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In long-term bone marrow cultures, stroma-adherent progenitors proliferate significantly less than nonadherent progenitors. Thus, close progenitor-stroma interactions may serve to regulate or restrict rather than promote hematopoietic progenitor proliferation. We hypothesized that signaling through adhesion receptors on hematopoietic cells may contribute to the inhibition of proliferation observed when progenitors are in contact with stroma. We demonstrate that progenitors cultured physically separated from stroma in a transwell proliferate significantly more than progenitors adherent to stroma. Furthermore, proliferation of colony forming cells (CFC) is reduced after specific adhesion to stroma, metabolically inactivated glutaraldehyde-fixed stroma, stromal-extracellular matrix, or the COOH-terminal heparin-binding domain of fibronectin. Nonspecific adhesion to poly-L-lysine fails to inhibit CFC proliferation. That the VLA-4 integrin is one of the receptors that transfers proliferation inhibitory signals was shown using blocking anti-alpha 4 monomeric F(ab) fragments. Furthermore, when synthetic peptides representing specific cell attachment sites within the heparin-binding domain of fibronectin were added to Dexter-type marrow cultures, significantly increased recovery and proliferation of CFC was observed, suggesting that these peptides disrupt adhesion-mediated proliferation inhibitory events. Thus, negative regulation of hematopoiesis may not only depend on the action of growth inhibitory cytokines but also on growth inhibitory signals resulting from direct adhesive interactions between progenitors and marrow stroma.

Delay in hematologic recovery after bone marrow transplantation (BMT) can extend and amplify the risks of infection and hemorrhage, compromise patients' survival, and increase the duration and cost of hospitalization. Because current studies suggest that granulocyte-macrophage (GM) colony-stimulating factor (CSF) may potentiate the sensitivity of hematopoietic progenitor cells to G-CSF, we performed a prospective, randomized trial comparing GM-CSF (250 micrograms/m2/d x 14 days) versus sequential GM-CSF x 7 days followed by G-CSF (5 micrograms/kg/d x 7 days) as treatment for primary or secondary graft failure after BMT. Eligibility criteria included failure to achieve a white blood cell (WBC) count > or = 100/microL by day +21 or > or = 300/microL by day +28, no absolute neutrophil count (ANC) > or = 200/microL by day +28, or secondary sustained neutropenia after initial engraftment. Forty-seven patients were enrolled: 23 received GM-CSF (10 unrelated, 8 related allogeneic, and 5 autologous), and 24 received GM-CSF followed by G-CSF (12 unrelated, 7 related allogeneic, and 5 autologous). For patients receiving GM-CSF alone, neutrophil recovery (ANC > or = 500/microL) occurred between 2 and 61 days (median, 8 days) after therapy, while those receiving GM-CSF+G-CSF recovered at a similar rate of 1 to 36 days (median, 6 days; P = .39). Recovery to red blood cell (RBC) transfusion independence was slow, occurring 6 to 250 days (median, 35 days) after enrollment with no significant difference between the two treatment groups (GM-CSF: median, 30 days; GM-CSF+G-CSF; median, 42 days; P = .24). Similarly, platelet transfusion independence was delayed until 4 to 249 days (median, 32 days) after enrollment, with no difference between the two treatment groups (GM-CSF: median, 28 days; GM-CSF+G-CSF: median, 42 days; P = .38). Recovery times were not different between patients with unrelated donors and those with related donors or autologous transplant recipients. Survival at 100 days after enrollment was superior after treatment with GM-CSF alone. Only 1 of 23 patients treated with GM-CSF died versus 7 of 24 treated with GM-CSF+G-CSF who died 16 to 84 days (median, 38 days) after enrollment, yielding Kaplan-Meier 100-day survival estimates of 96% +/- 8% for GM-CSF versus 71% +/- 18% for GM-CSF+G-CSF (P = .026). These data suggest that sequential growth factor therapy with GM-CSF followed by G-CSF offers no advantage over GM-CSF alone in accelerating trilineage hematopoiesis or preventing lethal complications in patients with poor graft function after BMT.(ABSTRACT TRUNCATED AT 400 WORDS)

The bone marrow microenvironment supports and regulates the proliferation and differentiation of hematopoietic cells. Dysregulated hematopoiesis in chronic myelogenous leukemia (CML) is caused, at least in part, by abnormalities in CML hematopoietic progenitors leading to altered interactions with the marrow microenvironment. The role of the microenvironment itself in CML has not been well characterized. We examined the capacity of CML stroma to support the growth of long-term culture-initiating cells (LTC-IC) obtained from normal and CML marrow. The growth of normal LTC-IC on CML stroma was significantly reduced compared with normal stroma. This did not appear to be related to abnormal production of soluble factors by CML stroma because normal LTC-IC grew equally well in Transwells above CML stroma as in Transwells above normal stroma. In addition, CML and normal stromal supernatants contained similar quantities of both growth-stimulatory (granulocyte colony-stimulating factor (CSF), interleukin-6, stem cell factor, granulocyte-macrophage CSF, and interleukin-1 beta) and growth-inhibitory cytokines (transforming growth factor-beta, macrophage inflammatory protein-1 alpha, and tumor necrosis factor-alpha). The relative proportion of different cell types in CML and normal stroma was similar. However, polymerase chain reaction and fluorescence in situ hybridization studies showed the presence of bcr-abl-positivo cells in CML stroma, which were CD14+ stromal macrophages. To assess the effect of these malignant macrophages on stromal function, CML and normal stromal cells were separated by fluorescence-activated cell sorting into stromal mesenchymal cell (CD14-) and macrophage (CD14+) populations. CML and normal CD14- cells supported the growth of normal LTC-IC equally well. However, the addition of CML macrophages to normal or CML CD14- mesenchymal cells resulted in impaired progenitor support. This finding indicates that the abnormal function of CML bone marrow stroma is related to the presence of malignant macrophages. In contrast to normal LTC-IC, the growth of CML LTC-IC on allogeneic CML stromal layers was not impaired and was significantly better than that of normal LTC-IC cocultured with the same CML stromal layers. These studies demonstrate that, in addition to abnormalities in CML progenitors themselves, abnormalities in the CML marrow microenvironment related to the presence of malignant stromal macrophages may contribute to the selective expansion of leukemic progenitors and suppression of normal hematopoiesis in CML.

