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D C Dale

Publications and source records attributed to D C Dale.

At least 19 recordsLinked to original sources
PubMed2001

Impaired survival of bone marrow hematopoietic progenitor cells in cyclic neutropenia.

Cyclic neutropenia (CN) is a congenital hematopoietic disorder characterized by remarkably regular oscillations of blood neutrophils from near normal to extremely low levels at 21-day intervals. Recurring episodes of severe neutropenia lead to repetitive and sometimes life-threatening infections. To investigate the cellular mechanism of CN, the ultrastructure and the proliferative and survival characteristics of bone marrow-derived CD34(+) early progenitors, CD33(+)/CD34(-) myeloid progenitors, and CD15(+) neutrophil precursors from CN patients and healthy volunteers were studied. The ultrastructural studies showed profound apoptotic features in bone marrow progenitor cells in CN. Colony-forming assays demonstrated a 75% decrease in the number of early myeloid-committed colonies compared with controls. Long-term culture-initiating cell assays demonstrated a 6-fold increase in production of primitive progenitor cells in CN. To determine whether accelerated apoptosis might account for the underproduction of myeloid progenitors, the hematopoietic subpopulations were labeled with fluorescein isothiocyanate-annexin V and analyzed by flow cytometry. Short-term culture of CN cells resulted in apoptosis of approximately 65% of CD34(+) cells, 80% of CD33(+)/CD34(-) cells, and more than 70% of CD15(+) cells, as compared with 20%, 7%, and 15% apoptosis in respective control subpopulations. Evidence of accelerated apoptosis of bone marrow progenitor cells was observed in all 8 patients participating in the study, regardless of the stage in the CN cycle in which bone marrow aspirations were obtained. Granulocyte colony-stimulating factor therapy of CN patients significantly improved survival of bone marrow progenitor cells. These data indicate that ineffective production of neutrophils is due to accelerated apoptosis of bone marrow myeloid progenitor cells in CN.

Annexin A5↗
PubMed2001

Mutations in the neutrophil elastase gene in cyclic and congenital neutropenia.

Severe neutropenia disorders are characterized by extremely low levels of peripheral blood neutrophils, a maturation block of bone marrow progenitor cells and recurring severe bacterial and fungal infections. Recent reports indicated that severe neutropenia is a consequence of an impaired survival and abnormal cell cycle progression of myeloid progenitor cells in both cyclic and severe congenital neutropenia. Mutations in the neutrophil elastase gene were identified in all patients with cyclic neutropenia and most of the patients with severe congenital neutropenia. We hypothesize that expression of mutant neutrophil elastase protein results in deregulation of intracellular activity and premature cell death of myeloid-committed progenitor cells in these disorders, resulting in the lack of peripheral blood neutrophils. The potential molecular mechanisms of mutant-protein-mediated neutropenia is discussed.

Humans↗
PubMed2001

Granulocyte transfusion therapy: update on potential clinical applications.

The clinical usefulness of granulocyte transfusions for treatment or prevention of life-threatening bacterial and fungal infections remains controversial. Clinical benefit has long been limited by insufficient donor stimulation regimens and suboptimal leukapheresis techniques. Methodologic progress, in particular mobilization of neutrophils in healthy donors by administration of G-CSF, has significantly enhanced leukapheresis yields. A newly published study indicates that unrelated community donors can be effectively and safely used as an alternative to related family donors. Furthermore, several recent studies suggest that it may be possible to store granulocyte concentrates for 24 to 48 hours with adequate preservation of neutrophil function. This review summarizes the current role of granulocyte transfusion therapy in infectious diseases and highlights important recent advances.

Granulocyte Colony-Stimulating Factor↗
PubMed2000

Current status of granulocyte (neutrophil) transfusion therapy for infectious diseases.

The transfusion of neutrophils, or granulocyte transfusion therapy, has long been considered as a logical approach to the treatment of severe bacterial and fungal infections in patients with prolonged neutropenia or intrinsic defects in neutrophil function. However, despite numerous clinical trials, the efficacy and safety of granulocyte transfusion therapy remain controversial. Efficacy has been compromised largely by the inability to transfuse sufficient quantities of functionally active neutrophils to patients. The recent use of recombinant granulocyte colony-stimulating factor (G-CSF) to mobilize neutrophils in donors before centrifugation leukapheresis has rekindled interest in the potential clinical applications of granulocyte transfusion therapy. This review focuses on the use of G-CSF for donor stimulation and summarizes the current status of granulocyte transfusion therapy for treatment of infectious diseases.

