Prognostic Implications and Clinical Characteristics Associated with Bone Marrow Fibrosis in Patients with Myelofibrosis

Blood ◽  
2011 ◽  
Vol 118 (21) ◽  
pp. 2824-2824
Author(s):  
Aziz Nazha ◽  
Zeev Estrov ◽  
Jorge E. Cortes ◽  
Sherry Pierce ◽  
Hagop M. Kantarjian ◽  
...  
Keyword(s):  
Bone Marrow ◽  
Conflicts Of Interest ◽  
World Health ◽  
Cancer Center ◽  
Bone Marrow Fibrosis ◽  
Jak2 Mutation ◽  
Hematopoietic Stem ◽  
Md Anderson ◽  
The Impact ◽  
Marrow Fibrosis

Abstract Abstract 2824 Background: Myelofibrosis (MF) is a heterogeneous, hematopoietic stem cell malignancy characterized by abnormal proliferation of myeloid cells with varying maturity and function. Bone marrow fibrosis (BMF), which results from abnormal deposition of stromal reticulin and collagen fibers, plays a major role in the pathophysiology of MF. Objectives: To investigate the characteristics associated with the extent of BMF and its implications on the clinical manifestation, overall survival (OS), event-free survival (EFS), and transformation to acute leukemia in patients with primary or secondary myelofibrosis. Methods: We conducted a retrospective chart review analysis of 514 patients who were diagnosed with myelofibrosis according to World Health Organization criteria (353 patients with primary myelofibrosis, 82 with post polycythemia vera [Post-PV] MF, and 79 with post essential thrombocythemia [Post-ET] MF) and were referred to MD Anderson Cancer Center between February 2005 and December 2009. Results of the first bone marrow biopsy done at MD Anderson were reviewed. BMF was documented according to the European consensus grading system (MF 0–3), in which MF-3 is the most severe grade of fibrosis. Result: Of 514 patients, 7 (1%) had MF-0, 44 (9%) had MF-1, 171 (33%) had MF-2, and 292 (57%) had MF-3. Table 1 summarizes patient characteristics and outcomes by grade. Conclusion: Severe bone marrow fibrosis was associated with lower Hgb, lower WBC count, larger spleen and abnormal cytogenetics. There was no association between JAK2 mutation and the severity of BMF. The OS, EFS and transformation to leukemia were similar among patients with various degrees of fibrosis. Similar results were achieved in patients with primary, post-PV MF, and post-ET MF. This might explain the heterogeneity of the disease course and its prognosis. Longer follow-up is needed to further investigate the impact of BMF on OS, EFS and PFS. Disclosures: No relevant conflicts of interest to declare.

Primary Myelofibrosis In Children

Blood ◽  
2010 ◽  
Vol 116 (21) ◽  
pp. 3079-3079
Author(s):  
Melissa R. DeLario ◽  
Andrea Sheehan ◽  
Ramona Ataya ◽  
Alison A. Bertuch ◽  
Carlos Vega ◽  
...  
Keyword(s):  
Bone Marrow ◽  
Conflicts Of Interest ◽  
Case Series ◽  
Primary Myelofibrosis ◽  
Jak2v617f Mutation ◽  
World Health ◽  
Bone Marrow Fibrosis ◽  
Hematopoietic Stem ◽  
Molecular Features ◽  
Marrow Fibrosis

