High-throughput sequencing of cerebrospinal fluid for diagnosis of chronic Propionibacterium acnes meningitis in an allogeneic stem cell transplant recipient.

BACKGROUND: A 40-year-old man with chronic myelogenous leukemia presented multiple times over a period of 3 years with episodes of confusion, wide-based gait and falls because of recurrent hydrocephalus despite repeated therapeutic lumbar punctures. These problems occurred in the context of persistent cerebrospinal fluid (CSF) pleocytosis and leptomeningeal enhancement. Extensive diagnostic workups and therapeutic trials had failed to identify a clinically plausible cause or produce any significant improvement in the CSF and neuroimaging abnormalities. METHODS: We used high-throughput metagenomic shotgun sequencing to identify microbes in 2 CSF samples collected from the patient during his illness. These results were compared to sequence data from 1 CSF sample collected during treatment and 5 control CSF samples from other patients. RESULTS: We found sequences representing 53% and 67% of the Propionibacterium acnes genome in 2 CSF samples collected from the patient during his illness. Directed antimicrobial therapy was administered for 6 weeks with resolution of CSF and neuroimaging abnormalities. Sequencing of a sample obtained during treatment demonstrated that the P. acnes levels were decreased to background levels. After insertion of a ventriculo-peritoneal shunt, the patient returned to baseline status. CONCLUSIONS: High-throughput metagenomic shotgun sequencing revealed P. acnes as the cause of chronic meningitis that had eluded conventional attempts at diagnosis. Treatment directed at this organism resulted in cure of the infection and clinical improvement.

Preclinical evaluation of Mab CC188 for ovarian cancer imaging.

Cancer stem cells (CSCs) have been successfully isolated from solid tumors and are believed to be initiating cells of primary, metastatic and recurrent tumors. Imaging and therapeutic reagents targeted to CSCs have potential to detect subclinical tumors and completely eradicate the disease. Previously, we have demonstrated that Mab CC188 binds to colon cancer CD133- and CD133+ (CSCs) cells. In this study, we examined the reactivity of Mab CC188 to ovarian cancer cells including CD133+ cells and primary tumor tissues using immunofluorescence staining methods and tissue microarray technique. We also explored the feasibility of using NIR dye-labeled Mab CC188 probe to image ovarian tumors in vivo. Mab CC188 stains both CD133- and CD133+ cells of ovarian cancer. Tissue microarray analysis reveals that 75% (92/123) of ovarian cancer cases are positively stained with Mab CC188. Weak positive (±), positive (+), strong positive (++) and very strong positive (+++) stains are 14.8, 3.7, 11 and 24.4%, respectively. In contrast, Mab CC188 staining is low in normal cells and tissues. In vivo study show that significant amounts of the probe accumulates in the excretion organs in the early period postinjection. At 24 hr, the imaging probes have largely accumulates in the tumor, while the intensity of the imaging probe decreases in the liver. The tumor uptake was still evident at 120-hr postinjection. Our work suggests that Mab CC188-based imaging and therapeutic reagents are capable of detecting early stage ovarian tumors and effectively treating the tumor.

Oral valganciclovir versus ganciclovir as delayed pre-emptive therapy for patients after allogeneic hematopoietic stem cell transplant: a pilot trial (04-0274) and review of the literature.

BACKGROUND: Cytomegalovirus (CMV) infection is an important cause of morbidity and mortality after allogeneic hematopoietic stem cell transplant (HSCT). This pilot prospective randomized clinical trial compares valganciclovir (VGV) to ganciclovir (GCV) as pre-emptive therapy for CMV viremia in the post-allogeneic HSCT population. METHODS: Patients undergoing allogeneic HSCT who were at risk for CMV viremia were monitored post HSCT by weekly quantitative whole blood polymerase chain reaction. Pre-emptive therapy was delayed until the viral load (VL) was >10,000 copies/mL once, or >5000 copies/mL twice. Patients were randomized to either GCV 5 mg/kg twice a day (b.i.d.) for 7 days followed by daily GCV 5 mg/kg for up to 21 days, or VGV 900 mg b.i.d. for 7 days followed by 900 mg daily for up to 21 days. The primary endpoint was clearance of viremia (VL <5000 copies/mL) within 28 days of initiation of therapy. RESULT: In total, 37 patients were enrolled; 19 patients received treatment with VGV and 18 patients received treatment with GCV. The VGV was not inferior in efficacy to GCV as pre-emptive therapy, with rates of viral clearance at 28 days of 89.5% and 83%, respectively (P-value for non-inferiority = 0.030). Toxicities were similar between the 2 arms. No patients developed CMV disease. CONCLUSIONS: In this trial, the rates of clearance of viremia appear to be similar with VGV and GCV.

