The clinical impact of antibacterial prophylaxis and cycling antibiotics for febrile neutropenia in a hematological malignancy and transplantation unit.

Febrile neutropenia is an expected complication during treatment of aggressive hematological malignancies and hematopoietic cell transplantation. We conducted a prospective cohort trial to determine the effects and safety of prophylactic fluoroquinolone administration, and rotation of empiric antibiotics for neutropenic fever in this patient population. From March 2002 through 2004, patients were treated with prophylactic levofloxacin during prolonged neutropenia, and a cycling schedule of empiric antibiotic therapy for neutropenic fever was initiated. The rates of bacteremia, resistance and complications were compared to a retrospective cohort of previously treated patients. The rate of gram-negative bacteremia decreased after the initiation of prophylactic levofloxacin (4.7 vs 1.8 episodes/1000 patient days, P<0.05). Gram-positive bacteremia rates remained unchanged, but more isolates of Enterococcus faecium were resistant to vancomycin after the intervention began. Resistance to the antibiotic agents used in the rotation did not emerge. There was no change in mortality during the intervention period. A prophylactic and cycling antibiotic schedule was successfully implemented on a hematological malignancy and hematopoietic cell transplant unit. gram-negative bacteremia was significantly decreased, without emergence of resistance. Concerns with Gram-positive resistance will require further observation.

Thiotepa and fractionated TBI conditioning prior to allogeneic stem cell transplantation for advanced hematologic malignancies: a phase II single institution trial.

Relapse of hematologic malignancies after allogeneic stem cell transplantation remains a common problem, in particular for patients who have advanced disease at the time of transplantation. Thiotepa has excellent antileukemic and immunosuppressive activity, and could therefore be a useful drug in the conditioning regimen for patients with advanced hematologic neoplasms. We retrospectively analyzed toxicity, engraftment and survival data of 41 patients who received a conditioning regimen of thiotepa (600 mg/m2) and hyperfractionated TBI (10 Gy) prior to matched related (n = 25) or matched unrelated (n = 16) allogeneic stem cell transplantation. The mean age at transplantation was 37.8 years (range 20-59), all but five patients had advanced hematologic malignancies at the time of transplantation. GVHD prophylaxis was with standard cyclosporine and methotrexate. Engraftment was excellent, but the regimen was associated with a high incidence of grade III renal (41%) and hepatic (15%) toxicity, and high transplant-related mortality (44% at day +90). The 3-year event-free survival was 13% and overall survival 14%. We conclude that this regimen requires modification to reduce toxicity.

Inverted spin method for removing RBCs from BM buffy coat products.

BACKGROUND: Inverted spin is a method of removing RBCs that historically has been part of blood banking practice. We investigated the feasibility of using this method for RBC depletion of BM buffy coat products in situations where recipient RBC Abs have been identified to donor RBC Ags. METHODS: The BM buffy coat product was placed in a transfer pack, inverted, centrifuged at 600 g for 10 min, suspended and the RBCs removed slowly into another transfer pack. Nine patients treated between April 1998 and February 2001 received products prepared by our version of the inverted spin procedure. RESULTS: We removed a median value of 81.2% of the RBCs, while still recovering a median of 94.3% of the mononuclear cells (median: 0.35 x 10(8)/kg; range: 0.17-0.9 x 10(8)/kg). The median volume of RBCs remaining in the product was 15.0 mL (range: 7.3-21.9 mL). The CD34(+) cell dose of the final product ranged from 1.0 x 10(6)/kg to 4.8 x 10(6) cells/kg (median: 1.9 x 10 6/kg). Granulocyte recovery (defined as ANC count >or=500/microL for a period of 3 consecutive days) ranged from 18-30 days post-infusion of the allograft (median: 24.0 days). One patient died shortly after his transplant from complications of his disease. No patient had any evidence of an acute hemolytic reaction. DISCUSSION: Advantages of the inverted spin method include no need for additives (e.g. hydroxyethyl starch, HSA, or O negative RBC), and use of equipment readily available in most processing laboratories.

Recombinant human thrombopoietin (rhTPO) after autologous bone marrow transplantation: a phase I pharmacokinetic and pharmacodynamic study.