Lupus inhibitors have been reported in a number of pathologic states in which there is a disruption of normal immunoregulation. We report here the development of new lupus inhibitors following bone marrow transplantation. Retrospective analysis of 1292 patients undergoing transplantation at the University of Minnesota over a 10 year period demonstrated newly recognized lupus inhibitors in 3% of the patients. These inhibitors were usually detected in the first 1-2 months after transplant. They occurred more frequently in children, with a particularly high incidence in patients with Hurler syndrome. The development of inhibitors was associated with the use of cyclosporine A (CsA) or T depletion for GVHD prophylaxis, with the use of busulfan/cytoxan as a preparative regimen (which includes phenytoin for seizure prophylaxis) and with the occurrence of viral infections. Lupus inhibitors were not associated with development of GVHD, or with any diagnosis other than Hurler syndrome. Thrombotic complications were rare as would be expected in this severely thrombocytopenic population. The incidence of lupus inhibitors that we recognized may substantially underestimate the true incidence as frequent routine coagulation studies were not performed in these patients. Prospective evaluation of lupus inhibitors during bone marrow transplant may provide insight into the pathogenesis of these inhibitors in other disease states.

Immunotherapy with recombinant interleukin-2 (rIL-2) activated natural killer cells (ANK) may be useful in the treatment of malignancies. Difficulties in large scale cultivation of purified ANK have hampered clinical trials. In a first set of experiments designed to characterize ANK precursors in blood we demonstrated that both FACS purified CD56+/CD3- and CD56-/CD3- cultured with rIL-2 give rise to an expanded cell population bearing the CD56+(bright)/CD3- phenotype and having both NK and lymphokine-activated killer (LAK) activity. Cultivation of NK was markedly enhanced by autologous monocytes. We next demonstrated that panning of peripheral blood stem cells on CD5/CD8 coated flasks yielded a starting population enriched for monocytes and NK precursors which after cultivation resulted in production of 4 x 10(10) highly cytotoxic ANK adequate for in vivo clinical trials. Finally, we demonstrated that ANK generated in high dose IL-2 maintain NK and LAK activity for up to 6 days when cultured in as little as 1 U/ml rIL-2. This may allow infusion of ANK with a rIL-2 dose achievable in vivo that does not produce significant systemic toxicity. We plan to test the efficacy of ANK to prevent relapse in a minimal residual disease state following autologous bone marrow transplant.

Significantly more primitive human hematopoietic progenitors are maintained and differentiate when cultured separately from the stroma by a microporous membrane ("stroma-noncontact" cultures) than when cultured in direct contact with stromal layers ("stroma-contact" cultures). This suggests that diffusible stroma-derived factors may be sufficient for the in vitro induction of progenitor proliferation and differentiation. To further characterize stroma-derived factors that maintain long-term bone marrow culture initiating cells (LTBMC-IC), we compared the hematopoietic supportive capacity of human marrow stroma with that of the murine marrow stroma-derived fibroblast cell line M2-10B4 as well as two embryonic fibroblast cell lines, the human FHS-173-WE and the murine NIH-3T3 cell lines. We demonstrate that LTBMC-IC, present in human CD34+/HLA-DR- (DR- cells), are maintained equally well and give rise to similar numbers of committed progenitors, that is--colony-forming cells (CFC)--when cultured in contact with human marrow stroma or any cell line feeder (stroma-contact cultures). LTBMC-IC, cultured in marrow stroma or M2-10B4 stroma-noncontact cultures, were maintained significantly better and gave rise to significantly more CFC than when cultured in human marrow stroma or M2-10B4 contact cultures. However, LTBMC-IC maintenance and differentiation in FHS-173-WE or NIH-3T3 noncontact cultures was significantly less than in human marrow stroma or M2-10B4 noncontact cultures. These studies indicate that systematic comparison of diffusible growth stimulatory factors in conditioned media from M2-10B4 cells and FHS-173-WE may lead to the characterization of growth regulatory factors required for in vitro maintenance and differentiation of human primitive LTBMC-IC. Since diffusible factors from the M2-10B4 cell line can support human hematopoiesis, our observations may also have important implications for in vitro stem cell expansion protocols.

Interleukin-1 alpha (IL-1 alpha) can act as both a hematopoietic growth factor and a stimulant of cellular and humoral immune responses. To promote acceleration of hematologic recovery and induce immune antitumor activity, we initiated a phase I/II dose escalation trial of 6-hour daily infusions of recombinant human IL-1 alpha after autologous transplantation. Forty patients with Hodgkin's disease (n = 9) and non-Hodgkin's lymphoma (n = 31) transplanted with unmobilized autologous peripheral blood stem cells or bone marrow stem cells received daily 6-hour infusions of IL-1 alpha (day 0 to day +13) at daily doses between 0.1 to 10 micrograms/m2/d; 7 patients received only 7 planned days of IL-1 alpha (day 0 through 6). Most patients received all 14 days of therapy, although 5 patients discontinued treatment early (after 1 to 6 doses) because of fever and severe chills. Toxicity included IL-1 alpha-related fever (occurring on a median of 9 of 14 treatment days), fatigue, and severe chills. Hypotension was dose-limiting and led to discontinuation of IL-1 alpha in both patients receiving 10 micrograms/m2/d. IL-1 alpha-treated patients receiving 3.0 micrograms/m2/d (the maximum tolerated dose) achieved neutrophil recovery (absolute neutrophil count greater than 500/microL) significantly earlier (median, 12 days; range, 11 to 27) than untreated control patients or those receiving IL-1 alpha at 0.1 to 1.0 micrograms/m2/d (median, 27; range, 9 to 63; P < .0001). In addition, the IL-1 alpha patients' bone marrows at day +14 were significantly enriched with committed myeloid progenitor cells. Strong trends to earlier freedom from red blood cell (P = .06) and platelet (P = .09) transfusions were also noted after IL-1 alpha treatment. This earlier hematopoietic engraftment after 3.0 micrograms/m2/d IL-1 alpha allowed earlier hospital discharge (median, 25 v 37 days for control or low-dose IL-1 alpha patients [P < .0001]) and a concomitant reduction (by $38,000) in median hospital charges (P = .01). The clinical toxicities of IL-1 alpha infusion are substantial, though not life-threatening. The accelerated hematopoiesis and immune response activation observed in this trial suggest the value of its further investigation in controlled trials and perhaps in combination with other hemopoietins after transplantation.

