be suspected if neurological symptoms are observed in stem cell transplant recipients. Prompt commencement of antifungal therapy and debridement are crucial because mucormycosis has a poor prognosis.

[A favorable clinical course of acute myeloid leukemia with t (6;21;8)(p23;q22;q22)].

Variants of the t (8;21) (q22;q22) involving chromosome 8, 21, and other chromosomes account for about 3% of all t (8;21) (q22;q22) in patients with acute myeloid leukemia (AML). However, the prognosis of AML with variant t (8;21) remains unknown due to the scarcity of reported cases. Herein we report a case of AML with t (6;21;8) (p23;q22;q22). Fluorescence in situ hybridization confirmed a RUNX1-RUNX1T1 fusion signal on the derivative chromosome 8. This is the first report on a variant of t (8;21) involving the breakpoint 6p23. After induction chemotherapy, our patient achieved complete remission and has been stable for four years.

Cyclophosphamide-induced cardiotoxicity at conditioning for allogeneic hematopoietic stem cell transplantation would occur among the patients treated with 120 mg/kg or less.

Cyclophosphamide (CY)-induced cardiotoxicity involves rare lethal complications. We previously reported the cardiac events of 811 allogeneic hematopoietic stem cell transplant (allo-HSCT) recipients; 12 out of 811 recipients (1.5%) developed fatal heart failure. The mortality rate was also very high (91.6%, 11/12). CY dose (200 mg/kg or more) was reported as the independent risk factor. The main disease in patients treated with 200 mg/kg or more of CY was severe aplastic anemia (AA). Therefore, we reduced the dose of CY during conditioning for AA (from 200 to 100 mg/kg), and then we analyzed the clinical features of 294 patients who received a total dose of at least 100 mg/kg of CY. We also compared the clinical features between the current study and our previous study. The proportion of patients treated with at least 200 mg/kg of CY was reduced from 4.2% to 0%. However, CY-induced heart failure occurred in four of the 294 patients (1.4%), which was similar to the finding reported in our previous study (1.5%). Two of these four patients received a post-transplant CY (PTCy) regimen (CY 100 mg/kg). All four patients were treated in the cardiac intensive care unit (C-ICU), and two patients survived. In summary, even the CY dose of 120 mg/kg or less would cause cardiotoxicity. We should also carefully monitor patients treated with PTCy, considering the possibility of CY-induced cardiotoxicity. Early diagnosis and ICU management have contributed to improved outcomes.

Retrospective comparison of hematopoietic stem cell transplantation following reduced-intensity conditioning with fludarabine/low-dose melphalan plus 4 Gy TBI versus fludarabine/ busulfan plus 4 Gy TBI.

Fludarabine with intravenous busulfan (6.4 mg/kg; FB2) and fludarabine with intermediate-dose melphalan (140 mg/m2; FM140) are the most widely used reduced-intensity conditioning (RIC) regimens for allogeneic hematopoietic stem cell transplantation. FM140 generally has a lower relapse rate and higher non-relapse mortality (NRM), resulting in overall survival (OS) comparable to that seen with FB2. To evaluate the effect of reducing the melphalan dose, we retrospectively compared transplant outcomes in 156 patients who received FB2 (n = 103) or FM80 (n = 53) at our center (median age: 63 years; range 27-72 years). All patients received 4-Gy total body irradiation. Three-year OS, the cumulative incidence of relapse, and NRM were comparable between groups (FB2 vs. FM80, 58% vs. 47%, p = 0.24; 30% vs. 36%, p = 0.57; 17% vs. 21%, p = 0.44, respectively). There was no significant difference in the cumulative incidence of graft-versus-host disease (GVHD) at day 100, chronic GVHD at 3 years, or the 3-year GVHD-free/relapse-free survival rate. In the high-risk disease group, patients receiving FM80 tended to have lower 3-year OS (FB2 vs. FM80, 48% vs. 17%, p = 0.06). In summary, transplant outcomes following FB2 or FM80 were comparable except in patients with high-risk disease.

Cytomegalovirus reactivation is associated with an increased risk of late-onset invasive aspergillosis independently of grade II-IV acute graft-versus-host disease in allogeneic hematopoietic stem cell transplantation: JSTCT Transplant Complications Working Group.