Thrombocytopenia following myelotoxic therapy is a common problem and when severe (<20,000/microl) can lead to severe morbidity and mortality. Thrombopoietin (TPO) is a naturally occurring glycosylated peptide which stimulates the differentiation of bone marrow stem cells into megakaryocyte progenitor cells, induces the expression of megakaryocyte differentiation markers, promotes megakaryocyte proliferation, polyploidization and, ultimately, the formation of increased numbers of platelets in the circulation. TPO has now been produced by recombinant technology and has entered clinical trials. This open label phase I study was designed to determine the safety, tolerance and pharmacokinetics of recombinant thrombopoietin (rhTPO) when administered to patients after undergoing high-dose chemotherapy followed by autologous bone marrow transplantation. rhTPO was administered intravenously by bolus injection at doses ranging from 0.3 to 4.8 microg/kg/day every 3 days to 30 patients and 0.6 microg/kg daily to three patients. rhTPO was begun the day after marrow infusion and continued until platelet recovery to >20,000/microl. G-CSF was concomitantly administered to promote myeloid recovery. Serious adverse events or neutralizing antibodies to rhTPO were not observed during the study. Median platelet recovery after ABMT was 19 days (range, 11-41). Neither the dose nor the schedule of rhTPO appeared to have any impact upon the time course of platelet recovery. In this phase I study, rhTPO was found to be well tolerated without the development of neutralizing antibodies and without compromising neutrophil recovery. Platelet recovery was similar for all doses studied warranting further evaluation in phase II and III trials designed to test for platelet recovery efficacy.

Mobilization, collection, and processing of autologous peripheral blood stem cells: development of a clinical process with associated costs.

We surveyed five academic medical centers to develop a clinical process for patients undergoing cytokine mobilization and leukapheresis prior to autologous peripheral blood stem cell transplantation. Costs were obtained from three centers and applied to each component of the pathway. Costs were divided into three categories: (1) pre-apheresis evaluation; (2) process of apheresis; (3) post-apheresis and peripheral blood stem cells processing. All centers participated in the development of the leukapheresis pathway. Because charges vary greatly among institutions, costs were determined from three of the institutions and a mean was calculated for each of the components of the process. Pre-apheresis costs consisted of central line placement, blood work, and the price of cytokine (rhG-CSF). Costs associated with apheresis included professional fees (for physicians and nurses), leukapheresis with stem cell cryopreservation, storage, sterility testing, analysis of circulating CD34+ cell counts, and 1 day of cytokine therapy. The post-apheresis process included thawing with sterility testing along with CD34+ cell number analysis and the performance of clonogenic assays. Total costs were as follows: (1) pre-apheresis, $2711; (2) apheresis, $2990; and, (3) post-apheresis/stem cell processing, $754. This survey from five academic medical centers provides the average costs associated with three main components of the apheresis procedure. Because many patients require multiple aphereses, interventions to achieve target CD34+ cell collections in as few collections as possible would result in significant cost reduction.

Effects of the protein tyrosine phosphatase CD45 on FcgammaRIIa signaling and neutrophil function.

OBJECTIVE: Neutrophil receptors for the Fc portion of IgG (FcgammaR) trigger immune responses following cross-linking by IgG-coated foreign particles or immune complexes. Membrane-associated CD45, a protein tyrosine phosphatase termed leukocyte common antigen, has been shown to be essential for antigen receptor kinase mediated signaling in lymphocytes, and we hypothesized that CD45 may play a similar role in FcgammaR-mediated signaling and immune function in human neutrophils. METHODS: The experimental approach was that of cell surface molecule ligation via cross-linking with specific antibodies. Antibody dependent cellular cytotoxicity (ADCC) was assessed using a single-cell plaque assay and IL-6 production measured using ELISA. Tyrosine phosphorylation levels were assessed with anti-phospho-tyrosine blots and F-actin polymerization by flow cytometry and confocal microscopy. RESULTS: Neutrophils pretreated with anti-CD45 had a reduced ability to perform ADCC compared to untreated neutrophils. FcgammaRIIa cross-linking resulted in significantly increased concentrations of secreted IL-6 compared to untreated neutrophils, and IL-6 production was further enhanced by cocross-linking CD45 with FcgammaRIIa. Cross-linking CD45 alone also induced IL-6 production. FcgammaRIIa cross-linking resulted in increased protein tyrosine phosphorylation and F-actin polymerization in neutrophils. Cocross-linking CD45 with FcgammaRIIa resulted in abrogation of FcgammaRIIa mediated tyrosine phosphorylation and F-actin polymerization. CONCLUSIONS: These data provide evidence that CD45 can regulate or enhance the stimulation and function of human neutrophils mediated through FcgammaR(s). In addition, CD45 ligation may play an essential role in cytokine induction pathways that lead to inflammatory reactions in vivo.