Close interaction of human hematopoietic progenitors with the bone marrow microenvironment is important for the ordered progression of human hematopoiesis. Progenitor cell adhesion to stroma has a complex molecular basis, involving various cell-extracellular matrix and cell-cell interactions. We have previously shown that adhesion of colony-forming cells (CFC) to fibronectin, present in stromal extracellular matrix, involves multiple sites, including two heparin-binding synthetic peptides (FN-C/H I and FN-C/H II) and the alpha 4 beta 1 integrin-binding peptide CS1. These synthetic peptides are located in close proximity in the type III repeat 14 and the immediately adjacent type IIIcs region of fibronectin. In the current study, we evaluate receptors expressed by CFC responsible for their adhesion to fibronectin. We show that the alpha 4 beta 1 integrin mediates adhesion to CFC to the peptides FN-C/H I and CS1. Adhesion of CFC to fibronectin is also mediated by proteoglycans, because removal of cell surface chondroitin-sulfate proteoglycans resulted in decreased adhesion of CFC to FN-C/ I and FN-C/H II. The core protein of this proteoglycan was identified by immunoprecipitation as a 90-kD member of the CD44 group of adhesion molecules. Interestingly, although the proteoglycan core protein failed to adhere to FN-C/H II affinity columns, anti-CD44 monoclonal antibodies blocked CFC adhesion to FN-C/H II, indicating that these monoclonal antibodies may interfere with core protein-mediated intracellular signalling. Finally, we show that CD44 and alpha 4 beta 1 may cooperate in establishing progenitor adhesion, because anti-CD44 antibodies potentiated the adhesion-inhibitory effects of suboptimal concentrations of anti-alpha 4 or anti-beta 1 monoclonal antibodies. These results provide a working model for progenitor cell recognition of fibronectin (and possibly the marrow micro-environment) in which the coordinated action of integrins and cell surface proteoglycans is necessary for cell adhesion. This model can now be used to study the complex relationship between progenitor cell adhesion and the regulation of their proliferation and differentiation.

The factors that induce proliferation of the human hematopoietic stem cell are ill defined. Further characterization of such growth factors will be needed to develop ex vivo culture systems that induce prolonged proliferation and expansion of human hematopoietic stem cells. Human or murine hematopoietic progenitors that can initiate and sustain long-term culture systems (LTC-IC) represent a population of very primitive hematopoietic progenitors. When cultured in direct contact with stromal layers, we and others have demonstrated that a fraction of such LTC-IC can be maintained. In addition, stroma-free long-term cultures supplemented with two to nine cytokines can induce proliferation and differentiation of immature human hematopoietic progenitors. However, 70-90% of primitive LTC-IC are lost after five weeks in such cultures. We describe a "stroma-non-contact" culture system, in which progenitors are cultured separated from stroma by a 0.4 micron microporous membrane which prevents cell stroma contact but allows free passage of diffusible factors. Primitive progenitors in such cultures can not only differentiate into committed progenitors but also are maintained to a greater extent than in Dexter cultures. We will discuss the relative contribution of 1) direct contact between hematopoietic progenitors and bone marrow stroma, 2) soluble stroma-derived factors and 3) previously characterized growth promoting and presumed growth inhibitory cytokines in the in vitro maintenance and potential expansion of LTC-IC.

Human hematopoietic stem cells are thought to express the CD34 stem cell antigen, low numbers of HLA-DR and Thy1 antigens, but no lineage commitment antigens, CD38, or CD45RA antigens. However, fluorescence-activated cell sorted CD34+ subpopulations contain not more than 1% to 5% primitive progenitors capable of initiating and sustaining growth in long-term bone marrow culture initiating cells (LTBMC-ICs). We have recently shown that culture of fresh human marrow CD34+/HLA-DR- cells separated from a stromal layer by a microporous membrane ("stroma-noncontact" culture) results in the maintenance of 40% of LTBMC-ICs. We hypothesized that reselection of CD34+ subpopulations still present after several weeks in stroma-noncontact cultures may result in the selection of cells more highly enriched for human LTBMC-ICs. Fresh marrow CD34+/HLA-DR- cells were cultured for 2 to 3 weeks in stroma-noncontact cultures. Cultured progeny was then sorted on the basis of CD34, HLA-DR, or CD33 antigen expression, and sorted cells evaluated for the presence of LTBMC-ICs by limiting dilution analysis. We show that (1) LTBMC-ICs are four times more frequent in cultured CD34+/HLA-DR- cells (4.6% +/- 1.7%) than in cultured CD34+/HLA-DR- cells (1.3% +/- 0.4%). This suggests that HLA-DR antigen expression may depend on the activation status of primitive cells rather than their lineage commitment. We then sorted cultured cells on the basis of the myeloid commitment antigen, CD33. (2) These studies show that cultured CD34+/CD33- cells contain 4% to 8% LTBMC-ICs, whereas cultured CD34+/CD33+bright cells contain only 0.1% +/- 0.03% LTBMC-ICs. Because LTBMC-ICs are maintained significantly better in stroma-noncontact cultures supplemented with macrophage inflammatory protein 1 alpha (MIP-1 alpha) and interleukin-3 (IL-3) (Verfaillie et al, J Exp Med 179:643, 1994), we evaluated the frequency of LTBMC-ICs in CD34+/CD33- cells present in such cultures. (3) CD34+/CD33- cells present in MIP-1 alpha + IL-3-supplemented cultures contain up to 30% LTBMC-ICs. The increased frequency of LTBMC-ICs in cultured CD34+ subpopulations may be the result of terminal differentiation of less primitive progenitors, loss of cells that fail to respond to the culture conditions or recruitment of quiescent LTBMC-ICs. The capability to select progenitor populations containing up to 30% LTBMC-ICs should prove useful in studies examining the growth requirements, self-renewal, and multilineage differentiation capacity of human hematopoietic stem cells at the single-cell level.

Treatment of chronic myelogenous leukemia (CML) with interferon-alpha frequently results in normalization of peripheral blood counts and, in up to 20% of patients, reestablishment of normal hematopoiesis. We hypothesize that interferon-alpha may restore normal adhesive interactions between CML progenitors and the bone marrow microenvironment and restore normal growth regulatory effects resulting from these progenitor-stroma interactions. We demonstrate that treatment with interferon-alpha induces a significant, dose-dependent increase in the adhesion of primitive long-term culture initiating cells and committed colony-forming cells (CFC) from CML bone marrow to normal stroma. Adhesion of CFC seen after interferon-alpha treatment could be inhibited by blocking antibodies directed at the alpha 4, alpha 5, and beta 1 integrins and vascular cell adhesion molecule, but not CD44 or intracellular adhesion molecule, suggesting that interferon-alpha induces normalization of progenitor-stroma interactions in CML. Because FACS analysis showed that the level of alpha 4, alpha 5, and beta 1 integrin expression after interferon-alpha treatment is unchanged, this suggests that interferon-alpha may restore normal beta 1 integrin function. Normalization of interactions between CML progenitors and the bone marrow microenvironment may then result in the restoration of normal regulation of CML progenitor proliferation, and explain, at least in part, the therapeutic efficacy of interferon-alpha in CML.

Primary lymphoma of the heart is an extremely rare tumor. It is associated with a high mortality rate because of the advanced stage of myocardial involvement at initial presentation. Conventional surgical and medical treatments have not met with much success. This article reports the first case of primary cardiac lymphoma treated with orthotopic heart transplantation. The patient had hemodynamically significant severe acute rejection, neutropenic sepsis, and tumor recurrence during the late postoperative period, illustrating the difficulties associated with concomitant immunosuppression and tumor chemotherapy. Unfortunately, the patient died after a period of remission. Our approach to the integration of immunosuppression with chemotherapy, posttransplantation follow-up, and complications is discussed.

