Myeloid Progenitor Cells In Patients Research Articles

Reprogramming of bone marrow myeloid progenitor cells in patients with severe coronary artery disease.

Atherosclerosis is the major cause of cardiovascular disease (CVD). Monocyte-derived macrophages are the most abundant immune cells in atherosclerotic plaques. In patients with atherosclerotic CVD, leukocytes have a hyperinflammatory phenotype. We hypothesize that immune cell reprogramming in these patients occurs at the level of myeloid progenitors. We included 13 patients with coronary artery disease due to severe atherosclerosis and 13 subjects without atherosclerosis in an exploratory study. Cytokine production capacity after ex vivo stimulation of peripheral blood mononuclear cells (MNCs) and bone marrow MNCs was higher in patients with atherosclerosis. In BM-MNCs this was associated with increased glycolysis and oxidative phosphorylation. The BM composition was skewed towards myelopoiesis and transcriptome analysis of HSC/GMP cell populations revealed enrichment of neutrophil- and monocyte-related pathways. These results show that in patients with atherosclerosis, activation of innate immune cells occurs at the level of myeloid progenitors, which adds exciting opportunities for novel treatment strategies.

Analysis of the Genetic Background in Patients with Myeloid Malignancies and Divergent Findings Regarding Blasts As Determined By Cytomorphology and Flow Cytometry

Background: Diagnostics of hematologic malignancies is based on an integrated application of various methods. Different methods targeting the same structures, e.g. cytomorphology and flow cytometry both applied to identify and quantify pathologic cell populations, are aiming at revealing consistent results. While in the majority of cases achievement of such consistency is straight forward and in other cases both methods complement each other the alignment between cytomorphologically defined blasts and flow cytometrically defined myeloid progenitor cells (MPC) sometimes is challenging, in particular in myelodysplastic syndromes (MDS), acute myeloid leukemia (AML) and related diseases (thresholds defined for cytomorphology in WHO classification). We therefore identified such cases with higher percentages of cytomorphologically defined blasts than flow cytometrically defined MPCs and analyzed their genetic background in comparison to MDS cases with consistently low percentages by both methods and to acute myeloid leukemia (AML) cases with consistently high percentages by both methods. Aim: To clarify divergent findings between cytomorphology and flow cytometry on blasts and MPCs in patients with MDS and related diseases by analyzing the genetic background. Patients and methods: We identified 49 cases analyzed for myeloid malignancies, which were found to have higher percentages of cytomorphologically defined blasts than flow cytometrically defined MPCs (group 1). For comparison 83 patients with AML (group 2) and 53 cases with MDS (group 3) were selected in which percentages of cytomorphologically defined blasts (%B) were matching flow cytometrically defined percentages of MPCs (%MPC). All samples analyzed were bone marrow aspirates. Patients´ ages ranged from 40 to 60 (median 74), 23 to 89 (69) and 46 to 93 (76) years, respectively, in groups 1, 2 and 3 and sex distribution was 26/23 (f/m), 35/48 and 20/33, respectively. The median %B were 24% (range 11 to 62), 46% (20 to 98) and 5% (0 to 18), respectively, for groups 1, 2 and 3. The respective figures for %MPC were 9% (0.1 to 18), 52% (20 to 94) and 3% (0.3 to 16), respectively. The three groups were compared regarding cytogenetics based on chromosome banding analysis as well as regarding NGS data on mutations in 34 genes associated with myeloid malignancies. Results: Normal karyotypes were present in 37/49 (76%), 42/83 (51%) and 34/53 (64%) cases, respectively in groups 1, 2 and 3 (p=0.02). The respective figure for complex karyotypes was 5/49 (10%), 15/83 (18%) and 5/53 (9%, n.s.). Other chromosomal aberrations occurred less frequently and did not differ significantly between groups. Thus, karyotypes observed in group 1 were more similar to MDS than to AML. Regarding mutational profiling group 1 was characterized by a mutation spectrum similar to MDS developing into secondary AML while AML cases displayed a different spectrum as anticipated. Thus, in group 1, as compared to groups 2 and 3, the following gene were found more frequently mutated: ASXL1 (45% vs. 16% vs. 30%, p=0.001), SRSF2 (43% vs. 24% vs. 23%, p=0.042), TET2 (36% vs. 13% vs. 29%, p=0.014), RUNX1 (27% vs. 15% vs. 17%, n.s.). Interestingly, these genes were mutated at the lowest frequencies in group 2 most probably reflecting the low proportion of AML evolved as secondary disease after MDS. In contrast, SF3B1, which confers a favorable prognosis in MDS, was present at low frequencies in both groups 1 and 2 and at higher frequency in group 3 reflecting the low rate of AML progression in MDS with SF3B1 mutations (8% vs. 4% vs. 21%, p=0.005). Matching these findings mutations in genes typically associated with de novo AML were found most frequently in group 2 and only at low frequencies in groups 1 and 3: NPM1 (6% vs. 22% vs. 0%, p<0.001), FLT3-ITD (5% vs. 16% vs. 0%, p=0.001). No significant differences between the three groups were observed for mutations in the remaining genes. Conclusions: The genetic findings in the present series point to a similarity between cases with MDS and cases which display a lower level of %MPC and a higher level of %B at the same time. Therefore, while the latter cases based on WHO classification are defined as MDS-EB2 and AML, respectively, the genetic profile is matching better to the lower %PMC values. This may be used as a basis to more extensively integrate mutation data into the classification of these myeloid neoplasms. Disclosures Kern: MLL Munich Leukemia Laboratory: Employment, Equity Ownership. Meggendorfer:MLL Munich Leukemia Laboratory: Employment. Baer:MLL Munich Leukemia Laboratory: Employment. Haferlach:MLL Munich Leukemia Laboratory: Employment, Equity Ownership. Haferlach:MLL Munich Leukemia Laboratory: Employment, Equity Ownership.

