摘要:

AbstractSevere chronic neutropenia (SCN) is a rare but important cause of recurrent fevers, oropharyngeal ulcerations and severe infections. In three forms of SCN, i.e., congenital neutropenia (Kostmann's syndrome and related syndromes), idiopathic neutropenia (both childhood and adult), and cyclic neutropenia, it is now established that long‐term treatment with the hematopoietic growth factor, recombinant human granulocyte colony stimulating factor (rHuG‐CSF or Filgrastim), can elevate blood neutrophil counts to the normal range in most patients, with a concomitant reduction in infection‐related events including fever, oral ulcerations, antibiotic use and symptoms of inflammation. Treatment with this growth factor causes an increase in the number and maturity of marrow cells of the neutrophilic series; other cell lines are largely unaffected. Marrow stimulation and expansion are reflected by the occurrence of bone pain early in therapy, as well as some increase in spleen size in most cases. Adverse effects of therapy are infrequent in both children and adults, and long‐term treatment with daily or every‐other‐day s.c. injections of rHuG‐CSF are well accepted. Because of the risk that some patients with chronic neutropenia may have or develop myelodysplasia and/or leukemia, careful pretreatment evaluations (blood, bone marrow and cytogenetics) and long‐term observations are extremely important. An international registry for patients with SCN has been established to maintain records and further investigate t

ISSN:1066-5099    

DOI:10.1002/stem.5530130201

出版商:John Wiley&Sons, Ltd.    

年代:1995

数据来源: WILEY

摘要:

AbstractWe have taken advantage of the permissive environment of the early gestational age fetus to engraft human hematopoletic stem cells (HSC) into preimmune fetal lambs. The resulting chimeras exhibit long‐term multilineage engraftment of human cells in the bone marrow (BM) and peripheral blood (PB). Long‐term multilineage reconstitution of second generation recipients by human cells isolated from chimeric sheep BM indicates that the engraftment in this model involved long‐term repopulating human HSC. The model appears to be sensitive enough to detect relatively small numbers of transplanted HSC from pre‐ and postnatal human sources. Finally, transplantation of mature T lymphocyte‐containing cells from a variety of sources results in lethal graft‐versus‐host disease (GVHD), analogous to clinical BM transplantation, suggesting that, at least in some respects, the model is biologically relevant. The human‐sheep model is promising and may have important advantages over murine models for the in vivo study of normal and abnormal hematopoiesis and as a potential assay syste

ISSN:1066-5099    

DOI:10.1002/stem.5530130202

出版商:John Wiley&Sons, Ltd.    

年代:1995

数据来源: WILEY

摘要:

AbstractPost‐remission high‐dose chemotherapy has been an important advance in the treatment of adult acute leukemia (AAL). Without the use of colony‐stimulating factors (CSFs) in this program, the mortality rate varies from 5 to 17%, and infectious complications arise in more than 50%. These findings limit the widespread use of such forms of therapy. The use of high‐dose ara‐C (HIDAC) alone or in combination with other drugs is the most common regimen studied, however neither other drug combinations nor the addition of supporting CSFs have been extensively explored. For this reason we studied the effect of high‐dose cyclophosphamideetoposide (CECY) plus recombinant human granulocyte‐macrophage (rHuGM)‐CSF with the intention of decreasing morbimortality and prolonging disease‐free survival (DFS). Since 1992 we have included 51 complete remission patients with AAL in the CECY plus rHuGM‐CSF protocol. The maximal myelosuppression occurred in a mean of 6.4 days, and the mean days required for absolute neutrophil count recovery was 13 days and for platelets 21 days (p<0.0001). No toxic deaths occurred and only two serious infectious complications were seen. After two years of follow‐up, 50% of de novo acute myelogenous leukemia patients had relapsed at 13 months, and 50% of de novo adult acute lymphocytic leukemia patients had relapsed at 15 months. In a recent update, we have not seen a significant difference when compared to historic groups. The CECY protocol does not appear to be superior in prolonging DFS compared to HIDAC as a post‐remission strategy for newly diagnosed AAL. The main difference was the absence of toxic deaths and minimal serious infectious complications in the CECY protocol. Therefore, we suggest that the use of rHuGM‐CSF in post‐remission programs should be

ISSN:1066-5099    

DOI:10.1002/stem.5530130203

出版商:John Wiley&Sons, Ltd.    