The growth kinetics and population dynamics of recombinent interleukin-2 (rlL-2) stimulated human natural killer (NK) cell-enriched populations were studied in vitro. The NK-enriched populations was obtained from normal peripheral blood mononuclear cells (PBMNC) by immunomagnetic bead depletion of CD3(+) and CD5(+) T cells. The growth kinetics of NK cells, T cells, monocytes, and total cells are shown. In the absence of PBMNC accessory cells, the NK-enriched population showed limited expansion. In the presence of PBMNC accessory cells, the NK-enriched population expanded threefold more than in the absence of accessory cells due to increased NK cell growth rate and increased duration of exponential growth. Using a Transwell system, which separates two cell population by a polycarbonate membrane, the accessory cells were shown to act on the NK-enriched population via a diffusible factor. Accessory cell conditioned media was able to replace the accessory cell population to stimulate NK cell expansion. A monocyte-enriched population prepared by sheep red blood cell rosetting of T cells was extensively phenotyped and compared with the NK-enriched populations. Although the final cultured cells were phenotypically homogeneous for CD56(+)/CD3(-) NK cells, the initial NK precusor populations appear to be different. Namely, the NK cell precursors in the monocyte-enriched population were predominantly CD56(+)/CD2(-). Kinetic equations were formulated for this culture system and the effects of major culture variables are investigated.

Ex vivo depletion of lymphocytes has been used to decrease the incidence of acute graft-versus-host disease following the allogeneic bone marrow transplantation. Many depletion techniques also remove natural killer (NK) cells that may mediate a beneficial graft-versus-leukemia effect. In this paper we review our studies on ex vivo expansion and activation of NK cells for use in the therapy of chronic myelogenous leukemia.

Factors that induce proliferation of the human hematopoietic stem cell are ill-defined. Primitive hematopoietic progenitors can be maintained and differentiate in stroma-dependent, long-term bone marrow cultures (LTBMC), originally described by Dexter et al. (Dexter, T. M., L. H. Coutinho, E. Spooncer, C. M. Heyworth, C. P. Daniel, R. Schiro, J. Chang, and T. D. Allen. 1990. Molecular Control of Haemopoiesis). However, 70-80% of primitive progenitors capable of reinitiating secondary stromal cultures (LTBMC-initiating cells [IC]) are lost over a period of 5 wk in such cultures. We have recently described a novel "stroma-noncontact" culture system, in which hematopoietic progenitors are separated from the stromal layer by a 0.4-micron microporous filter membrane. Primitive progenitors in such cultures can not only differentiate into committed progenitors, but are also maintained to a greater extent than in "Dexter" cultures. However, still only 50% of the originally seeded LTBMC-IC are recovered at week 5. Since maintenance of primitive progenitors may depend not only on growth-promoting factors but also on factors that inhibit differentiation and/or proliferation, we evaluated the effect of macrophage inflammatory protein 1 alpha (MIP-1 alpha) or "stem cell inhibitor" in combination with the growth-inducing factor interleukin 3 (IL-3) on the recovery of LTBMC-IC from stroma-noncontact cultures. We demonstrate that addition of MIP-1 alpha alone to stroma-noncontact cultures does not change the number of LTBMC-IC present after 8 wk, indicating that this factor may not directly inhibit or stimulate proliferation of primitive progenitors. Addition of the growth stimulatory cytokine, IL-3, alone results in exhaustion of LTBMC-IC after 8 wk of culture, possibly as a result of their terminal differentiation. However, LTBMC-IC can be maintained for at least 8 wk when grown in stroma-noncontact cultures supplemented with both MIP-1 alpha plus IL-3. This effect depends on soluble (ill-defined) stromal factors, and results from a direct interaction of these cytokines with the progenitor population or its progeny, but not the stroma.

Primitive human hematopoietic progenitors containing a high proportion of long-term culture-initiating cells (LTCICs) are found in the 34+DR- fraction of bone marrow mononuclear cells (BMMNCs). These progenitors adhere selectively to the 33/66-kD binding domain of fibronectin and to the FN-CHII binding site, unlike more committed progenitors, which adhere less selectively to fibronectin components. These differences in adhesion to stromal components may explain selective homing and release of progenitors at varying levels of differentiation from the marrow compartment. In additional studies, we demonstrate that cultivation of primitive progenitors in a stroma noncontact long-term culture allows both differentiation of primitive progenitors and conservation of LTCICs. These observations (1) demonstrate that expansion of primitive progenitors does not require stromal contact, (2) shed light on the regulatory role of stroma in myeloid differentiation, and (3) suggest strategies for both ex vivo myeloid progenitor expansion and retrovirus gene insertion. Finally, we demonstrate that a natural killer cell population can be derived from primitive hematopoietic progenitors in a modified long-term culture model. Our findings suggest an important role for marrow stroma in lymphoid differentiation from primitive progenitors and in expression of CD2, a lymphoid marker ordinarily associated with passage of T-lymphocyte progenitors through the thymus.

Donor marrow transplantation can cure chronic myelogenous leukemia (CML). Unfortunately, the procedure is associated with severe complications and is limited to the minority of potential recipients with suitably matched donors. Autologous marrow transplantation using negative selection approaches such as incubation with gamma interferon (IFN-gamma) can produce cytogenetic and clinical remissions, but they are often associated with recurrent evidence of leukemia. A primitive progenitor population can be separated from normal human marrow on the basis of morphologic characteristics and cell surface antigen expression. Cell populations with similar morphologic and phenotypic characteristics obtained by positive selection from the marrow of patients with CML appear to be benign. Benign primitive and committed progenitors selected in this fashion can be expanded ex vivo when cultured in a "Transwell" system which physically separates hematopoietic cells from stromal feeder layers. Positive selection and ex vivo cultivation of benign progenitors from CML marrow may provide a source of hematopoietic stem cells suitable for autologous marrow transplantation. Autologous natural killer (NK) cells obtained from the peripheral blood of patients with CML are of benign origin and have antileukemia activity. Interleukin 2 (IL-2) activated autologous NK cells may be used in post-transplant cellular therapy to prevent recurrence of CML.

