Autonomous growth potential of leukemia blast cells is associated with poor prognosis in human acute leukemias

We have described a severe combined immunodeficiency (SCID) mouse model that permits the subcutaneous growth of primary human acute leukemia blast cells into a measurable subcutaneous nodule which may be followed by the development of disseminated disease. Utilizing the SCID mouse model, we examined the growth potential of leukemic blasts from 133 patients with acute leukemia, (67 acute lymphoblastic leukemia (ALL) and 66 acute myeloid leukemia (AML)) in the animals after subcutaneous inoculation without conditioning treatment. The blasts displayed three distinct growth patterns: "aggressive", "indolent", or "no tumor growth". Out of 133 leukemias, 45 (33.8%) displayed an aggressive growth pattern, 14 (10.5%) displayed an indolent growth pattern and 74 (55.6%) did not grow in SCID mice. The growth probability of leukemias from relapsed and/or refractory disease was nearly 3 fold higher than that from patients with newly diagnosed disease. Serial observations found that leukemic blasts from the same individual, which did not initiate tumor growth at initial presentation and/or at early relapse, may engraft and grow in the later stages of disease, suggesting that the ability of leukemia cells for engraftment and proliferation was gradually acquired following the process of leukemia progression. Nine autonomous growing leukemia cell lines were established in vitro. These displayed an aggressive proliferation pattern, suggesting a possible correlation between the capacity of human leukemia cells for autonomous proliferation in vitro and an aggressive growth potential in SCID mice. In addition, we demonstrated that patients whose leukemic blasts displayed an aggressive growth and dissemination pattern in SClD mice had a poor clinical outcome in patients with ALL as well as AML. Patients whose leukemic blasts grew indolently or whose leukemia cells failed to induce growth had a significantly longer DFS and more favorable clinical course

Bone Marrow Mesenchymal Stem Cells for Improving Hematopoietic Function: An In Vitro and In Vivo Model. Part 2: Effect on Bone Marrow Microenvironment

The aim of the present study was to determine how mesenchymal stem cells (MSC) could improve bone marrow (BM) stroma function after damage, both in vitro and in vivo. Human MSC from 20 healthy donors were isolated and expanded. Mobilized selected CD34+ progenitor cells were obtained from 20 HSCT donors. For in vitro study, long-term bone marrow cultures (LTBMC) were performed using a etoposide damaged stromal model to test MSC effect in stromal confluence, capability of MSC to lodge in stromal layer as well as some molecules (SDF1, osteopontin,) involved in hematopoietic niche maintenance were analyzed. For the in vivo model, 64 NOD/SCID recipients were transplanted with CD34+ cells administered either by intravenous (IV) or intrabone (IB) route, with or without BM derived MSC. MSC lodgement within the BM niche was assessed by FISH analysis and the expression of SDF1 and osteopontin by immunohistochemistry. In vivo study showed that when the stromal damage was severe, TP-MSC could lodge in the etoposide-treated BM stroma, as shown by FISH analysis. Osteopontin and SDF1 were differently expressed in damaged stroma and their expression restored after TP-MSC addition. Human in vivo MSC lodgement was observed within BM niche by FISH, but MSC only were detected and not in the contralateral femurs. Human MSC were located around blood vessels in the subendoestal region of femurs and expressed SDF1 and osteopontin. In summary, our data show that MSC can restore BM stromal function and also engraft when a higher stromal damage was done. Interestingly, MSC were detected locally where they were administered but not in the contralateral femur

Clinical, hematological and cytogenetic characteristics of atypical chronic myeloid leukemia.

