Morphologic and functional characterization of granulocytes and macrophages in embryonic and adult zebrafish

The zebrafish is a useful model organism for developmental and genetic studies. The morphology and function of zebrafish myeloid cells were characterized. Adult zebrafish contain 2 distinct granulocytes, a heterophil and a rarer eosinophil, both of which circulate and are generated in the kidney, the adult hematopoietic organ. Heterophils show strong histochemical myeloperoxidasic activity, although weaker peroxidase activity was observed under some conditions in eosinophils and erythrocytes. Embryonic zebrafish have circulating immature heterophils by 48 hours after fertilization (hpf). A zebrafish myeloperoxidase homologue (myeloid-specific peroxidase; mpx) was isolated. Phylogenetic analysis suggested it represented a gene ancestral to the mammalian myeloperoxidase gene family. It was expressed in adult granulocytes and in embryos from 18 hpf, first diffusely in the axial intermediate cell mass and then discretely in a dispersed cell population. Comparison of hemoglobinized cell distribution, mpx gene expression, and myeloperoxidase histochemistry in wild-type and mutant embryos confirmed that the latter reliably identified a population of myeloid cells. Studies in embryos after tail transection demonstrated that mpx- and peroxidase-expressing cells were mobile and localized to a site of inflammation, indicating functional capability of these embryonic granulocytes. Embryonic macrophages removed carbon particles from the circulation by phagocytosis. Collectively, these observations have demonstrated the early onset of zebrafish granulopoiesis, have proved that granulocytes circulate by 48 hpf, and have demonstrated the functional activity of embryonic granulocytes and macrophages. These observations will facilitate the application of this genetically tractable organism to the study of myelopoiesis.

Zebrafish--an emerging genetic model for the study of cytokines and hematopoiesis in the era of functional genomics

Now that whole genomes are sequenced, the identification of gene function rather than gene discovery is a major challenge. Saturation mutagenesis and screening for mutant phenotypes are methods that allow sampling of the genome for lesions in genes critical for particular physiological processes. This approach promises to provide new insights into gene function, even for molecularly well-characterized processes such as hematopoiesis and cytokine signaling. Animal models for such genetic approaches have traditionally included Drosophila and the mouse. Recently, the zebrafish (Danio rerio) has emerged as a flexible and informative vertebrate for genetic studies. Zebrafish hematopoiesis has a morphological and molecular complexity closer to that of mammals than does Drosophila, providing scope for recognizing mutant zebrafish phenotypes representing finely tuned lesions in these processes. Compared to mice, zebrafish represent an economical, flexible, and genetically tractable animal model for mutagenesis studies. The structure of the teleost genome creates several phylogenetic issues in assessing zebrafish and piscine orthologues and paralogues of known mammalian genes, here exemplified by a cytokine ligand (interleukin-1beta), kinase receptors (c-kit and c-fins), and a family of intracellular signaling molecules (JAK kinases). Several anemic zebrafish mutants are now genetically characterized, and others present hematopoietic phenotypes that promise novel insights into the regulation of hematopoiesis.

Comparison of effects of the tyrosine kinase inhibitors AG957, AG490, and STI571 on BCR-ABL--expressing cells, demonstrating synergy between AG490 and STI571

STI571 (formerly CGP57148) and AG957 are small molecule inhibitors of the protein tyrosine kinase (PTK) p145(abl) and its oncogenic derivative p210(bcr-abl). AG490 is an inhibitor of the PTK Janus kinase 2 (JAK2). No direct comparison of these inhibitors has previously been reported, so this study compared their effects on factor-dependent FDC-P1, 32D, and MO7e cells and their p210(bcr-abl)-expressing factor-independent derivatives. STI571 was a more potent inhibitor of (3)H-thymidine incorporation in p210(bcr-abl)-expressing cells than was AG957, and it showed superior discrimination between inhibitory effects on parental cell lines and effects on their p210(bcr-abl)-expressing derivatives. Assays performed with and without growth factor demonstrated that STI571 but not AG957 reversed the p210(bcr-abl)-driven factor independence of cell lines. p210(bcr-abl)-expressing cells were less sensitive to AG490 than to AG957 or STI571. However, for p210(bcr-abl)-expressing clones from all 3 cell lines, synergistic inhibition was demonstrated between STI571 and concentrations of AG490 with no independent inhibitory effect. Inhibition of nucleic acid synthesis with AG957 treatment was associated with reduced cell numbers, reduced viability, and small pyknotic apoptotic cells. At concentrations of STI571 that reversed the p210(bcr-abl) factor-independent phenotype, STI571 treatment and growth factor deprivation together were sufficient to induce apoptosis. This study concludes that, for the cell lines studied, (1) STI571 is a more potent and more selective inhibitor of a p210(bcr-abl)-dependent phenotype than AG957; (2) AG490 synergizes with STI571 to enhance its inhibitory effect on p210(bcr-abl)-driven proliferation; and (3) the combination of p210(bcr-abl)-tyrosine kinase inhibition and growth factor signal withdrawal can be sufficient to induce apoptotic death of transformed cells. (Blood. 2001;97:2008-2015)