We have recently shown that conservation and differentiation of primitive human hematopoietic progenitors in in vitro long-term bone marrow cultures (LTBMC) occurs to a greater extent when hematopoietic cells are grown separated from the stromal layer than when grown in direct contact with the stroma. This finding suggests that hematopoiesis may depend mainly on soluble factors produced by the stroma. To define these soluble factors, we examine here whether a combination of defined early-acting cytokines can replace soluble stroma-derived biologic activities that induce conservation and differentiation of primitive progenitors. Normal human Lineage-/CD34+/HLA-DR- cells (DR-) were cultured either in the absence of a stromal layer ("stroma-free") or in a culture system in which DR- cells were separated from the stromal layer by a microporous membrane ("stroma-noncontact"). Both culture systems were supplemented three times per week with or without cytokines. These studies show that culture of DR- cells for 5 weeks in a "stroma-free" culture supplemented with a combination of four early acting cytokines (Interleukin-3 [IL-3], stem cell factor [SCF], leukemia-inhibitory factor [LIF], and granulocyte colony-stimulating factor [G-CSF]) results in a similar cell expansion as when DR- cells are cultured in "stroma-noncontact" cultures supplemented with the same cytokines. However, generation of committed progenitors and conservation of the more primitive long-term bone marrow culture initiating cells (LTBMC-IC) was far superior in "stroma-noncontact" cultures supplemented with or without IL-3 than in "stroma-free" cultures supplemented with IL-3 alone or a combination of IL-3, LIF, G-CSF, and SCF. These studies indicate that human BM stroma produces soluble factors that can either alone or in synergy with defined cytokines (1) conserve primitive LTBMC-IC, (2) induce early differentiation of a fraction of the primitive progenitors, and (3) prevent their terminal differentiation. We show here that these stroma-derived factors are not likely to be the known early acting cytokines IL-3, SCF, LIF, or G-CSF. Characterization of the stroma-derived factor(s) may have important implications for clinically relevant studies, such as in vitro stem cell expansion in cancer treatment and gene therapy.

We have adapted the stroma-dependent long-term bone marrow culture (LTBMC) system to study the development of human natural killer cells (NK) from the CD34+/HLA-DR- (CD34+/DR-) BM mononuclear cell (BMMNC) population. The CD34+/DR- population does not express any known antigens associated with myeloid or lymphoid lineage and has been shown by us and others to contain primitive hematopoietic progenitors capable of both self-renewal and differentiation to myeloid lineage. CD34+/DR- cells obtained from normal human BM by fluorescence-activated cell sorting were plated on allogeneic, irradiated BM stromal layers. After 5 weeks of culture in the presence of media containing recombinant interleukin-2 and human serum, 147- +/- 21-fold expansion of cells with the morphologic appearance of large granular lymphocytes was observed. Cultured cells (84.8% +/- 1.5%) expressed the characteristic CD56+/CD3- phenotype of NK. A proportion of CD56+/CD3- cells expressed other markers of lymphoid lineage that have been associated with mature NK, including CD2 (7.8% +/- 1.2%), CD7 (19.5% +/- 2.8), CD8 (3.1% +/- 1.0%), and CD16 (4.5% +/- 1.3%). The cultured cells did not express other antigens associated with T-lymphocyte (CD3, CD5, T-cell receptor [TCR] alpha/beta and TCR gamma/delta), B-lymphocyte (CD19), myeloid (MY8, CD33, and CD71), or monocytoid (CD14 and CD15) lineage and did not express the CD34 antigen associated with hematopoietic progenitors present on the starting population. This NK population was cytotoxic against both K562 (E:T 20:1; 79% +/- 1.9%) and Raji (E:T 20:1; 38% +/- 5.7%) target cell lines. The NK progenitor frequency in the CD34+/DR- cell population determined by limiting dilution of CD34+DR- on stromal layers followed by a functional chromium release assay against K562 targets was 1:169 +/- 50 CD34+/DR- cells. The data suggest that human LTBMC developed to study myeloid differentiation can be modified to study the origin and development of the NK and possibly other lymphoid lineages. Modified cultures show that cells with morphologic, phenotypic, and functional characteristics of NK can be derived from a population of BMMNC with the phenotype of primitive hematopoietic progenitors and without phenotypic evidence of lymphoid- or myeloid-lineage commitment. Further studies will address the cell of origin and the ontogeny of human NK and other lymphoid lineages.

We have studied the mechanisms underlying expansion of recombinant interleukin-2 (rIL-2)-stimulated natural killer (NK) cells in vitro. A population of NK cells expressing the CD56+/CD3-phenotype (98.9% +/- 0.42%) was obtained from normal human peripheral blood mononuclear cells (PBMNC) by fluorescence-activated cell sorting (FACS). Culture of NK cells in media containing rIL-2 (1,000 U/mL) for 18 days resulted in a population of activated NK cells (ANK) with significantly enhanced cytotoxicity, but only 2.6 +/- 0.56-fold expansion of cell number compared with the starting NK population. Culture of starting NK populations and autologous PBMNC in a Transwell system (Costar, Cambridge, MA), providing separation of the two cell populations by a 0.4-microns pore membrane, resulted in a dose-dependent increase in fold expansion of ANK (expansion = 19.9 +/- 4.0-fold; P < .001; n = 22) significantly greater than that observed when NK were cultured alone. Further experiments using the Transwell system showed that the stimulatory effect of autologous PBMNC on ANK progenitor proliferation resides in the CD14+ monocyte fraction (maximal expansion = 14.5 +/- 1.5-fold; n = 17) and not in the CD5+ T-lymphocyte or CD19+ B-lymphocyte fractions. Direct coculture of purified NK and autologous monocytes in the same compartment, thus permitting cell-cell contact, resulted in significantly greater expansion of the ANK population (30.6 +/- 4.7-fold expansion, P < .001; n = 10) than that observed when NK and monocytes were separated by the Transwell membrane. Finally, depletion of PBMNC of cells bearing CD5 and CD8 by panning on antibody-coated plastic flasks resulted in a starting cell population enriched for NK progenitors and for monocytes. Cultures of this resultant population for 18 days in the presence of rIL-2 yielded an ANK population similar to that obtained when CD56+/CD3- cells obtained by FACS were cocultured with autologous monocytes. These results suggest that proliferation of ANK requires autologous monocytes and is in part mediated by humoral factors, but is enhanced when NK and monocytes are in direct cell-cell contact. Depletion of cells bearing CD5 and CD8 from PBMNC is a single efficient method for obtaining a starting population capable of producing large numbers of ANK in culture that may lead to new therapeutic uses for the ANK population.