Regulation of BAX and BCL-2 expression in breast cancer cells by chemotherapy.

Optimizing chemotherapeutic drug delivery strategies relies, in part, on identification of the most clinically effective sequence, dose, and duration of drug exposure. The combination of dose intensive etoposide (VP-16) followed by cyclophosphamide has clinical efficacy in the treatment of advanced breast cancer. However, molecular mechanisms that underlie the effectiveness of this combination of chemotherapeutic agents have not been investigated. In this study we investigated regulation of BAX and BCL-2 expression by VP-16 and cyclophosphamide as a potential mechanism for the induction of breast cancer cell death induced by this regimen. There was a dose and time dependent increase in BAX expression in the breast cancer cell lines MCF-7, MDA-MB-435S, and MDA-MB-A231 following in vitro treatment with 50-100 microM VP-16. Elevation of BAX protein expression in the presence of VP-16 alone did not correlate with reduced viability or induction of apoptosis in MCF-7, MDA-MB-435S, or MDA-MB-A231. VP-16 did effectively block the breast cancer cell lines evaluated (MCF-7 and MDA-MB-435S) at G2/M phase of the cell cycle, confirming activity of the drug in vitro. MCF-7 and MDA-MB-435S cells that were pre-treated with VP-16 and subsequently exposed to 1.0-12.0 microg/ml 4-hydroperoxycyclophosphamide (4HC), an active metabolite of cyclophosphamide, had markedly reduced viability when compared to matched controls treated with either VP-16 or 4HC individually. Consistent with this loss of viability, exposure of all three cell lines to the combination of VP-16 and 4HC resulted in higher BAX protein levels than those observed following treatment with either single agent. This combination of chemotherapeutic agents also resulted in reduced BCL-2 expression. These observations suggest that combination chemotherapy may derive its efficacy, in part, through coordinated regulation of specific gene products associated with apoptosis. Characterization of molecular events that underlie susceptibility of specific tumor cells to combination chemotherapeutic regimens may lead to additional improvements in treatment strategies for this disease.

Fluorescence-imaging assay for cytotoxic plaque formation and for growth toward confluency of adherent cells.

A nondestructive fluorescence-imaging assay is described for quantitating the number and size of plaques formed over time by cytotoxic effector cells in a monolayer of target cells. It can also be used to assay the growth of adherent cells toward confluence. The method involves the use of fluorescein conjugated to high molecular weight dextran. The dextran is excluded by adherent cells, thereby making the medium around cells more fluorescent than the cells themselves. The area of the plate that is fluorescent can be determined by confocal fluorescence imaging microscopy. With this new method, changes in the confluency of adherent cells or in the number and area of cytotoxic plaques can be assayed repeatedly over an extended period of time, without manipulation of the cells or of the medium.

Interleukin-6 production by human neutrophils after Fc-receptor cross-linking or exposure to granulocyte colony-stimulating factor.

Polymorphonuclear neutrophils (PMNs) are essential effector cells in host defense and tissue inflammatory responses. These responses may be initiated after cross-linking of cell surface Fc receptors that bind the constant portion of IgG (FcgammaR). We evaluated the effect of cross-linking FcgammaRI or FcgammaRII on interleukin-6 (IL-6) production by purified PMNs from normal donors or from patients being treated with recombinant human granulocyte colony-stimulating factor (rhG-CSF). In PMNs from normal donors, IL-6 mRNA was detected by reverse transcriptase-polymerase chain reaction only after FcgammaRI or FcgammaRII cross-linking. We also found that IL-6 mRNA could be detected in PMNs after either in vitro or in vivo rhG-CSF treatment in the absence of FcgammaR cross-linking. IL-6 protein was found to be produced intracellularly and secreted by PMNs after cross-linking FcgammaRI or FcgammaRII or after rhG-CSF stimulation. Cross-linking FcgammaRI or FcgammaRII on PMNs from patients treated with rhG-CSF resulted in a synergistic increase in IL-6 secretion. Upregulation of IL-6 production by PMNs after rhG-CSF treatment may contribute to a clinical engraftment syndrome that occurs during periods of rapid increase in PMN numbers in patients receiving rhG-CSF.

