Blood cells最新文献

Four patients with advanced solid tumors were treated by means of high-dose chemotherapy and HLA-mismatched and unrelated multi-cord blood transfusion. Of these patients, three achieved complete remission and one achieved a partial remission. Little or no graft vs. host disease (GVHD) was observed. Partial donor cell engraftment was suggested by 101 to 320 days for two patients by cytogenetic analysis and hemoglobin F levels in the peripheral blood. Recurrent disease was confirmed clinically on day 210 (4-year-old girl with liposarcoma) and on day 90 (11-year-old boy with non-Hodgkin's lymphoma). These results suggest the possibility that HLA-mismatched and unrelated multi-cord blood transfusion may engraft with little or no GVHD and hasten recovery from marrow suppression that is due to chemotherapy. It remains to be determined, however, whether these results document true stem/progenitor cell engraftment or alternatively transient engraftment of more mature cells along with repopulation by autologous cells.

A variety of genetic disorders are treatable by allogeneic bone marrow transplantation. Predictive genetic testing and HLA typing of cultured fetal cells enable one to know early in a pregnancy that a fetus is genetically normal and is HLA-identical to a sibling affected with a genetic disease. Umbilical cord blood can be collected at the delivery of an HLA-matched normal sibling and used for stem/progenitor cell transplantation for the affected child. Our experience with families of children with Fanconi anemia has shown that the deliberate conception of a fetus for the possibility of providing a transplant donor is often undertaken. This paper reviews the genetic diseases potentially treatable by cord blood transplantation and the methods and pitfalls of prenatal testing for these conditions. Our laboratory's extensive experience with prenatal diagnosis for Fanconi anemia is discussed and provides the framework for an examination of the ethical issues related to the conception of a fetus for the purpose of providing a transplant donor.

The in vitro interactions between human osteosarcoma (HOS) cells and platelets were studied in real time using video-enhanced microscopy. Interference reflection techniques showed that platelets were lysed within minutes after contacting HOS cells that had been treated with interferon-gamma. Untreated HOS cells lysed platelets less efficiently. Platelet lysis depended on platelet-tumor cell contact and on extracellular Ca2+. A number of possible mechanisms were excluded. Lysis of platelets in proximity to tumor cells can provide these with growth factors and thereby contribute to the metastasis-enhancing effect of platelets.

Expansion of stem/progenitor cells has important implications for transplantation. We recently reported that a factor or factors in cord blood (CB), but not adult peripheral blood (PB), plasma enhanced replating of granulocyte erythroid macrophage megakaryocyte colony-forming units (CFU-GEMM) progenitors, a measure of self-renewal capacity. In this context, we evaluated effects of CB plasma, in comparison with PB plasma and fetal bovine serum (FBS), on ex vivo expansion of CD34+ column-separated (72-98% CD34+) CB cells using stroma-free cultures in the absence and presence of either PIXY321 (a granulocyte-macrophage colony-stimulating factor/interleukin-3 [GM-CSF/IL-3] fusion protein), IL-3+IL-6+IL-1, or steel factor (SLF) -/+ PIXY. CB plasma, PB plasma, or FBS alone did not sustain cell numbers. Combinations of CB plasma +SLF+PIXY induced maximal cumulative nucleated cell expansion (1044-fold), which was greater than that of PB plasma plus cytokines (633-fold) and FBS plus cytokines (142-fold). Total CD34+ cells peaked by day 7 with 7-fold expansion in the presence of CB plasma+SLF+PIXY compared with PB plasma or FBS with these same cytokines (threefold each). By day 7, total CFU-GEMM production in the presence of either PIXY, SLF+PIXY, or IL-3+IL-6+IL-1 was greater with CB plasma (maximum 11.4-fold average increases) than with PB plasma (6.8-fold increase). These increases were greater than with FBS. However, PB plasma was at least as good as CB plasma for expansion of immature and mature subsets of CFU-GM. The frequency of progenitors decreased with time, and expansion was coupled with differentiation. Although the proliferative capacity of CFU-GEMM was maintained, the capacity of CFU-GEMM to be replated decreased after time in suspension culture, suggesting age-related commitment of cells. Moreover, with plasma +SLF+PIXY for 7 days, expansion of more mature CFU-GM (responsive to GM-CSF) was greater (16-146-fold with CB plasma and 31-208-fold with PB plasma) than immature CFU-GM (responsive to GM-CSF+SFL) (4- to 14-fold with CB plasma and 6- to 17-fold with PB plasma). The results suggest that CB plasma enhances expansion of CFU-GEMM to a greater extent than PB plasma or FBS, but expansion in these cultures favors more mature subsets of cells.

We have studied several features of pluripotent hematopoietic stem cells (PHSCs) and day-12 spleen colony-forming units (CFU-S) obtained from adult murine bone marrow. Single-cell suspensions of C57BL/6J mouse bone marrow were fractionated by counterflow centrifugal elutriation at flow rates (FR) of 15, 25, 30, and 35 ml/min, and with the rotor off (R/O). The fractions FR25 and FR35 contained approximately equal numbers of PHSC that could repopulate W/Wv mice. These PHSCs were further enriched by subtracting lineage-positive cells using monoclonal antibodies (MAb) and magnetic immunobeads. The resulting lineage-negative cells (Lin-) were then stained with a MAb for the c-kit receptor and sorted by flow cytometry. Both subsets were fractionated into cells expressing high (bright) (c-kitBR), low (dull) c-kitDULL and no (negative, c-kitNEG) c-kit receptor. As few as 100 to 200 c-kitBR cells could repopulate the entire thymus and bone marrow in W/Wv mice. No PHSCs were present in the c-kitDULL and c-kitNEG fractions. We assayed fresh bone marrow and elutriation fractions FR25 and FR35 for gene expression by reverse transcriptase polymerase chain reaction. Using a semiquantitative protocol, we detected mRNA for beta-globin and flk-2, a protein tyrosine kinase receptor, in all samples except the FR25 Lin- c-kitBR subset. We consider the cells in FR25 Lin- c-kitBR to be the most primitive set of hematopoietic stem cells.