We studied the adhesion of primitive and committed progenitors from chronic myelogenous leukemia (CML) and normal bone marrow to stroma and to several extracellular matrix components. In contrast to benign primitive progenitors from CML or normal bone marrow, Ph1-positive primitive progenitors from CML bone marrow fail to adhere to normal stromal layers and to fibronectin and its proteolytic fragments, but do adhere to collagen type IV, an extracellular matrix component of basement membranes. Similarly, multilineage colony-forming unit (CFU-MIX) progenitors from CML bone marrow do not adhere to fibronectin or its adhesion promoting fragments but adhere to collagen type IV. Unlike committed progenitors from normal bone marrow, CML single-lineage burst-forming units-erythroid and granulocyte/macrophage colony-forming units fail to adhere to fibronectin or its components but do adhere to both collagen type IV and laminin. Evaluation of adhesion receptor expression demonstrates that fibronectin receptors (alpha 4, alpha 5, and beta 1) are equally present on progenitors from normal and CML bone marrow. However, a fraction of CML progenitors express alpha 2 and alpha 6 receptors, associated with laminin and collagens, whereas these receptors are absent from normal progenitors. These observations indicate that the premature release of malignant Ph1-positive progenitors into the circulation may be caused by loss of adhesive interactions with stroma and/or fibronectin and acquisition of adhesive interactions with basement membrane components. Further study of the altered function of cell-surface adhesion receptors characteristic of the malignant clone in CML may lead to a better understanding of the mechanisms underlying both abnormal expansion and abnormal circulation of malignant progenitors in CML.

Long-term bone marrow cultures support both differentiation and conservation of primitive human hematopoietic progenitors in the absence of exogenous cytokines. It is believed that hematopoiesis in such cultures requires direct contact between hematopoietic progenitors and stroma. In the present study, we demonstrate that primitive progenitors physically separated from the stromal layer by a 0.45-microns microporous membrane continue to generate differentiated progenitors for at least 8 weeks. Moreover, primitive progenitors are conserved to a greater extent under these conditions, as when cultured in direct contact with the stroma. However, excessive production of granulocyte-macrophage progenitors occurs when primitive progenitors are not allowed to interact directly with the stroma. Thus, direct contact between hematopoietic and stromal cells is not required for either differentiation or conservation of primitive hematopoietic progenitors but is essential for the regulated production of mature blood elements. These findings can now be used to define the role of diffusible factors and cell-cell or cell-extracellular matrix adhesion events in the regulation of conservation, proliferation, and differentiation of primitive human hematopoietic progenitors in vitro.

Chronic myelogenous leukemia (CML) is a lethal malignancy of the human hematopoietic stem cell. Here we report that coexistent benign, primitive hematopoietic progenitors can be distinguished from their malignant counterparts in CML bone marrow by differences in cell surface antigen expression. Selection of bone marrow cells expressing the CD34 antigen but lacking the HLA-DR antigen results in recovery of small lymphocyte-like blasts, which initiate and sustain production of myeloid clonogenic progeny in vitro. Secondary clonogenic cells derived at week 1, 5, and 8 from long-term bone marrow cultures (LTBMCs) initiated with primitive progenitors, which lack HLA-DR antigens, exhibit neither the Philadelphia chromosome (Ph1) nor the corresponding bcr/abl mRNA characteristic of CML. In contrast, clonogenic cells recovered at week 1, 5, and 8 from LTBMCs initiated with the CML HLA-DR+ population contain Ph1 and express bcr/abl mRNA. This observation indicates that it may be possible to select a population of viable, exclusively benign hematopoietic stem cells from CML bone marrow capable of repopulating the hematopoietic compartment following autologous bone marrow transplantation.

We have previously demonstrated that primitive progenitors from human bone marrow termed long term bone marrow culture initiating cells (LTBMC-IC) adhere avidly to irradiated bone marrow stroma, while more mature clonogenic progenitors fail to do so. In this study we examine the interaction between these progenitors and components of the bone marrow stroma. (a) We demonstrate that both primitive LTBMC-IC and more mature clonogenic progenitors adhere to intact fibronectin. (b) Primitive LTBMC-IC and multi-lineage CFU-MIX progenitors adhere to the 33/66 kD COOH-terminal heparin-binding cell-adhesion promoting fragment of fibronectin, but adhere significantly less to its 75 kD RGDS-dependent cell-binding fragment. In contrast, more differentiated single-lineage progenitors adhere equally well to the 33/66 kD RGDS independent and the 75 kD RGDS-dependent cell-adhesion fragments of fibronectin. (c) Both primitive LTBMC-IC and clonogenic progenitors adhere to the three known cell-attachment sites in the 33/66 kD cell-adhesion promoting fragment, FN-C/H I, FN-C/H II and CS1. However, LTBMC-IC and CFU-MIX progenitors adhere significantly better to FN-C/H II than to the flanking FN-C/H I and CS1 cell-attachment sites. In contrast, single-lineage progenitors adhere equally well to all three cell attachment sites in the 33/66 kD cell-adhesion promoting fragment. (d) Finally, adhesion of primitive LTBMC-IC to intact irradiated stroma can be inhibited partially by peptide FN-C/H II and almost completely by a combination of FN-C/H II and peptide FN-C/H I and CS1. This study demonstrates that adhesive interactions between primitive hematopoietic progenitors and the extracellular matrix component fibronectin can occur. Specific changes in adhesion to the 33/66 kD cell-adhesion promoting fragment and the 75 kD RGDS-dependent cell-adhesion fragment of fibronectin are associated with differentiation of primitive multi-lineage progenitors into committed single-lineage progenitors. Such differences in adhesive interaction with fibronectin may allow hematopoietic progenitors at various stages of differentiation to interact with specific supportive loci of the bone marrow microenvironment. Finally, the ability to block adhesion of LTBMC-IC to intact irradiated stroma with peptides FN-C/H II, FN-C/H I and CS1 suggests that receptors responsible for this interaction may be important in the homing of primitive progenitors to the bone marrow.

We studied the incidence, outcome and risk factors for systemic Candida infection in 665 recipients of allogeneic, syngeneic and autologous bone marrow transplantations (BMT) between 1979 and 1987. Systemic Candida infection, defined as occurrence of one or more positive blood or CSF cultures for Candida sp., or presence of Candida sp. in culture or biopsy of deep tissue, was detected in 76 patients (12.5%) in the first year following BMT. Candida infection was independently associated with increasing age (p less than 0.0001), detection of one or more positive surveillance cultures for Candida sp. (p less than 0.0001), increased duration of granulocytopenia (p = 0.0005) and total body irradiation as part of the preparative regimen compared with chemotherapy only or chemotherapy and total lymphoid irradiation (p = 0.02). Other patient characteristics including underlying disease, origin of graft, recipient sex, graft-versus-host disease (GVHD) prophylaxis and occurrence of acute GVHD or chronic GVHD were not independently associated with Candida infection following BMT: 60/76 patients with Candida infections have died, and in 19/60 cases death could be directly attributed to Candida infection. Awareness of the serious nature and the risk features for Candida infections may be useful in developing strategies of prevention and treatment.