The role of polymorphonuclear neutrophils (PMNs) in clearance of granulocyte colony-stimulating factor (G-CSF) in vivo and in vitro.

Previous studies have suggested that in vivo granulocyte colony-stimulating factor (G-CSF) pharmacokinetics may change over time. We studied three patients treated with high-dose chemotherapy followed by autologous bone marrow transplantation (ABMT) for metastatic breast cancer after intravenous administration of recombinant human (rh) G-CSF (5 or 16 microg/kg/day). We investigated plasma G-CSF concentrations and absolute neutrophil counts (ANCs/pL) in these patients on three separate days. G-CSF plasma clearance increased with time post-ABMT with no change in the apparent volume of distribution (Vd) of G-CSF. Regression analysis of G-CSF plasma clearance and ANCs revealed a linear relationship, with r2 = 0.85 (p = 0.00025). We further investigated this phenomenon in vitro by estimating pharmacokinetic parameters for rhG-CSF using a model in which polymorphonuclear neutrophils (PMNs) were incubated with rhG-CSF. We found that, at low G-CSF concentrations in vitro, there was an increase in G-CSF clearance with increasing ANCs, but at higher G-CSF concentrations this relationship did not hold. We suggest that this finding resulted from aggregation and polymerization of G-CSF at high concentrations when kept at 37 degrees C for 24-48 hours in vitro. Using fluorescence staining techniques, our data suggest there are changes over time in the amount of G-CSF bound to PMNs. These changes may reflect reexpression or recycling of the G-CSF receptor, and could explain the continuing clearance of G-CSF by PMNs in vitro. The strong positive correlation between G-CSF plasma clearance and ANCs in vivo is compatible with the hypothesis that neutrophils mediate one of the major pathways for rhG-CSF clearance.

Disruption of bone marrow stromal cell function by etoposide.

Long-term deficits in hematopoietic reconstitution following aggressive chemotherapeutic regimens used before transplantation may be a result, in part, of damage to the bone marrow microenvironment. Disruption of the hematopoietic microenvironment is indicated by delays in functional recovery of the immune system in spite of delivery of healthy peripheral blood or bone marrow progenitor cells. Cultures of primary human bone marrow stromal cells and a cloned murine stromal cell line, S10, were evaluated for functional changes following in vitro exposure to the chemotherapeutic agent, etoposide (VP-16). Stromal cells had reduced capacity to support lymphoid or myeloid cell proliferation following chemotherapy treatment. A consistent reduction of vascular cell adhesion molecule-1 (VCAM-1) on bone marrow stromal cells also followed VP-16 exposure. These observations indicate that functional disruption of the bone marrow microenvironment by chemotherapeutic regimens must be considered when attempting to optimize patient recovery from hematopoietic transplantation.

Monoclonal antibody 197 (anti-Fc gamma RI) infusion in a patient with immune thrombocytopenia purpura (ITP) results in down-modulation of Fc gamma RI on circulating monocytes.