Molecular Studies of Neutropenia in Barth Syndrome.

The Barth syndrome is a rare mitochondrial disease that causes dilated cardiomyopathy, skeletal myopathy, and severe neutropenia. It has been reported that at least two patients with Barth syndrome died from septicemia attributed to neutropenia. The disease is an X-linked autosomal recessive disorder caused by mutations in the G4.5 or TAZ (tafazzin) gene, which introduce truncations, substitution, or alternative splice sites. Hematological investigations revealed normal chemotaxis, but the presence cytoplasmic vacuoles in myeloid cells and maturation arrest of neutrophil development at the myelocyte stage. Thus, a defect in neutrophil formation appears to be the primary reason for neutropenia and the susceptibility to infections in the Barth syndrome patients. Recent studies were mostly focused on cardiac, genetic and metabolic abnormalities associated with the disorder. However, the neutropenia aspect of the Barth syndrome remains unclear. The TAZ gene mutations appear to truncate the tafazzin protein likely resulting in the loss of function. Although a drosophila model of the Barth syndrome was recently reported, the cellular or mouse models of this disorder are not available yet. Thus, the link between TAZ mutations and severe neutropenia remains unknown. We hypothesized that TAZ mutations, which lead to the loss of function of tafazzin protein, trigger impaired cell survival and reduced production of neutrophils and their neutrophil precursors, thus resulting in severe neutropenia in Barth syndrome. To test this hypothesis, we attempted to knock-down the expression of the tafazzin gene in human myeloid progenitor cells using TAZ-specific shRNA. Four shRNA sequences specific to exons 4 through 7 were used for transfection of human myeloid progenitor cells that were later examined by flow cytometry and Western blot analyses. At least 2 of the shRNA constructs resulted in a substantial down-regulation in the expression level of the tafazzin protein in transfected myeloid progenitor cells as determined by Western blot. Flow cytometry analyses revealed that the knock-down of TAZ gene expression was associated with approximately 40–50% increase in proportion of apoptotic annexin-positive cells compared with cells transfected with control scrambled shRNA. These data suggest that the loss of function of TAZ gene is cytotoxic to hematopoietic cells and that severe neutropenia is due to the accelerated apoptosis of myeloid progenitor cells in patients with Barth syndrome. Further studies needed to elucidate the specific signaling pathways and to identify potentially therapeutic agents capable of controlling accelerated apoptosis of myeloid cells in Barth syndrome.

LEF‐1 Is a Decisive Transcription Factor in Neutrophil Granulopoiesis

We found that lymphoid enhancer-binding factor 1 (LEF-1) is a decisive transcription factor in granulopoiesis controlling proliferation, proper lineage commitment, and granulocytic differentiation via regulation of its target genes C/EBP-alpha, cyclin D1, c-myc, and survivin. Myeloid progenitor cells of patients with severe congenital neutropenia (CN) showed a severe downregulation of LEF-1 and its target genes expression. Expression of neutrophil elastase (NE) is also severely reduced in CN myeloid progenitors. Intriguingly, ELA2 gene promoter is positively regulated by direct binding of LEF-1 or LEF-1 target gene C/EBP-alpha. In summary we demonstrated that LEF-1 is not only crucial in lymphopoiesis, but also in myelopoiesis, documenting new functions of LEF-1.