Bacterial Infections↗
PubMed2000

Spontaneous remission of granulocyte colony-stimulating factor-associated leukemia in a child with severe congenital neutropenia.

Leukemia is observed with increased frequency in patients with severe congenital neutropenia (SCN). In the past decade, recombinant human granulocyte colony-stimulating factor (rh G-CSF) has prolonged the survival of patients with SCN increasingly reported to have leukemias. In this communication acute myelogenous leukemia (AML) associated with a mutation of the G-CSF receptor (G-CSF-R) developed in a patient with SCN maintained on long-term G-CSF therapy. The blast count in the blood and bone marrow fell to undetectable levels twice on withholding G-CSF and without chemotherapy administration, but the mutant G-CSF-R was detectable during this period. The patient subsequently underwent successful allogeneic bone marrow transplantation. After transplantation, the patient's neutrophil elastase (ELA-2) mutation and G-CSF-R mutation became undetectable by polymerase chain reaction. This report provides novel insights on leukemia developing in congenital neutropenia.

Bone Marrow Transplantation↗
PubMed2000

Mutations in the gene encoding neutrophil elastase in congenital and cyclic neutropenia.

Congenital neutropenia and cyclic neutropenia are disorders of neutrophil production predisposing patients to recurrent bacterial infections. Recently the locus for autosomal dominant cyclic neutropenia was mapped to chromosome 19p13.3, and this disease is now attributable to mutations of the gene encoding neutrophil elastase (the ELA2 gene). The authors hypothesized that congenital neutropenia is also due to mutations of neutrophil elastase. Patients with congenital neutropenia, cyclic neutropenia, or Shwachman-Diamond syndrome were referred to the Severe Chronic Neutropenia International Registry. Referring physicians provided hematologic and clinical data. Mutational analysis was performed by sequencing polymerase chain reaction (PCR)-amplified genomic DNA for each of the 5 exons of the neutrophil ELA2 gene and 20 bases of the flanking regions. RNA from bone marrow mononuclear cells was used to determine if the affected patients expressed both the normal and the abnormal transcript. Twenty-two of 25 patients with congenital neutropenia had 18 different heterozygous mutations. Four of 4 patients with cyclic neutropenia and 0 of 3 patients with Shwachman-Diamond syndrome had mutations. For 5 patients with congenital neutropenia having mutations predicted to alter RNA splicing or transcript structure, reverse transcriptase-PCR showed expression of both normal and abnormal transcripts. In cyclic neutropenia, the mutations appeared to cluster near the active site of the molecule, whereas the opposite face was predominantly affected by the mutations found in congenital neutropenia. This study indicates that mutations of the gene encoding neutrophil elastase are probably the most common cause for severe congenital neutropenia as well as the cause for sporadic and autosomal dominant cyclic neutropenia.

Adolescent↗
PubMed2000

Myelodysplasia syndrome and acute myeloid leukemia in patients with congenital neutropenia receiving G-CSF therapy.