Abstract Abstract 3079 Primary myelofibrosis is a chronic myeloproliferative disorder characterized by cytopenias, leukoerythroblastosis, extramedullary hematopoiesis, hepatosplenomegaly and bone marrow fibrosis. It is a serious medical condition in adults, often requiring major interventions such as hematopoietic stem cell transplantation (HSCT) for cure. In comparison to adults, children are rarely affected by this entity; the largest case series reports on four such patients. Most of these reports suggest that the majority of affected children have spontaneous resolution of their myelofibrosis with no long term complications. To better describe the clinical characteristics and outcomes of pediatric primary myelofibrosis, we performed a retrospective chart review of children diagnosed with myelofibrosis by bone marrow pathology at our institution from 1996 to 2009. Eighteen patients with primary myelofibrosis were identified. At presentation, all patients had one or more cytopenias and only one had leukoerythroblastosis. Three of 11 patients tested (27%) had cytogenetic abnormalities, as opposed to up to two-thirds of adults with primary myelofibrosis. Eleven of 18 patients (61%) demonstrated erythroid hypoplasia in the bone marrow, which is uncommon in adults. Based on recent molecular studies of myeloproliferative disorders in adults, the World Health Organization now includes the presence of a clonal marker such as JAK2V617F as a major criterion for diagnosis of myelofibrosis in adults. In contrast to approximately half of adults (43-63%) with primary myelofibrosis, JAK2V617F mutation in the bone marrow has not been reported in children. JAK2V617F mutation analysis was negative on 16 of 18 bone marrow specimens tested. In this series, only 5 of the 18 children (27.8%) had spontaneous recovery. No child developed malignant transformation. Eight children underwent HSCT, four of whom were cured of their myelofibrosis; the remaining four children died from infections acquired during transplantation. Four children died prior to transplantation, or were identified as having myelofibrosis at autopsy. One child transferred care to another facility and thus outcome data was not available. In all children, infection was the most common cause of death. Notably, the degree of bone marrow fibrosis did not correlate with outcome. Our series demonstrates that children with primary myelofibrosis have hematologic, bone marrow and molecular features that differ from adults. In contrast to what is found in the literature, our series of pediatric patients with primary myelofibrosis, the largest reported thus far, indicates a poor outcome for the majority of these patients. Disclosures: No relevant conflicts of interest to declare.

Clinical Significance of Bone Marrow Fibrosis in Patients with Polycythemia Vera

Blood ◽  
2011 ◽  
Vol 118 (21) ◽  
pp. 5149-5149
Author(s):  
Aziz Nazha ◽  
Jorge E. Cortes ◽  
Zeev Estrov ◽  
Sherry Pierce ◽  
Hagop M. Kantarjian ◽  
...  
Keyword(s):  
Bone Marrow ◽  
Acute Leukemia ◽  
Polycythemia Vera ◽  
Clinical Manifestation ◽  
World Health ◽  
Prognostic Impact ◽  
Bone Marrow Fibrosis ◽  
Md Anderson ◽  
The Impact ◽  
Marrow Fibrosis

Abstract Abstract 5149 Background: Polycythemia vera (PV) is a heterogeneous myeloproliferative disease characterized by expansion of morphologically normal red blood cells, granulocytes, and platelets with varying degrees of bone marrow fibrosis (BMF) during the disease course. BMF as a result of abnormal deposition of reticulin and collagen fibers in bone marrow stroma plays a role in the pathophysiology and clinical manifestation of myeloproliferative disorders in general. However, in PV, older age and previous history of thrombosis remain the only two major risk factors for consideration in decisions regarding therapy. Objectives: To investigate the characteristics associated with BMF and its prognostic impact on clinical manifestation, overall survival (OS), and transformation to primary myelofibrosis and acute leukemia in patients with PV. Methods: We conducted a retrospective chart review analysis of 115 patients who were diagnosed with PV according to World Health Organization criteria and were referred to MD Anderson Cancer Center between May 2000 and December 2009. Results of the first bone marrow biopsy done at MD Anderson were reviewed. BMF was documented according to the European consensus grading system (MF0-3), in which MF-3 is the most severe grade of fibrosis. Results: Of the 115 patients, 23 (20%) had MF-0, 46 (40%) MF-1, 36 (31%) MF-2, and 10 (9%) MF-3. Table 1 summarizes patient characteristics and outcomes by grade. Conclusion: Severe BMF was associated with higher risk of bleeding and thrombosis and larger spleen in patients with PV. There was no association between BMF severity and the demographic or symptoms of the disease. There was no association between BMF severity and the presence of JAK2 mutation or cytogenetic abnormalities. There was no impact of BMF on OS, EFS, or transformation to myelofibrosis or acute leukemia. However, longer follow-up is needed to investigate further the impact of BMF on OS and transformation-free survival. Disclosures: No relevant conflicts of interest to declare.

