UMLS:C0027947 - FACTA Search

Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Target Concepts:

Query: UMLS:C0027947 (neutropenia)
17,527 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

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.
...
PMID:Spontaneous remission of granulocyte colony-stimulating factor-associated leukemia in a child with severe congenital neutropenia. 1107 67

Mutations in the genes of hematopoietic growth factor receptors as a cause of congenital cytopenia, such as congenital amegakaryocytic thrombocytopenia (CAMT) or severe congenital neutropenia (CN), are discussed. There are striking differences in the relevance of receptor mutations in these diseases. CAMT is a rare disease characterized by severe hypomegakaryocytic thrombocytopenia during the first years of life that develops into pancytopenia in later childhood. In patients with CAMT, we found inherited mutations in c-mpl, the gene coding for the thrombopoietin receptor, in 8 out of 8 cases. The type of mutation seems to correlate with the clinical course seen in the patients. Functional studies demonstrated defective thrombopoietin (TPO) reactivity in hematopoietic progenitor cells and platelets in CAMT patients. CN is a group of hematopoietic disorders characterized by profound, absolute neutropenia due to a maturation arrest of myeloid progenitor cells. About 10% of all patients develop secondary MDS/leukemia. The malignant progression is associated with acquired nonsense mutations within the G-CSF receptor gene that lead to the truncation of the carboxy-terminal cytoplasmic domain of the receptor protein involved in maturation of myeloid progenitor cells. This seems to be one important step in leukemogenesis in CN patients. CAMT is caused by inherited mutations in c-mpl, the gene for the thrombopoietin receptor, which lead to reduced or absent reactivity to TPO. In contrast, mutations in the G-CSF receptor in CN are acquired and are most probably connected with progression of the neutropenia into MDS/leukemia as a result of a loss of differentiation signaling.
...
PMID:Implications of mutations in hematopoietic growth factor receptor genes in congenital cytopenias. 1145 19

Granulocyte colony-stimulating factor (G-CSF) has had a major impact on the management of "severe chronic neutropenia" (SCN), 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 and Shwachman-Diamond syndrome (SDS) have developed myelodysplastic syndrome and acute myeloid leukemia (MDS/AML), which raises the question of the role of G-CSF in pathogenesis. The issue is complicated because both disorders have a propensity for MDS or AML as part of their natural history. To address this, the Severe Chronic Neutropenia International Registry (SCNIR) used its large database of chronic neutropenia patients treated with G-CSF to determine the incidence of malignant myeloid transformation in the two disorders, and its relationship to treatment and to other patient characteristics. No statistically significant relationships were found between age at onset of MDS or AML and patient gender, G-CSF dose, or duration of G-CSF therapy. What was observed, however, was the multistep acquisition of aberrant cellular genetic changes in marrow cells from patients who transformed, including activating ras oncogene mutations, clonal cytogenetic abnormalities, and G-CSF receptor mutations. In murine models, the latter produces a hyperproliferative response to G-CSF, confers resistance to apoptosis, and enhances cell survival. Since congenital neutropenia and SDS are inherited forms of bone marrow failure, G-CSF may accelerate the propensity for MDS/AML in the genetically altered stem and progenitor cells, especially in those with G-CSF receptor and ras mutations (82% and 50% of patients who transform, respectively). Alternatively, and equally plausible, G-CSF may simply be an "innocent bystander" that corrects neutropenia, prolongs patient survival, and allows time for the malignant predisposition to declare itself. In patients who transform to overt MDS or AML, hematopoietic stem cell transplantation is the only chance for cure. In those with "soft" signs of MDS, such as an isolated clonal cytogenetic change but without other evidence of MDS, or with an isolated G-CSF receptor mutation, there is room for conservative management. One option is to reduce the G-CSF dosage as much as possible, and observe the tempo of progression, if any, to more overt signs of malignancy.
...
PMID:Risk of myelodysplastic syndrome and acute myeloid leukemia in congenital neutropenias. 1195 96

Severe congenital neutropenia (SCN) is characterized by profound neutropenia, recurrent severe bacterial infections and maturation arrest in the myeloid lineage. Granulocyte colony-stimulating factor (G-CSF) treatment results in clinical improvement in over 90% of cases. Point mutations of the G-CSF receptor (G-CSFR) have been implicated in the progression of SCN to acute myeloid leukaemia (AML). Data are presented here on the 9-year follow-up of seven patients and the further screening of 18 other cases. One of the two original cases with a G-CSFR mutation has improved clinically; nevertheless, mutant DNA could still be detected at a very low level > 8 years after identification. The second child with a mutation progressed to myelodysplasia/AML 5 years after her mutation was detected. No mutations were found in the 18 new cases. One of three transformed cases had a G-CSFR mutation. This work is in agreement with the suggestion that G-CSFR mutations may provide a survival advantage to haemopoietic stem cells, but argues against the inevitability of leukaemic progression in their presence. Furthermore, the low frequency of G-CSFR mutations in SCN and the importance of regular screening and close clinical and laboratory follow-up if a mutation is found were demonstrated.
...
PMID:Long-term follow-up of granulocyte colony-stimulating factor receptor mutations in patients with severe congenital neutropenia: implications for leukaemogenesis and therapy. 1258 57