Granulocyte colony-stimulating factor (G-CSF) has had a major impact on management of "severe chronic neutropenia," a collective term referring to congenital, idiopathic, or cyclic neutropenia. Almost all patients respond to G-CSF with increased neutrophils, reduced infections, and improved survival. Some responders with congenital neutropenia have developed myelodysplastic syndrome and acute myeloblastic leukemia (MDS/AML), which raises the question of the role of G-CSF in pathogenesis. The Severe Chronic Neutropenia International Registry (SCNIR), Seattle, WA, has data on 696 neutropenic patients, including 352 patients with congenital neutropenia, treated with G-CSF from 1987 to present. Treatment and patient demographic data were analyzed. The 352 congenital patients were observed for a mean of 6 years (range, 0.1-11 years) while being treated. Of these patients, 31 developed MDS/AML, for a crude rate of malignant transformation of nearly 9%. None of the 344 patients with idiopathic or cyclic neutropenia developed MDS/AML. Transformation was associated with acquired marrow cytogenetic clonal changes: 18 patients developed a partial or complete loss of chromosome 7, and 9 patients manifested abnormalities of chromosome 21 (usually trisomy 21). For each yearly treatment interval, the annual rate of MDS/AML development was less than 2%. No significant relationships between age at onset of MDS/AML and patient gender, G-CSF dose, or treatment duration were found (P >.15). In addition to the 31 patients who developed MDS/AML, the SCNIR also has data on 9 additional neutropenic patients whose bone marrow studies show cytogenetic clonal changes but the patients are without transformation to MDS/AML. Although our data does not support a cause-and-effect relationship between development of MDS/AML and G-CSF therapy or other patient demographics, we cannot exclude a direct contribution of G-CSF in the pathogenesis of MDS/AML. This issue is unclear because MDS/AML was not seen in cyclic or idiopathic neutropenia. Improved survival of congenital neutropenia patients receiving G-CSF therapy may allow time for the expression of the leukemic predisposition that characterizes the natural history of these disorders. However, other factors related to G-CSF may also be operative in the setting of congenital neutropenia. (Blood. 2000;96:429-436)

Adolescent↗
PubMed2000

Modeling complex neutrophil dynamics in the grey collie.

We have developed a mathematical model for the peripheral regulation of neutrophil production mediated by granulocyte colony-stimulating factor. We have used that model to show that the pattern of neutrophil oscillations in nine grey collies is consistent with the hypothesis that cyclical neutropenia is due to an oscillatory stem cell input to the neutrophil regulatory system, and not due to autonomous oscillations in the peripheral neutrophil regulatory system. In the process of interfacing our model with the laboratory data, we have estimated parameters for the peripheral neutrophil control system consistent with higher than normal apoptotic cell loss within the recognizable neutrophil precursors. This is in agreement with other experimental data. Our estimated model parameters also predict that the peripheral neutrophil production system is globally stable in the grey collies we studied. This further supports our hypothesis that the origin of the oscillatory behavior in cyclical neutropenia is in the stem cell population, consistent with other clinical and experimental evidence.

Animals↗
PubMed2000

Phase I/II trial of neutrophil transfusions from donors stimulated with G-CSF and dexamethasone for treatment of patients with infections in hematopoietic stem cell transplantation.

We examined the feasibility of a community blood bank granulocyte transfusion program utilizing community donors stimulated with a single-dose regimen of subcutaneous granulocyte colony-stimulating factor (G-CSF) plus oral dexamethasone. The recipients of these transfusions were neutropenic stem cell transplantation patients with severe bacterial or fungal infection. Nineteen patients received 165 transfusions (mean 8.6 transfusions/patient, range 1-25). Community donors provided 94% of the transfusions; relatives accounted for only 6% of the transfusions. Sixty percent of the community donors initially contacted agreed to participate, and 98% of these individuals indicated willingness to participate again. Transfusion of 81.9 +/- 2.3 x 10(9) neutrophils (mean +/- SD) resulted in a mean 1-hour posttransfusion neutrophil increment of 2. 6 +/- 2.6 x 10(3)/microL and restored the peripheral neutrophil count to the normal range in 17 of the 19 patients. The buccal neutrophil response, a measure of the capacity of neutrophils to migrate to tissue sites in vivo, was restored to normal in most patients following the transfusion. Chills, fever, and arterial oxygen desaturation of >/= 3% occurred in 7% of the transfusions, but these changes were not sufficient to limit therapy. Infection resolved in 8 of 11 patients with invasive bacterial infections or candidemia. These studies indicate that transfusion of neutrophils from donors stimulated with G-CSF plus dexamethasone can restore a severely neutropenic patient's blood neutrophil supply and neutrophil inflammation response. Further studies are needed to evaluate the clinical efficacy of this therapy.

Administration, Oral↗
PubMed2000

Stem cell transplantation in patients with severe congenital neutropenia without evidence of leukemic transformation.