There is a matter of debate about the clinical impact of cytomegalovirus (CMV) reactivation on the development of late-onset invasive aspergillosis (IA), which occurs 40 days or later after allogeneic hematopoietic stem cell transplantation (HSCT). Using a Japanese transplant registry database, we analyzed the risk factors for the development of late-onset IA in 21,015 patients who underwent their first allogeneic HSCT between 2006 and 2017. CMV reactivation was defined as the initiation of preemptive anti-CMV antiviral therapy. Overall, there were 582 cases of late-onset IA, which occurred at a median of 95 days after HSCT. The 2-year cumulative incidence was 3.4% (95% confidence interval (CI), 3.0-3.9) in patients with CMV reactivation within 40 days after HSCT and 2.5% (95% CI, 2.3-2.8) in those without it (P < 0.001). In a multivariate analysis, CMV reactivation as a time-dependent covariate was significantly associated with the development of late-onset IA (hazard ratio (HR) 1.40, P < 0.001), as well as grade II-IV acute GVHD, age > 50 and HCT-CI ≥ 3 in the entire cohort. If we focus on the subgroup without grade II-IV acute GVHD, which is generally an indication for systemic corticosteroid therapy (n = 12,622), CMV reactivation was still a significant factor for the development of late-onset IA (HR 1.37, P = 0.045) as well as age > 50 years, HCT-CI ≥ 3, and cord blood transplantation. In conclusion, CMV reactivation was associated with an increased risk of late-onset IA after allogeneic HSCT independently of acute GVHD. Close monitoring for late-onset IA is necessary for patients who develop CMV reactivation even without grade II-IV acute GVHD.

Outcome of allogeneic hematopoietic stem cell transplantation for T-cell lymphoblastic leukemia/lymphoma: A single-center study.

Although the indications for allogeneic hematopoietic stem cell transplantation (allo-HSCT) as a treatment for T-cell acute lymphoblastic leukemia/lymphoma (T-ALL/LBL) and Philadelphia chromosome (Ph)-negative B-cell acute lymphoblastic leukemia (B-ALL) are similar, few studies have compared its outcomes for T-ALL/LBL and Ph-negative B-ALL. The clinical data of 28 patients with T-ALL, 16 with T-LBL, and 99 with Ph-negative B-ALL who underwent the first allo-HSCT from 2000 to 2019 were retrospectively analyzed. Complete remission (CR) rates at allo-HSCT were 79 %, 63 %, and 75 % for T-ALL, T-LBL, and B-ALL, respectively; the 3-year overall survival (OS) rates were 55.7 %, 56.2 %, and 58.6 %, respectively (p = 0.92). Univariate analysis revealed that disease subtypes were not significantly associated with OS (B-ALL vs. T-ALL: hazard ratio [HR]=0.89, p = 0.70; T-LBL vs. T-ALL: HR=0.87, p = 0.75), and CR at allo-HSCT was the only prognostic factor for OS (HR=0.25, p < 0.001). Multivariate analysis demonstrated that CR at allo-HSCT was the only predictor of OS (HR=0.24, p < 0.001). In all three disease subtypes, patients in CR at allo-HSCT tended to have a lower cumulative incidence of relapse than did those in non-CR (T-ALL: 13.6 % vs. 50.0 %, p = 0.10; T-LBL: 20.0 % vs. 50.0 %, p = 0.21; B-ALL: 10.0 % vs. 56.0 %, p < 0.01). Thus, the outcomes of allo-HSCT for T-ALL/LBL were comparable to those of Ph-negative B-ALL. Irrespective of the disease subtypes, achieving CR before allo-HSCT was associated with a favorable OS. Further advances in chemotherapy before allo-HSCT and defining the optimal timing of allo-HSCT would improve the prognosis of patients with T-ALL/LBL.

Successful Cord Blood Transplantation for Idiopathic CD4+ Lymphocytopenia.