年代:1995

数据来源: WILEY

摘要:

AbstractIn 1994, an estimated 12,700 new cases of multiple myeloma (MM) will be diagnosed in the USA and 9,800 patients will die from this disease. At present, a cure for MM has not been achieved with any chemotherapeutic regimen. Therefore, it is important to develop novel therapeutic approaches to treat this fatal disease.This review focuses on new concepts in the immunotherapy of MM. Thus far, interferons and anti‐human interleukin (IL)‐6 monoclonal antibodies (MAbs) have been used to treat patients with this disease. Bone marrow transplantation using autologous marrow purged with MAbs and complement, with anti‐myeloma immunotoxins (ITs), or MAb‐magnetic bead conjugates has been reported. Adoptive cellular therapy, in vivo with anti‐CD3 and IL‐2, as well as transplantation of purified autologous CD34+peripheral blood stem cells, is now being evaluated in clinical trials. Anti‐human IL‐6 receptor (IL‐6R) and anti‐CD54 (ICAM‐1) MAbs have shown promising results in the therapy of human myeloma cell lines in SCID mice, while an IL‐6 antagonist protein, anti‐gp130 MAbs, recombinant soluble gp130, anti‐B7, anti‐HLA‐DR, and recombinant soluble CD16 also inhibit the growth of myeloma cell lines in vitro. These experimental therapeutic modalities hold promise for use in humans and may also provide further insig

ISSN:1066-5099    

DOI:10.1002/stem.5530130204

出版商:John Wiley&Sons, Ltd.    

年代:1995

数据来源: WILEY

摘要:

AbstractGlycoprotein (GP)IIb/IIIa is an integrin complex normally restricted in its expression to platelets and the megakaryocytes from which they are derived. This complex functions as a receptor for fibrinogen and other ligands and is involved in platelet aggregation. The receptor complex is expressed at high levels during final megakaryocyte differentiation. Further, while GPIIIa is expressed in other tissues as part of the vitronectin receptor, GPIIb is only expressed on maturing megakaryocytes and the platelets derived from them. Thus studies of the GPIIb gene may serve as a model of gene regulation during this process. Over the past several years, the genes for both GPIIb and IIIa have been cloned and analyzed. The GPIIb gene contains 30 exons over 18 kilobases (kb). The transcriptional start site has been determined and there does not appear to be a TATA‐box immediately upstream of this site. Studies have been done to define regulatory elements upstream of the transcriptional start site. Most of these studies focused on the human promoter and on studies using megakaryocytic cell lines. These studies have defined several important tissue‐specific promoter elements including a GATA454site (454 basepairs upstream of the transcriptional start site that involves a GATA‐binding consensus sequence), a GATA54site and an Ets35site (that involves an Ets‐binding consensus sequence). Expression studies with megakaryocytic cell lines suggest that each of these sites effects expression approximately threefold. Further, an Ets510site was also described that had a similar effect. While these studies were underway, we pursued studies of the rat 5'‐flanking region using a rat primary marrow expression system. Qualitatively, our data support the human data; however, quantitatively, we found significant differences from the human studies done in cell lines. We found that the major tissue‐specific promoter element was the GATA454site. Mutations altering this site result in an approximately fiftyfold drop in expression. In comparison, eliminating the Ets510site by truncation or point mutation had only a twofold effect on expression. Mutations at the Ets35site did effect expression at a high level, decreasing expression approximately fifteenfold, while mutations at the GATA54site effected expression by approximately ninefold. In addition, using 50 bp deletions, we have preliminarily defined two domains from ‐450 to ‐351 bp and ‐150 to ‐101 bp upstream of the transcriptional start site that effected expression. The former appears to contain a positive regulatory element, while the latter appears to be a silencer element. In expression studies with the rat GPIIb promoter in human megakaryocytic cell lines, we have obtained results similar to those seen with the human GPIIb promoter region in the same human cell line. Thus, we believe that the differences seen are not due to species differences in GPIIb gene regulation, but rather due to differences in studies involving terminal differentiation of megakaryoblasts into normal megakaryocytes versus studies involving multilineage tumor cell lines. The focus of future studies will be to fully delineate the promoter elements in the 5'‐flanking region of the GPIIb gene, and how they determine tissu

ISSN:1066-5099    

DOI:10.1002/stem.5530130205

出版商:John Wiley&Sons, Ltd.    