BACKGROUND: Atypical chronic myeloid leukemia (aCML) is an infrequent chronic myeloproliferative disorder characterized by leukocytosis, absence of Philadelphia chromosome or BCR-ABL rearrangement, and marked myeloid dysplasia. Some cases have an absolute monocytosis but can be distinguished from chronic myelomonocytic leukemia (CMML) by the presence of a higher percentage (> 15%) of circulating immature granulocytes. PATIENTS AND METHODS: In a series of 11 patients with a diagnosis of aCML according to the FAB proposals we have analyzed the most relevant clinical, hematological and cytogenetic characteristics. RESULTS: The median age was 65 years (16-84). All but one case showed, at time of diagnosis, leukocytosis (median WBC was 36 x 10(9)/l), 55% had moderate anemia and 36% had thrombocytopenia. Most cases had marked dysplasia, particularly in the granulocytic lineage (82% of the cases), and all cases showed bone marrow red hypoplasia. Cytogenetic abnormalities were present in 9 out of the 11 patients. Trisomy 8 was observed in three cases and other clonal chromosomal abnormalities included deletions of 5q, 13q, 17p, 12q, and 11q as well as a t(6;8)(p23;q22) translocation. Fluorescence in situ hybridization (FISH) studies failed to demonstrate ETV-6 gene involvement. The median survival time from diagnosis was only 14 months (range 3-56 months). CONCLUSIONS: These data suggest that aCML is a rare disease which is characterized by leukocytosis, with dysgranulopoiesis, BM erythroid hypoplasia, chromosomal, though not recurrent, abnormalities and poor prognosis

Ex vivo identification and characterization of a population of CD13(high) CD105(+) CD45(-) mesenchymal stem cells in human bone marrow

Introduction: Mesenchymal stem cells (MSCs) are multipotent cells capable of self-renewal and multilineage differentiation. Their multipotential capacity and immunomodulatory properties have led to an increasing interest in their biological properties and therapeutic applications. Currently, the definition of MSCs relies on a combination of phenotypic, morphological and functional characteristics which are typically evaluated upon in vitro expansion, a process that may ultimately lead to modulation of the immunophenotypic, functional and/or genetic features of these cells. Therefore, at present there is great interest in providing markers and phenotypes for direct in vivo and ex vivo identification and isolation of MSCs. Methods: Multiparameter flow cytometry immunophenotypic studies were performed on 65 bone marrow (BM) samples for characterization of CD13(high) CD105(+) CD45(-) cells. Isolation and expansion of these cells was performed in a subset of samples in parallel to the expansion of MSCs from mononuclear cells following currently established procedures. The protein expression profile of these cells was further assessed on (paired) primary and in vitro expanded BM MSCs, and their adipogenic, chondrogenic and osteogenic differentiation potential was also determined. Results: Our results show that the CD13(high) CD105(+) CD45(-) immunophenotype defines a minor subset of cells that are systematically present ex vivo in normal/reactive BM (n = 65) and that display immunophenotypic features, plastic adherence ability, and osteogenic, adipogenic and chondrogenic differentiation capacities fully compatible with those of MSCs. In addition, we also show that in vitro expansion of these cells modulates their immunophenotypic characteristics, including changes in the expression of markers currently used for the definition of MSCs, such as CD105, CD146 and HLA-DR. Conclusions: BM MSCs can be identified ex vivo in normal/reactive BM, based on a robust CD13(high) CD105(+) and CD45(-) immunophenotypic profile. Furthermore, in vitro expansion of these cells is associated with significant changes in the immunophenotypic profile of MSCs

Unrelated cord blood transplantation in adults with myelodysplasia or secondary acute myeloblastic leukemia : a survey on behalf of Eurocord and CLWP of EBMT

Item does not contain fulltextThe aim of our study was to evaluate, through the Eurocord and European Group for Blood and Marrow Transplantation (EBMT) registries, outcomes and risk factors for outcomes in adult patients who underwent single or double unrelated cord blood transplantation (UCBT) for myelodysplastic syndrome (MDS) or secondary acute myeloblastic leukemia (sAML). A total of 180 adults with MDS (n=39) or sAML (n=69) were analyzed. Risk factors for outcomes were analyzed using the Fine and Gray method and the Cox model. Median age was 43 (18-72) years. In all, 77 patients (71%) received a single UCBT. Myeloablative conditioning regimen (MAC) was given to 57 (53%) patients. Median numbers of nucleated and CD34(+) cells at freezing were 3.6 x 10(7) and 1.1 x 10(5) kg. At 60 days, cumulative incidence of neutrophil recovery was 78+/-4% and was independently associated with the number of CD34(+) cells per kg (>1.1 x 10(5); P=0.005) and advanced disease status (blasts 5% and International Prognostic scoring system (IPSS) intermediate-2 or high in MDS) had significant poorer DFS (hazard ratio (HR): 1.76; P=0.047). In spite of high NRM, these data indicate that UCBT is an acceptable alternative option to treat adults with high-risk MDS or sAML, without a suitable human leukocyte antigen (HLA)-matched donor