Impact Of Myelofibrosis (MF) In MDS Treated With Azacitidine (AZA). A Single Center Study

Blood ◽  
2013 ◽  
Vol 122 (21) ◽  
pp. 1539-1539
Author(s):  
Clemence Legoupil ◽  
Marie Sebert ◽  
Thorsten Braun ◽  
Claude Gardin ◽  
Antoine Martin ◽  
...  
Keyword(s):  
Bone Marrow ◽  
Conflicts Of Interest ◽  
Fish Analysis ◽  
Trisomy 8 ◽  
Bone Marrow Fibrosis ◽  
Monosomy 7 ◽  
Poor Prognostic Factor ◽  
Bone Marrow Trephine Biopsy ◽  
The Impact ◽  
Marrow Fibrosis

Abstract Background Bone marrow fibrosis is observed in 10-20% of MD, and is a poor prognostic factor, both in lower and higher risk MDS (Della Porta, JCO 2009). AZA, the current reference treatment for higher risk MDS, approved in EU for patients with up to 30% bone marrow blasts not candidates to intensive chemotherapy (IC) or allogeneic SCT, gives 50-60% responses and improves OS in higher-risk MDS but its role in MDS with myelofibrosis remains unknown. Methods Between 2004 and 2012, we treated at our center 172 consecutive MDS patients (pts) including FAB RAEB-T / WHO AML with 20-30% blasts, with AZA (75 mg/m2/d x7 d every 4 weeks, for a median of 6 cycles). We assessed in those patients the impact of myelofibrosis (MF), evaluated on bone marrow trephine biopsy and graded according to the European consensus on grading bone marrow fibrosis. Results Median age of the 172 pts was 73 years and 67% were males. According to WHO classification, 1 had del(5q) syndrome, 4 RARS/RCMD-RS, 24 RCMD, 37 RAEB-1, 54 RAEB-2, 29 AML (20-30% blasts), 17 CMML and 6 MDS unclassified. Median Hb level, WBC, platelet count and marrow blast count were 9.4 g/dl (range 3.5-15), 1.6 G/L (0-58), 75G/l (8-1080) and 12%(1-29), respectively. IPSS was low, Int-1, Int-2, High and a failure in 1(>1%), 29(17%), 65 (38%), 59 (34%) and 18 (11%) patients, respectively. Twenty-three pts (13%) had grade 2-3 myelofibrosis (MF). Patients with MF were younger (median 68 vs. 74 years, p= 0.04), but had similar hematological characteristics: hemoglobin (median 9 vs. 9.45g/dl, p= 0.69); WBC (2.2 vs. 1.6 G/l, p= 0.48) Platelet (47 vs 77 G/l,p= 0.43) and bone marrow blast (10 vs. 12%, p=0.67). IPSS was int 1, int 2, high and a failure in 4, 7, 6 and 6 patients respectively without difference compared to patients without fibrosis. Cytogenetics was complex in 8, del(20q) +/- 1 additional abn in 5 patients, normal in 4 patients, failed in 6 patients (but with trisomy 8 and monosomy 7, resp, detected in 2 patients by FISH analysis). Overall, 73 (42%) patients achieved a response according to IWG2006 criteria, including 31 (18%) CR. The response rate and CR rate were 52% and 17% respectively in pts with MF, compared to 44% and 20% in pts without MF (p= 0.507 and p=1.00, respectively). With a median follow-up of 6.5 yr, median OS was 12 months in pts with MF, compared to 16 months in pts without MF (p=0.45). Conclusion In this MDS series, presence of MF was not associated with specific features (but blasts were often counted on marrow aspirates, with a possible underestimate in case of MF). Response to AZA and survival after AZA onset did not significantly differ based on the presence of MF. Disclosures: No relevant conflicts of interest to declare.