Idiopathic CD4+ lymphocytopenia (ICL) is the depletion of CD4+ lymphocytes to <300 cells/mm3 without human immunodeficiency virus infection or other causes of lymphocytopenia. ICL causes fatal infections; its etiology remains unclear and it lacks consensus regarding therapeutic options. We report the first patient with ICL who had a successful clinical course following a cord blood transplant (CBT). A 45-year-old woman was diagnosed with ICL and underwent partial hepatectomy for an abscess caused by the Mycobacterium avium complex. No specific gene alterations were detected through next generation sequencing-based evaluation. Following a reduced-intensity conditioning (RIC) regimen consisting of fludarabine, busulfan, and 4 Gy total body irradiation, a single-unit CBT was performed. Neutrophils were engrafted on day +14. CD4+ lymphocyte counts increased to over 300 cells/mm3 on day +436. After 75 months, she was alive without any sequelae. CBT with an RIC regimen could be a curable treatment option for ICL.

Impact of the combination of donor age and HLA disparity on the outcomes of unrelated bone marrow transplantation.

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.

Changes in vaccination strategies contribute to the development of invasive pneumococcal disease in allogeneic hematopoietic stem cell transplantation recipients: a retrospective study for promoting vaccination.

Allogeneic hematopoietic stem cell transplantation (allo-HSCT) recipients are at high risk of developing invasive pneumococcal disease (IPD) with substantial morbidity and mortality. Pneumococcal polysaccharide vaccine (PPSV23) and pneumococcal conjugate vaccine (PCV13) are the primary prevention strategy. The difference between the Japanese and international guidelines is limited except when to start PCV13. However, Japanese data regarding the incidence of IPD after allo-HSCT that include vaccination status are limited. Therefore, we aimed to study the clinical characteristics of patients with IPD following allo-HSCT, focusing on unvaccinated patients. We retrospectively reviewed allo-HSCT recipients between April 2005 and December 2018 at Komagome Hospital. Among 1,091 recipients, 11 (1008/100,000 recipients) developed 13 episodes of IPD. The median period from the first allo-HSCT to the first IPD episode was 686 days (10-3040 days). Ten patients developed IPD before vaccination, and seven of these unvaccinated patients with late-onset IPD were ineligible for vaccination based on domestic guidelines. Although appropriate treatments resulted in a good short-term prognosis, most episodes of IPD developed in unvaccinated allo-HSCT recipients. Our data support the promotion of better adherence to the current guidelines and the importance of pneumococcal vaccination even years after allo-HSCT to protect against late-onset IPD.

Prognostic impact of TP53 mutation, monosomal karyotype, and prior myeloid disorder in nonremission acute myeloid leukemia at allo-HSCT.

Outcomes after allogeneic hematopoietic stem cell transplantation (allo-HSCT) in nonremission acute myeloid leukemia (AML) are dismal [2-year overall survival (OS): 20-30%]. Though several risk classifications have been used, some factors are unavailable until the start of conditioning or transplantation. We analyzed prognostic gene mutations by targeted next-generation sequencing to identify predisposing factors for predicting OS at 1 month before transplantation. We enrolled 120 patients with nonremission AML who underwent first allo-HSCT between 2005 and 2018. Mutations were found in 98 patients; frequently mutated genes were FLT3-ITD, TP53, RUNX1, and WT1. TP53 mutation was detected in 21 patients and was the only predictor of poor OS. Multivariate analysis using Cox regression hazard model revealed primary AML, monosomal karyotype (MK), and TP53 mutation as independent factors for predicting poor OS. Based on these, patients were stratified into three groups. The low-risk group included patients with prior myeloid disorder without MK (n = 26). Among the rest, patients with TP53 mutation were assigned to the high-risk group (n = 19) and the rest into the intermediate-risk group (n = 75). Two-year OS in low-, intermediate-, and high-risk groups differed significantly (50.0%, 24.9%, and 0%, respectively). This suggests that the indication of allo-HSCT should be carefully judged for high-risk patients.

Mechanical stimulation is a risk factor for phlebitis associated with peripherally inserted central venous catheter in neonates.

BACKGROUND: Our peripherally inserted central venous catheter (PICC) management plan for neonates previously included routine inspection for swelling and induration of the insertion site of a PICC using palpation. However, we discontinued routine palpation from July 13, 2018, owing to a peculiarly high incidence of PICC-related phlebitis. The aim of this study was to prove that routine palpation was the cause of PICC-related phlebitis. METHODS: We retrospectively reviewed medical records of infants who were admitted to the neonatal intensive care unit and underwent PICC placement from January 2018 to January 2019. The infants were classified into palpating (before July 13, 2018) and non-palpating (after or on July 13, 2018) groups. We analyzed and compared the incidence of PICC-related phlebitis in the two groups. RESULTS: Phlebitis related to PICC was more frequently observed in the palpating group (10/29 infants, 34.5%) than in the non-palpating group (1/31, 3.2%) (P = 0.002). After discontinuation of routine palpating in PICC management, the frequency of non-scheduled removal of the PICC due to phlebitis decreased. The indwelling period was significantly longer in the non-palpating group than in the palpating group. CONCLUSIONS: Our results suggest that mechanical stimulation using palpation of the insertion site was the cause of PICC-related phlebitis, resulting in early non-scheduled removal.

