Kostmann syndrome: severe congenital neutropenia associated with defective expression of Bcl-2, constitutive mitochondrial release of cytochrome c, and excessive apoptosis of myeloid progenitor cells

Blood ◽  
2004 ◽  
Vol 103 (9) ◽  
pp. 3355-3361 ◽  
Author(s):  
Göran Carlsson ◽  
Andrew A. G. Aprikyan ◽  
Ramin Tehranchi ◽  
David C. Dale ◽  
Anna Porwit ◽  
...  
Keyword(s):  
Bone Marrow ◽  
Cytochrome C ◽  
Progenitor Cells ◽  
B Cell Lymphoma ◽  
Severe Congenital Neutropenia ◽  
Congenital Neutropenia ◽  
Cytochrome C Release ◽  
Myeloid Progenitor ◽  
Kostmann Syndrome ◽  
Myeloid Progenitor Cells

Abstract Kostmann syndrome, or severe congenital neutropenia (SCN), is an autosomal recessive disorder of neutrophil production. To investigate the potential role of apoptosis in SCN, bone marrow aspirates and biopsies were obtained from 4 patients belonging to the kindred originally described by Kostmann and 1 patient with SCN of unknown inheritance. An elevated degree of apoptosis was observed in the bone marrow of these patients, and a selective decrease in B-cell lymphoma-2 (Bcl-2) expression was seen in myeloid progenitor cells. Furthermore, in vitro apoptosis of bone marrow-derived Kostmann progenitor cells was increased, and mitochondrial release of cytochrome c was detected in CD34+ and CD33+ progenitors from patients, but not in controls. Administration of granulocyte colony-stimulating factor (G-CSF) restored Bcl-2 expression and improved survival of myeloid progenitor cells. In addition, cytochrome c release was partially reversed upon incubation of progenitor cells with G-CSF. In sum, these studies establish a role for mitochondria-dependent apoptosis in the pathogenesis of Kostmann syndrome and yield a tentative explanation for the beneficial effect of growth factor administration in these patients. (Blood. 2004;103:3355-3361)

Diversity and Molecular Modeling of Neutrophil Elastase Mutations in Patients with Severe Congenital Neutropenia and Acute Myelogenous Leukemia.

Blood ◽  
2004 ◽  
Vol 104 (11) ◽  
pp. 1454-1454
Author(s):  
Andrew A.G. Aprikyan ◽  
Steve Stein ◽  
Nara A. Markosyan ◽  
Maxim Totrov ◽  
Ruben Abagyan ◽  
...  
Keyword(s):  
Bone Marrow ◽  
Progenitor Cells ◽  
Neutrophil Elastase ◽  
Apoptotic Cell ◽  
Myelogenous Leukemia ◽  
Congenital Neutropenia ◽  
Deletion Mutations ◽  
Myeloid Progenitor ◽  
Myeloid Progenitor Cells ◽  
Acute Myelogenous