scholarly journals The Platelet Millionaire: A Rare Cause of Thrombocytosis in an Adolescent

Blood ◽  
2019 ◽  
Vol 134 (Supplement_1) ◽  
pp. 5391-5391
Author(s):  
Ritika Walia ◽  
Theresa Sepulveda ◽  
Sharon Wretzel ◽  
Philip H Brandt
Keyword(s):  
Bone Marrow ◽  
Bone Marrow Biopsy ◽  
Primary Care Physicians ◽  
Conflicts Of Interest ◽  
Abdominal Ultrasound ◽  
Cell Transplant ◽  
Peripheral Smear ◽  
Hematopoietic Stem ◽  
Marrow Fibrosis

Objectives: Primary myelofibrosis is rare in pediatrics, often manifesting as persistent idiopathic thrombocytosis.Transitions from pediatric to adult medical care can be complicated by workup requiring invasive procedures. J.M., an 18-year-old healthy male, presented for excessive gingival bleeding after wisdom tooth extraction. Workup revealed persistent thrombocytosis to 1,165K, prompting a referral to hematology-oncology. A peripheral smear was notable for many platelets but normal RBC morphology. He had splenomegaly on abdominal ultrasound and a decreased von-Willebrand's activity to antigen ratio, suggesting acquired vWD. A bone marrow biopsy was advised; however, J.M. became lost to follow up for over 9 months owing to self-reported anxiety about the procedure. He remained asymptomatic in this interim until he re-presented to clinic for easy bruising, with no other evidence of bleeding at the time. The biopsy was pursued, revealing hypercellular marrow for age with left shifted granulocytic and erythroid maturation, abnormal megakaryocytes, and 3% blasts. This was consistent with primary early myelofibrosis (PMF), positive for MF-1, CALR, and TP53 mutations and negative for JAK2 and BCR-ABL. He was transitioned to adult hematology, maintained on baby aspirin, and referred for potential allogeneic hematopoietic stem cell transplant (HSCT). PMF is characterized by marrow fibrosis due to secretion of fibroblast growth factor by clonally proliferative megakaryocytes. It is a disease of adulthood, with 67 years being the median age at diagnosis. Only 100 cases have been reported in children, most of which are secondary to AML, ALL or other malignancies.1 Most patients present with complications of extramedullary hematopoiesis or bleeding.2 Diagnosis is suggested by a leukoerythroblastic picture on peripheral smear and confirmed with a bone marrow biopsy "dry tap" revealing marrow fibrosis.3 Prognosis in pediatric PMF is difficult to predict but outcomes tend to be worse;4 TP53 mutation is rare and based on limited adult studies may portend a poorer prognosis.5 Our young patient with this rare mutation was therefore referred for HSCT evaluation. Further complicating this case was J.M.'s anxiety, which delayed definitive diagnosis by biopsy. He only agreed to it when, at the med-peds clinic, the concept of local pain management was discussed. Anticipation of upcoming procedures by primary care physicians and close follow-up is especially important for patients transitioning from pediatric to adult providers. Disclosures No relevant conflicts of interest to declare.

scholarly journals Idiopathic myelofibrosis mimicking hemolytic anemia

2012 ◽  
Vol 2 (4) ◽  
pp. 324-327
Author(s):  
R Baral ◽  
G Aryal ◽  
KC Shiva Raj
Keyword(s):  
Bone Marrow ◽  
Clinical Course ◽  
Myeloproliferative Disorder ◽  
Severe Anemia ◽  
Idiopathic Myelofibrosis ◽  
Blood Picture ◽  
Bone Marrow Fibrosis ◽  
Hematopoietic Stem ◽  
Chronic Myeloproliferative Disorder ◽  
Marrow Fibrosis