Perforin/granzyme-dependent and independent mechanisms are both important for the development of graft-versus-host disease after murine bone marrow transplantation.

Graft-versus-host disease (GvHD) is the major limiting toxicity of allogeneic bone marrow transplantation. T cells are important mediators of GvHD, but the molecular mechanisms that they use to induce GvHD are controversial. Three effector pathways have been described for cytotoxic T lymphocytes: one requires perforin and granzymes, the second Fas (APO-1; CD95) and its ligand. Thirdly, secreted molecules (e.g., TNF-alpha, gamma-IFN) can also mediate cytotoxicity. Together, these mechanisms appear to account for virtually all cytotoxicity induced by activated CTL in standard in vitro lytic assays. Using transplants across histocompatibility barriers, we were able to analyze the contributions of these effector molecules to cell-mediated cytotoxicity in vivo in a GvHD model. We found that Fas ligand is an important independent mediator of class II-restricted acute murine GvHD, while perforin/granzyme-dependent mechanisms have only a minor role in that compartment. In contrast, perforin/ granzyme-dependent mechanisms are required for class I-restricted acute murine GvHD, while Fas ligand is not. The perforin/granzyme pathway may therefore represent a novel target for anti-GvHD drug design. In support of this approach, we provide additional data suggesting that specific perforin/granzyme inhibitors should not adversely affect hematopoietic recovery after transplantation.

Prognostic significance of early lymphocyte recovery after post-autografting administration of GM-CSF in non-Hodgkin's lymphoma.

The purpose of this study was to analyze the prognostic significance of early lymphocyte recovery after autologous SCT (ASCT) in the setting of routine post transplant administration of GM-CSF in patients with non-Hodgkin's lymphoma (NHL). This is a single institution retrospective comparative outcome analysis in a cohort of 268 relapsed chemosensitive NHL patients divided into two groups (early and late lymphocyte recovery) based on absolute lymphocyte counts (ALC) obtained on post transplant day +15 (ALC > or = 500, n=151 (56%) and ALC < 500, n=117 (44%)). Patient's characteristics were well-balanced between the two groups with regard to age, sex, preparative regimen, prior therapy, time from diagnosis to transplant and number of CD34+ cells infused. Post transplant complications were comparable in the two groups. Late lymphocyte recovery (ALC < 500 on day +15) was independently associated with a delay in platelet recovery (29 vs 21 days, P=0.0003) in patients who have not received pre-transplant rituximab. With a median follow-up of 22 months, no associations between early lymphocyte recovery and improvement of disease-free and overall survival were observed for either low- or intermediate-grade NHL. In conclusion, in this large single-centered retrospective analysis, where patients received routine post transplant GM-CSF, early lymphocyte recovery was not associated with favorable outcomes.

Donor-lymphocyte infusion following haploidentical hematopoietic cell transplantation with peripheral blood stem cell grafts and PTCy.

