Immunohistopathological Analysis of Extramedullary Hematopoiesis and Angiogenesis of Spleen in a Case of Primary Myelofibrosis with Huge Splenomegaly.

Although splenomegaly is one of the important signs of primary myelofibrosis, the differential diagnosis varies from malignant disorders to benign disorders, including malignant lymphoma and sarcoidosis. The patient was a 67-year-old male who developed anemia and huge splenomegaly. The laboratory findings include human T-cell leukemia virus type 1 (HTLV-1) antibody, elevated soluble interleukin-2 receptor, hypocellular bone marrow, and uptake in the spleen on positron emission tomography/computed tomography scan. Additionally, we performed laparoscopic splenectomy to alleviate the clinical symptoms and to rule out malignant lymphoma. Histological findings revealed extramedullary hematopoiesis, characterized by the presence of erythroid islands and clusters of dysplastic megakaryocytes with increased reticulin fibrosis. Immunohistochemical staining revealed the presence of von Willebrand factor, dysplastic megakaryocytes, myeloperoxidase, myeloid-predominant proliferations, and CD34 immature myeloid cells. Furthermore, regarding the angiogenesis in the spleen, the endothelial cells of the capillaries and those of the sinusoidal vascular system that were reactive for CD34 and CD8, respectively, were also detected. Consequently, the histological findings revealed both extramedullary hematopoiesis and angiogenesis in spleen. Based on the histological findings and the identification of Janus activating kinase 2 (JAK-2) mutation, the patient was diagnosed with primary myelofibrosis. Splenectomy reduces blood transfusion requirements after surgery. The patient was carefully followed-up without further treatments. Thus, primary myelofibrosis is the crucial differential diagnosis of huge splenomegaly.

Single cord blood transplantation for acute myeloid leukemia patients aged 60 years or older: a retrospective study in Japan.

The availability of alternative donor sources could allow elderly patients to receive allogeneic hematopoietic cell transplantation (HCT). We retrospectively evaluated the outcomes of single-unit cord blood transplantation (CBT) in 1577 patients aged ≥60 years with acute myeloid leukemia (AML) in Japan between 2002 and 2017. In total, 990 (63%) patients were not in complete remission (CR) at the time of CBT. A myeloablative conditioning regimen (52%) and calcineurin inhibitor (CI) + mycophenolate mofetil (MMF)-based graft-versus-host disease (GVHD) prophylaxis (45%) were more commonly used. With a median follow-up for survivors of 31 months, the probability of overall survival and the cumulative incidence of leukemia-related mortality at 3 years was 31% and 29%, respectively. The cumulative incidence of non-relapse mortality (NRM) at 100 days and 3 years were 24% and 41%, respectively. The cumulative incidences of grade II-IV and grade III-IV acute GVHD at 100 days and extensive chronic GVHD at 2 years were 44%, 16%, and 14%, respectively. The cumulative incidence of neutrophil engraftment was 80% at 42 days. Results of multivariate analysis indicated that the following factors were significantly associated with higher overall mortality: performance status ≥1, hematopoietic cell transplantation-specific comorbidity index ≥3, adverse cytogenetics, extramedullary disease at diagnosis, and non-CR status at CBT. By contrast, female sex, HLA disparities ≥2, mycophenolate mofetil-based GVHD prophylaxis, and recent CBT were significantly associated with lower overall mortality. In conclusion, single CBT offers a curative option for AML patients aged ≥60 years with careful patient selection.

Updated Comparison of 7/8 HLA Allele-Matched Unrelated Bone Marrow Transplantation and Single-Unit Umbilical Cord Blood Transplantation as Alternative Donors in Adults with Acute Leukemia.