[Vacuolar myelopathy after allogeneic bone marrow transplantation in a patient with acute lymphoblastic leukemia].

Vacuolar myelopathy (VM) is known to be a neurological complication in patients with acquired immunodeficiency syndrome (AIDS). In autopsy-based studies, VM was reported in approximately 20-50% of patients with AIDS. It manifests in various says, mainly presenting as a painless spastic paraparesis with a sensory ataxia. We present a rare case of VM after bone marrow transplantation (BMT) in a patient without AIDS. A 50-year-old man developed weakness in the lower legs, leg muscle atrophy, and difficulty in walking 86 days after BMT. The patient died from septic shock on day 309. The autopsy revealed intralamellar vacuolation in the spinal white matter, which was compatible with VM.

T-cell receptor repertoire of cytomegalovirus-specific cytotoxic T-cells after allogeneic stem cell transplantation.

Cytomegalovirus (CMV) infection is a major complication during allogeneic stem cell transplantation (allo-SCT). However, mechanisms of adaptive immunity that drive this remain unclear. To define early immunological responses to CMV after transplantation, we using next-generation sequencing to examine the repertoire of T-cell receptors in CD8+/CMV pp65 tetramer+ cells (CMV-CTLs) in peripheral blood samples obtained from 16 allo-SCT recipients with HLA-A*24:02 at the time of CMV reactivation. In most patients, TCR beta repertoire of CMV-CTLs was highly skewed (median Inverse Simpson's index: 1.595) and, 15 of 16 patients shared at least one TCR-beta clonotype with ≥ 2 patients. The shared TCRs were dominant in 12 patients and, two clonotypes were shared by about half of the patients. Similarity analysis showed that CDR3 sequences of shared TCRs were more similar than unshared TCRs. TCR beta repertoires of CMV-CTLs in 12 patients were also analyzed after 2-4 weeks to characterize the short-term dynamics of TCR repertoires. In ten patients, we observed persistence of prevailing clones. In the other two patients, TCR repertoires became more diverse, major clones declined, and new private clones subsequently emerged. These results provided the substantive clue to understand the immunological behavior against CMV reactivation after allo-SCT.

Prebiotics protect against acute graft-versus-host disease and preserve the gut microbiota in stem cell transplantation.

Acute graft-versus-host disease (aGVHD) is a major cause of morbidity and mortality after allogeneic hematopoietic stem cell transplantation (allo-HSCT). Therefore, management of aGVHD is important for successful transplantation. Mucosal damage and alteration of the gut microbiota after allo-HSCT are key factors in the development of aGVHD. We conducted a prospective study to evaluate the ability of prebiotics, which can alleviate mucosal damage and manipulate the gut microbiota, to mitigate posttransplantation complications, including aGVHD. Resistant starch (RS) and a commercially available prebiotics mixture, GFO, were administered to allo-HSCT recipients from pretransplantation conditioning to day 28 after allo-HSCT. Prebiotic intake mitigated mucosal injury and reduced the incidence of all aGVHD grades combined and of aGVHD grades 2 to 4. The cumulative incidence of skin aGVHD was markedly decreased by prebiotics intake. Furthermore, the gut microbial diversity was well maintained and butyrate-producing bacterial population were preserved by prebiotics intake. In addition, the posttransplantation fecal butyrate concentration was maintained or increased more frequently in the prebiotics group. These observations indicate that prebiotic intake may be an effective strategy for preventing aGVHD in allo-HSCT, thereby improving treatment outcomes and the clinical utility of stem cell transplantation approaches. This study was registered on the University Hospital Medical Information Network (UMIN) clinical trials registry (https://www.umin.ac.jp/ctr/index.htm) as #UMIN000027563.