Abstract Severe congenital neutropenia (SCN) is an inheritable hematopoietic disorder that is characterized by extremely low levels of neutrophils in peripheral circulation and maturation arrest of bone marrow myeloid progenitor cells at the promyelocytic stage of differentiation. SCN patients have recurring severe infections and approximately 10% of these patients evolve to develop acute myelogenous leukemia. Recently we reported that an impaired cell survival and cell cycle arrest of bone marrow myeloid progenitor cells was observed in SCN patients compared with controls. We also reported various heterozygous mutations in the neutrophil elastase (NE) gene encoding a serine protease in approximately 80% of SCN patients. We hypothesized that mutations in the NE gene trigger apoptotic cell death of myeloid progenitor cells and subsequent severe neutropenia. Mutational analysis of 15 families with one or more affected family members revealed that mutant NE was present only in affected but not in healthy members of these families suggesting the causative role for mutant NE in pathogenesis of SCN. Sequencing analysis revealed that none of SCN patients negative for NE mutations examined had mutations in the Gfi-1 or WAS gene. Sequencing DNA samples of SCN and SCN/AML patients revealed 40 mutations that are distributed primarily throughout the exons 2 through 5 of the NE gene and result in substitution, deletion, insertion, or truncation mutations. Molecular modeling of the tertiary structure of NE revealed that all these mutations can be grouped into three major categories. The first category includes 19 substitution and insertion mutations that are grouped around the N-glycosylation sites of the neutrophil elastase and may lead to abnormal targeting and subcellular localization of the mutant protease. The second group includes 9 substitution and deletion mutations that alter the side loop of the NE that is necessary for proper oligomerization of neutrophil elastase. The third category includes 12 substitution, truncation, and deletion mutations that either alter or completely eliminate the carboxy-terminus of the mutant protein leading to conformational changes of the binding pocket of the NE, and subsequently to altered substrate specificity and/or an acquired resistance to elastase inhibitors. SCN patients that evolved to develop AML had either substitution, deletion, or truncation mutations from each of the three categories described above. Most mutations are clearly non-conservative, have destabilizing effect on oligomeric structure of mutant protein, and alter dramatically the affinity of mutant NE to various factors participating in its processing and intracellular transport. Flow cytometry analysis of annexin V-labeled cells revealed that expression of representative mutant but not normal NE from each of the three categories of NE mutations in human promyelocytic HL-60 cells triggered apoptotic cell death similar to that observed in bone marrow progenitor cells in SCN patients. These data indicate that impaired cell survival and block of differentiation in SCN is due to heterozygous mutations in the neutrophil elastase gene. Current studies focused on design and screen of specific protease inhibitors capable of blocking the pro-apoptotic effect of mutant neutrophil elastase.

Defective Expression of LEF-1 Transcription Factor mRNA and - Protein in Patients with Severe Congenital Neutropenia (Kostmann’S Syndrome).

Blood ◽  
2004 ◽  
Vol 104 (11) ◽  
pp. 782-782
Author(s):  
Julia Skokowa ◽  
Gunnar Cario ◽  
Zheng Wang ◽  
Cornelia Zeidler ◽  
Martin Stanulla ◽  
...  
Keyword(s):  
Protein Expression ◽  
Mrna Expression ◽  
Progenitor Cells ◽  
Healthy Controls ◽  
Severe Congenital Neutropenia ◽  
Healthy Individuals ◽  
Congenital Neutropenia ◽  
Cyclic Neutropenia ◽  
Myeloid Progenitor ◽  
Myeloid Progenitor Cells