Severe congenital neutropenia (CN) (Kostmann syndrome) is a hematologic disorder characterized by a maturation arrest of myelopoiesis at the promyelocyte/myelocyte stage of development. This arrest results in severe neutropenia leading to absolute neutrophil counts (ANC) below 0.2 x 10(9)/L associated with severe bacterial infections from early infancy. Data on over 300 patients with CN collected by the Severe Chronic Neutropenia International Registry (SCNIR) beginning in 1994 indicate that more than 90% of these patients respond to recombinant human granulocyte-colony stimulating factor (r-HuG-CSF) treatment with an ANC greater than 1. 0 x 10(9)/L. For patients who are refractory to r-HuG-CSF treatment and continue to have severe and often life-threatening bacterial infections, hematopoietic stem cell transplantation is the only currently available treatment. We report on a total of 11 patients with CN reported to the SCNIR who underwent transplantation for reasons other than malignant transformation between 1976 and 1998. Of these patients, 8 were nonresponders or showed only partial response to r-HuG-CSF treatment with ongoing infections. Results from these patients suggest that transplantation of stem cells from an HLA-identical sibling is beneficial for patients refractory to r-HuG-CSF. (Blood. 2000;95:1195-1198)

Adolescent↗
PubMed2000

Myelokathexis, a congenital disorder of severe neutropenia characterized by accelerated apoptosis and defective expression of bcl-x in neutrophil precursors.

Myelokathexis is a congenital disorder that causes severe chronic leukopenia and neutropenia. Characteristic findings include degenerative changes and hypersegmentation of mature neutrophils and hyperplasia of bone marrow myeloid cells. The associated neutropenia can be partially corrected by treatment with granulocyte colony-stimulating factor (G-CSF) or granulocyte-macrophage colony-stimulating factor (GM-CSF). These features led us to propose that accelerated apoptosis of neutrophil precursors might account for the neutropenic phenotype. Blood and bone marrow aspirates were obtained from 4 patients (2 unrelated families) with myelokathexis before G-CSF therapy and from 2 of the affected persons after G-CSF therapy (1 microg/kg per day subcutaneously for 3 weeks). Bone marrow was fractionated using immunomagnetic bead cell sorting into CD34(+), CD33(+)/CD34(-), and CD15(+)/CD34(-)/CD33(- )cell populations. Examination of these cells by flow cytometry and electron microscopy revealed abundant apoptosis in the CD15(+) neutrophil precursor population, characterized by enhanced annexin-V binding, extensive membrane blebbing, condensation of heterochromatin, and cell fragmentation. Colony-forming assays demonstrated significant reduction in a proportion of bone marrow myeloid-committed progenitor cells. Immunohistochemical analysis revealed a selective decrease in bcl-x, but not bcl-2, expression in the CD15(+)/CD34(-)/CD33(-)cell population compared with similar subpopulations of control bone marrow-derived myeloid precursors. After G-CSF therapy, apoptotic features of patients' bone marrow cells were substantially reduced, and the absolute neutrophil counts (ANC) and expression of bcl-x in CD15(+)/CD34(-)/CD33(-)cells increased. The authors concluded that myelokathexis is a disease characterized by the accelerated apoptosis of granulocytes and the depressed expression of bcl-x in bone marrow-derived granulocyte precursor cells. These abnormalities are partially corrected by the in vivo administration of G-CSF. (Blood. 2000;95:320-327)

Adult↗
PubMed2000

Combined administration of G-CSF and dexamethasone for the mobilization of granulocytes in normal donors: optimization of dosing.