Donor-lymphocyte infusion (DLI) for relapse following haploidentical hematopoietic cell transplantation (haploHCT) with post-transplant cyclophosphamide (PTCy) has been described in recipients of bone marrow grafts, but not recipients of G-CSF mobilized peripheral blood (PB) grafts. We retrospectively identified patients who underwent DLI following PB-haploHCT with PTCy for relapse, or loss of chimerism (LOC). Twelve patients (57%) received DLI for hematologic relapse/persistent disease, seven (33%) for extramedullary relapse and two (10%) for LOC. Sixteen (76%) received chemotherapy prior to DLI, which did not correlate with response. The most common first dose was 1 × 106 CD3+ cells/kg. Two patients developed grade I aGvHD post DLI, one had grade II and two had grade III. One developed mild skin cGvHD 1361 days post DLI. Pre-DLI aGvHD predicted post-DLI aGvHD (P=0.025). Six patients achieved CR after DLI for overt relapse, one achieved full donor chimerism after LOC. Patients with LOC or EM relapse had superior relapse-free survival following DLI (P=0.029). DLI following PB-haploHCT with PTCy is a viable salvage therapy for overt relapse or LOC without a substantial increase in GvHD, and donor lymphocytes may be collected simultaneously with graft collection to facilitate availability in patients at high risk of relapse.

Dynamic changes in the clonal structure of MDS and AML in response to epigenetic therapy.

Traditional response criteria in myelodysplastic syndrome (MDS) and acute myeloid leukemia (AML) are based on bone marrow morphology and may not accurately reflect clonal tumor burden in patients treated with non-cytotoxic chemotherapy. We used next-generation sequencing of serial bone marrow samples to monitor MDS and AML tumor burden during treatment with epigenetic therapy (decitabine and panobinostat). Serial bone marrow samples (and skin as a source of normal DNA) from 25 MDS and AML patients were sequenced (exome or 285 gene panel). We observed that responders, including those in complete remission (CR), can have persistent measurable tumor burden (that is, mutations) for at least 1 year without disease progression. Using an ultrasensitive sequencing approach, we detected extremely rare mutations (equivalent to 1 heterozygous mutant cell in 2000 non-mutant cells) months to years before their expansion at disease relapse. While patients can live with persistent clonal hematopoiesis in a CR or stable disease, ultimately we find evidence that expansion of a rare subclone occurs at relapse or progression. Here we demonstrate that sequencing of serial samples provides an alternative measure of tumor burden in MDS or AML patients and augments traditional response criteria that rely on bone marrow blast percentage.

Once daily ganciclovir as initial pre-emptive therapy delayed until threshold CMV load > or =10000 copies/ml: a safe and effective strategy for allogeneic stem cell transplant patients.

Quantitative polymerase chain reaction (QPCR) for cytomegalovirus (CMV) is emerging as the preferred screening method for detection of CMV viremia in patients following allogeneic bone marrow and peripheral blood stem cell transplant. However, there are currently no universally accepted QPCR treatment thresholds at which to start pre-emptive therapy. We report here results of a pre-emptive therapy strategy using ganciclovir (GCV) 5 mg/kg initiated once daily (ODG) delayed till a threshold CMV load of > or =10 000 copies/ml whole blood in clinically stable patients. Sixty-nine at risk patients underwent allogeneic stem cell transplant. 48/69 (70%) patients had an initial episode of CMV viremia. 5/48 (10%) cleared viremia without requiring treatment. 28/43 (65%) patients requiring treatment initiated treatment with ODG. 17/28 (61%) patients successfully cleared CMV viremia on ODG, 10/28 (36%) patients required dose escalation to twice daily GCV for increasing viral loads. There were two cases of CMV disease (colitis) and no deaths due to CMV disease in patients initiating treatment with ODG. We conclude delaying pre-emptive therapy with ODG until whole blood QPCR> or =10 000 copies/ml is a safe and effective strategy for CMV viremia after allogeneic stem cell transplant in clinically stable patients.

Vancomycin-resistant enterococcal bloodstream infections on a hematopoietic stem cell transplant unit: are the sick getting sicker?