Abstract Severe congenital neutropenia (SCN) is characterized by “maturation arrest” of myeloid progenitor cells at the promyelocytic/myelocytic stage with the absence or only few mature neutrophils in the bone marrow and peripheral blood. Significant progress in the treatment of SCN patients has been achieved in the last 15 years by administration of granulocyte colony-stimulating factor (G-CSF), which significantly increases the number of neutrophils leading to an improvement of the quality of life. To date, the pathophysiology and underlying genetic defect in patients with congenital neutropenia is still under investigation. Wnt signalling pathway orchestrates a number of cellular programs such as proliferation, differentiation and cell fate determination in many tissues. In the present study we investigated the mRNA and protein expression patterns of Wnt signalling peptides, such as the High Mobility Group (HMG) box containing transcription factors such as lymphoid enhancer factor-1 (LEF-1) and T cell factors (TCFs), as well as β-catenin in CD33+ bone marrow myeloid progenitor cells from SCN patients (n = 6) in comparison to those of patients with cyclic neutropenia (n = 4) and G-CSF-treated healthy controls (n = 3). All SCN and cyclic neutropenia patients are under G-CSF therapy. mRNA expression of genes of interest was measured by quantitative real-time PCR. Protein expression was assessed by immunofluorescence staining, visualized and recorded by confocal microscopy. We found that CD33+ cells from patients with SCN exhibited 20 times lower or even absent expression of LEF-1 mRNA and protein, as compared to healthy G-CSF treated controls (mRNA expression ratio: SCN patients 0.83 ± 0.38 AU vs. healthy controls: 15.1 ± 0.4 AU; p < 0.0001). Intriguingly, LEF-1 mRNA expression levels on CD33+ cells from cyclic neutropenia patients were comparable to those of healthy controls. Immunostaining with anti-LEF-1 polyclonal antibody (kindly provided by Dr. R. Grosschedl) and confocal microscopy analysis revealed that LEF-1 protein was detectable at the expected level in CD33+ cells from healthy G-CSF treated controls. In patients with cyclic neutropenia LEF-1 protein expression in myeloid progenitor cells was comparable to healthy individuals. In contrast, in CD33+ cells from patients with SCN, LEF-1 protein was not detectable. mRNA expression of other TCFs: TCF-1, TCF-3, TCF-4 in SCN was not significantly different from healthy individuals. However, the expression level of LEF-1 binding partner in the Wnt pathway, β-catenin, was increased in SCN patients (SCN patients: 224.7 ± 42.4 AU vs. healthy controls: 107.2 ± 7.3 AU, p = 0.052). The defect in LEF-1 expression in SCN patients was further substantiated by the fact that mRNA expression of LEF-1 target genes such as c-myc, cyclin D1, survivin and neutrophil elastase were also significantly downregulated. In conclusion, our results suggest that defective LEF-1 expression might have an impact on the pathogenesis of SCN. In addition, it may help to distinguish SCN from cyclic neutropenia patients.

scholarly journals Abnormal responses of myeloid progenitor cells to recombinant human colony-stimulating factors in congenital neutropenia

Blood ◽  
1990 ◽  
Vol 75 (11) ◽  
pp. 2143-2149 ◽  
Author(s):  
M Kobayashi ◽  
C Yumiba ◽  
Y Kawaguchi ◽  
Y Tanaka ◽  
K Ueda ◽  
...  
Keyword(s):  
Bone Marrow ◽  
Progenitor Cells ◽  
Bone Marrow Cells ◽  
Normal Subjects ◽  
Inhibitory Effect ◽  
Congenital Neutropenia ◽  
Agar Culture ◽  
Myeloid Progenitor ◽  
Myeloid Progenitor Cells ◽  
Marrow Cells

Abstract The effects of recombinant human interleukin-3 (IL-3) and recombinant human granulocyte colony-stimulating factor (G-CSF) on the growth of myeloid progenitor cells (CFU-C) in semisolid agar culture were studied in two patients with Kostmann-type congenital neutropenia. CFU-C growth in bone marrow cells from patients was significantly reduced in response to various concentrations of either IL-3 or G-CSF alone, compared with that from normal subjects. There was no inhibitory effect of bone marrow cells from patients on normal CFU-C formation supported by IL-3 or G-CSF. However, the simultaneous stimulation with IL-3 and G- CSF induced the increase of CFU-C formation in patients with congenital neutropenia. Furthermore, CFU-C growth in both patients was supported when bone marrow cells were preincubated with IL-3 in liquid culture followed by the stimulation with G-CSF in semisolid agar culture. In contrast, that was not supported by the preincubation with G-CSF and the subsequent stimulation with IL-3. This evidence suggests that the hematopoietic progenitor cells in patients with congenital neutropenia have the potential for developing CFU-C in the combined stimulation with IL-3 and G-CSF, and that this growth may be dependent on the priming of IL-3 followed by the stimulation with G-CSF. The level of mature neutrophils in peripheral blood was not fully restored to normal levels by the daily administration of G-CSF in doses of 100 to 200 micrograms/m2 of body surface area for 20 to 25 days in both patients. These observations raise the possibility that the combination of IL-3 and G-CSF might have a potential role for the increase of neutrophil counts in patients with congenital neutropenia.