T lymphocytes from granulocyte colony-stimulating factor-/- mice produce large quantities of interferon-gamma in a chronic infection model

Little is known about the role of granulocyte colony-stimulating factor (G-CSF) in the response to chronic bacterial infections. To address this we infected G-CSF knock out (G-CSF-/-) mice with Mycobacterium avium. Infection was not exacerbated in G-CSF-/- mice despite a deficiency in the total bone marrow cells, colony-forming haemopoietic cells, granulocytes and monocyte precursors in the bone marrow. Peritoneal cells from G-CSF-/- produced less nitric oxide (NO) upon culture in vitro with antigen than did wild-type (WT) cells. Unexpectedly, T cells from infected G-CSF-/- mice were able to produce significantly more interferon-gamma (IFN-gamma) than the wild type (WT) controls. T cells from G-CSF-/- mice still produced more IFN-gamma even when in vitro NO production was inhibited, while enzyme-linked immunospot assay (ELISPOT) assays showed more IFN-gamma-producing cells in the G-CSF-/- mice. This was confirmed by intracellular cytokine staining (ICCS), which showed that there were more IFN-gamma producing T cells in vivo in the G-CSF-/- than the WT controls following M. avium infection. It is possible that a deficit of NO in vivo allows T cells to develop a higher IFN-gamma-producing phenotype. Thus we show a novel relationship between G-CSF and IFN-gamma production by T cells revealed in this chronic bacterial infection model.

Functional deficiencies of peritoneal cells from gene-targeted mice lacking G-CSF or GM-CSF

Gene-targeted mice lacking the hemopoietic growth factors, granulocyte colony-stimulating factor (G-CSF) or granulocyte-macrophage (GM)-CSF, show increased susceptibility to infection with the facultative intracellular bacterium, Listeria monocytogenes. The resident peritoneal cell populations from G-CSF(-/-) and GM-CSF(-/-) mice showed reduced production of the bactericidal molecule nitric oxide. Macrophage-mediated tumoricidal activity and phagocytosis of Listeria were reduced in G-CSF(-/-), but not in GM-CSF(-/-), mice. In G-CSF(-/-) mice, there was an unexpected expansion (from 18% in WT to 38%) of a population of cells with morphology intermediate between typical macrophages and typical lymphocytes. These cells had some of the features of poorly differentiated macrophages, being adherent to plastic but poorly phagocytic, nonspecific esterase positive but myeloperoxidase negative. They were largely negative for the macrophage marker F4/80 and for Thy1, B220, and Gr1. Their disproportionate presence, and the corresponding deficiency in typical macrophages, possibly accounts for some of the functional deficiencies observed in G-CSF(-/-) mice.

Essential roles for granulocyte-macrophage colony-stimulating factor (GM-CSF) and G-CSF in the sustained hematopoietic response of Listeria monocytogenes-infected mice

The in vivo roles of granulocyte-macrophage colony-stimulating factor (GM-CSF) and granulocyte (G)-CSF were studied in factor-deficient gene-targeted knockout mice infected with the facultative intracellular bacterium Listeria monocytogenes. Previous results showed that G-CSF-/- mice had an underlying selective deficiency in granulopoiesis, but GM-CSF-/- mice had little disturbance in resting hematopoiesis. Nevertheless, in this study it is revealed that 3 days after intraperitoneal infection with 2 x 10(5) Listeria, GM-CSF-/- mice harbored 50-fold more organisms in their spleen and liver than similarly infected wild-type mice. This was accompanied by a severe depletion of bone marrow hematopoietic cells and a deficient inflammatory response in their peritoneal cavity. Thus, GM-CSF is essential for emergency, but not resting, hematopoiesis. In contrast, G-CSF-/- mice were markedly susceptible to low doses (2 x 10(4)) of Listeria intraperitoneally. After infection, the acute (1 day) granulocyte infiltration to the peritoneal cavity was normal compared with wild type, but the more prolonged monocyte response was deficient, reflecting a continued decrease in bone marrow cellularity and hematopoiesis over 3 days, which was not observed in infected wild-type mice. It is thus apparent that G-CSF deficiency affects monocytopoiesis as well as granulopoiesis during infection.