Patients with hematologic malignancies and hematopoietic stem cell transplant (HSCT) recipients are at high risk for bacterial bloodstream infections (BSI) owing to resistant organisms. Data describing the outcomes of vancomycin-resistant enterococcal (VRE) BSI in this patient population are limited. We performed a retrospective cohort study of all cases of VRE BSI that occurred between February 1996 and December 2002 on the Leukemia/HSCT unit at Barnes-Jewish Hospital. There were 68 episodes of VRE BSI in 60 patients with acute (53%) or chronic (8%) leukemia, non-Hodgkin's lymphoma (22%) or other malignant hematologic disorders (17%). A total of 13, 32 and 32% were recipients of autologous, related and matched-unrelated transplants, respectively. Forty-two of allograft recipients had active acute graft-versus-host disease (GVHD) and 32% chronic GVHD. Only 57% were neutropenic, 52% had refractory/relapsed malignancy and 60% had end organ dysfunction with a median APACHE II score of 17. Median survival after VRE BSI was 19 days. Pneumonia, receipt of anti-fungal drugs and low APACHE II score at the time of the VRE BSI remained significant risk factors for death on multivariable analysis. Our analysis suggests that in patients with hematological malignancies or HSCT, VRE may not have the behavior of a virulent pathogen. VRE BSI may simply be a marker of these patients' already existing critical medical condition.

Post-transplant high-dose cyclophosphamide after HLA-matched vs haploidentical hematopoietic cell transplantation for AML.

Post-transplant cyclophosphamide (PT-Cy) is the backbone of GvHD prophylaxis following haploidentical hematopoietic cell transplantation (haplo-HCT). PT-Cy has also been used in matched related (MRD) and unrelated (MUD) settings. It is not known whether outcomes are similar between haplo-HCT and MRD/MUD HCT when PT-Cy is used. We performed a retrospective analysis of 83 patients with AML who underwent HCT (using PT-Cy-based GvHD prophylaxis) from MRD, MUD or haploidentical donors. The groups were similar in baseline characteristics with the exception of older age in the MRD/MUD group (P=0.012). In multivariate analysis, the effect of donor type (MRD/MUD vs haploidentical) on transplant outcomes was not significant in any of the models except for faster neutrophil recovery after MRD/MUD transplants (hazard ratio: 2.21; 95% confidence interval: 1.31-3.72, P=0.002). In conclusion, we showed similar outcomes in MRD/MUD vs haploidentical HCT (except slower count recovery following haplo-HCT) when PT-Cy is used for GvHD prophylaxis. Although slower count recovery following haplo-HCT (compared with MRD/MUD transplants without PT-Cy) has been attributed to using PT-Cy, our results suggest that HLA disparity is the primary cause of this difference. Furthermore, our analysis supports PT-Cy as a viable option for GvHD prophylaxis after MRD/MUD transplants.

Long-term follow-up of high-risk allogeneic peripheral-blood stem-cell transplant recipients: graft-versus-host disease and transplant-related mortality.

PURPOSE: To determine the risks of graft-versus-host disease (GVHD) and transplant-related mortality after allogeneic peripheral-blood stem-cell (PBSC) transplantation. PATIENTS AND METHODS: Between December 1994 and July 1996, 50 consecutive patients with high-risk hematologic malignancies in first remission or relapse received high-dose therapy followed by transplantation of granulocyte colony-stimulating factor-mobilized, allogeneic PBSCs collected from HLA-identical siblings. GVHD prophylaxis included cyclosporine and corticosteroids. RESULTS: As of April 1, 1998, 18 patients (36%+/-13%) survived with a median follow-up period of 767 days (range, 602 to 1,127 days). The actuarial probability of grades 2-4 acute GVHD was 0.37+/-0.14 (95% confidence interval). Of 36 assessable patients, 26 (72%+/-15%) developed chronic GVHD. The actuarial probability of chronic GVHD 2 years after transplantation was 0.87+/-0.15. Of 14 progression-free survivors, 11 (79%+/-22%) have active, chronic GVHD. All 11 patients require ongoing immunosuppression, and nearly two thirds have extensive disease. Thirteen patients died as a result of transplant-related mortality (26%+/-12%), six (12%) before and seven (14%) after day +100. CONCLUSION: We observed a high risk of chronic GVHD after allogeneic PBSC transplantation, which compromised the performance status of most long-term survivors and resulted in a relatively high risk of late transplant-related mortality. Approximately 75% of transplant-related deaths were associated with GVHD; thus, reduction in transplant-related mortality after allogeneic PBSC transplantation will require more effective strategies for the prophylaxis and/or treatment of GVHD.

