Treatment of hairy-cell leukemia.

Hairy-cell leukemia is an unusual chronic lymphoid leukemia with distinctive clinical and pathological features. The management of this disorder has been revolutionized in the last decade with the discovery of the efficacy of alpha interferon and the inhibitors of adenosine metabolism, deoxycoformycin and chlorodeoxyadenosine. The best treatment protocol for hairy-cell leukemia has not yet been defined. Patients may still die from their disease, particularly in the early phases of treatment. Conversely, some patients appear not to require treatment and others respond well to splenectomy and need no further therapy. An individualized clinical approach is recommended, with a role for splenectomy in the patient with cytopenia and a relatively low number of hairy cells in the bone marrow. The first line drug treatment remains interferon alpha given for 12-18 months, following which the patient is observed for clinical relapse. Deoxycoformycin remains a useful experimental agent but cannot be recommended for routine clinical use until issues of long term toxicity are resolved. Chlorodeoxyadenosine is a very promising experimental drug, but confirmation of the early data in larger group trials is required. Similarly the adjunctive use of granulocyte colony stimulating factor appears useful, but will need further study in larger groups of patients. There is little or no role for alkylating agents or more intensive chemotherapy in the modern management of hairy-cell leukemia.

The biology of the cytokine sequence cascade.

Pretransplant and posttransplant use of hematopoietic growth factors in bone marrow transplantation (BMT) has shortened the time to engraftment. Severe neutropenia and thrombocytopenia have been the major clinical problems associated with autologous BMT. Efforts to maintain posttransplant levels of circulating neutrophils have focused on exploiting the synergistic action between various hematopoietic growth factor families. Ex vivo generation of distinct populations of expanded cells through simultaneous and sequential addition of hematopoietic growth factors was attempted. Cultures of CD34-selected cells with combinations of growth factors consisting of either recombinant human stem cell factor (rhSCF), recombinant human interleukin-6 (rhIL-6), and recombinant human interleukin-3 (rhIL-3) or rhSCF, rhIL-3, and recombinant human granulocyte-colony stimulating factor (rhG-CSF) generated two distinct but overlapping populations of cells. Delayed addition (on day 7) of rhIL-3 and rhIL-6 to cells cultured with rhSCF generated a population of cells significantly less mature than those cultured with continuous rhSCF, rhIL-3, and rhIL-6 alone. It appears that optimal generation of immediate and delayed cell populations can be achieved by simultaneous culture with rhSCF, rhIL-3, and rhG-CSF; and with rhSCF, rhIL-6, and rhIL-3. Questions remain regarding the cell populations most effective for generating and sustaining the required neutrophil numbers.

Similar outcomes using myeloablative vs reduced-intensity allogeneic transplant preparative regimens for AML or MDS.

Although reduced-intensity conditioning (RIC) and non-myeloablative (NMA)-conditioning regimens have been used for over a decade, their relative efficacy vs myeloablative (MA) approaches to allogeneic hematopoietic cell transplantation in patients with AML and myelodysplasia (MDS) is unknown. We compared disease status, donor, graft and recipient characteristics with outcomes of 3731 MA with 1448 RIC/NMA procedures performed at 217 centers between 1997 and 2004. The 5-year univariate probabilities and multivariate relative risk outcomes of relapse, TRM, disease-free survival (DFS) and OS are reported. Adjusted OS at 5 years was 34, 33 and 26% for MA, RIC and NMA transplants, respectively. NMA conditioning resulted in inferior DFS and OS, but there was no difference in DFS and OS between RIC and MA regimens. Late TRM negates early decreases in toxicity with RIC and NMA regimens. Our data suggest that higher regimen intensity may contribute to optimal survival in patients with AML/MDS, suggesting roles for both regimen intensity and graft vs leukemia in these diseases. Prospective studies comparing regimens are needed to confirm this finding and determine the optimal approach to patients who are eligible for either MA or RIC/NMA conditioning.

The role of the homeobox gene, HOX B7, in human myelomonocytic differentiation.