Mice lacking both granulocyte colony-stimulating factor (CSF) and granulocyte-macrophage CSF have impaired reproductive capacity, perturbed neonatal granulopoiesis, lung disease, amyloidosis, and reduced long-term survival

Mice lacking granulocyte colony-stimulating factor (G-CSF) are neutropenic with reduced hematopoietic progenitors in the bone marrow and spleen, whereas those lacking granulocyte-macrophage colony-stimulating factor (GM-CSF) have impaired pulmonary homeostasis and increased splenic hematopoietic progenitors, but unimpaired steady-state hematopoiesis. These contrasting phenotypes establish unique roles for these factors in vivo, but do not exclude the existence of additional redundant functions. To investigate this issue, we generated animals lacking both G-CSF and GM-CSF. In the process of characterizing the phenotype of these animals, we further analyzed G-CSF- and GM-CSF-deficient mice, expanding the recognized spectrum of defects in both. G-CSF-deficient animals have a marked predisposition to spontaneous infections, a reduced long-term survival, and a high incidence of reactive type AA amyloidosis. GM-CSF-deficient mice have a modest impairment of reproductive capacity, a propensity to develop lung and soft-tissue infections, and a similarly reduced survival as in G-CSF-deficient animals. The phenotype of mice lacking both G-CSF and GM-CSF was additive to the features of the constituent genotypes, with three novel additional features: a greater degree of neutropenia among newborn mice than in those lacking G-CSF alone, an increased neonatal mortality rate, and a dominant influence of the lack of G-CSF on splenic hematopoiesis resulting in significantly reduced numbers of splenic progenitors. In contrast to newborn animals, adult mice lacking both G-CSF and GM-CSF exhibited similar neutrophil levels as G-CSF-deficient animals. These findings demonstrate that the additional lack of GM-CSF in G-CSF-deficient animals further impairs steady-state granulopoiesis in vivo selectively during the early postnatal period, expand the recognized roles of both G-CSF and GM-CSF in vivo, and emphasize the utility of studying multiply deficient mouse strains in the investigation of functional redundancy.

Increased tolerance to endotoxin by granulocyte-macrophage colony-stimulating factor-deficient mice

The contribution of granulocyte-macrophage CSF (GM-CSF) to endotoxin-mediated septic shock has been assessed by treating GM-CSF-deficient mice with LPS. Hypothermia and loss in body weight were markedly attenuated in LPS-treated GM-CSF-deficient mice compared with similarly treated control mice; moreover, the levels of circulating IFN-gamma, IL-1alpha, and IL-6 were lower in LPS-treated GM-CSF-deficient mice than LPS-treated control mice. Intriguingly, the peak levels of TNF-alpha in response to LPS treatment were the same in the serum of GM-CSF-deficient mice and control mice, although in GM-CSF-deficient mice, TNF-alpha persisted longer. Activation of macrophages by LPS, resulting in expression of cytokines including TNF-alpha and IL-1, is thought to underlie endotoxin-mediated effects. Accordingly, the response of peritoneal macrophages from GM-CSF-deficient mice to LPS was studied in vitro. LPS-stimulated peritoneal macrophages from GM-CSF-deficient mice produced significantly less IL-1alpha and nitric oxide than macrophages from wild-type mice, although there was no difference in TNF-alpha production. Collectively, these observations indicate that GM-CSF contributes to cytokine production in LPS-mediated septic shock, and that the attenuated production of these secondary cytokines (IFN-gamma, IL-1alpha, and IL-6) may contribute to the endotoxin-resistant phenotype of GM-CSF-deficient mice.

Increased tolerance to endotoxin by granulocyte-macrophage colony-stimulating factor-deficient mice

The contribution of granulocyte-macrophage CSF (GM-CSF) to endotoxin-mediated septic shock has been assessed by treating GM-CSF-deficient mice with LPS. Hypothermia and loss in body weight were markedly attenuated in LPS-treated GM-CSF-deficient mice compared with similarly treated control mice; moreover, the levels of circulating IFN-gamma, IL-1alpha, and IL-6 were lower in LPS-treated GM-CSF-deficient mice than LPS-treated control mice. Intriguingly, the peak levels of TNF-alpha in response to LPS treatment were the same in the serum of GM-CSF-deficient mice and control mice, although in GM-CSF-deficient mice, TNF-alpha persisted longer. Activation of macrophages by LPS, resulting in expression of cytokines including TNF-alpha and IL-1, is thought to underlie endotoxin-mediated effects. Accordingly, the response of peritoneal macrophages from GM-CSF-deficient mice to LPS was studied in vitro. LPS-stimulated peritoneal macrophages from GM-CSF-deficient mice produced significantly less IL-1alpha and nitric oxide than macrophages from wild-type mice, although there was no difference in TNF-alpha production. Collectively, these observations indicate that GM-CSF contributes to cytokine production in LPS-mediated septic shock, and that the attenuated production of these secondary cytokines (IFN-gamma, IL-1alpha, and IL-6) may contribute to the endotoxin-resistant phenotype of GM-CSF-deficient mice.