The outcomes of 7/8 allele-matched unrelated bone marrow transplantation (7/8 UBMT) and umbilical cord blood transplantation (UCBT) have been improving. We retrospectively analyzed adults with acute leukemia who underwent their first 7/8 UBMT or UCBT in Japan. Between January 2008 and December 2017, a total of 4150 patients were recorded, including 488 who underwent 7/8 UBMT and 3662 who underwent UCBT. Only 32 patients with 7/8 UBMT had graft-versus-host-disease (GVHD) high-risk HLA mismatched pairs. Overall survival at 3 years was 54% for 7/8 the UBMT group and 46% for the UCBT group, a nonsignificant difference in multivariate analysis (hazard ratio [HR], 1.01; 95% confidence interval [CI], .88 to 1.17; P = .89). The 7/8 UBMT and UCBT groups showed a similar nonrelapse mortality rate (HR, 1.16; 95% CI, .96 to 1.45; P = .16) and relapse rate (HR, .85; 95% CI, .71 to 1.02; P = .08). However, the UCBT group had a lower risk of grade II-IV acute GVHD (HR, .76; 95% CI, .65 to .88; P < .001) and chronic GVHD (HR, .77; 95% CI, .66- .91; P = .002) compared with the 7/8 UBMT group. In stratified analyses combining disease risk with conditioning intensity, 7/8 UBMT showed superior overall survival to UCBT in standard risk and myeloablative conditioning (HR, .72; 95% CI, .56 to .93; P = .014). Both 7/8 UBMT and UCBT are appropriate alternative donor procedures. The stem cell source can be selected on the basis of disease risk, patient tolerability, or concerns regarding GVHD.

Safety and Seropositivity after Live Attenuated Vaccine in Adult Patients Receiving Hematopoietic Stem Cell Transplantation.

Vaccination against vaccine-preventable diseases (VPDs) is highly recommended for hematopoietic stem cell transplantation (HSCT) recipients by several guidelines; however, the safety and seropositivity after live attenuated vaccines remain unclear in adult HSCT recipients. We analyzed titers of antibodies against measles, rubella, mumps, and varicella zoster virus (VZV) from Japanese adult patients who underwent allogeneic HSCT (allo-HSCT) (n = 74), autologous HSCT (auto-HSCT) (n = 39), or chemotherapy (n = 93). The seropositive rates for measles, rubella, mumps, and VZV in allo-HSCT recipients were 20.2%, 36.4%, 5.4%, and 55.4%, respectively. These rates were equivalent to those in auto-HSCT recipients but were significantly lower than those in patients receiving chemotherapy. Antibody titers tended to gradually decrease with time. Twenty-nine allo-HSCT recipients and 8 auto-HSCT recipients received live attenuated vaccines against VPDs for which they tested seronegative. The titers of antibodies against measles, rubella, and mumps significantly increased after 2 shots of vaccine, and the seropositive rate increased up to 19%, 30%, and 27%, respectively. Three patients (8.1%) experienced mild adverse events, which resolved promptly, indicating safe administration of the live attenuated vaccines. In multivariate analysis, history of chronic graft-versus-host disease was significantly associated with high seropositivity for measles as well as high seroconversion rate for measles after vaccination. Live attenuated vaccines against VPDs were safely administered in seronegative adult HSCT recipients. A further observational study is crucial to evaluate the efficacy of vaccination in seronegative HSCT patients.

Comparison of calcineurin inhibitors in combination with conventional methotrexate, reduced methotrexate, or mycophenolate mofetil for prophylaxis of graft-versus-host disease after umbilical cord blood transplantation.

Umbilical cord blood transplantation (UCBT) is a curative treatment for hematological malignancies. However, appropriate prophylaxis against graft-versus-host disease (GVHD), aimed at obtaining rapid and stable engraftment and avoiding toxicity, remains controversial in UCBT. We retrospectively compared outcomes in 409 patients who received calcineurin inhibitors (CIs) plus conventional-dose methotrexate (conv-MTX/CIs, n = 77; methotrexate, 10 mg/m2 on day 1, 7 mg/m2 on days 3 and 6) with those who received CIs plus reduced-dose methotrexate (reduced-MTX/CIs, n = 209; methotrexate, 5 mg/m2 or 5 mg/body on days 1, 3, and 6) or CIs with mycophenolate mofetil (MMF/CIs, n = 123) for GVHD prophylaxis after UCBT. The cumulative incidence of neutrophil engraftment was significantly higher in the reduced-MTX/CI (82.3%) and MMF/CI (86.6%) groups than the conv-MTX/CI (71.4%) group (p = 0.014), although there were no differences in platelet recovery or infectious complications among the three groups. The incidence and severity of GVHD were comparable among the three groups, and there were no significant differences in transplantation-related mortality among the three groups. In conclusion, GVHD prophylaxis with reduced-dose methotrexate and MMF was closely associated with high incidence of neutrophil engraftment without an effect on the incidence and severity of GVHD, which was compared to GVHD prophylaxis with conventional-dose methotrexate.