Idiopathic Myelofibrosis is an infrequent chronic myeloproliferative disorder characterized by varying degrees of bone marrow fibrosis and extra medullary hematopoiesis, with the fibrosis being a reactive phenomenon to a neoplastic proliferation of a pluripotent hematopoietic stem cell. Idiopathic Myelofibrosis is heterogeneous in presentation and clinical course, with anemia being one of the most important problems. We present a case of a 59 year old male who presented with severe anemia, the peripheral blood picture mimicking hemolysis with numerous schistocytes and teardrop cells.Journal of Pathology of Nepal (2012) Vol. 2, 323-327DOI: http://dx.doi.org/10.3126/jpn.v2i4.6888

Effects of G-CSF On Acute Lymphoblastic Leukemia.

Blood ◽  
2012 ◽  
Vol 120 (21) ◽  
pp. 2564-2564
Author(s):  
Jordan Basnett ◽  
Adam Cisterne ◽  
Kenneth F Bradstock ◽  
Linda J Bendall
Keyword(s):  
Bone Marrow ◽  
Disease Progression ◽  
Microarray Analysis ◽  
Environmental Changes ◽  
Conflicts Of Interest ◽  
Lymphoblastic Leukemia ◽  
Hematopoietic Stem ◽  
Childhood All ◽  
Extracellular Matrix Components ◽  
The Impact

Abstract Abstract 2564 G-CSF is commonly used to treat chemotherapy-induced neutropenia and for the mobilization of hematopoietic stem cells for transplantation in patients with leukemia. Administration of G-CSF has profound effects on the bone marrow microenvironment including the cleavage of molecules required for the maintenance of lymphopoiesis, including CXCL12 and VLA-4. We have recently reported that G-CSF results in the dramatic suppression of B-lymphopoiesis. This, together with previous reports by ourselves, and others, showing that disruption of CXCL12 or VLA-4 slow the progression of B-lineage ALL lead us to consider that G-CSF may similarly antagonize the progression of ALL. To explore this possibility, we examined the impact of G-CSF administration on six human ALL xenografts using a NOD/SCID mouse model. Mice were engrafted without radiation and G-CSF commenced when 1% of the bone marrow consisted of ALL cells. G-CSF was administered twice daily for 10 days, at which time all animals were culled and leukemia assessed in the blood, bone marrow and spleens. Surprisingly G-CSF was found to increase disease progression in two of xenografts investigated (1345 and 0398, referred to as G-CSF responsive xenografts hereafter), while the remainder demonstrated a small reduction in leukemia, with one showing a statistical significant decrease. No evidence for a direct mitogenic effect of G-CSF could be demonstrated in any of the xenografts using exogenous G-CSF in vitro cultures in the presence or absence of human or murine stromal support. Consistent with these findings, and previous reports, little to no G-CSF receptor was detected by flow cytometry or microarray analysis of xenografts. Microarray analysis of the xenografts revealed significant differences in gene expression between the G-CSF responsive xenografts and the remainder of the samples. A total of 83 genes were expressed at a higher level and 127 genes at a lower level in the G-CSF responsive xenografts. The more highly expressed genes included cell cycle regulators (eg cyclin A1), adhesion molecules (eg ALCAM), extracellular matrix components and surface receptors. Perhaps the most interesting was the exclusive expression of the acetylcholine receptor (cholinergic receptor, nicotinic, beta 4, nAChRb4) in the G-CSF responsive cases. Analysis of a large public dataset of childhood ALL samples revealed significantly higher expression of this gene in ALL samples with rearranged MLL (p<0.03). However, small numbers of cases in all ALL subgroups had greater than an 2 fold higher expression compared to normal B cell progenitors. The role of nAChR in the response of ALL cells to micro-environmental changes induced by G-CSF remains to be determined, however, nAChR has known roles in cell proliferation and inhibition of apoptosis. Furthermore G-CSF is known to induce acetylcholine production in other tissues. In summary, G-CSF inhibited leukemia progression in the majority of patient xenografts, however, in a subset of samples G-CSF accelerated disease progression. Clinically, G-CSF administration to ALL patients has not been associated with any major adverse outcomes. However our data suggest that a small subset of patients may experience accelerated disease. Identification of features associated with adverse responses to G-CSF will permit the identification of patients for whom G-CSF may present a risk for increased disease progression. Disclosures: No relevant conflicts of interest to declare.