The influence of granulocyte/macrophage colony-stimulating factor on dendritic cell levels in mouse lymphoid organs

To ascertain whether the development of dendritic cells (DC) in mouse lymphoid organs is dependent on granulocyte/macrophage colony-stimulating factor (GM-CSF), we determined the number of DC in the thymus, spleen and lymph nodes of normal mice, of mice with the genes coding for GM-CSF or its receptor inactivated, and of transgenic mice with excessive levels of GM-CSE DC were extracted from the tissues and enriched prior to flow cytometric analysis. The total DC level and the incidence of DC expressing lymphoid-related markers (CD8(hi) CD11b(lo)) and myeloid-related markers (CD8(lo) CD11b(hi)) were monitored. Both in GM-CSF null mice, and GM-CSF receptor null mice, DC of all surface phenotypes were present in all lymphoid organs; only small decreases in DC levels were recorded, except for the lymph nodes of GM-CSF receptor null mice which showed a more pronounced (threefold) decrease in DC numbers. Since the GM-CSF receptor null mice lacked the beta chain common to the GM-CSF, interleukin (IL)-3 and IL-5 receptors, the development of DC in the absence of GM-CSF was not due to common beta chain mediated developmental signals elicited by IL-3 or IL-5. In GM-CSF transgenic mice, there was only a 50 % increase in DC numbers in thymus and spleen, paralleling an increase in overall cellularity, but a more pronounced (threefold) increase in DC numbers in lymph nodes. There was no evidence that GM-CSF had a selective effect on any particular DC subpopulation defined by CD8 or CD11b expression. We conclude that the development of most lymphoid tissue DC can proceed in the absence of GM-CSF, although this cytokine can produce some elevation of DC levels. It is not clear whether the enhancing effect of GM-CSF is direct or an indirect effect mediated by other cytokines.

CSF-deficient mice--what have they taught us?

Haemopoietic growth factor-deficient mice have been particularly instructive for defining the usual physiological role of these factors. Mice now exist lacking the granulopoietic factors G-CSF, GM-CSF, M-CSF (CSF-1), SCF, several other factors influencing haemopoiesis (including erythropoietin, interleukins 5 and 6), combinations of these factors (GM- & M-CSF; G- & GM-CSF; G- & GM- & M-CSF) and several CSF receptor components. Most of these mice were generated by targeted gene disruption, others are spontaneously arising mutants. The phenotypes of these mice indicate that the granulopoietic factors have both unique and redundant roles in vivo. Some factors are uniquely important in baseline myelopoiesis. Experimental infection of CSF-deficient mice indicates unique roles for some factors in emergency 'overdrive' haemopoiesis. Recovery from myeloablation evaluates the role of CSFs in emergency 'restoring normality' haemopoiesis. Redundancy also exists in the capacity of CSFs to support complete granulocyte development in vivo. Some factors are not involved in all the in vivo roles suggested by the range of their actions demonstrable in vitro. Some CSFs have indispensable roles in non-haemopoietic tissues. Some factors have in vivo roles not anticipated from previous studies. Mice deficient in several factors have identified compensating roles for factors by revealing exacerbated and additional phenotypic features, and may unmask additional in vivo roles.

Bioactive murine and human interleukin-12 fusion proteins which retain antitumor activity in vivo

Interleukin-12 (IL-12) is unique amongst cytokines in being a disulfide-linked heterodimer of two separately encoded subunits (p35 and p40). We expressed single chain IL-12 proteins from retroviral constructs in which the two IL-12 subunits were linked by a 6-15 amino acid polypeptide linker, with deletion of the 22 amino acid leader sequence of the trailing subunit. The murine fusion protein IL-12.p40.L.delta p35 containing a (Gly4Ser)3 linker was stably expressed, bioactive in vitro, and had an apparent specific activity comparable to that of native and recombinant IL-12. Western blotting confirmed that murine IL-12.p40.L.delta p35 retained the linking polypeptide sequences. The analogous human IL-12.p40.L.delta p35 fusion protein containing a Gly6Ser linker was bioactive with an apparent specific activity comparable to recombinant human IL-12. In a preexisting CMS-5 tumor model, CMS-5 cells secreting either native or fusion protein forms of IL-12 prolonged survival and led to complete tumor regression.