scholarly journals Abnormal responses of myeloid progenitor cells to recombinant human colony-stimulating factors in congenital neutropenia

Blood ◽  
1990 ◽  
Vol 75 (11) ◽  
pp. 2143-2149 ◽  
Author(s):  
M Kobayashi ◽  
C Yumiba ◽  
Y Kawaguchi ◽  
Y Tanaka ◽  
K Ueda ◽  
...  
Keyword(s):  
Bone Marrow ◽  
Progenitor Cells ◽  
Bone Marrow Cells ◽  
Normal Subjects ◽  
Inhibitory Effect ◽  
Congenital Neutropenia ◽  
Agar Culture ◽  
Myeloid Progenitor ◽  
Myeloid Progenitor Cells ◽  
Marrow Cells

The effects of recombinant human interleukin-3 (IL-3) and recombinant human granulocyte colony-stimulating factor (G-CSF) on the growth of myeloid progenitor cells (CFU-C) in semisolid agar culture were studied in two patients with Kostmann-type congenital neutropenia. CFU-C growth in bone marrow cells from patients was significantly reduced in response to various concentrations of either IL-3 or G-CSF alone, compared with that from normal subjects. There was no inhibitory effect of bone marrow cells from patients on normal CFU-C formation supported by IL-3 or G-CSF. However, the simultaneous stimulation with IL-3 and G- CSF induced the increase of CFU-C formation in patients with congenital neutropenia. Furthermore, CFU-C growth in both patients was supported when bone marrow cells were preincubated with IL-3 in liquid culture followed by the stimulation with G-CSF in semisolid agar culture. In contrast, that was not supported by the preincubation with G-CSF and the subsequent stimulation with IL-3. This evidence suggests that the hematopoietic progenitor cells in patients with congenital neutropenia have the potential for developing CFU-C in the combined stimulation with IL-3 and G-CSF, and that this growth may be dependent on the priming of IL-3 followed by the stimulation with G-CSF. The level of mature neutrophils in peripheral blood was not fully restored to normal levels by the daily administration of G-CSF in doses of 100 to 200 micrograms/m2 of body surface area for 20 to 25 days in both patients. These observations raise the possibility that the combination of IL-3 and G-CSF might have a potential role for the increase of neutrophil counts in patients with congenital neutropenia.

Administration of Granulocyte Colony-Stimulating Factor Does Not Restore Defective Expression of bcl-2 and bcl-2-xL in Myeloid Progenitor Cells of Patients with Severe Congenital Neutropenia (Kostmann Syndrome).

Blood ◽  
2004 ◽  
Vol 104 (11) ◽  
pp. 1456-1456
Author(s):  
Gunnar Cario ◽  
Julia Skokowa ◽  
Zheng Wang ◽  
Vesna Bucan ◽  
Cornelia Zeidler ◽  
...  
Keyword(s):  
Progenitor Cells ◽  
Healthy Controls ◽  
Granulocyte Colony Stimulating Factor ◽  
Caspase 9 ◽  
Congenital Neutropenia ◽  
Myeloid Progenitor ◽  
Kostmann Syndrome ◽  
Myeloid Progenitor Cells ◽  
Stimulating Factor