Association of Functional Single Nucleotide Variation in the NLRP3 Gene with Survival Outcomes After Unrelated Bone Marrow Transplantation.

Blood ◽  
2012 ◽  
Vol 120 (21) ◽  
pp. 3140-3140
Author(s):  
Akiyoshi Takami ◽  
J. Luis Espinoza ◽  
Keitaro Matsuo ◽  
Yasuo Morishima ◽  
Makoto Onizuka ◽  
...  
Keyword(s):  
Bone Marrow ◽  
Conflicts Of Interest ◽  
Nucleotide Variation ◽  
Single Nucleotide Variation ◽  
Single Nucleotide ◽  
Hematopoietic Stem ◽  
Nlrp3 Gene ◽  
Transplant Outcomes ◽  
Functional Relevance ◽  
The Impact

Abstract Abstract 3140 NLRP3 is an intracellular trigger of IL-1β production that plays important roles in the regulation of inflammation and apoptosis. A single nucleotide variation in the 3'-untranslated region of the NLRP3 gene, rs10754558 (+29940G>C), is linked to several immunological diseases. When we examined the impact of the NLRP3 genotype in a cohort consisting of 392 pairs of patients with hematologic malignancies and their unrelated HLA 12/12 matched bone marrow donors transplanted through the Japan Donor Marrow Program, the recipient NLRP3 GG genotype was found to be associated with a significantly worse 5-year overall survival (OS) rate (34% vs. 50%, P=0.006) (Fig. 1) and a trend toward a higher transplant-related mortality (TRM) rate (39% vs. 27%, P=0.09) than the recipient CC or CG genotype. The recipient GG genotype remained statistically significant in the multivariate analysis for OS (hazard ratio [HR], 1.86; 95% confidence interval [CI], 1.22 to 2.22; P=0.004) and TRM (HR, 2.28; 95% CI, 1.20 to 4.35; P=0.01). The donor NLRP3 genotype did not significantly influence the transplant outcomes. Next, we investigated the functional relevance of the NLRP3 +29940G>C variant. When leukocytes from healthy individuals were stimulated in vitro with NLRP3 ligand, the leukocytes with the NLRP3 GG genotype produced significantly more IL-1β than those with the NLRP3 CC or CG genotype (Fig. 2). These findings substantiate the functional relevance of the NLRP3 variant, and suggest that the higher IL-1β secretion in the peri-transplant period by recipients with the NLRP3 GG genotype likely accounts for their poor transplant outcomes. NLRP3 genotyping could therefore be useful in predicting prognoses and creating therapeutic strategies for improving the final outcomes of patients who undergo allogeneic hematopoietic stem cell transplantation. Disclosures: No relevant conflicts of interest to declare.

Inhibition of HDAC8 Reactivates p53 and Abrogates Leukemia Stem Cell Activity in CBFβ-SMMHC Associated Acute Myeloid Leukemia

Blood ◽  
2014 ◽  
Vol 124 (21) ◽  
pp. 363-363
Author(s):  
Jing Qi ◽  
Qi Cai ◽  
Sandeep Singh ◽  
Ling Li ◽  
Hongjun Liu ◽  
...  
Keyword(s):  
Bone Marrow ◽  
Acute Myeloid Leukemia ◽  
Myeloid Leukemia ◽  
Bone Marrow Cells ◽  
Conflicts Of Interest ◽  
Cell Activity ◽  
Disease Free Survival ◽  
Hematopoietic Stem ◽  
The Impact ◽  
Acute Myeloid