Increased non-relapse mortality due to high-dose cytarabine plus CY/TBI in BMT/PBSCT for acute lymphoblastic leukaemia in adults.

The efficacy of high-dose cytarabine (HDCA) plus cyclophosphamide/total-body irradiation (CY/TBI) has been proved in cord blood transplantation (CBT) for acute lymphoblastic leukaemia (ALL), but not in bone marrow or peripheral blood stem cell transplantation (BMT/PBSCT). In this cohort study, we compared the prognosis of CY/TBI (N = 1244) and HDCA/CY/TBI (N = 316) regimens in BMT/PBSCT for ALL. The addition of HDCA decreased post-transplant relapse, while significantly increasing non-relapse mortality (risk ratio, 1·33), and overall survival was not improved. The positive effects of HDCA reported in CBT cannot be extrapolated to BMT/PBSCT, and HDCA may not be recommended in these procedures.

Mogamulizumab Treatment Prior to Allogeneic Hematopoietic Stem Cell Transplantation Induces Severe Acute Graft-versus-Host Disease.

Mogamulizumab (MOG), a humanized anti-CC chemokine receptor 4 (CCR4) monoclonal antibody, has recently played an important role in the treatment of adult T cell leukemia/lymphoma (ATLL). Because CCR4 is expressed on normal regulatory T cells as well as on ATLL cells, MOG may accelerate graft-versus-host disease (GVHD) by eradicating regulatory T cells in patients with allogeneic hematopoietic stem cell transplantation (allo-HSCT). However, there is limited information about its safety and efficacy in patients treated with MOG before allo-HSCT. In the present study, 25 patients with ATLL were treated with MOG before allo-HSCT, after which 18 patients (72%) achieved remission. The overall survival and progression-free survival at 1 year post-transplantation were 20.2% (95% CI, 6.0% to 40.3%) and 15.0% (95% CI, 4.3% to 32.0%), respectively. The cumulative incidence of acute GVHD was 64.0% (95% CI, 40.7% to 80.1%) for grade II-IV and 34.7% (95% CI, 15.8% to 54.4%) for grade III-IV. The cumulative incidence of transplantation-related mortality (TRM) was 49.0% (95% CI, 27.0% to 67.8%). Six of 7 patients with acute GVHD grade III-IV died from GVHD, which was the leading cause of death. In particular, a shorter interval from the last administration of MOG to allo-HSCT was associated with more severe GVHD. MOG use before allo-HSCT may decrease the ATLL burden; however, it is associated with an increase in TRM due to severe GVHD. Because MOG is a potent anti-ATLL agent, new treatment protocols should be developed to integrate MOG at suitable doses and timing of administration to minimize unwanted GVHD development.

Significance of monitoring trough plasma concentration levels for invasive fungal infection prophylaxis with itraconazole oral solution in patients with hematological malignancies: a prospective study.

In this prospective study, we examined the prophylactic effect of itraconazole oral solution (ITCZ-OS) against invasive fungal disease in hematologic malignancy patients. The participants were 36 patients, at least 16 years of age, with hematologic malignancies treated at our hospital. ITCZ-OS 200 mg/day was administered orally twice a day with a target trough plasma concentration of 350 ng/ml. If the patient did not achieve the target trough plasma concentration, the dose was increased. The success rate of achieving the target trough plasma concentration of ITCZ with a dose of 200 mg/day was 63.9%. During the observation period, 2 patients (5.6%) were diagnosed with possible invasive fungal disease according to the EORTC/MSG 2008 criteria. Adverse events were observed in 2 patients (5.6%). The results showed administration of ITCZ-OS while monitoring ITCZ trough plasma concentrations to be effective for preventing invasive fungal disease, and no serious adverse events occurred. Since predicting trough levels in response to ITCZ administrations is difficult, its measurement is necessary to maintain the prophylactic effect of ITCZ.