Granulocyte-macrophage colony-stimulating factor is not responsible for the correction of hematopoietic deficiencies in the maturing op/op mouse

Osteopetrotic (op/op) mice are characterized by an autosomal recessive inactivating mutation resulting in the absence of biologically active colony-stimulating factor-1 (CSF-1). Consequently, young op/op mice have a severe deficiency of macrophages and osteoclasts resulting in excessive bone formation, occlusion of the marrow cavity, and reduced marrow hematopoietic activity. Recently, we showed that the osteopetrosis and hematopoietic deficiencies evident in young op/op mice are not permanent but are progressively corrected with age. There are increases in osteoclast activity; bone resorption; femoral marrow space; and marrow hematopoietic activity, cellularity, and macrophage content. In the present study we show that CSF-1-/- granulocyte-macrophage colony-stimulating factor (GM-CSF)(-/-)-deficient mice also undergo the same pattern of hematopoietic correction as the op/op mouse. Also, like the op/op mouse, the peritoneal cellularity and macrophage content of CSF-1/GM-CSF-deficient mice remains severely reduced. Our data show that the "knockout" of GM-CSF does not change the op/op phenotype, and that GM-CSF is not essential for the correction of the hematopoietic deficiencies in the op/op mouse. Importantly, the data also show that neither GM-CSF nor CSF-1 is an absolute requirement for the commitment of primitive hematopoietic stem cells to the macrophage lineage or for the differentiation of at least some classes of macrophages. This finding suggests that an alternate regulatory factor can be involved in macrophage and osteoclast commitment, differentiation, and function in vivo.

Development of functional macrophages from embryonal stem cells in vitro

When cultured under appropriate in vitro conditions, embryonal stem cells (ESCs) form embryoid bodies (EBs) that contain mature hematopoietic cells, including cells of the monocyte-macrophage lineage. A two-step in vitro culture system for generation of ESC-derived macrophages has been developed and optimized. Maximum numbers of macrophage-containing colonies developed in secondary hematopoietic cultures of cells from disrupted EBs after 9 to 12 days of differentiation when interleukin-3 (IL-3) and macrophage colony-stimulating factor (M-CSF) were included in both primary and secondary cultures. Over 10(5) viable, phagocytically active macrophages were generated from cultures initiated by 7500 ESCs. The inclusion of stem cell factor (SCF) in primary cultures not only increased the frequency of progenitor cells but also the cellular heterogeneity of colonies. SCF in secondary cultures increased the cellularity, but not the frequency, of macrophage-containing colonies; although cellular heterogeneity was also increased, there was still an overall increase in yield of macrophages.

Filgrastim in patients with chemotherapy-induced febrile neutropenia. A double-blind, placebo-controlled trial

OBJECTIVE

To determine if filgrastim (recombinant human methionyl granulocyte colony-stimulating factor) used in addition to standard inpatient antibiotic therapy accelerated recovery from infection associated with chemotherapy-induced neutropenia.

DESIGN

Randomized, double-blind, placebo-controlled trial.

SETTING

Hematology and oncology wards of four teaching hospitals.

PATIENTS

218 patients with cancer who had fever (temperature > 38.2 degrees C) and neutropenia (neutrophil count < 1.0 x 10(9)/L) after chemotherapy.

INTERVENTION

Patients were randomly assigned to receive filgrastim (12 micrograms/kg of body weight per day) (n = 109) or placebo (n = 107) beginning within 12 hours of empiric therapy with tobramycin and piperacillin. Patients received treatment and remained in the study until the neutrophil count was greater than 0.5 x 10(9)/L and until 4 days without fever (temperature < 37.5 degrees C) had elapsed.

MEASUREMENTS

Days of neutropenia and fever and days in the study (hospitalization); time to resolution of fever and febrile neutropenia; and frequency of the use of alternative antibiotics.

RESULTS

Compared with placebo, filgrastim reduced the median number of days of neutropenia (3.0 compared with 4.0 days of a neutrophil count of < 0.5 x 10(9)/L; P = 0.005) and the time to resolution of febrile neutropenia (5.0 compared with 6.0 days; P = 0.01) but not days of fever (3.0 days for both groups). The frequency of the use of alternative antibiotics was similar in the two groups (46% compared with 41%; P = 0.48). The median number of days patients were hospitalized while on study was the same (8.0 days; P = 0.09); however, filgrastim decreased the risk for prolonged hospitalization (> 11 days, 4th quartile) by half (relative risk, 2.1 [95% CI, 1.1 to 4.1]; P = 0.02). In exploratory subset analyses, filgrastim appeared to provide the greatest benefit in patients with documented infection and in patients presenting with neutrophil counts of less than 0.1 x 10(9)/L.