Heterogeneous expression pattern of pro‐ and anti‐apoptotic factors in myeloid progenitor cells of patients with severe congenital neutropenia treated with granulocyte colony‐stimulating factor

Apoptosis is accelerated in the myeloid progenitor cells of patients with severe congenital neutropenia (CN). Granulocyte colony-stimulating factor (G-CSF) increases neutrophil numbers in most CN patients. The effect of G-CSF on apoptosis in CN was analysed by apoptosis rate and expression of anti- and pro-apoptotic factors. G-CSF-treated patients showed higher apoptosis frequency, lower expression of bcl-2 and bcl-xL, but higher expression of bfl-1/A1 and mcl-1. Caspase 9 was highly expressed in patients and controls after G-CSF administration. Thus, G-CSF acts on apoptosis regulation, but additional mechanisms leading to the increase of neutrophil numbers must be assumed.

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).

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., Blood 2004; 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.

Increased cell apoptosis in bone marrow trephine biopsies and immunomagnetically isolated myeloid progenitor cells in patients with chronic idiopathic neutropenia.

The frequency of apoptotic cells in bone marrow trephine biopsies and cytospins of immunomagnetically isolated myeloid progenitor cells was determined in 39 patients with chronic idiopathic neutropenia (CIN) and 12 hematologically normal individuals using the in situ end-labeling (ISEL) apoptosis detection method. We found that 66.7% of the patients but none of the normal controls displayed apoptotic cells equal to or higher than 5% of the total mononuclear cells in bone marrow biopsies (p<0.01). In the double stain, we also found that the proportion of apoptotic CD15(+) myeloid precursor cells did not differ significantly between patients and control subjects, while the proportion of apoptotic CD34(+) hemopoietic cells could not be estimated with accuracy because of the presence of CD34(+) endothelial cells. Significantly increased apoptosis was noted in cytospins of immunomagnetically isolated patient CD34(+) and CD34(+)/CD33(+) cells but not CD34(-)/CD33(+) cells, compared to the controls ( p<0.001, p<0.02 and p>0.05, respectively). These findings confirm and extend our previous observations in flow-cytometric studies of apoptosis in CIN, indicating that increased apoptosis in CIN bone marrow concerns mainly the CD34(+) and CD34(+)/CD33(+) progenitor cell compartments. We conclude that the accelerated apoptosis in these compartments may account for the impaired neutrophil production in CIN patients.

Calcium ionophore activation of chronic myelogenous leukemia progenitor cells into dendritic cells is mediated by calcineurin phosphatase

We have previously demonstrated that Ph+ myeloid progenitor cells of patients with chronic myeloid leukemia (CML) can acquire characteristics of mature dendritic cells (DC) following calcium mobilization with calcium ionophore (A23187, CI). In this study we characterize the intracellular signaling pathway by which CI induces the acquisition of DC features in these leukemic cells. CI-induced activation of CML cells is attenuated by the calcineurin phosphatase inhibitor cyclosporin A (CsA) as well as the calmodulin (CaM) antagonist W-7. These cause ablation of both the CI-induced immunophenotypic expression of DC markers and immunostimulatory properties in mixed leukocyte responses (MLR). Minimal blocking effect was observed when Ca 2+/CaM kinase II (281–301) inhibitor was added to the cultures. These findings suggest a Ca 2+-dependent mechanism for the CI-induced activation of CML cells into antigen-presenting cells (APC), which is primarily mediated through the CaM/calcineurin pathway.

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

AbstractAlthough 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.

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

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.

Calcium signaling induces acquisition of dendritic cell characteristics in chronic myelogenous leukemia myeloid progenitor cells.