The clinical impact of the ratio of C-reactive protein to albumin (CAR) in patients with acute- and lymphoma-type adult T-cell leukemia-lymphoma (ATL).

Recently, the ratio of C-reactive protein to albumin (CAR) is used as an inflammatory marker that has been demonstrated to be a simple and reliable prognostic factor in solid tumors and hematological malignancy. However, no studies of the CAR have been performed in patients with adult T-cell leukemia-lymphoma (ATL). We retrospectively analyzed the clinical features and outcomes in 68 newly diagnosed acute- and lymphoma-type ATL [(acute-(n=42) or lymphoma-type (n=26)] patients in Miyazaki Prefecture from 2013 to 2017. Furthermore, we investigated correlations between pretreatment CAR levels and clinical features. The median age was 67 years (range, 44 - 87). Patients were initially treated by either palliative therapy (n=14) or chemotherapy [n=54; CHOP therapy (n=37)/ VCAP-AMP-VECP therapy (n=17)], and showed median survival durations of 0.5 months and 7.4 months, respectively. The factors affecting OS by multivariate analysis were age, BUN, and CAR. Importantly, we revealed that the high CAR group (optimal cut-off point; 0.553) was a significant indicator of worse OS by multivariate analysis (p< 0.001, HR; 5.46). The median survival of patients with a CAR< 0.553 was 8.37 months, while patients with a CAR>0.553 had a median survival of 3.94 months. The different clinical features between high CAR and low CAR groups were hypoproteinemia and the implementation of chemotherapy. Furthermore, in the chemotherapy group, but not the palliative therapy group, CAR was a significant prognostic marker. Our study indicated that CAR may be a new simple and significant independent prognostic marker in acute- and lymphoma-type ATL patients.

Clinical characteristics of Japanese patients with myelodysplastic/myeloproliferative neoplasm with ring sideroblasts and thrombocytosis.

Myelodysplastic/myeloproliferative neoplasm with ring sideroblasts and thrombocytosis (MDS/MPN-RS-T) is a rare disease, which presents with features of myelodysplastic syndromes with ring sideroblasts and essential thrombocythemia, as well as anemia and marked thrombocytosis. SF3B1 and JAK2 mutations are often found in patients, and are associated with their specific clinical features. This study was a retrospective analysis of 34 Japanese patients with MDS/MPN-RS-T. Median age at diagnosis was 77 (range, 51-88) years, and patients had anemia (median hemoglobin: 9.0 g/dL) and thrombocytosis (median platelet count: 642 × 109/L). Median overall survival was 70 (95% confidence interval: 68-not applicable) months during the median follow-up period of 26 (range: 0-91) months. A JAK2V617F mutation was detected in 46.2% (n = 12) of analyzed patients (n = 26), while an SF3B1 mutation was detected in 87.5% (n = 7) of analyzed patients (n = 8). Like those with myelodysplastic syndromes or myeloproliferative neoplasms, patients often received erythropoiesis-stimulating agents and aspirin to improve anemia and prevent thrombosis. This study, which was the largest to describe the real-world characteristics of Japanese patients with MDS/MPN-RS-T, showed that the patients had similar characteristics to those in western countries.

Clinical features and treatment outcomes of isolated secondary central nervous system lymphomas in Miyazaki Prefecture.