The marrow stromal microenvironment is essential for maintaining normal haematopoiesis. Chemotherapy drugs, such as the nitrosoureas, may impair the ability of the stroma to support haematopoiesis. To assess the effects of 1,3-bis-(2-chloroethyl)-1-nitrosourea (BCNU) on in vitro haematopoiesis, stromal monolayers were treated with BCNU, 5 micrograms/ml weekly for 3 weeks, then seeded 24 h after the third treatment with haematopoietic progenitors. Three weeks after seeding, total adherent and non-adherent cell numbers were similar in treated and control flasks as were adherent granulocyte/macrophage colony forming cell (GM-CFC) numbers. In contrast, non-adherent GM-CFC were significantly reduced in treated flasks, to 40-60% of controls. However, no reduction in non-adherent GM-CFC number was seen if seeding was delayed for 7 d following BCNU treatment, suggesting the effects are reversible. Conditioned media from treated and control monolayers, harvested at a time corresponding to the time of seeding, showed no difference in colony stimulating activity. In addition, extracts of bound growth factors from treated and control monolayers also showed no differences in colony stimulating activity. Thus, BCNU can alter haematopoiesis through a reversible effect on the marrow stroma and this effect does not appear to be mediated by a change in stromal growth factor production.

We have generated a homogeneous population of recombinant interleukin-2 (rIL-2)-stimulated effector cells termed adherent lymphokine-activated killer cells (A-LAK) from peripheral blood mononuclear cells (PBMNC) of 14 normal individuals and tested the effect of A-LAK cells on autologous hematopoietic bone marrow (BM) progenitor growth. Enrichment of A-LAK from PBMNC depended on the propensity of A-LAK precursors to adhere to plastic and proliferate in the presence of rIL-2. The resultant population had the morphologic appearance of large granular lymphocytes, and the majority of cells (73% +/- 4%) expressed the CD56+/CD3- phenotype associated with rIL-2-stimulated natural killer (NK) cells. The A-LAK population had potent lytic activity in chromium release assays against both NK-sensitive (K562) and NK-resistant (Raji) targets. When BM mononuclear cells (BMMNC) were coincubated with autologous A-LAK and rIL-2 (1,000 U/mL) added at the start of culture, dose-dependent suppression of burst-forming unit-erythroid (BFU-E) and colony-forming unit mix (CFU-MIX) colony growth was observed at effector to target ratios (E:T) ranging from 0.25:1 to 5:1 (maximal suppression BFU-E = 85% +/- 6%; CFU-MIX = 95% +/- 3%). This suppression was rIL-2 dose-dependent, and no suppression was seen in the absence of rIL-2. Depletion of BM monocytes and T lymphocytes did not alter A-LAK suppression of progenitors coincubated with A-LAK cells. Addition of polyclonal neutralizing antibodies against both interferon-gamma (IFN-gamma) and tumor necrosis facto alpha (TNF-alpha) to the coincubation culture completely abrogated the suppressive effect of A-LAK on BFU-E and CFU-MIX colony growth while each neutralizing antibody used alone had intermediate effects. In contrast to coincubation studies, 36 hours of preincubation of A-LAK cells with autologous BM (E:T 2.2:1) and rIL-2 (1,000 U/mL) followed by plating of preincubated BM cells in hematopoietic progenitor culture produced significant suppression of day 14 BFU-E (47% +/- 5%), but spared the more primitive CFU-MIX (7% +/- 9%), suggesting a divergent effect of A-LAK cells on hematopoietic progenitors at different stages of differentiation. Addition of neutralizing antibodies against IFN-gamma and TNF-alpha in preincubation failed to abrogate the suppressive effect of A-LAK on BFU-E colony growth, suggesting that this suppression occurs by a different mechanism than that seen in coincubation studies. Previous studies have demonstrated that the A-LAK population has cytotoxic and proliferative advantages over other killer cell populations.(ABSTRACT TRUNCATED AT 400 WORDS)

We investigated the in vitro hematopoietic stimulatory activity of leukemia inhibitory factor/human interleukin for DA cells (LIF/HILDA) on bone marrow progenitor populations in 17 normal individuals. In serum-free cultures LIF/HILDA did not induce colony growth. In serum containing media, LIF/HILDA stimulated the growth of colony forming unit (CFU)-MIX and CFU-EO in a dose-dependent fashion and resulted in an increased CFU-MIX and burst forming unit-erythrocytes (BFU-E) colony size. Similar stimulatory effects were seen on a highly purified hematopoietic progenitor population obtained after immunomagnetic depletion of mature myeloid precursors and lymphoid cells. Addition of LIF/HILDA to cultures containing maximally stimulatory concentrations of recombinant human interleukin-3 (rhuIL3), rhuIL3 + rhuIL6, or rhu granulocyte-macrophage colony-stimulating factor (rhu GM-CSF) in serum containing media significantly increased the number of CFU-MIX and eosinophil colonies and increased size and cluster number of CFU-MIX and BFU-E. Depletion of accessory T lymphocytes or monocytes from bone marrow progenitors did not alter the response of hematopoietic precursors to LIF/HILDA. A similar increased colony growth was seen when LIF/HILDA was added to cultures of positively selected CD34/HLA-DR+ or CD34+/HLA-DR- bone marrow hematopoietic progenitor cells stimulated with maximally stimulatory concentrations of rhuIL3 + rhuIL6. LIF/HILDA is a novel cytokine capable of stimulating growth and proliferation of multi-lineage, erythroid, and eosinophil colonies in the presence of serum. LIF/HILDA exerts its activity by direct interaction with highly purified immature bone marrow progenitor cells, has an additive effect when used with other cytokines known to stimulate primitive hematopoietic precursors, and does not require accessory cells.