Homeobox genes encode transcription factors known to be important morphogenic regulators during embryogenesis. An increasing body of work implies a role for homeobox genes in both hematopoiesis and oncogenesis. We have analyzed the role of the homeobox gene, HOX B7, in the program of differentiation of the biphenotypic myeloid cell line, HL60. Induction of monocytic differentiation in HL-60 cells by vitamin D3 resulted in rapid expression of HOX B7 mRNA, but stimulation with phorbol ester or dimethyl sulfoxide (DMSO) did not. Constitutive overexpression of HOX B7 in the HL60 cell line inhibited the granulocytic differentiation associated with stimulation with DMSO or retinoic acid, but had no effect on the monocytic differentiation induced by vitamin D3. Normal human monocytes do not constitutively express HOX B7, nor are they able to be induced to do so by stimulation with colony-stimulating factor 1 (CSF-1) and gamma interferon (IFN gamma), or with vitamin D3 and lipopolysaccharide. Human bone marrow (BM) cells were found to express HOX B7 in response to granulocyte-macrophage CSF (GM-CSF) and antisense oligonucleotides directed against HOX B7 inhibited the formation of colonies derived from GM-CSF-stimulated BM. These data suggest a critical role for HOX B7 in myelomonocytic differentiation.

Production of functional myeloid cells from CD34-selected hematopoietic progenitor cells using a clinically relevant ex vivo expansion system.

There is increasing clinical interest focused on ex vivo manipulation and expansion of hematopoietic cells. In this study, we demonstrate that a simple combination of growth factors can expand progenitors to yield functional myeloid cells. Furthermore, this system can produce mature, functionally competent cells in the absence of fetal bovine serum (FBS), which will enhance the clinical utility of this approach. Hematopoietic progenitor cells obtained from normal bone marrow and from leukapheresis products were studied. The mononuclear fraction was enriched for CD34 cells using the Ceprate CD34 biotin kit (CellPro #LC34-1 or LC34-2). The selected cells were expanded for two weeks in Iscove's medium supplemented with 20% FBS and various combinations of interleukin-3 (IL-3), granulocyte colony-stimulating factor (G-CSF), stem cell factor (SCF) and interleukin -6 (IL-6) added either simultaneously or sequentially. The optimal combination of these factors identified for myeloid expansion was simultaneous addition of IL-3, SCF and G-CSF (at 50 ng/ml each), resulting in an average 773 +/- 133-fold expansion of nucleated cells (n = 5). When corrected for the purity of CD34 cells in the starting population, the mean fold expansion with IL-3, SCF and G-CSF was 2,265 +/- 729. A mean of 74.7 +/- 10.5% (n = 3) of the expanded cells was positive for CD11b; 86-91% (n = 2) of the cells were promyelocytes or more mature granulocytes. Functional assays demonstrated normal phagocytosis and intracellular killing of Staphylococcus aureus (S. aureus) by the expanded cell population. Studies performed using cells expanded in defined serum-free media demonstrated that fold expansion was decreased and that the cells produced were less mature and functionally less competent than cells expanded with FBS. The decreased expansion could be partially reversed, and the functionality almost completely restored by the addition of autologous plasma.

Cord Blood Transplantation Study (COBLT): cord blood bank standard operating procedures.

In 1995, the National Heart Lung and Blood Institute (NHLBI) solicited requests for a proposal (RFP) entitled "Transplant Centers for Clinical Research on Transplantation of Umbilical Cord Stem and Progenitor Cells." Three banks, six transplant centers, and one medical coordinating center (MCC) (Table 1) were funded with the overall goal of banking cord blood units (CBU) using a single manual of operations. Furthermore, the clinical protocols to evaluate the transplant outcome for adult and pediatric recipients of these well-characterized CBU would be analyzed in a uniform fashion. Because of the intense interest of the transplantation community in the policies and procedures for cord blood collection and processing, the principal investigators of the cord blood banks (CBB) and NHLBI elected to submit for publication the rationale and an abridged, but detailed, version of the standard operating procedures (SOP) developed between October 1996 and July 1998 prior to the initiation of the clinical protocols to be performed with these CBU. As the SOP will be refined over time, the complete SOP and subsequent amendments will be published and continually updated on the websites from the MCC-The EMMES Corporation (www.EMMES.com). All forms referred to in this document may be obtained from the EMMES website. It is hoped that the publication of this document will lay down a framework that will not only facilitate the development of other CBB but also help us more rapidly define what constitutes an "acceptable" CBU product.