BACKGROUND: Secondary central nervous system lymphoma (SCNSL) without extra-central nervous system (CNS) involvement is characterized by isolated secondary CNS relapse in malignant lymphoma patients. SCNSL is a rare disease, and no standard treatment has yet been established. PATIENTS AND METHODS: To elucidate the clinical characteristics and outcomes of SCNSL, we retrospectively analyzed 12 patients (median age 67 years) in Miyazaki prefecture for the last 5 years. RESULTS: The initial histological diagnoses of the patients were diffuse large B-cell lymphoma (DLBCL), mantle-cell lymphoma, and adult T-cell lymphoma in 9, 2, and 1 patient, respectively. We focused on analysis of the 9 SCNSL cases originating from DLBCL. The locations of CNS relapse were the cerebral hemisphere, basal ganglia, and cerebellum in 7, 1, and 1 patient, respectively. Three patients were treated with high-dose methotrexate (HD-MTX) therapy; 4 with whole-brain radiation therapy (WBRTX); and 1 with both HD-MTX and WBRTX. The remaining patients were treated with rituximab. Partial remission was achieved in 6 out of 9 patients (67%); the other 3 patients (33%) did not respond to therapy. Median survival of the 9 patients with CNS relapse was 253 days; 6 of the 9 patients survived for more than 6 months. As of March 2011, 2 HD-MTX group patients but none of the WBRTX group patients were alive. CONCLUSIONS: In this retrospective study, 6 of 9 patients with SCNSL originating from DLBCL survived for more than 6 months. Both HD-MTX and WBRTX had clinical benefits in the treatment of SCNSL.

Secondary Skin Cancer in a Case with Long-term Voriconazole after Allogeneic Hematopoietic Stem Cell Transplantation for Acute Myeloid Leukemia.

Secondary malignancies that develop after allogeneic-hematopoietic stem cell transplantation (allo-HSCT) have become serious issues. A 47-year-old man who developed acute myeloid leukemia in 2009 and subsequently underwent allo-HSCT twice: in 2009 and 2011. In 2015, voriconazole for lung aspergillus was started. In 2018, chronic graft-versus-host disease (GVHD) and multiple actinic keratoses manifested at his head. In 2020, some lesions were diagnosed as squamous cell carcinoma, so voriconazole was withdrawn, and subsequent surgery and radiation led to remission. Long-term administration of voriconazole in addition to allo-HSCT and chronic GVHD may be closely related to secondary skin cancer.

Circulating CD34+ cells of primary myelofibrosis patients contribute to myeloid-dominant hematopoiesis and bone marrow fibrosis in immunodeficient mice.

INTRODUCTION: Primary myelofibrosis (PMF) is a clonal stem cell disorder characterized by myeloid dominant hematopoiesis and dysregulated proliferation of fibroblasts in the bone marrow. However, how these aberrant myeloid cells and fibroblasts are produced remains unclear. AIM AND METHODS: In this study, we examined in vivo engraftment kinetics of PMF patient-derived CD34+ cells in immunecompromised NOD/SCID/IL2rgKO (NSG) mice. Engrafted human cells were analyzed with flow cytometry, and proliferation of fibroblastic cells and bone marrow fibrosis were assessed with the histo-pathological examination. RESULTS: Transplantation of PMF patient-derived circulating CD34+ fractions into NSG newborns recapitulates clinical features of human PMF. Engraftment of human CD45+ leukocytes resulted in anemia and myeloid hyperplasia accompanied by bone marrow fibrosis by six months post-transplantation. Fibrotic bone marrow contained CD45-vimentin+ cells of both human and mouse origin, suggesting that circulating malignant CD34+ subsets contribute to myelofibrotic changes in PMF through direct and indirect mechanisms. CONCLUSION: A patient-derived xenotransplantation (PDX) model of PMF allows in vivo examination of disease onset and propagation originating from immature CD34+ cells and will support the investigation of pathogenesis and development of therapeutic modalities for the disorder.

Impact of donor types on reduced-intensity conditioning allogeneic stem cell transplant for mature lymphoid malignancies.

We retrospectively compared the outcomes of reduced-intensity conditioning (RIC) transplantation from matched related donors (MRD; n = 266), matched unrelated donors (MUD; n = 277), and umbilical cord blood (UCB; n = 513) for mature lymphoid malignancies. The 3-year overall survival rates for the MRD, MUD, and UCB groups were 54%, 59%, and 40%, respectively (P < 0.001). Multivariate analysis showed no differences in survival between the MRD group and the MUD or UCB group. However, survival was significantly affected by the conditioning regimen and graft-versus-host disease (GVHD) prophylaxis in the UCB group, but not in the MRD and MUD groups. Notably, multivariate analysis showed that the risk of overall mortality in the UCB recipients who received the optimal conditioning regimen and GVHD prophylaxis (n = 116) was lower than that in the MRD group (relative risk [RR], 0.69; P = 0.03) and tended to be lower than that in the MUD group (RR, 0.75; P = 0.09). Our results suggest that UCB transplantation performed with the optimal conditioning regimen and GVHD prophylaxis is highly effective. Moreover, UCB is readily available. Thus, UCB transplantation with the optimal conditioning regimen and GVHD prophylaxis is preferable to MUD transplantation when MRD are not available in the setting of RIC transplantation for mature lymphoid malignancies.