Effective host T lymphocyte sensitization to malignant cells depends on successful antigen presentation. In this study, we examined the capacity of malignant myeloid progenitor cells of patients in the chronic phase of chronic myelogenous leukemia (CML) to acquire characteristics of activated dendritic cells (DCs) after intracellular calcium mobilization, thereby bypassing a need for third-party antigen-presenting cells. Treatment of purified CD33(+) CML cells from 15 patients with calcium ionophore (CI) consistently resulted in de novo expression of the costimulatory molecules CD80 (B7.1) and CD86 (B7.2), CD40 and the DC-specific activation marker CD83, as well as marked up-regulation of MHC class I and II molecules and the adhesion molecule CD54. Most of these changes occurred within 24 hr of treatment. Morphologically, CI-treated CML cells developed long dendritic projections similar to those seen in mature DCs. Functionally, CI-treated CML cells provided stimulation of allogeneic T lymphocytes 10- to 20-fold that of untreated CML cells or untreated monocytes. Fluorescent in situ hybridization of CI-activated CML cells confirmed their leukemic origin by displaying the typical bcr/abl fusion signal. No difference in bcr/abl translocation percentages between untreated and CI-treated CML nuclei was observed. These observations indicate that calcium mobilization may constitute a valuable approach for rapidly and reliably generating CML-derived DCs for immunotherapy of CML.

Myeloid Progenitor Cell Proliferation and Mobilization Effects of BB10010, a Genetically Engineered Variant of Human Macrophage Inflammatory Protein-1α, in a Phase I Clinical Trial in Patients with Relapsed/Refractory Breast Cancer

ABSTRACT: Macrophage Inflammatory Protein (MIP)-1α is myelosuppressivein vitroandin vivofor hematopoietic stem and immature subsets of myeloid progenitor cells, demonstrates some myeloprotective effects in mice treated with Ara-C and hydroxyurea, and has stem/progenitor cell mobilizing activity in mice. Based on these observations, BB10010, a genetic variant of MIP-1α, was assessed for effects on marrow and blood myeloid progenitor cells in patients with relapsed/refractory breast cancer. MIP-1α readily polymerizes, whereas BB10010 has a reduced tendency to form large polymers at physiological pH and ionic strength and retains biological activity. Patients were injected with 5, 10, 30 or 100 μg/kg BB10010 s.c. daily for 3 days. BB10010 significantly reduced the cycling status of marrow myeloid progenitors from pretreatment levels of 39-58% to 0 - 11% one day after the third and last injection of BB10010. This was associated with significant decreases in frequency of marrow progenitors (number of colonies formed per number of cells plated) and percent biopsied marrow CD34+cells. The suppressive effects were reversible in patients and the rapidity of this reversal demonstrated in mouse studies. BB10010 had no effect on nucleated cellularity or on the proliferation of nucleated cells as assessed in marrow biopsies from the patients. These latter effects may in part reflect the noted decreased apoptosis of nucleated cells by BB10010. BB10010 also demonstrated significant but modest myeloid progenitor cell mobilizing capacity. Blood progenitors were in a slow or non-cycling state prior to treatment and this did not change after administration of BB10010. The above effects of BB10010 were similar at the four different dosage levels assessed. These results demonstrate in humans the suppressive and mobilizing effects of MIP-1α and BB10010 previously notedin vivoin mice.

Abnormal colony formation and prostaglandin E responsiveness of myeloid progenitor cells in patients cured of germ cell neoplasms after combination chemotherapy.

Myelopoiesis was evaluated in 16 patients in complete remission for a minimum of 9 months after treatment with cisplatin-based combination chemotherapy for metastatic germ cell tumors. None had overt hematopoietic abnormalities. Bone marrow aspirates were obtained for routine morphologic evaluation in seven patients, and myeloid precursor cells were studied for both colony/cluster formation and sensitivity to prostaglandin E-(PGE) mediated growth inhibition in 13 patients. Routine stained marrow smears appeared normal. Six of 13 patients demonstrated abnormal colony/cluster formation. Four patients had no colony formation at all. Ten of 12 patients showed decreased sensitivity of granulocyte-macrophage colony-forming cells (CFU-GM) to PGE inhibition. The studies suggest that defects in myelopoiesis are detectable in patients treated for germ cell tumors with combination chemotherapy. The clinical significance of these findings requires long-term follow-up and surveillance for overt hematopoietic abnormalities in survivors of testicular cancer.