Abstract Severe congenital neutropenia (SCN; Kostmann syndrome) is characterized by a maturation block in the myelopoiesis at the promyelocytic/myelocytic stage leading to decreased amounts of neutrophils in bone marrow and peripheral blood. This maturation arrest was previously associated with an accelerated apoptosis. Administration of recombinant human granulocyte colony-stimulating factor (G-CSF) sufficiently increases neutrophil numbers in most patients. Recently, it was demonstrated that the elevated degree of apoptosis was accompanied by a selective decreased expression of the anti-apoptotic Bcl-2 protein in myeloid progenitor cells in 4 surviving members of the original “Kostmann family” and 1 patient with SCN of unknown inheritance (Carlsson et al., Blood2004; 103: 3355–3361). In these patients, it was shown that the administration of G-CSF restored Bcl-2 expression and corrected the abnormal acceleration of apoptosis. To test whether this observation is a common feature of SCN patients myeloid progenitor cells, we analyzed the mRNA and protein expression of bcl-2 in CD33+ bone marrow myeloid progenitor cells from 6 G-CSF treated SCN patients not related to the original “Kostmann family” in comparison to that of 2 long-term G-CSF treated patients with neutropenia other than SCN and healthy controls without and after administration of G-CSF (4 and 3, respectively). Additionally, the mRNA expression of the Bcl-2-related genes, bcl-xL (anti-apoptotic) and bax (pro-apoptotic), and the expression of caspase 9, an important intracellular amplifier of apoptotic signaling was investigated. Gene expression was measured by quantitative real-time PCR, and protein expression by immunofluorescence and confocal microscopy. We observed a significant increase of bcl-2 expression after administration of G-CSF in CD33+ cells of healthy controls (fold change (FC) = 1.7, p = 0.0011, t-test). In contrast, bcl-2 was significantly lower expressed in CD33+ cells from long-term G-CSF treated SCN patients as compared to that of long-term G-CSF treated patients with neutropenia other than SCN (FC = 20, p = 0.015, t-test), and healthy controls without (FC = 7, p < 0.0001) and after administration of G-CSF (FC = 13, p < 0.0001). The expression of bcl-xL did show a similar pattern with a significant difference comparing SCN patients and healthy controls without G-CSF (FC = 4.4, p = 0.018). In contrast, the expression of caspase 9 was significantly upregulated in CD33+ cells of SCN patients as well as G-CSF treated controls compared to healthy controls without G-CSF administration (FC = 8.9, p = 0.002). Bax was similarly expressed in all groups. The expression pattern of bcl-2 was confirmed on the protein level. In summary, the expression of bcl-2 was defective in SCN patients as it was described by Carlsson et al., and a similar pattern was observed for bcl-xL. In contrast to published data, long-time administration of G-CSF did not normalize the expression of both anti-apoptotic Bcl-2 family members in our patients. We conclude, that a mechanism other than the restoration of Bcl-2 and Bcl-xL expression is responsible for the increase of neutrophils after G-CSF treatment in our patient sample.

Dispensable Role of Neutrophil Elastase in Survival and Differentiation of Human Myeloid Progenitor Cells

Blood ◽  
2008 ◽  
Vol 112 (11) ◽  
pp. 3561-3561
Author(s):  
Andrew A Aprikyan ◽  
Vahagn Makaryan ◽  
Qian Si ◽  
Kelly Treonze ◽  
Nara Markosyan ◽  
...  
Keyword(s):  
Cell Survival ◽  
Progenitor Cells ◽  
Neutrophil Elastase ◽  
Autosomal Dominant ◽  
Myeloid Differentiation ◽  
Severe Congenital Neutropenia ◽  
Wild Type ◽  
Congenital Neutropenia ◽  
Myeloid Progenitor ◽  
Myeloid Progenitor Cells