Azacitidine for the treatment of patients with relapsed acute myeloid leukemia after allogeneic stem cell transplantation.

We retrospectively analyzed 38 patients with AML who received azacitidine (AZA) to treat disease relapse after allogeneic hematopoietic stem cell transplantation (allo-HSCT). Patients with objective response (OR) (n = 20) after AZA had significantly higher 2-year overall survival (OS) (45.0% vs 5.6%; p = 0.004) than progressive disease. The 2-year OS was significantly higher in the retransplant group (n = 23) than in the nonretransplant group (n = 15) (34.8% vs 13.3%; p = 0.034). We analyzed 167 patients who underwent the second allo-HSCT to clarify the impact of pretransplant AZA after the second allo-HSCT. Patients in the AZA group (n = 21) had significantly higher 2-year disease-free survival (DFS) (32.7% vs 14.5%; p = 0.012) and OS (38.1% vs 17.5%; p = 0.044) than those in the SOC group (n = 146). Our data demonstrate that AZA is an effective and well-tolerated bridging therapy to the second allo-HSCT.

Pharmacokinetics of anti-thymocyte globulin in a patient with severe aplastic anemia treated with allogeneic bone marrow transplantation from a matched unrelated donor.

Anti-thymocyte globulin (ATG) is an important component of preparative regimens for allogeneic bone marrow transplantation (BMT) for aplastic anemia (AA). However, the pharmacokinetics (PK) of ATG are unclear. A 38-year-old woman with severe AA underwent BMT using a fludarabine (Flu)-based and reduced-dose cyclophosphamide (CPA)-conditioning regimen comprising rabbit ATG (2.5 mg/kg, days -7 and -6), Flu (30 mg/sqm, days -5 to -2), CPA (25 mg/kg, days -5 to -2), and total body irradiation (2 Gy, day -1), following a human leukocyte antigen-match with an unrelated donor. Notably, ATG was administered earlier than that recommended by conventional schedules. The engraftment was achieved on day 15 without reactivation of the Epstein-Barr virus and residual recipient cells. Absolute lymphocyte recovery (>0.5×109/L) was achieved on day 22. The ATG concentration on day 0 and the area under the concentration-time curve (AUC) for ATG after allogeneic BMT were 21.8 µg/mL and 464 µg・day/mL, respectively. The patient remained disease-free for 6 years after BMT without acute or chronic graft-versus-host disease. Moreover, based on serum PK monitoring of ATG, including ATG concentration on day 0 and the AUC for ATG after BMT, the patient safely underwent the less-toxic, Flu-based, reduced-dose CPA regimen containing a low dose of ATG. In conclusion, we present the first report that analyzed the PK of ATG in a patient with AA treated with BMT from a matched unrelated donor. These findings might be helpful to determine ATG dosages for such patients receiving similar transplantations.

Three cases of late-onset anthracycline-related cardiomyopathy due to chemotherapies for hematological malignancy.