We enriched bone marrow cells from 10 normal individuals for primitive hematopoietic progenitors using a two-step technique, and examined resultant primitive progenitors for their in vitro long-term repopulating capacity and their ability to adhere to irradiated stroma. Immunomagnetic depletion of mature myeloid and lymphoid progenitors resulted in a lineage-negative (Lin-) cell population. Subsequent dual-color fluorescence activated sorting of cells with low forward and vertical light scatter properties, expressing CD34 antigen (34+) and either bearing (DR+) or lacking (DR-) the HLA-DR antigen, resulted in the selection of Lin-34+ DR+ and Lin-34+ DR- cell populations. When the Lin-34+ DR+ cell fraction was cultured in a short-term methylcellulose assay, we demonstrated a 61-fold enrichment for colony forming cells (CFC) compared with undepleted bone marrow mononuclear cells. In contrast to the Lin-34+ DR+ cells, direct culture of Lin-34+ DR- cells in short-term methylcellulose generated significantly less CFC (p less than or equal to 0.001). We then compared the capacity of Lin-34+ DR+ and Lin-34+ DR- cells to generate sustained hematopoiesis when plated in long-term bone marrow culture (LTBMC). When LTBMC were initiated with plated Lin-34+ DR+ cells, we recovered high numbers of CFC during the first week, but observed a rapid decline in the number of harvested CFC over the following weeks. No CFC could be recovered after week 7. In contrast, LTBMC initiated with plated Lin-34+ DR- cells yielded significantly greater numbers of CFC than LTBMC initiated with plated Lin-34+ DR+ cells (p less than or equal to 0.001), and this was sustained for at least 12 wk of culture. The Lin-34+ DR+ population was only 6.6-fold enriched for primitive progenitors capable of initiating and sustaining hematopoiesis in LTBMC when compared with undepleted bone marrow mononuclear cells, while the Lin-34+ DR- population was 424-fold enriched for such primitive progenitors (p less than or equal to 0.001). Finally, we examined the capacity of both Lin-34+ DR+ and Lin-34+ DR- populations to adhere to irradiated allogeneic stroma. We used a previously described "panning method" in which cells are plated onto stroma for 2 h, the nonadherent cells removed by extensive washing, and the adherent fraction maintained under conditions favoring LTBMC growth. When stroma was panned with Lin -34+ DR+ cells, 79 +/- 10% of the cells were recovered in the panning effluent. In contrast, when stroma was panned with Lin -34 + DR- cells, significantly fewer (37 +/- 7%) (p less than or equal to 0.001) cells were recovered in the panning effluent. Unlike LTBMC initiated with plated Lin -34 + DR+ cells, virtually no CFC were recovered from LTBMC initiated with panned Lin -34 + DR+ cells.(ABSTRACT TRUNCATED AT 400 WORDS)

We have compared the proliferative and cytotoxic capacities of a highly purified population of recombinant interleukin-2 (rIL-2)-activated peripheral blood mononuclear cells (PBMNC), termed adherent lymphokine-activated killer cells (A-LAK), in 15 chronic phase (CP) and 10 advanced disease (AD) Ph-positive chronic myelogenous leukemia (CML) patients. The selective enrichment of CML A-LAK cells depended on their propensity to adhere to plastic and to proliferate when cultured in the presence of rIL-2 for 14 days. In both CP and AD patients, 14-day culture resulted in growth of a uniform population of large granular lymphocytes. While less than 10% of the A-LAK cells were CD56-/CD3+ (mature T lymphocytes), 82% +/- 12% of A-LAK cells from early CP patients (diagnosed less than 1 year from study), 84% +/- 3% of A-LAK cells from late CP patients (studied greater than 1 year after diagnosis), and 87% +/- 3% of A-LAK cells from AD patients were CD56+/CD3- (activated natural killer [NK] cells). No bcr gene rearrangement could be found in A-LAK cells from 13 CP and six AD CML patients studied. A-LAK cells from seven early CP CML patients displayed similar cytotoxicity against K562 (80% +/- 7% lysis at effector:target ratio of 20:1) and against Raji (80% +/- 12% lysis) compared with A-LAK from 17 normal individuals (72% +/- 3% K562 lysis, P = .21; 74% +/- 5% Raji lysis, P = .39). However, the cytotoxicity of A-LAK cells from eight late CP patients (59% +/- 5% K562 lysis, P = .02; 52% +/- 8% Raji lysis, P = .02) and that of 10 AD patients studied at any point after diagnosis (31% +/- 3% K562 lysis, P less than .001; 25% +/- 6% Raji lysis, P less than .001) was significantly lower than that of seven early CP CML patients and 17 normals. The proliferative potential of A-LAK cells from seven early CP CML patients (291 +/- 191-fold) was significantly greater than that of A-LAK cells from 17 normal individuals (23 +/- 3-fold, P = .03), eight late CP patients (46 +/- 17-fold, P = .02), and 10 AD patients (5.4 +/- 1.9-fold, P = .01). In contrast to CML A-LAK, K562 cytotoxicity of unstimulated mature peripheral blood NK cells was significantly lower in early CP CML patients than in normals and remained low at all stages of disease.(ABSTRACT TRUNCATED AT 400 WORDS)

The effects of prenalterol, a selective beta 1-adrenoreceptor agonist, were studied in a patient with the Shy-Drager syndrome, presenting with incapacitating orthostatic hypotension. The main haemodynamic defect was an impressive postural fall in stroke volume and cardiac output pointing to denervation of the capacitance vessels. Prenalterol 4 X 30 mg orally produced a marked increase in supine and standing blood pressure, along with substantial symptomatic improvement. Notable positive chronotropic and inotropic effects were observed. Association of fludrocortisone 0.5 mg/day resulted in further haemodynamic and symptomatic improvement, presumably due to plasma volume expansion. Haemodynamically, prenalterol and fludrocortisone resulted in a substantial increase in standing cardiac output, primarily due to the chronotropic effects of prenalterol. In addition to the haemodynamic effects, prenalterol stimulated the renin-aldosterone system and restored the normal diurnal pattern of water and sodium excretion, the latter may have contributed to the improvement of orthostatic tolerance. Prenalterol could be a valuable adjunct to the existing treatment schedules of neurogenic orthostatic hypotension.

A case of typical T-acute lymphoblastic leukemia (T-ALL) is reported in which, at diagnosis, 100% of bone marrow metaphases showed a Philadelphia (Ph) translocation, t(9;22). These cells completely disappeared following chemotherapy. The significance of the Ph chromosome in T and B leukemic cells is discussed.

Treatment of idiopathic orthostatic hypotension is often unsatisfactory. A patient with the Shy-Drager syndrome, in which the most important symptom is orthostatic hypotension, was treated with prenalterol, initially 30 mg six times daily. The dosage was reduced to 30 mg four times daily because of the development of complex ventricular premature beats. Orthostatic symptoms were reduced and standing blood pressure increased. Fludrocortisone 0.5 mg a day was added to treatment with further improvement. This clinical effect was maintained throughout 12 months of follow up, during which the treatment was continued unchanged. Prenalterol was effective in reducing orthostatic symptoms in this patient. Further studies in patients with a similar haemodynamic pattern are indicated.

Marked elliptocytosis and schistocytosis are described as unusual manifestations of haematopoietic dysplasia in two patients. The first patient, whose history was negative for inherited haemolytic anaemias, presented these prominent features on his first admission; 22 months later he developed an acute myeloblastic leukaemia. In the second patient, followed since 4 years for an autoimmune thrombocytopenic purpura, elliptocytosis and schistocytosis appeared 17 months before a pancytopenia established. The patient is now on follow-up and is treated for a refractory anaemia. In both cases bone marrow examinations revealed the typical criteria for myelodysplasia and this diagnosis was confirmed by cytogenetic analysis.