CONCLUSIONS

Filgrastim treatment used with antibiotics at the onset of febrile neutropenia in patients with cancer who have received chemotherapy accelerated neutrophil recovery and shortened the duration of febrile neutropenia.

Mice lacking granulocyte colony-stimulating factor have chronic neutropenia, granulocyte and macrophage progenitor cell deficiency, and impaired neutrophil mobilization

Mice lacking granulocyte colony-stimulating factor (G-CSF) were generated by targeted disruption of the G-CSF gene in embryonal stem cells. G-CSF-deficient mice (genotype G-CSF-/-) are viable, fertile, and superficially healthy, but have a chronic neutropenia. Peripheral blood neutrophil levels were 20% to 30% of wild-type mice (genotype G-CSF+/+) and mice heterozygous for the null mutation had intermediate neutrophil levels, suggesting a gene-dosage effect. In the marrow of G-CSF-/- mice, granulopoietic precursor cells were reduced by 50% and there were reduced levels of granulocyte, macrophage, and blast progenitor cells. Despite G-CSF deficiency, mature neutrophils were still present in the blood and marrow, indicating that other factors can support neutrophil production in vivo. G-CSF-/- mice had reduced numbers of neutrophils available for rapid mobilization into the circulation by a single dose of G-CSF. G-CSF administration reversed the granulopoietic defect of G-CSF-/- mice. One day of G-CSF administration to G-CSF-/- mice elevated circulating neutrophil levels to normal, and after 4 days of G-CSF administration, G-CSF+/+ and G-CSF-/- marrows were morphologically indistinguishable. G-CSF-/- mice had a markedly impaired ability to control infection with Listeria monocytogenes, with diminished neutrophil and delayed monocyte increases in the blood and reduced infection-driven granulopoiesis. Collectively, these observations indicate that G-CSF is indispensible for maintaining the normal quantitative balance of neutrophil production during "steady-state" granulopoiesis in vivo and also implicate G-CSF in "emergency" granulopoiesis during infections.

Mice lacking both macrophage- and granulocyte-macrophage colony-stimulating factor have macrophages and coexistent osteopetrosis and severe lung disease

Mice deficient in granulocyte-macrophage colony-stimulating factor (GM-CSF) and macrophage colony-stimulating factor (M-CSF, CSF-1) were generated by interbreeding GM-CSF-deficient mice generated by gene targeting (genotype GM-/-) with M-CSF-deficient osteopetrotic mice (genotype M-/-, op/op). Mice deficient in both GM-CSF and M-CSF (genotype GM-/-M-/-) are viable and have coexistent features corresponding to mice deficient in either factor alone. Like M-CSF-deficient mice, they have osteopetrosis and are toothless because of failure of incisor eruption. Like GM-CSF-deficient mice, they have a characteristic alveolar-proteinosis-like lung pathology, but it is more severe than that of GM-CSF-deficient mice and is often fatal. In particular, in GM-/-M-/- mice the accumulation of lipo-proteinaceous alveolar material is more marked, and bacterial pneumonic infections are more prevalent and more extensive, particularly involving Gram-negative bacteria. Neutrophilia consistently accompanies pulmonary infections, and some older GM-/-M-/- mice have polycythemia. Survival of GM-/-M-/- mice is significantly reduced compared with mice deficient in either factor alone, and all GM-/-M-/- mice have broncho- or lobar-pneumonia at death. These observations indicate that in vivo, M-CSF is involved in modulating the consequences of GM-CSF deficiency in the lung. Interestingly, GM-/-M-/- mice have circulating monocytes at levels comparable with those in M-CSF-deficient mice and the diseased lungs of all GM-/-M-/- mice contain numerous phagocytically active macrophages, indicating that in addition to GM-CSF and M-CSF, other factors can be used for macrophage production and function in vivo.

Granulocyte/macrophage colony-stimulating factor-deficient mice show no major perturbation of hematopoiesis but develop a characteristic pulmonary pathology

Mice homozygous for a disrupted granulocyte/macrophage colony-stimulating factor (GM-CSF) gene develop normally and show no major perturbation of hematopoiesis up to 12 weeks of age. While most GM-CSF-deficient mice are superficially healthy and fertile, all develop abnormal lungs. There is extensive peribronchovascular infiltration with lymphocytes, predominantly B cells. Alveoli contain granular eosinophilic material and lamellar bodies, indicative of surfactant accumulation. There are numerous large intraalveolar phagocytic macrophages. Some mice have subclinical lung infections involving bacterial or fungal organisms, occasionally with focal areas of acute purulent inflammation or lobar pneumonia. Some features of this pathology resemble the human disorder alveolar proteinosis. These observations indicate that GM-CSF is not essential for the maintenance of normal levels of the major types of mature hematopoietic cells and their precursors in blood, marrow, and spleen. However, they implicate GM-CSF as essential for normal pulmonary physiology and resistance to local infection.