Abstract Severe congenital neutropenia (SCN) is a rare autosomal dominant or recessive disorder with a characteristic “maturation arrest” at the promyelocytic stage of differentiation in the bone marrow and extremely low level of neutrophils in peripheral circulation. SCN patients may evolve to develop myelodysplastic syndrome and acute myeloid leukemia (MDS/AML) with ~30% cumulative incidence of leukemia. Heterozygous mutations in the neutrophil elastase (NE, ELA2) gene have been identified in most of SCN patients with acquired and autosomal dominant inheritance (Dale et al., Blood 2000). It has been reported that accelerated apoptosis of bone marrow myeloid progenitor cells is the cellular mechanism of severe neutropenia in SCN. We and others also reported that expression of mutant elastase triggers impaired cell survival in human myeloid progenitor cells (Aprikyan et al., Exp Hem 2003; Massullo et al, Blood 2005; Kollner et al, Blood 2006; Grenda et al, Blood 2007). However, it remains unclear whether the abnormal cell survival and impaired myeloid differentiation in SCN is due to the gain-of-function or dominant negative effect of mutant NE. To answer these questions, we established tet-off HL-60 human myeloid progenitor cell lines with inducible expression of mutant or normal forms of NE and examined their survival and differentiation characteristics. Induced expression of del.145–152 mutant NE resulted in a significantly increased apoptosis of myeloid cells and a characteristic block of myeloid differentiation (p<0.05, n=4), thus closely recapitulating the human SCN phenotype. Importantly, induced overexpression of wild type NE in the myeloid progenitor cells did not alter the cell survival characteristics as determined by flow cytometry analyses of annexin V or DIOC6 stained cells (p>0.05, n=4). In addition, the overexpression of wild type NE had no effect on differentiation capacity of myeloid progenitor cells induced into granulocytic differentiation with retinoic acid compared with control cells expressing physiological levels of endogenous NE as determined by morphological evaluation of stained cells. Furthermore, nearly complete inhibition of NE proteolytic activity in control human myeloid progenitor cells expressing endogenous elastase with a cell-penetrant small molecule inhibitor of NE (Merck, NJ) also had no significant effect and impaired neither the cell survival nor their differentiation characteristics compared with control untreated cells (p>0.05, n=3). Thus, these data demonstrate that neutrophil elastase appears to be dispensable for the formation and differentiation of HL-60 human myeloid progenitor cells and accelerated apoptosis and impaired myeloid differentiation in SCN is attributable to a gain-of-function effect of pro-apoptotic mutant elastase. These data also suggest that small molecule inhibitors of NE may represent a promising therapy in severe congenital neutropenia.

Defective Proliferation of Primitive Myeloid Progenitor Cells in Patients With Severe Congenital Neutropenia

Blood ◽  
1999 ◽  
Vol 94 (12) ◽  
pp. 4077-4083 ◽  
Author(s):  
Nakao Konishi ◽  
Masao Kobayashi ◽  
Shin-ichiro Miyagawa ◽  
Takashi Sato ◽  
Osamu Katoh ◽  
...  
Keyword(s):  
Progenitor Cells ◽  
Bone Marrow Cells ◽  
Receptor Gene ◽  
Normal Subjects ◽  
Polymorphism Analysis ◽  
Severe Congenital Neutropenia ◽  
Congenital Neutropenia ◽  
Myeloid Progenitor ◽  
Myeloid Progenitor Cells ◽  
Hematopoietic Factors

Abstract Although several mechanisms have been proposed to explain the pathophysiology of severe congenital neutropenia (SCN), the precise defect responsible for SCN remains unknown. We studied the responsiveness of primitive myeloid progenitor cells to hematopoietic factors in 4 patients with SCN. The number of granulocyte-macrophage (GM) colonies formed in patients was decreased in response to granulocyte colony-stimulating factor (G-CSF) in both serum-supplemented and serum-deprived culture. The polymerase chain reaction–single-strand conformational polymorphism analysis of the G-CSF receptor gene showed no variance in structure conformation between the 4 patients and the normal subjects. In patients with SCN, the nonadherent light density bone marrow cells and cells that were purified on the basis of the expression of CD34 and Kit receptor (CD34+/Kit+ cells) showed the reduced response to the combination of steel factor (SF), the ligand for flk2/flt3 (FL), and interleukin-3 (IL-3) with or without G-CSF in serum-deprived culture. Furthermore, when individual CD34+/Kit+ cells from patients were cultured in the presence of SF, FL, and IL-3, with or without G-CSF for 10 days, the number of clones proliferated and the number of cells per each proliferating clone was significantly less than those in normal subjects. These results suggest that primitive myeloid progenitor cells of patients with SCN have defective responsiveness to not only G-CSF, but also the early- or intermediate-acting hematopoietic factors, SF, FL, and IL-3.

