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.
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)2rγnull mice carrying a complete null mutation of the cytokine γc 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.
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.
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.
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.
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.
The effects of stem cell transplantation (SCT) in patients with peripheral T-cell lymphoma not otherwise specified (PTCL-NOS) and angioimmunoblastic T-cell lymphoma (AITL) remain controversial. We ...analyzed the feasibility of SCT and risk factors associated with outcomes of PTCL-NOS and AITL patients to identify the potential clinical efficacy of SCT. We retrospectively analyzed the data of PTCL-NOS (
n
= 83) and AITL (
n
= 112) patients who received autologous (
n
= 10 and 16, respectively) or allogeneic (
n
= 12 and 4, respectively) SCT, or no SCT (
n
= 61 and 92, respectively) between 2008 and 2018. All PTCL-NOS and AITL diagnoses were reconfirmed by an experienced hematopathologist. Median age at PTCL-NOS and AITL diagnoses in the SCT group was younger than that in the no SCT group. Significant risk factors for lower overall survival were intermediate–high and high-risk international prognostic indexes in PTCL-NOS patients (
P
= 0.0052), and a > 2 modified prognostic index for T-cell lymphoma (
P
= 0.0079) and no SCT (
P
= 0.028) in AITL patients. Autologous or allogeneic SCT compared with no SCT in AITL patients resulted in 3-year overall survival of 68.6% and 100% vs. 57.2% (
P
= 0.018). Strategies should be developed to improve selection of PTCL-NOS and AITL patients suitable for SCT and/or additional novel therapies.
Objective To elucidate the clinical impact of humanized CCR4 antibody (mogamulizumab) on adult T-cell leukemia-lymphoma (ATL), we retrospectively analyzed the clinical and pathological features and ...treatment outcomes of aggressive ATL. Methods Twenty-two patients (median age: 65 years) with aggressive ATL acute- (n=16) or lymphoma-type (n=6) had their characteristics analyzed. All cases were treated with mogamulizumab at our institution from 2012 to 2018. In addition, we subjected 14 specimens of ATL to histological, immunological, and genetic analyses. Results Regarding the patient outcomes, the overall response rates were 68.1% and 31.8% after 4 and 8 courses (or after the final courses), respectively. The median overall survival (OS) was 95.5 days, while the OS rates at 6 and 12 months were 31.5% and 21.1%, respectively. Concerning patient pathological characteristics, 6 of the 14 patients examined (42.9%) had CCR4 mutations. Regarding the clinicopathological findings related to the mogamulizumab response, notably, the cases with somatic CCR4 mutation tended to have a poorer response (16.7%) than those with wild-type CCR4 (62.5%) after 4 cycles of mogamulizumab. Furthermore, the CCR4 global score tended to be higher in the responder cases than in the non-responder cases. Conclusion The present findings suggest that the CCR4 expression may be related to the mogamulizumab response, although no other significant predictive markers were identified in this study. Further studies will be needed in order to identify more markers related to the mogamulizumab response.
As opportunistic infections among human T-lymphotrophic virus type 1 (HTLV-1) carriers and patients with adult T-cell leukemia/lymphoma (ATL) pose a serious problem, it is necessary to clarify their ...clinical characteristics and outcomes in these patients. We retrospectively analyzed the clinical features and outcomes of opportunistic infections in 127 HTLV-1 carriers and 153 ATL patients between 2006 and 2016. The cumulative incidence rates of opportunistic infections among HTLV-1 carriers and ATL patients were 1.5% (2/127) and 6.5% (10/153), respectively. The etiology of opportunistic infections was as follows: fungal infections (3 cases), pneumocystis pneumonia, and cytomegalovirus (CMV) infections. Even after aggressive treatment, the prognosis of opportunistic infections was poor (50% of overall survival at 28 days). Regarding prognostic factors affecting the OS of opportunistic infections, higher SOFA scores (especially the respiratory subscore) and higher LDH values were identified by univariate analysis. Moreover, 3 out of 6 patients achieved spontaneous remission of ATL as the short-term outcome after the development of opportunistic infection. However, 5 out of 6 surviving patients exhibited ATL progression or relapse after a median of 194 days (133–226) after contracting an opportunistic infection as the long-term outcome of ATL. In conclusion, opportunistic infections should be carefully followed among HTLV-1 carriers and ATL patients because of their aggressive clinical course and poor outcomes. Furthermore, early diagnosis and subsequent prompt treatment are necessary in clinical practice.
Objective We elucidated the effectiveness of a humanized CCR4 antibody (mogamulizumab) on adult T-cell leukemia-lymphoma (ATL), which typically has a poor outcome. Methods We retrospectively analyzed ...14 patients with aggressive ATL who had been treated at our institution with weekly cycles of mogamulizumab for eight weeks from 2012-2014. Results The patients (median age: 63 years old) were classified as having acute- (n=10) or lymphoma-type (n=4) ATL. The prior treatment regimens consisted of CHOP, VCAP-AMP-VECP, DeVIC and CHASE, with an average of two courses (range: 1-4). The prior disease responses were partial remission (n=3) and progressive disease (n=11). The treatment was administered in the primary refractory setting (n=8), for relapse (n=2), or as bridging therapy before hematopoietic stem cell transplantation (n=4). The overall response rates were 64% and 43% after four and eight cycles (or after the final cycles), respectively. The median overall survival (OS), OS rate at six months and OS rate at 12 months were 66 days, 41.7% and 20.8%, respectively. All of the patients with acute-type ATL who showed a response to treatment had an early response. Notably, six of the 14 ATL patients showed somewhat prolonged survival (>100 days). However, relapse or disease progression in the peripheral blood, central nervous system, lymph nodes, skin, and/or bone occurred within a relatively short period after treatment. The adverse effects were tolerable, and included lymphopenia, cytomegalovirus infection and skin rash. Conclusion Mogamulizumab therapy resulted in an early and high remission rate and somewhat prolonged survival in patients with refractory ATL. However, the duration of remission was short, and there was early relapse and disease progression. This study may show the current impact of mogamulizumab in clinical practice.
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