BACKGROUND: The clinical utility of neutrophil (polymorphonuclear leukocyte, PMN) transfusion therapy has been compromised, in part, by the inability to obtain sufficient quantities of functional neutrophils from donors. Mobilization of PMNs in the peripheral blood of normal volunteers has been shown to be superior when G-CSF is administered in conjunction with dexamethasone to that when either agent is administered alone. The current study was conducted to determine the optimal dosages of G-CSF and dexamethasone to be administered to donors in a granulocyte transfusion program. STUDY DESIGN AND METHODS: Five normal subjects were randomly assigned to each of the following single-dose regimens over five consecutive weeks: 1) subcutaneous (SC) G-CSF at 600 microg and oral (PO) dexamethasone at 8 mg; 2) SC G-CSF at 450 microg and PO dexamethasone at 8 mg; 3) SC G-CSF at 450 microg and PO dexamethasone at 12 mg; 4) SC G-CSF at 450 microg; and 5) PO dexamethasone at 12 mg. Venous blood was collected at 0, 6, 12, and 24 hours after drug administration for determination of absolute neutrophil count (ANC). Side effects of drug administration were recorded by using a standardized symptom questionnaire. RESULTS: Maximal ANC was achieved at 12 hours after administration of drugs under each regimen. All four regimens containing G-CSF caused greater than 10-fold increases in the ANC. When administered in conjunction with dexamethasone, G-CSF resulted in statistically similar PMN mobilization at dosages of 450 microg and 600 microg. The combined single-dose regimen of SC G-CSF at 450 microg and PO dexamethasone at 8 mg increased the mean ANC from a baseline value of 2800 per microL to 37,900 per microL at 12 hours after administration. This regimen was well tolerated by the normal volunteers. CONCLUSION: In a single-dose format designed for clinical granulocyte transfusion programs, optimal PMN mobilization can be achieved in normal donors with a combined regimen of SC G-CSF at 450 microg, and PO dexamethasone at 8 microg.

Administration, Oral↗
PubMed2000

Use of G-CSF for granulocyte transfusion therapy.

Patients with neutropenia, especially neutropenia following aggressive myeloablative therapy, are at high risk for developing infectious complications caused by bacteria and opportunistic fungi. Infections remain one of the leading causes of treatment failure in patients with cancer. Thus, new and innovative therapeutic strategies are needed for management of neutropenic patients with infection. Because neutrophils represent the first line of host defense, granulocyte transfusion therapy should be a logical therapeutic approach. Although such therapy has been employed sporadically for several decades, clinical benefit has been compromised by technical problems and low granulocyte yields resulting from inadequate donor stimulation. The discovery of granulocyte colony-stimulating factor (G-CSF) as a means to elevate blood neutrophil counts when administered to normal donors has rekindled interest in granulocyte transfusion therapy. Extensive experience has been gained worldwide with G-CSF in clinical practice, and adverse events have been minimal when G-CSF has been administered to patients or healthy persons in human trials. This review focuses on the use of G-CSF in granulocyte transfusion therapy, including technical considerations of granulocyte leukapheresis and storage, donor selection and stimulation, as well as treatment results and associated risks.

Blood Donors↗
PubMed2000

Inhibition of in vivo neutrophil transmigration by a novel humanized anti-CD11/CD18 monoclonal antibody.

Leukocyte adhesion receptors, including the beta-integrin (CD11/CD18) family, play an important role in inflammation via their regulatory effects on leukocyte adhesion, transmigration, and function. A randomized, placebo-controlled, double-blind study was conducted in healthy volunteers to evaluate the in vivo effects of a humanized anti-CD11/CD18 monoclonal antibody, Hu23F2G, on leukocyte activation and transmigration. Neutrophil migration to a site of cutaneous inflammation in vivo, as measured by the skin chamber technique, was significantly reduced in subjects 24 hours after Hu23F2G administration. At 96 hours, neutrophil migration was not significantly different in subjects who received Hu23F2G or placebo. In contrast, delayed-type hypersensitivity (DTH) testing, which involves activation and migration of T lymphocytes and macrophages, was unaffected by the Hu23F2G treatment. These responses to Hu23F2G in vivo are similar to the clinical phenotype of leukocyte adhesion deficiency (LAD) type 1, a congenital disorder of CD18 deficiency. The in vivo properties of Hu23F2G suggest therapeutic potential for use in the treatment of acute non-infectious inflammatory disorders mediated predominantly by neutrophils.

Adult↗
PubMed2000

Return of granulocyte transfusions.

Recently, several groups have begun to administer granulocyte colony-stimulating factor (G-CSF), a hematopoietic growth factor, with or without dexamethasone to mobilize peripheral blood neutrophils. Granulocyte colony-stimulating factor (600 microg subcutaneously) and dexamethasone (8 mg orally) given 12 hours before standard leukapheresis routinely results in the collection of approximately 80 x 10(9) granulocytes. This number of cells is sufficient to increase the neutrophil count of a severely neutropenic patient to normal and restore the recipients' ability to develop a neutrophil response in tissues. Several trials are ongoing to establish the clinical benefit of this new approach to supportive care for neutropenic patients.

Child↗