In this study we define hematopoietic stem cells (HSCs) as a population of cells that, when sorted as single cells, gives rise to both myeloid as well as lymphoid progeny. We sorted single cells from four populations of CD34+ cells from fetal bone marrow: (1) CD38- HLA-DR-, (2) CD38- HLA-DR+, (3) CD38+ HLA-DR-, and (4) CD38+ HLA-DR+ into liquid culture media supplemented with interleukin-3 (IL-3) IL-6, stem cell factor (SCF), granulocyte-macrophage colony-stimulating factor, erythropoietin, basic fibroblast growth factor (bFGF) and insuline-like growth factor (IGF-1). The HSCs were found in the cell populations lacking CD38, the plating efficiency was highest in the CD34+ CD38- HLA-DR+ cell population (48% n = 12); however, only a small proportion of the CD34+ CD38- HLA-DR+ cells showed both lymphoid and myeloid growth potential. When the identical cell populations were sorted into liquid culture media supplemented with bFGF and IGF-1, cell growth was noted from only 1%-5% of the sorted CD34+ CD38- HLA-DR- cells. The cells have the potential to grow and differentiate in vitro to form complex structures that recapitulate normal bone formation. Serial passages of the progeny from these cultures resulted in the formation of similar structures.

Over time CD34+ cells purified from human cord blood generate large numbers of progenitor and precursor cells in liquid culture under serum-deprived conditions if stimulated with a cocktail of growth factors which include stem cell factor (SCF). The ex vivo expansion observed in liquid cultures is not homogeneous over time but involves the recruitment of different cell compartments and can be triggered by different growth factor combinations. We have recognized at least three phases in these liquid cultures. Phase I spans the first 20 days of culture. In this phase, progenitor and precursor cells are generated from the progenitor cell compartment itself in response to SCF in combination with either IL-3, erythropoietin, or G-CSF. Phase II spans the second month of culture and involves the recruitment of less and less differentiated cells by IL-3 and SCF. Phase III spans from the third month on and results in the indefinite proliferation of human mast cells. These results raise caution on the biological equivalence of liquid culture en vivo expanded hematopoietic cells at different time points.

Nonadherent, low-density T-lymphocyte-depleted (NALT-) CD34 cells from normal human cord blood were assessed in suspension culture for the effects of recombinant cytokines on their proliferation, differentiation, and generation of myeloid progenitor cells. In this cell population, 82% of cells expressed c-kit protein as assessed by in situ hybridization, and their cloning efficiency was 85% when cells were plated at low cell numbers with combinations of growth factors. CD34 cells were sorted as 1, 5, or 10 cell(s) per well and also at 5000 cells per dish to initiate stromal-free suspension cultures in the presence of steel factor (SLF), interleukin (IL)-1 alpha, and IL-3. Forty-eight percent of the wells started with a single CD34 cell were positive for growth after 14 days, and the wells contained greater than 5 x 10(3) cells by 21-28 days. Progenitors were assayed weekly with cultures initiated with 1 or 5000 cells. While the fold expansion of nucleated cells was greater in cultures initiated with one cell per well (> 5000 compared to 791-fold expansion for 5000 cells), the fold expansion of progenitors was greater than 5000 cells were used to initiate cultures. Under optimal conditions, there was, respectively, a 160-, 164-, and 57-fold output of high proliferative potential colony-forming cells, granulocyte-macrophage colony-forming units, and erythroid burst-forming units/granulocyte erythroid macrophage megakaryocyte colony-forming units within 1-3 weeks for cultures initiated with 5000 CD34 cells compared with respective fold increases of 29, 16, and 1, for single-initiated cultures. These results demonstrate the expansion capacity of single CD34 cord blood cells and demonstrate that factors in addition to SLF, IL-1 alpha, and IL-3 are necessary for optimal expansion of progenitors from single isolated CD34 cells.

Hematopoietic stem and progenitor cells present in umbilical cord blood at the birth of a child are efficiently transduced ex vivo by genes using retroviral vectors in combination with exposure of these cells to combinations of growth factors. Because retroviral-mediated gene transduction of adult bone marrow and blood hematopoietic stem and progenitor cells is greatly enhanced by growth factors, we evaluated the possibility that cord blood progenitors, which have extensive proliferative and replating capacity, could be efficiently transduced with a TK neo gene in a retroviral vector in the absence of growth factors, and also determined the influence of exogenously added growth factors on this transduction. Highly purified CD34+ (62% pure) cord blood cells isolated by magnetic bead separation were cultured in suspension for 72 hours with viral supernatant in the absence and presence of interleukin-3 (IL-3), IL-6, and steel factor. Evaluation of progenitor cell-derived colonies and polymerase chain reaction (PCR)/Southern analysis of the TK neo gene in resultant colony cells demonstrated that some gene transduction was apparent in the absence of growth factors (12.8-14.3% by PCR), but that this was greatly enhanced (40.0-44.4%) by addition of growth factors. Reverse transcription PCR analysis of the expression of IL-3, IL-6, and granulocyte-macrophage colony-stimulating factor genes in this population of cells suggested that the transduction, although at a lower efficiency, in the absence of added growth factors might in part be due to "constitutive" and viral supernatant-induced expression of these cytokine genes in the CD34(+)-enriched cell population.(ABSTRACT TRUNCATED AT 250 WORDS)