Abnormalities of primitive myeloid progenitor cells expressing granulocyte colony-stimulating factor receptor in patients with severe congenital neutropenia

Blood ◽  
2000 ◽  
Vol 96 (13) ◽  
pp. 4366-4369 ◽  
Author(s):  
Kazuhiro Nakamura ◽  
Masao Kobayashi ◽  
Nakao Konishi ◽  
Hiroshi Kawaguchi ◽  
Shin-ichiro Miyagawa ◽  
...  
Keyword(s):  
Progenitor Cells ◽  
Bone Marrow Cells ◽  
Flow Cytometric Analysis ◽  
Granulocyte Colony Stimulating Factor ◽  
Colony Stimulating Factor ◽  
Severe Congenital Neutropenia ◽  
Congenital Neutropenia ◽  
Myeloid Progenitor ◽  
Myeloid Progenitor Cells ◽  
Stimulating Factor

To define the basis for faulty granulopoiesis in patients with severe congenital neutropenia (SCN), the expression of granulocyte colony-stimulating factor receptor (G-CSFR) in primitive myeloid progenitor cells and their responsiveness to hematopoietic factors were studied. Flow cytometric analysis of bone marrow cells based on the expression of CD34, Kit receptor, and G-CSFR demonstrated a reduced frequency of CD34+/Kit+/ G-CSFR+cells in patients with SCN. The granulocyte-macrophage colony formation of CD34+/Kit+/G-CSFR+ cells in patients was markedly decreased in response to G-CSF alone and to the combination of stem cell factor, the ligand for flk2/flt3, and IL-3 with or without G-CSF in serum-deprived semisolid culture. In contrast, no difference in the responsiveness of CD34+/Kit+/G-CSFR− cells was noted between patients with SCN and subjects without SCN. These results demonstrate that the presence of qualitative and quantitative abnormalities of primitive myeloid progenitor cells expressing G-CSFR may play an important role in the impairment of granulopoiesis in patients with SCN.

Abnormalities of primitive myeloid progenitor cells expressing granulocyte colony-stimulating factor receptor in patients with severe congenital neutropenia

Blood ◽  
2000 ◽  
Vol 96 (13) ◽  
pp. 4366-4369 ◽  
Author(s):  
Kazuhiro Nakamura ◽  
Masao Kobayashi ◽  
Nakao Konishi ◽  
Hiroshi Kawaguchi ◽  
Shin-ichiro Miyagawa ◽  
...  
Keyword(s):  
Progenitor Cells ◽  
Bone Marrow Cells ◽  
Flow Cytometric Analysis ◽  
Granulocyte Colony Stimulating Factor ◽  
Colony Stimulating Factor ◽  
Severe Congenital Neutropenia ◽  
Congenital Neutropenia ◽  
Myeloid Progenitor ◽  
Myeloid Progenitor Cells ◽  
Stimulating Factor

Abstract To define the basis for faulty granulopoiesis in patients with severe congenital neutropenia (SCN), the expression of granulocyte colony-stimulating factor receptor (G-CSFR) in primitive myeloid progenitor cells and their responsiveness to hematopoietic factors were studied. Flow cytometric analysis of bone marrow cells based on the expression of CD34, Kit receptor, and G-CSFR demonstrated a reduced frequency of CD34+/Kit+/ G-CSFR+cells in patients with SCN. The granulocyte-macrophage colony formation of CD34+/Kit+/G-CSFR+ cells in patients was markedly decreased in response to G-CSF alone and to the combination of stem cell factor, the ligand for flk2/flt3, and IL-3 with or without G-CSF in serum-deprived semisolid culture. In contrast, no difference in the responsiveness of CD34+/Kit+/G-CSFR− cells was noted between patients with SCN and subjects without SCN. These results demonstrate that the presence of qualitative and quantitative abnormalities of primitive myeloid progenitor cells expressing G-CSFR may play an important role in the impairment of granulopoiesis in patients with SCN.

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