Mobilization of peripheral-blood stem cells by concurrent administration of daniplestim and granulocyte colony-stimulating factor in patients with breast cancer or lymphoma.

PURPOSE: To evaluate the safety and hematopoietic activity of daniplestim administered concurrently with granulocyte colony-stimulating factor (G-CSF) for peripheral-blood stem-cell (PBSC) mobilization. PATIENTS AND METHODS: In the initial dose-escalation phase, 25 patients with adenocarcinoma of the breast (AB; 13 patients) or lymphoma (12 patients) were given daniplestim at doses ranging from 0.1 to 3.75 microgram/kg/d plus G-CSF 10 microgram/kg/d. In the randomized phase, 52 patients with AB (27 patients) or lymphoma (25 patients) were randomized within disease categories to the daniplestim dose chosen in the dose-escalation phase plus G-CSF 10 microgram/kg/d (D+G) or placebo plus G-CSF 10 microgram/kg/d (P+G) for up to 7 days. RESULTS: A daniplestim dose of 2. 5 microg/kg/d was chosen for further study because it was hematopoietically active and had an acceptable side-effect profile. In the randomized phase, in patients with AB, D+G was associated with a higher probability (P =.0696) of collecting >/= 2.5 x 10(6) CD34(+) cells/kg and significantly higher circulating CD34(+) cell counts (P =.0498) on days 6 through 9 after the initiation of dosing. The target level was more likely to be reached with additional leukaphereses in the patients given D+G. Patients given P+G did not benefit from additional leukaphereses beyond the first procedure. The type of mobilization did show a trend toward a shorter duration of neutropenia in the D+G group. The adverse events with D+G consisted largely of mild to moderate flu-like symptoms, including headache and fever, and occurred more frequently than with P+G. CONCLUSION: Daniplestim administered at 2.5 microgram/kg/d is tolerable and active when combined with G-CSF, and the combination may prove more effective than G-CSF alone in promoting the collection of adequate numbers of CD34(+) cells for PBSC infusion in patients with AB.

Reduced risk of acute GVHD following mobilization of HLA-identical sibling donors with GM-CSF alone.

We retrospectively reviewed the results of transplanting peripheral blood progenitor cell (PBPC) allografts from HLA-matched sibling donors mobilized using various hematopoietic cytokines. Patients had received allografts mobilized with Granulocyte colony-stimulating factor (G-CSF) (G, N = 65) alone, G plus Granulocyte-macrophage colony stimulating factor (GM-CSF) (G/GM, N = 70), or GM-CSF alone at 10 or 15 microg/kg/day (GM, N = 10 at 10 microg/kg/day and 21 at 15 microg/kg/day). The CD34+ and CD3+ cell content of grafts were significantly lower following GM alone compared to G alone (P < 0.001 and 0.04, respectively). Nonhematopoietic toxicity observed in donors precluded dose escalation of GM-CSF beyond 10 microg/kg/day. Hematopoietic recovery was similar among all three groups. Grades II-IV acute graft-versus-host disease (GVHD) was observed in only 13% of patients in the GM alone group compared to 49 and 69% in the G alone or G/GM groups, respectively (P < 0.001). In a multivariate analysis, receipt of PBPC mobilized with GM alone was associated with a lower risk of grades II-IV acute GVHD (hazard ratio 0.21; 95% CI 0.073, 0.58) compared to G alone or G/GM. There were no differences in relapse risk or overall survival among the groups. Donor PBPC grafts mobilized with GM-CSF alone result in prompt hematopoietic engraftment despite lower CD34+ cell doses and may reduce the risk of grades II-IV acute GVHD following HLA-matched PBPC transplantation.

Characterization of the adherence of normal and leukemic CD34+ cells to endothelial monolayers.