Abstract The inv(16)-created CBFβ-SMMHC fusion protein inhibits differentiation of hematopoietic stem and progenitor cells (HSPCs) and creates pre-leukemic populations predisposed to acute myeloid leukemia (AML) transformation. However, the molecular mechanism underlying the leukemogenic function of CBFβ-SMMHC has been elusive. Given the low TP53 mutation rate in AML, alternative mechanisms disrupting p53 function are expected. We showed thatCBFβ-SMMHC impairs p53 acetylation and p53 target gene activation through formation of an aberrant protein complex with p53 and HDAC8 (Blood, 120: A772; 122(21): 224). We now show that CBFβ-SMMHC binds to p53 and HDAC8 independently through distinct regions and that HDAC8 mediates the deacetylation of p53 associated with CBFβ-SMMHC. In addition, we generated mice carrying a floxed Hdac8 (Hdac8f) allele and crossed with Cbfb56M/+/Mx1-Cre (Kuo YH et al, Cancer Cell 2006). Deletion of Hdac8 signifiacntly (p<0.0001) reduced the incidence of AML and prolonged disease-free survival. Pharmacologic inhibition of HDAC8 activity with HDAC8-selective inhibitors (HDAC8i) reactivates p53 and selectively induces apoptosis of inv(16)+ AML CD34+ cells while sparing normal HSPCs. To test the effect of HDAC8i on LSC engraftment and leukemia-initiating capacity, we generated Cbfb56M/+/Mx1-Cre mice with a Cre-reporter line expressing tdTomato fluorescence protein following Cre-mediated recombination. AML cells (dTomato+/cKit+) treated with HDAC8i (22d) ex vivo showed reduced engraftment (p=0.025) and enhanced survival (p=0.025) in transplanted mice. To examine whether HDAC8i 22d treatment affects the engraftment capacity on surviving cells, we transplanted equal number (2 x 106) of AML cells treated with either 22d or vehicle in another cohort of mice (n=4). We show that HDAC8i 22d treatment reduced the engraftment of dTomato+/cKit+ AML cells and enhanced survival, suggesting that the engraftment capacity is altered in addition to reducing AML cell survival. We next performed preclinical studies to determine the efficacy of in vivo administration of HDAC8i 22d. AML transplanted mice were randomized into two groups, one group treated with vehicle and the other treated with HDAC8i 22d for 2 weeks. Flow cytometry analysis revealed significantly reduced frequency (p=0.0097) and number (p=0.0101) of dTomato+/cKit+ AML cells in the bone marrow and spleen of 22d treated mice compared to vehicle treated group. To further assess the impact on LSC activity, we transplanted bone marrow cells from these treated mice into secondary recipients and analyzed for AML engraftment. Significant reduction in the frequency (p<0.0001) and the number (p=0.0006) of dTomato+/cKit+ AML cells was observed in the bone marrow and spleen. Furthermore, HDAC8i 22d treated transplants showed no signs of leukemia while vehicle treated transplants are moribund with aggressive AML. These results indicate that HDAC8 inhibition by 22d treatment effectively eliminates engraftment and leukemia-initiating capacity of AML LSCs. In conclusion, our studies identify a novel post-translational p53-inactivating mechanism and demonstrate selective HDAC8 inhibition as a promising approach to target inv(16)+ AML LSCs. Disclosures No relevant conflicts of interest to declare.

Impact of Infusion Rate on the Early Engraftment Following Allogeneic Intra Bone Marrow Infusion of Hematopoietic Stem Cells in a Canine DLA-Identical Reduced Intensity Transplantation Model

Blood ◽  
2015 ◽  
Vol 126 (23) ◽  
pp. 5406-5406
Author(s):  
Stephanie Schaefer ◽  
Juliane Werner ◽  
Sandra Lange ◽  
Katja Neumann ◽  
Christoph Machka ◽  
...  
Keyword(s):  
Stem Cells ◽  
Bone Marrow ◽  
Hematopoietic Stem Cells ◽  
Infusion Rate ◽  
Conflicts Of Interest ◽  
Conditioning Regimen ◽  
Hematopoietic Stem ◽  
Time Points ◽  
The Impact ◽  
Reduced Intensity