Granulocyte colony-stimulating factor (G-CSF) is the principal cytokine regulating granulopoiesis. G-CSF receptor-deficient mice (G-CSFR-/-) are neutropenic but have only a modest reduction of committed myeloid progenitors. Since it is likely that compensatory mechanisms are induced by the severe neutropenia present in G-CSFR-/- mice, a competitive repopulation assay was performed. These data show that under basal conditions, G-CSF drives nearly all of granulopoiesis through multiple mechanisms. Most importantly, G-CSFR signals regulate the production and/or maintenance of committed-myeloid progenitors. Surprisingly, G-CSFR signals also play a significant role in the regulation of primitive multipotential progenitors in vivo. The contribution of G-CSFR-/- cells to the hematopoietic stem cell compartment is modestly reduced. Moreover, a marked decrease in the contribution of G-CSFR-/- cells to other progenitors in the myeloid pathway, including erythroid and megakaryocytic progenitors, is observed. In contrast, relative to the hematopoietic stem cell compartment, the contribution of G-CSFR-/- cells to the lymphoid lineages is increased. These data suggest that G-CSFR signals may play a role in directing the commitment of primitive hematopoietic progenitors to the common myeloid lineage. Thus, regulation of G-CSF levels may provide a mechanism for directing primitive hematopoietic progenitors into the common myeloid lineage in response to environmental stresses.
...
PMID:Pivotal role of granulocyte colony-stimulating factor in the development of progenitors in the common myeloid pathway. 1289 69

A significant advance in the field of neutrophil growth factors has occurred with the commercial availability of pegfilgrastim (Neulasta, Amgen, Thousand Oaks, CA), a new-generation, pegylated filgrastim molecule with a sustained duration of action. Pegylation of filgrastim allows once-per-chemotherapy cycle frequency of administration, in contrast to repeated daily administration of filgrastim. Clinical data from two randomized trials demonstrate equivalence of pegfilgrastim and filgrastim in duration of severe neutropenia and recovery from absolute neutrophil count nadir following myelosuppressive chemotherapy. In addition, secondary endpoint results in both trials suggest an enhanced reduction in the overall incidence of febrile neutropenia with pegfilgrastim. Neutrophil kinetic studies demonstrate steady serum neutrophil levels following pegfilgrastim administration, in contrast to the peak-and-trough neutrophil effects observed following filgrastim administration. Granulocyte colony-stimulating factor (G-CSF) therapy has an antiapoptotic effect on neutrophils, which may be enhanced by continuous serum concentrations of pegfilgrastim. Monocytes possess a G-CSF receptor, and this finding has fueled investigational analysis of the role of G-CSF as a mediator in the host inflammatory response to foreign pathogens. The data demonstrate that depending on the timing of administration, G-CSF may function as a proinflammatory mediator or an anti-inflammatory mediator. It is likely that the early, prophylactic administration of pegfilgrastim creates an environment in which an anti-inflammatory response predominates. Additional investigational studies will be necessary to confirm and better define the mechanism for enhanced benefit of pegfilgrastim over filgrastim. The recent biologic findings of the mechanism of G-CSF therapy reviewed here provide a strong basis from which further research initiatives may be conducted.
...
PMID:Neutrophil growth factors. 1290 Nov 30

Severe chronic neutropenia (SCN) is characterized by a profound neutropenia, which mostly presents during the neonatal period. The precise genetic basis of SCN remains elusive. Acquired somatic mutations involving the carboxy-terminus of the G-CSF receptor (G-CSFR) have been found, often in association with myelodysplastic syndrome. The authors describe a girl with SCN who did not respond to pharmacologic doses of filgrastim. Genetic analysis of bone marrow and germline cells revealed a 182-bp deletion in the extracellular domain of the G-CSFR. Co-precipitation studies showed an association between the wild-type and mutant G-CSFR, confirmed by their co-localization by confocal microscopy. Coexpression of the mutant receptor inhibited the wild-type response in Ba/F3 cells. These findings establish a novel constitutional defect in the G-CSFR that supports a partial dominant negative mechanism for receptor dysfunction in SCN.
...
PMID:Deletional mutation of the external domain of the human granulocyte colony-stimulating factor receptor in a patient with severe chronic neutropenia refractory to granulocyte colony-stimulating factor. 1452 2