年代:1995

数据来源: WILEY

摘要:

AbstractNumerous mutations have been related to various types of cancer. Short tandem repeats (STRs) are repetitive DNA elements that are often polymorphic in normal populations. Triplet repeat expansion has been related pathogenetically to six diseases: fragile × syndrome, fragile × E syndrome, spinobulbar muscular atrophy, myotonic dystrophy, Huntington's disease, and spinocerebellar ataxia type 1. The characteristics of the GC‐rich repeat expansion are diverse and result in profound changes in phenotype, sometimes within a single generation in affected families. We expect that simple repeat expansion will cause some cancers based on our knowledge of these unstable DNA sequences in the previously mentioned genes. This may occur by alteration of tumor suppressor gene expression, alteration in coding features of proteins, or change in bystander oncogene expression such as that which occurs with DNA methylation. The demonstrated meiotic instability could link this mechanism of mutation to familial cancer syndromes. The recent discovery of STR instability at multiple sites in hereditary nonpolyposis colon cancer suggests sequence instability may be a factor in cancer progression. Continued identification of candidate genes containing triplet repeats should allow a ready testing of the hypothesis that unstable simple repeat sequences can cause can

ISSN:1066-5099    

DOI:10.1002/stem.5530130206

出版商:John Wiley&Sons, Ltd.    

年代:1995

数据来源: WILEY

摘要:

AbstractHuman umbilical cord blood (CB) is a rich source of hematopoietic stem cells for both research and stem cell transplantation. In clinical studies, it appears that recovery from myeloablative therapy using CB requires significantly fewer cells than a typical allogeneic marrow transplant. This suggests that CB may be enriched for early hematopoietic progenitors. The present studies were undertaken to determine the presence of CD34+cells in CB with the phenotypic characteristics of multi‐potential stem cells. In 22 CB harvests, the average percentage of CD34+cells was 1.33 ± 0.21% (SE), a value similar to that in adult normal bone marrows (BM). However, the distribution of CD34+cells was distinctly different from either BM or granulocyte colony‐stimulating factor (G‐CSF) mobilized peripheral blood stem cell harvests. CB contained a defined population of brightly staining CD34+cells with low side scatter. These CD34 (bright) cells comprised a mean of 14.5 ± 2.5% of the CB CD34+cells, whereas<1% of BM CD34+cells has been shown to be CD34‐bright. Eighty‐five to ninety percent were negative for three antigens expressed at an early stage of stem cell maturation: CD38, HLA‐DR and LFA‐1. Fifty‐five percent of these CD34 (bright) cells did not express the CD45RA isoform, an additional marker of immaturity. The antigen‐bright cells also lacked lineage‐specific antigens including CD33, CD56, CD19, CD10 and CD7 as well as CD71. Approximately 46% were Thy‐1+, and 40% expressedc‐kitreceptors. These data suggest that, by phenotypic criteria, CB may be a particularly enriched source of primitive

ISSN:1066-5099    

DOI:10.1002/stem.5530130207

出版商:John Wiley&Sons, Ltd.    

年代:1995

数据来源: WILEY

摘要:

AbstractA 96‐well‐based suspension culture system for human hematopoietic progenitor cells has been developed to monitor the commitment and differentiation of CD34+cells to specific lineages and the maintenance and expansion of CD34+cells in vitro. The expression of maturation and lineage markers on the cells in culture was measured by enzyme‐linked immunosorbent assay (ELISA). CD34+cells were isolated from umbilical cord blood and fetal liver (90% purity) and were grown in liquid culture in 96‐well plates for 10 days. The cells were then fixed with a glutaraldehyde‐paraformaldehyde mixture, attaching the cells firmly to the plastic. An ELISA was performed, using appropriate primary antibodies directed against cell surface markers. The expression of four different lineage markers was measured: CD14 (monocyte), CD15 (neutrophil), platelet glycoprotein (GP) IIb/IIIa (CD41a, megakaryocyte) and glycophorin A (erythroid). The two‐growth factor combination of interleukin 3 (IL‐3) and stem cell factor (SCF) stimulated expression of CD14, CD15 and GP IIb/IIIa. Lineage‐restricted growth factors such as erythropoietin (EPO), in combination with SCF, stimulated expression of glycophorin A. The three‐factor combination of IL‐3, SCF and EPO stimulated expression of all four lineage markers. Other multiple growth factor combinations all stimulated myeloid and megakaryocyte growth, as measured by ELISA and flow cytometry, but erythroid growth was present only when EPO was included in the growth factor mixture. In serum‐free medium or plasma‐containing medium, CD14 expression was markedly reduced, whereas glycophorin A expression was greatly elevated in serum‐free medium. The expression of CD34 was also measured over time in culture and was low but detectable and slightly increased over the culture period. CD34 expression was generally higher with fetal liver cells than with cord blood cells. This study demonstrates the detection of CD34 and lineage markers by ELISA as an objective, high‐capacity method of characteri