Granulocyte-macrophage colony-stimulating factor for cancer treatment

In the 5 years since granulocyte-macrophage colony-stimulating factor (GM-CSF) was first tested clinically, a number of different strategies for its use have been evaluated in patients with malignant disease. These include using GM-CSF to support standard and high-dose chemotherapy, to accelerate myeloid reconstitution following marrow transplantation, to mobilize peripheral blood progenitor cells into the circulation for harvesting and transplantation, and in combination with cycle-specific chemotherapy drugs to enhance their cytotoxicity to leukemic cells. Early results were encouraging and data from randomized studies are now being reported. These are enabling an assessment of the value of these strategies for GM-CSF use in the management of cancer.

Studies of oral neutrophil levels in patients receiving G-CSF after autologous marrow transplantation

Patients are at risk of mucositis and infections in the oral cavity during the neutropenic period after chemotherapy, which are significant causes of morbidity. In phase I/II studies with the haemopoietic growth factor granulocyte colony stimulating factor (G-CSF), a reduction in post-chemotherapy mucositis has been observed in addition to haematologic effects. To understand this phenomenon better in patients receiving G-CSF following high-dose chemotherapy with autologous bone marrow transplantation (ABMT), we studied the effects of G-CSF on levels of neutrophils recoverable from the oral cavity using a quantitative mouthrinse assay. In normal subjects, mouthrinses contained 472 +/- 329 x 10(3) neutrophils/mouthrinse. After chemotherapy followed by ABMT, mouthrinse neutrophil levels decreased to undetectable levels during the neutropenic period, but recovered 1-2 and 3-9 d before circulating neutrophil levels reached 0.1 and 1 x 10(9)/l respectively, whether or not patients received G-CSF. In patients who received G-CSF, the mean cumulative mucositis score was reduced from 35 +/- 9 to 21 +/- 12 (P < 0.05), and the maximum mean daily mucositis score was reduced from 2.8 +/- 0.5 to 1.7 +/- 0.9 (P < 0.01), compared to patients who did not receive G-CSF after ABMT. These studies provide in vivo evidence that neutrophils produced during G-CSF therapy are available to leave the circulation and enter tissues where their function is required for host defence. Since the usual temporal relationship between oral and peripheral blood neutrophil recovery was preserved during G-CSF administration after ABMT, these data support the hypothesis that the reduction in post-ABMT mucositis observed with G-CSF therapy may reflect a beneficial effect of G-CSF on the kinetics of oral mucosal neutrophil recovery in addition to the effect of G-CSF to accelerate peripheral blood neutrophil recovery.

The dissociation of GM-CSF efficacy from toxicity according to route of administration: a pharmacodynamic study

The pharmacokinetics and pharmacodynamics of bacterially synthesized granulocyte-macrophage colony stimulating factor (GM-CSF) were studied in 33 patients. GM-CSF (0.3-30 micrograms/kg/d) was administered subcutaneously (s.c.) or intravenously (i.v.) by bolus or 2 h infusion for 10 d to three patients at each dose level, and serum levels measured by enzyme-linked immunosorbent assay (ELISA). Relationships between pharmacokinetic variables and GM-CSF efficacy and toxicity were investigated. GM-CSF appeared more effective s.c. than i.v. Correlations with response improved when patients with neutropenia or marrow infiltration by tumour were excluded. For the remaining patients, the correlation coefficients between the day 10 leucocyte count was highest with dose (R = 0.629, P less than 0.01), the duration GM-CSF concentrations exceeded 1 ng/ml (r = 0.524, P less than 0.05) and area under the concentration-time curve (R = 0.508, P less than 0.05). There was no correlation with peak serum GM-CSF (Cmax) (R = 0.188, P = NS). In contrast, the first dose reaction (characterized by hypoxaemia and hypotension) was associated with high Cmax (P less than 0.01) and i.v. administration. Fever, liver enzyme elevation and pericarditis occurred at 10-30 micrograms/kg and were not influenced by route. Since the variables correlating with response differed from those correlating with these toxicities, it appears that the therapeutic index for GM-CSF can be increased by modifying the method of administration.