BACKGROUND: Although anthracycline-related cardiomyopathy is a life-threatening complication during intensive treatment for hematological malignancies, clinical features and outcomes of this type of cardiomyopathy have been unclear because of limited reports in the literature. METHODS: We analyzed three cases of anthracycline-related cardiomyopathy among 996 patients with either acute myelogenous leukemia (285), acute lymphoblastic leukemia (37), or malignant lymphoma (674) at our hospital during the period from 2006 to 2016. RESULTS: All patients showed accumulation of anthracycline within a proper range (< 500 mg/sqm). Two patients (Hodgkin lymphoma and acute lymphoblastic leukemia) showed acute heart failure (AHF) with ejection fraction (EF) of 30 and 40% after 4.5 and 5 years after diagnosis, respectively. For AHF, diuretics and carperitide were administered to control in-out balance. The remaining patient (follicular lymphoma) showed ventricular fibrillation (VF)/ventricular tachycardia (VT) with EF of 40% at 5 years after diagnosis. In this patient, immediate cardioversion made VF/VT to normal sinus rhythm, and then, amiodarone was given. Furthermore, implantable cardioverter defibrillator was set up for VF/VT. In all patients, ß blocker and/or angiotensin-converting enzyme inhibitor (ACE-I) were administrated to prevent recurrence of anthracycline-related cardiomyopathy. Consequently, two of three patients showed mild improvement of cardiac function. CONCLUSION: Our study indicates that late-onset (4 to 5 years) anthracycline-related cardiomyopathy can develop, though range of anthracycline accumulation is in proper range. Thus, a cautious follow-up by ECG and UCG is required. Furthermore, the early treatment after the onset of anthracycline-related cardiomyopathy should be also needed to improve the poor outcome.

Allogeneic Hematopoietic Cell Transplantation for Adolescent and Young Adult Patients with Acute Myeloid Leukemia.

Limited data exist regarding the outcomes of allogeneic hematopoietic cell transplantation (allo-HCT) among adolescent and young adult (AYA) patients with acute myeloid leukemia (AML). Here we analyzed the features and outcomes of AYA patients with AML who had achieved complete remission (CR) and those who had not (non-CR) at allo-HCT. We retrospectively analyzed 2350 AYA patients with AML who underwent allo-HCT with a myeloablative conditioning regimen and who were consecutively enrolled in the Japanese nationwide HCT registry. The difference in overall survival (OS) between younger (age 16 to 29 years) and older AYA (age 30 to 39 years) patients in CR at transplantation was not significant (70.2% versus 71.7% at 3 years; P = .62). Meanwhile, this difference trended toward a statistical significance between younger and older AYA patients in non-CR at transplantation (39.5% versus 34.3% at 3 years; P = .052). In AYA patients in CR and non-CR, the age at transplantation did not affect relapse or nonrelapse mortality (NRM). In AYA patients in CR, no difference in OS was observed between those who received total body irradiation (TBI) and those who did not (71.1% versus 70.5% at 3 years; P = .43). AYA patients who received TBI-based conditioning had a significantly lower relapse rate and higher NRM than those who underwent non-TBI-based conditioning (relapse: 19.8% versus 24.1% at 3 years [P = .047]; NRM: 14.7% versus 11.1% at 3 years [P = .021]). In contrast, among the non-CR patients, there were no differences between the TBI and non-TBI groups with respect to OS (P = .094), relapse (P = .83), and NRM (P = .27). Our data indicate that outcomes may be more favorable in younger AYA patients than in older AYA patients in non-CR at transplantation, and that outcomes of TBI-based conditioning could be comparable to those of non-TBI-based conditioning for AYA patients.

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.

Chemotherapy-resistant human AML stem cells home to and engraft within the bone-marrow endosteal region.

Acute myelogenous leukemia (AML) is the most common adult leukemia, characterized by the clonal expansion of immature myeloblasts initiating from rare leukemic stem (LS) cells. To understand the functional properties of human LS cells, we developed a primary human AML xenotransplantation model using newborn nonobese diabetic/severe combined immunodeficient/interleukin (NOD/SCID/IL)2r gamma(null) mice carrying a complete null mutation of the cytokine gamma c upon the SCID background. Using this model, we demonstrated that LS cells exclusively recapitulate AML and retain self-renewal capacity in vivo. They home to and engraft within the osteoblast-rich area of the bone marrow, where AML cells are protected from chemotherapy-induced apoptosis. Quiescence of human LS cells may be a mechanism underlying resistance to cell cycle-dependent cytotoxic therapy. Global transcriptional profiling identified LS cell-specific transcripts that are stable through serial transplantation. These results indicate the potential utility of this AML xenograft model in the development of novel therapeutic strategies targeted at LS cells.