ISSN:1066-5099    

DOI:10.1002/stem.5530130208

出版商:John Wiley&Sons, Ltd.    

年代:1995

数据来源: WILEY

摘要:

AbstractWe have investigated the mechanisms behind the hematopoietic stimulation mediated by AM5, a protein‐associated polysaccharide that stimulates in vivo the murine hematopoietic system. A dose‐dependent increase in hematopoietic progenitors was observed in long‐term bone marrow cultures (LTBMCs) treated in vitro with AM5. The stimulatory effect was more marked in colony‐forming units‐granulocyte‐macrophage (CFU‐GM) than in CFU‐spleen (CFU‐S) progenitors and also more significant in the supernatant than in the adherent layer. This stimulatory effect was reversible, and continuous stimulation with high doses of AM5 was conducive to a progressive exhaustion of the culture.The analysis of the CFU‐GM stimulating activity present in the supernatant of AM5‐treated cultures revealed a dose‐dependent induction of granulocyte‐macrophage colony‐stimulating activity (GM‐CSA), in contrast with control cultures in which no CSA was detected. Northern blots of LTBMC‐adherent layers obtained after in vitro treatment with AM5 revealed a significant mRNA expression for interleukin 1α (IL‐1α), granulocyte‐macrophage colony‐stimulating factor (GM‐CSF), macrophage CSF (M‐CSF) and granulocyte CSF (G‐CSF), in contrast with adherent layers from untreated cultures which only expressed, in detectable levels, M‐CSF and stem cell factor (SCF). The SCF expression was down‐modulated in AM5‐treated cultures. Our results strongly suggest that the hematopoietic stimulation induced by AM5 is mediated by the modulated ex

ISSN:1066-5099    

DOI:10.1002/stem.5530130209

出版商:John Wiley&Sons, Ltd.    

年代:1995

数据来源: WILEY

摘要:

AbstractWe describe the effects of stem cell factor (SCF) on the dendritic cell (DC) pathway and provide evidence for the existence of a post granulocyte‐macrophage colony‐forming unit (GM‐CFU) DC progenitor. When employed with cytokines regulating DC development (tumor necrosis factor [TNF] + GM colony‐stimulating factor [GM‐CSF]), SCF increased the size of monocyte (mono) and mono‐DC colonies arising from cord blood CD34+progenitor cells. The overall plating efficiency of these colonies increased approximately threefold, as compared with growth in TNF + GM‐CSF. Most (‐70%) of the CFUs were mono‐DC CFU, and SCF did not alter the proportion of mono‐DC CFU to mono‐CFU obtained with TNF + GM‐CSF alone. Proliferation, as measured by thymidine uptake and manual cell counts, at least doubled and occurred earlier (by day 4). In long‐term cultures established with TNF + GM‐CSF + SCF, high levels of proliferation were prolonged for up to three weeks. These were associated with extended DC development and the capacity to form 2* mono‐DC colonies. There was no induction of polymorphonuclear (PMN) cells in 2* cultures treated with either GM‐CSF, GM‐CSF + SCF or GM‐CSF + granulocyte CSF (G‐CSF), implying that the DC progenitor being replated was post GM‐CFU. DC progeny arising in the presence of SCF exhibited typical DC features including: the lack of nonspecific esterase and phagocytic activity, the presence of class II major histocompatibility complex (MHC) antigens, the absence of CD14 antigens, and the ability to induce a potent mixed leukocyte reaction.Thus, SCF augments DC growth from progenitor cells without altering the developmental commitment instituted by TNF + GM‐CSF. This enhancement follows the same general mechanisms previously reported for SCF‐mediated lineage enhancement, i.e., increas

ISSN:1066-5099    

DOI:10.1002/stem.5530130210

出版商:John Wiley&Sons, Ltd.    

年代:1995

数据来源: WILEY