Circulating myeloid progenitor cells in patients with aml after induction chemotherapy

In patients with acute nonlymphocytic leukemia (ANLL) it has previously been reported that the number of blood-derived hemopoietic stem cells (HSC) is very low during the remission phase.1,2 However, we and others have recently demonstrated that the concentration of granulocyte-macrophage precursors (CFU-GM cells) in the peripheral blood could be increased to 10- to 40-fold above the mean value in normal subjects during the period of marrow reconstitution following aplasia (or hypoplasia) induced by previous chemotherapy.1,3 To collect high numbers of circulating HSC, leukocyta-phereses could be performed during this short period of “recirculation” of blood-derived progenitors.However, patients with ANLL may be subjected to different chemotherapy regimens that vary according to the age of the patients, the status of the leukemia, and the therapeutic strategy. The amplitude of the recirculation of CFU-GM cells during remission is influenced mostly by the type of chemotherapy administered to the patient.1 In order to evaluate this phenomenon, we serially assayed peripheral blood CFU-CM cells in 26 ANLL patients. The mean value of the highest recorded peak (HRP) level was 4370 CFU-GM/mL (1133 to 9066) in 13 patients who achieved complete remission after a single course of induction treatment including cytosine arabinoside (Ara-c) (100 mg/m2 × 10 days) and daunorubicin (DNR) (60 mg/m2 × 3 days). As mentioned in a previous report, HPR levels of CFU-GM cells observed in two patients given a late, intensification treatment (with DNR: 300 mg/m2) were similar to those observed in these latter 13 patients.1 The recirculation of CFU-GM cells was less marked in seven patients who received two consecutive courses of induction chemotherapy or in four other patients receiving less intensive treatment as consolidation.1,2 These results confirm the results of our previous report and the data reported by To et al., who studied 13 ANLL patients during the very early remission phase following induction chemotherapy.3 They found that the mean value of the HRP level of CFU-GM cells was 2796/mL (370 to 14520) and concluded that the early remission period after one single course of chemotherapy could be the best time for collection of circulating HSC in ANLL patients.

In vitro differentiation of myeloid progenitor cells in patients with eosinophilia

In vitro differentiation of myeloid progenitor cells in patients with eosinophilia

In vitro differentiation of myeloid progenitor cells in patients with eosinophilia

Colony-forming cells of the granulocytic/macrophage ( CFCGM ) and eosinophilic ( CFCEo ) series were grown from bone marrow and/or peripheral blood of 20 patients with persistent eosinophilia mainly due to helminthic diseases and of 17 patients without eosinophilia. The semi-solid culture technique of haemopoietic cells was applied using different sources of colony-stimulating factor (CSF). After 14 d of incubation the number of CFCs as well as their differentiation into the CFCGM and CFCEo was evaluated. The total median CFC count in the bone marrow differed significantly between the patient and the control group. No difference of the total colony count was observed when culturing peripheral-blood lymphocytes of patients or controls. 47% Luxol-fast-blue positive colonies were identified in the peripheral blood cultures from patients with eosinophilia as compared with 56% from controls using human placenta-conditioned medium as source of CSF. In contrast, bone-marrow cultures showed a significantly lower proportion of CFCEo (14% v. 18% resp.). No difference could be observed with regard to the source of stimulus. Thus, the discrepancy of the peripheral-blood and bone-marrow eosinophilia and of the in vitro culture findings may indicate that the commitment of granulocytic progenitor cells into the eosinophilic series is unaffected by a defined stress, such as helminthic diseases or is not measurable in the culture dish.

Clonal Proliferation of Lymphoid and Myeloid Progenitor Cells in Patients with Hematological Abnormalities1

Myeloid and lymphoid stem cell colony formation (GM-CFU) and L-CFU) was studied in patients with lymphoproliferative diseases, aplastic anemia and other hematological abnormalities. Most patients with acute lymphatic leukemia had low number of L-CFU with decreased or normal GM-CFU, while in Hodgkin's disease and chronic lymphatic leukemia L-CFU growth was very poor with only minor abnormalities of GM-CFU formation. Aplastic anemia was characterized by a decreased GM-CFU and normal L-CFU. Coculture studies suggested that a diminished colony formation may be linked to circulating lymphocytes that inhibit L-CFU as well as the reduction in number of precursor cells.

Clonal Proliferation of Lymphoid and Myeloid Progenitor Cells in Patients with Hematological Abnormalities

Myeloid and lymphoid stem cell colony formation (GM-CFU and L-CFU) was studied in patients with lymphoproliférative diseases, aplastic anemia and other hematological abnormalities. Most patients with acute lymphatic leukemia had low number of L-CFU with decreased or normal GM-CFU, while in Hodgkin’s disease and chronic lymphatic leukemia L-CFU growth was very poor with only minor abnormalities of GM-CFU formation. Aplastic anemia was characterized by a decreased GM-CFU and normal L-CFU. Coculture studies suggested that a diminished colony formation may be linked to circulating lymphocytes that inhibit L-CFU as well as the reduction in number of precursor cells.