A 44-year old woman with refractory immune thrombocytopenia purpura was treated with the murine monoclonal antibody 197 in a phase 1 trial. It vitro studies have demonstrated that the monoclonal antibody 197 (subclass IgG2a) binds to two distinct epitopes of Fc gamma RI, with the constant domain binding to the Fc-binding portion of the Fc gamma RI and the variable domain binding to a different epitope, resulting in crosslinking and modulation of this receptor. The monoclonal antibody 197 was administered on days 1, 3 and 5 at doses of 0.25 mg/kg, 0.35 mg/kg and 0.45 mg/kg, respectively. The fusions were well tolerated with transient facial flushing, and wheal-and-flare rash during the first infusion, which resolved with a slower infusion rate and the administration of diphenhydramine and acetaminophen. Although a marked clinical improvement did occur with resolution of oral ecchymoses and epistaxis after the first mAb infusion, the initial platelet count of 6 x 10(9)/I did not change appreciable over the 5 d course of monoclonal antibody treatment. Binding of fluorescein-labelled monoclonal antibody 197 to peripheral monocytes showed a rapid and persistently decreased mean fluorescein intensity, indicated binding of administered 197 to the monocytes in vivo. Indirect staining for FcgammaRI using fluorescein-labelled goat anti-mouse immunoglobulin was also decreased, suggesting modulation of the receptor. The patient experienced monocytopenia which persisted throughout the 5 d of monoclonal antibody 197 therapy, but reversed following institution of intravenous IgG. These data indicate that intravenous monoclonal antibody 197 induces specific down-modulation of Fc gamma RI expression on monocytes.

Anti-body-dependent cellular cytotoxicity (ADCC) function of peripheral blood polymorphonuclear neutrophils (PMN) after autologous bone marrow transplantation (ABMT).

Rapid recovery of the number and function of polymorphonuclear neutrophils (PMN) is critical to recovery from bone marrow transplantation. Although it is relatively easy to measure PMN number recovery, the evaluation of the functional recovery of these cells has not been adequately examined. The ability of peripheral blood PMNs to perform antibody-dependent cellular cytotoxicity (ADCC) was assessed in 25 patients undergoing autologous bone marrow transplantation (ABMT). PMNs were evaluated at a single cell level for ADCC function as measured by their ability to form plaques in antibody-sensitized ox erythrocyte (oxE) monolayers. The PMNs demonstrated low or absent ADCC function in the first week after completion of high-dose chemotherapy, regardless of primary diagnoses or myeloablative regimens. Although recovery to a neutrophil count of 500/microliters was prolonged in patients with AML (mean 40.2 days; range 25-67 days), functional activity of PMNs appeared much earlier (mean 19.6 +/- 6.1 days; range 2-65 days) in this group of patients compared to the group of patients with other diagnoses in which recovery to a neutrophil count of 500/microliters and the recovery of functional activity of PMNs occurred at roughly the same time. This single cell assay provided a useful method for determining ADCC functional ability of recovering PMNs post-BMT since few cells were required for each assay. This approach may also be useful in determining optimal timing of immune therapies post-ABMT, relying on myeloid cells as effector cells.

Mature polymorphonuclear leukocytes express high-affinity receptors for IgG (Fc gamma RI) after stimulation with granulocyte colony-stimulating factor (G-CSF).

The high-affinity receptor for the constant region of immunoglobulin G IgG (Fc gamma RI; CD64) is virtually undetectable on mature polymorphonuclear neutrophils (PMNs) in healthy individuals but is expressed on PMNs in patients with certain infections and in patients treated with recombinant human granulocyte colony-stimulating factor (rhG-CSF). The induction of Fc gamma RI by rhG-CSF has previously been reported to result from effects on immature granulocyte progenitors. To evaluate the G-CSF effect on mature PMNs, we studied the correlation between G-CSF plasma concentration and expression of Fc gamma RI on PMNs in vivo as well as the effect of G-CSF on Fc gamma RI expression on mature PMNs in vitro. Fc gamma RI expression on PMNs correlated (R = 0.79; p < .001) with plasma concentrations of endogenous or recombinant G-CSF in healthy volunteers and in patients undergoing high-dose chemotherapy and autologous bone marrow transplantation. PMNs exhibited a unimodal distribution for elevated Fc gamma RI expression, suggesting that G-CSF induced increased expression of Fc gamma RI on mature as well as on immature PMNs. In vitro, incubation of mature PMNs with G-CSF induced mRNA for Fc gamma RI. Significant Fc gamma RI surface expression was induced in a time- and dose-dependent manner. Thus, G-CSF can act on mature PMNs to increase Fc gamma RI expression and may be useful for stimulating antibody mediated immune functions of PMNs in vivo.

The effect of recombinant human interleukin-3 and recombinant human granulocyte-macrophage colony-stimulating factor on Fc gamma receptor expression and antibody-dependent cellular cytotoxicity of hematopoietic progenitor cells during in vitro myeloid maturation.