Recombinant protein technology produces drugs for human therapy in unprecedented quantity and quality. Research is now focusing on the relationship between pharmacokinetic and pharmacodynamic properties of molecules, with the aim of engineering proteins that possess enhanced therapeutic characteristics in contrast to being used as simple replacements for the natural equivalent. The addition of a polyethylene glycol (PEG) moiety to filgrastim (rmetHu-G-CSF, Neupogen) resulted in the development of pegfilgrastim. Pegfilgrastim is a long-acting form of filgrastim that requires only once-per-cycle administration for the management of chemotherapy-induced neutropenia. The covalent attachment of PEG to the N-terminal amine group of the parent molecule was attained using site-directed reductive alkylation. Pegylation increases the size of filgrastim so that it becomes too large for renal clearance. Consequently, neutrophil-mediated clearance predominates in elimination of the drug. This extends the median serum half-life of pegfilgrastim to 42 hours, compared with between 3.5 and 3.8 hours for Filgrastim, though in fact the half-life is variable, depending on the absolute neutrophil count, which in turn reflects of the ability of pegfilgrastim to sustain production of those same cells. The clearance of the molecule is thus dominated by a self-regulating mechanism. Pegfilgrastim retains the same biological activity as filgrastim, and binds to the same G-CSF receptor, stimulating the proliferation, differentiation and activation of neutrophils. Once-per-chemotherapy cycle administration of pegfilgrastim reduces the duration of severe neutropenia as effectively as daily treatment with filgrastim. In clinical trials, patients receiving pegfilgrastim also had a lower observed incidence of febrile neutropenia than patients receiving filgrastim.
...
PMID:The design and development of pegfilgrastim (PEG-rmetHuG-CSF, Neulasta). 1507 38

Point mutations in the gene for the granulocyte colony-stimulating factor (G-CSF) receptor CSF3R have been implicated in the progression of severe congenital neutropenia (CN) to leukemia. In this study we present data on a total of 218 patients with chronic neutropenia, including 148 patients with CN (23/148 with secondary malignancies). We detected CSF3R nonsense mutations at 17 different nucleotide positions (thereof 10 new mutations) which lead to a loss of 1 to all 4 tyrosine residues in the intracellular domain of the receptor. Of 23 patients with CN with signs of malignant transformation, 18 (78%) were shown to harbor a CSF3R mutation, indicating that these mutations, although not a necessary condition, are highly predictive for malignant transformation even if detected in a low percentage of transcripts. In serial analyses of 50 patients with CSF3R mutations we were able to follow the clonal dynamics of mutated cells. We could demonstrate that even a highly clonal hematopoiesis did not inevitably show a rapid progression to leukemia. Our results strongly suggest that acquisition of a CSF3R mutation is an early event in leukemogenesis that has to be accompanied by cooperating molecular events, which remain to be defined.
...
PMID:Incidence of CSF3R mutations in severe congenital neutropenia and relevance for leukemogenesis: Results of a long-term survey. 1698 78

Granulocyte colony-stimulating factor (G-CSF) is the major hematopoietic cytokine involved in the control of neutrophil production and thus serves as a critical regulator of the innate immunity against bacterial infections. G-CSF is applied on a routine basis in the clinic for treatment of congenital and acquired neutropenias, diseases characterized by a critical shortage of neutrophils, leading to severe opportunistic bacterial infections. Very recently, it has become clear that therapeutic application of G-CSF may not be limited to different types of neutropenia, but may extend to non-hematological conditions, in particular cardiac and brain infarctions. G-CSF drives the proliferation, survival and neutrophilic differentiation of myeloid progenitor cells by activation of a receptor of the hematopoietin receptor superfamily, which subsequently triggers multiple signaling mechanisms. These mechanisms exert positive as well as negative effects on the signaling function of the G-CSF receptor. The integrated output of these signaling pathways provide the appropriate balance needed for accurate production of neutrophils under both steady state and "emergency" conditions. Here we review how these mechanisms are thought to act in concert to meet with these demands and how perturbations in the function of the G-CSF receptor are implicated in various types of myeloid disease.
...
PMID:Granulocyte colony-stimulating factor and its receptor in normal myeloid cell development, leukemia and related blood cell disorders. 1712 21

<< Previous 1 2 3 4 5 6 Next >>