The capacity of normal CD34+ marrow cells and CD34+ leukemic cell lines to adhere to human umbilical vein endothelial cells has been examined. Such interactions have importance since the processes of homing and egress within the marrow microenvironment involve the traverse of sinusoidal endothelium. Umbilical vein endothelial monolayers expressed CD44 and CD54 constitutively, and expression of both E-selectin (ELAM) and vascular cell adhesion molecule-1 (VCAM-1) were inducible with interleukin-1 (IL-1) alpha and beta and tumor necrosis factor (TNF). CD34+ marrow cells bound to unstimulated endothelial layers (33 vs. 16% to plastic), and their adhesion was significantly increased in the presence of IL-1 or TNF. This increased adhesion was not inhibited by functionally blocking antibodies to E-selectin or to CD54 but was partially inhibited by antibodies to VCAM. CD34+ KG1a cells also bound to endothelial monolayers (33 vs. 8% to plastic), and such adhesion was also upregulated by pretreatment of the endothelial cells with IL-1 or TNF. In contrast to normal CD34+ cells, this increased adhesion was inhibited by antibodies to E-selectin but not to VCAM. These findings indicate that adhesion of both normal CD34+ cells and leukemic blasts to endothelial cells can be upregulated by inflammatory mediators such as TNF and IL-1.

Effects of human GM-CSF on neutrophil degranulation in vitro.

Human granulocyte-macrophage colony-stimulating factor (GM-CSF) stimulates multiple differentiated functions of mature neutrophils. Increased expression of leukocyte adhesion molecules and chemotactic receptors on GM-CSF-treated neutrophils suggested that GM-CSF may stimulate neutrophil degranulation. were assessed by quantitating the release of an exclusive component of the specific granules, vitamin B12 binding protein. Incubation of neutrophils with GM-CSF alone resulted in a significant release of [57Co]-vitamin B12 binding protein quantitatively similar to that elicited by cytochalasin B or N-formyl-methionyl-leucylphenylalanine (f-Met-Leu-Phe) alone. In addition, cells preincubated with GM-CSF and subsequently stimulated with f-Met-Leu-Phe, platelet-activating factor, or the calcium ionophore, A23187, demonstrated enhanced degranulation, which greatly exceeded that produced by GM-CSF alone. These results demonstrate a small direct effect of GM-CSF on neutrophil degranulation, as well as enhanced degranulation in cells stimulated by chemotactic agents and calcium ionophore. Neutrophil degranulation in response to GM-CSF may be involved in the phlebitis associated with therapeutic administration of GM-CSF.

Granulocyte-macrophage colony-stimulating factor (GM-CSF) and granulocyte colony-stimulating factor (G-CSF): receptor biology, signal transduction, and neutrophil activation.

Granulocyte-macrophage colony-stimulating factor (GM-CSF) and granulocyte colony-stimulating factor (G-CSF) are two of the growing number of recognized cytokines involved in the regulation of hematopoiesis. The purification of these factors and the subsequent cloning of the cDNAs which encode these proteins have led to their widespread clinical use in the setting of therapy or disease-induced myelosuppression. Although originally purified on the basis of their colony-stimulating properties, GM-CSF and G-CSF may also play important roles in the regulation of effector cell function. The mechanisms underlying progenitor cell proliferation and effector cell stimulation remain poorly understood. However, the characterization of the GM-CSF and G-CSF receptors and recent work in signal transduction are helping to elucidate these mechanisms. This paper will review the biology of the GM-CSF and G-CSF receptors, the mechanisms of post-receptor signal transduction, and the resultant effects on neutrophil function. In addition, the current and potential clinical uses of these factors will be examined in light of their ability to activate and perhaps enhance the function of neutrophils.

Innovations in allogeneic stem-cell transplantation.