Enriched progenitor cell fractions from human bone marrow were induced to undergo myeloid maturation in culture using recombinant human interleukin-3 (rhIL-3) and granulocyte-macrophage colony stimulating factor (rhGM-CSF). A negative selection method using the murine monoclonal antibodies (MABs) PM81 (anti-CD15), AML-2-23 (anti-CD14), PC251 (anti-CD33), OKT11 (anti-CD2), and SCCL-1 (anti-CD71) and immunomagnetic beads coated with sheep anti-mouse IgG (Dynal A.S., Oslo, Norway) was used to remove the more mature cellular components of mononuclear cells from normal donor bone marrow samples. The resulting fraction of cells contained 35 to 40% CD34-positive cells, and less than 1% of cells expressed the receptors for the constant portion of immunoglobulin G Fc gamma RI or Fc gamma RII. A small population (3-5%) expressed Fc gamma RIII on day 0, and these cells were found by two-color flow cytometry to be primarily natural killer (NK) cells. The level of Fc gamma R expression was determined every 2 to 3 days on aliquots of the differentiating cells. Thirteen percent of the cultured bone marrow cells expressed Fc gamma RII after 48 hours in liquid culture with rhIL-3 and rhGM-CSF. The percent of cells expressing Fc gamma RII increased to a peak of 78% of the gated population on day 10. The mean fluorescence intensity (MFI) remained low for the first 8 to 10 days of culture, but at that time the MFI more than doubled. Fc gamma RI and Fc gamma RIII expression remained low throughout the culture period. The ability of the differentiating cells to perform antibody-dependent cellular cytotoxicity (ADCC) was determined at a single-cell level in a modified plaque assay using monolayers of ox erythrocyte (oxE) target cells. The purified progenitor cells, when placed in oxE monolayers sensitized with polyclonal rabbit anti-oxE antibody (AB), showed no plaque formation over control oxE layers. No increase in ability to generate cytolytic plaques in antibody-sensitized oxE layers was seen compared with unsensitized oxE layers until after 10 days of incubation in liquid culture. At that time, the percent of cells forming plaques in the AB-sensitized oxE layers was 34.4 +/- 10.7% (average +/- standard error of the mean [SEM]; n = 4) compared with 10.0 +/- 0.7% on the control oxE layers. The peak plaque formation appeared to coincide with the increase in MFI of a large population of the cultured cells.(ABSTRACT TRUNCATED AT 400 WORDS)

Engraftment of leukocyte subsets following autologous bone marrow transplantation in acute myeloid leukemia using anti-myeloid (CD14 and CD15) monoclonal antibody-purged bone marrow.

The cell surface phenotype of leukocyte subsets during reconstitution following autologous bone marrow transplantation (ABMT) using bone marrow purged with anti-myeloid monoclonal antibodies (MoAbs) and complement (C') was evaluated in 20 patients with acute myeloid leukemia (AML). Repopulation of B and T lymphocytes, natural killer (NK) cells, and myeloid cells was assessed by phenotypic analysis using two-color cytofluorography of peripheral blood mononuclear cells (PBMNC) at several time points up to 2 years post-transplantation. In spite of removal of the majority of monomyeloid cells of the autograft by purging with anti-CD14 and anti-CD 15, engraftment occurred rapidly. The myeloid cells appeared normal by surface phenotype. An early rise in NK cells, characterized by expression of CD57 and CD 16, was seen. The CD4:CD8 ratio remained low throughout the study period, primarily due to a persistently low CD4 level. ABMT using bone marrow purged with the anti-myeloid MoAbs PM-81 and AML-2-23 and C' resulted in prompt engraftment of neutrophils. Although there was a prolonged time for recovery of lymphocyte subsets, this did not result in an increased risk of early infectious complications. Late infectious complications post-transplantation were limited to herpes zoster infection in one patient 18 months post-transplantation, and bacterial meningitis in that same patient 2 months later. This study demonstrates that ABMT in patients with AML using bone marrow purged with the anti-myeloid MoAbs PM81 (anti-CD15) and AML-2-23 (anti-CD14) and C' results in rapid hematologic engraftment and delayed phenotypic immunologic reconstitution without significant acute or chronic clinical toxicities.