Abstract Introduction: Direct intra bonemarrow (IBM) infusion of hematopoietic stem cells (HSC) is assumed to improve the homing efficiency and to accelerate the early engraftment in comparison to the conventional intravenous application of HSC. Especially for transplantation of low cell numbers i.e. "weak grafts" that is generally associated with delayed engraftment. The direct infusion of HSC in close proximity to the HSC niche by intra bone marrow transplantation (IBMT) might be a promising way. Whether the HSC infusion rate might influence the homing process and therefore the outcome after IBMT is so far unknown. Aims: Herein, we analyzed in a canine DLA-identical littermate model the impact of different graft infusion rates on the hematopoietic recovery as well as on the engraftment kinetics after IBMT following reduced intensity conditioning. Methods: Recipient dogs received IBMT following a 4.5 Gy total body irradiation (TBI). From day (d) -1 until d+35 Cyclosporin A (15mg/kg) was administered orally twice a day as immunosuppression. For IBM transfusion the graft volume was reduced by buffy coat centrifugation and dogs obtained 2x25 ml simultaneously into the humerus and femur. The infusion rate of the graft was 25ml/10 min in group 1 (IBM10, n = 8) and 25 ml/60 min in group 2 (IBM60, n = 7). A 28 day follow-up is currently available for twelve dogs (IBM10 n = 7; IBM60 n = 5). The development of the peripheral blood mononuclear cell (PBMC) and granulocyte chimerism was tested weekly. Blood count, kidney and liver enzymes were monitored routinely. Results: All animals engrafted. One dog of the IBM10 group died at d+15 (infection) and was therefore not included into analysis. The median number of infused total nucleated cells were in IBM10 4.1*108/kg (range 2.3-6.0*108/kg) and in IBM60 3.2*108/kg (range 1.8-4.4*108/kg; p=0.4). The infused CD34+ numbers were median 3.2*106/kg (range: 1.2-10.0*106/kg; IBM10) and 3.6*106/kg (range: 1.5-6.8*106/kg; IBM60; p=0.7). Time of leukocyte recovery was median d+11 after IBMT in both groups (range: d+4 to d+11, IBM10; d+8 to d+14, IBM60; p= 0.5). Median leukocytes nadirs amounted to 0.2*109/l for IBM10 and 0.3*109/l for IBM60 (p= 0.08). The median duration of leukopenia (<1*109/l) were similar (6d, range: 4-11d, IBM10; 3-9d, IBM60) (p= 0.6). Median platelet nadir was 0*109/l for both cohorts (range: 0.0-7.0*109/l, IBM10; 0.0-1.0*109/l, IBM60). The period of thrombocytopenia (≤20.0*109/l) was significantly prolonged in the IBM60 group (median 10d, range) compared to 5d (range: 3-12d) in the IBM10 group (p=0.05). Donor PBMC chimerisms at d+7, d+14 and d+28 were median 22% (range: 8-34%), 50% (range: 29-53%) and 67% (range: 47-73%) in IBM10. The results of PBMC chimerism for IBM60 were 11% (range: 5-34%), 42% (range: 20-42%) and 59% (range: 44-66%) at these time points (p = n.s.). Donor granulocyte chimerisms of median 33% (range: 11-83%), 100% (range: 58-100%) and 100% (range: 82-100%) were detected at d+7, d+14 and d+28 after HSCT in IBM10, respectively. The granulocyte chimerism in IBM60 amounted to 34% (range: 3-87%), 96% (range: 94-100%) and 98% (range: 96-100%) at the above mentioned time points p=n.s. for all time points). Conclusion: Our data suggest that early granulocyte and PBMC engraftment is not influenced by modification of the HSC infusion rate. However, the period of thrombocytopenia seems to be prolonged following a 60 minutes application. Therefore, longer infusion times in an IBMT setting seem not to be beneficial following toxicity reduced conditioning regimen. Disclosures No relevant conflicts of interest to declare.

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