Allogeneic bone marrow transplantation (BMT) is associated with prolonged periods of neutropenia and thrombocytopenia, which can lead to severe infections and bleeding complications. Transplantation-related side effects might be ameliorated by use of cytokine-mobilized peripheral blood progenitor cells (PBPC) Instead of bone marrow. We have studied PBPC mobilization and transplantation in more than 150 patients with high-risk hematologic malignancies. Normal donors can be sufficiently mobilized with granulocyte colony-stimulating factor (G-CSF), with 91% of G-CSF-stimulated normal donors producing more than 2 x 10(6) CD34+ cells/kg by a single apheresis. The combination of G-CSF plus granulocyte-macrophage colony-stimulating factor (GM-CSF) was more effective than mobilization with G-CSF alone. A clear relationship was seen between numbers of resting CD34+ cells premobilization and numbers of PBPC collected by apheresis, indicating that resting CD34+ cells might be used to predict mobilization results and identify donors who could benefit from more effective mobilization regimens. Transplantation of G-CSF-mobilized PBPC was associated with a more rapid engraftment than that observed for BMT. While engraftment was safe and acute graft-versus-host disease (aGvHD) rates were not increased over BMT, chronic GvHD rates were higher after PBPC transplantation. An additional PBPC infusion on day +3 resulted in a further shortening of neutropenia and thrombocytopenia. Incorporation of these innovative approaches with "minimal" conditioning regimens has resulted in near-complete elimination of fever, neutropenia, thrombocytopenia, and the need for antibiotics and RBC and platelet transfusions after allogeneic transplantation.

Sequence analysis and functional studies of interleukin-3 receptor alpha subunit-encoding cDNAs amplified from KG-1 leukemic cells and normal human marrow.

Two partial cDNAs encoding the human interleukin-3 receptor alpha subunit (IL-3R alpha) were cloned from KG-1 leukemic cells using the polymerase chain reaction. Sequence analysis of these cDNAs predicted two single-amino-acid (aa) changes as compared with the published TF-1 leukemic cell IL-3R alpha sequence [Kitamura et al., Cell 66 (1991) 1165-1174]. These changes were confirmed by sequence analysis of a second set of independently derived cDNAs. Identical aa changes were found in the IL-3R alpha encoded by cDNAs cloned from normal CD34+ human marrow cells. Ligation of the partial cDNAs derived from KG-1 cells resulted in a full-length functional IL-3R alpha cDNA clone. Deletion of the extracellular 'LSXWS' consensus sequence resulted in complete loss of detectable [125I]IL-3 binding when this mutant receptor was co-expressed in COS-7 cells with the beta subunit of the IL-3 receptor.

Effects of GM-CSF on Ki67 expression and cell cycle traverse in acute myelogenous leukemia specimens and cell lines.

A new strategy in the treatment of acute myelogenous leukemia is to attempt to increase the growth fraction of clonal leukemic cells prior to administration of chemotherapeutic agents by the administration of hematopoietic growth factors. We have studied the effect of GM-CSF on the cell cycle status and Ki67 nuclear antigen expression of AML blasts in vitro. The effect of growth factors and stromal cell co-culture on Ki67 expression in leukemic cell lines was also examined. Neither stromal cell co-culture nor exposure of factor-dependent and factor-independent cell lines to GM-CSF, IL-3, SCF, or combinations thereof significantly changed the percentage of cells expressing Ki67. In the AML population analyzed as a whole, exposure of blasts to GM-CSF for up to 96 h did not significantly change the percentage of cells in S phase or expressing Ki67.

CD34+ progenitor cell isolation from blood and marrow: a comparison of techniques for small-scale selection.

The isolation and characterization of primitive hematopoietic cells and their purification in sufficient numbers is important in clinical and research marrow transplantation settings. As systems for large-scale isolation and amplification of such cells are developed, they may assume importance in transplantation, treatment of marrow failure and for gene therapy applications. Such cells have been isolated by numerous techniques and in this work, small-scale isolation of CD34+ cells by two immunoadsorption purification methods is compared with isolation by flow cytometry. While the immunoadsorption techniques allow for the processing of large numbers of density gradient-separated or unseparated cells for progenitor isolation, such techniques do not achieve the purity afforded by fluorescence activated cell sorter separation.