Recombinant alpha-2b interferon in patients with malignant carcinoid tumour

Seventeen patients with malignant carcinoid tumour, ten of whom had the malignant carcinoid syndrome, were treated with recombinant alpha-2b interferon by subcutaneous injection (3 MU per dose) three times per week for a median of 12 weeks (range 4-48). No objective tumour responses were observed; however, there was a greater than 50% reduction in 24-hour urinary 5-hydroxyindolacetic acid (5-HIAA) excretion in four of ten patients (40%) with elevated pretreatment levels. Five of ten patients (50%) with flushing, five of seven patients (71%) with diarrhoea and both patients with wheezing experienced relief of symptoms. Three of four patients (75%) with weight loss as their only problem experienced weight gain. Responses occurred within the first eight weeks of treatment, but were generally of short duration. Toxicity occurred in all patients, and consisted mainly of fever, chills, anorexia, fatigue and weight loss. Four patients ceased therapy due to toxic reactions. Although interferon has activity against carcinoid tumours, its benefits are short-lived and toxicity limits its use with increasing dose. Patients with carcinoid syndrome appear to achieve the best therapeutic response, and it is likely that low doses (9-20 million IU weekly) are as effective as higher doses (36-72 million IU weekly).

Phase I study of intravenously administered bacterially synthesized granulocyte-macrophage colony-stimulating factor and comparison with subcutaneous administration

A Phase I study of bacterially synthesized recombinant human granulocyte-macrophage colony-stimulating factor (rhGM-CSF) was undertaken in 21 patients with advanced malignancy or neutropenia. rhGM-CSF was administered once daily by i.v. bolus injection (0.3 to 3 micrograms/kg/day) or 2-h i.v. infusion (3 to 20 micrograms/kg day) for 10 days. rhGM-CSF at all i.v. doses caused an immediate transient decrease in circulating neutrophils, eosinophils, and monocytes. By 6 h after rhGM-CSF, circulating leukocyte levels were restored. Daily i.v. bolus dosing (0.3 to 3 micrograms/kg/day) did not elevate leukocyte levels except in one neutropenic patient. Daily 2-h i.v. infusions (10 to 20 micrograms/kg/day) caused a dose-dependent leukocytosis with increased levels of neutrophils (up to 4.3-fold), eosinophils (up to 18-fold), and monocytes (up to 3.5-fold). Marrow aspirates showed increased proportions of promyelocytes and myelocytes during rhGM-CSF administration. Retreatment after 10 days without rhGM-CSF resulted in a more marked leukocytosis at doses greater than or equal to 10 micrograms/kg/day. Platelet levels decreased for the first 3 days and then increased during the first course of rhGM-CSF administration. Two patients with chronic lymphocytic leukemia had a transient reduction in lymphocytosis. Serum cholesterol and albumin levels decreased, and vitamin B12 levels increased during rhGM-CSF treatment. At doses of up to 15 micrograms/kg/day, rhGM-CSF was relatively well tolerated by the patients, but adverse effects included bone pain, lethargy, fever, rash, and weight gain. A first dose reaction characterized by hypoxia and hypotension was identified at dose levels greater than or equal to 1 microgram/kg. Dosing i.v. was less potent at inducing a leukocytosis than previously observed for equivalent s.c. doses and was associated with a higher incidence of generalized rash and first dose reactions. The maximal tolerated dose of i.v. rhGM-CSF was 15 micrograms/kg/day. Phase II studies in which the derived effect is to raise leukocyte levels should be undertaken at rhGM-CSF doses of 3 to 15 micrograms/kg/day.

Endometrial adenocarcinoma presenting as pituitary apoplexy

The novel combination of disseminated primary endometrial adenocarcinoma and a symptomatic pituitary metastasis presenting as pituitary apoplexy is described for the first time. Pituitary apoplexy is an unusual manifestation of metastatic pituitary disease. The more common clinical features of pituitary metastases and an approach to their management are discussed. The usefulness of magnetic resonance imaging in assessing the base of skull is emphasised.

The effects of dose and route of administration on the pharmacokinetics of granulocyte-macrophage colony-stimulating factor

The pharmacokinetics of granulocyte-macrophage colony stimulating factor (GM-CSF) (0.3-30 micrograms/kg) were studied after subcutaneous bolus (n = 16) or intravenous bolus (n = 5) injection or 2 h intravenous infusion (n = 12). Each method of administration gave a different GM-CSF concentration-time profile. Highest peak serum concentrations (Cmax) followed the intravenous bolus, and the time GM-CSF persisted at a concentration greater than 1 ng/ml (t greater than 1 ng/ml) was longer after a subcutaneous than after an intravenous injection. Area under the concentration-time curve (AUC), Cmax and t greater than 1 ng/ml all increased with dose for each method of administration. After intravenous administration, there was a two-phase decline in concentration. The half-life (t1/2) of the terminal phase following an intravenous bolus ranged from 0.24 to 1.18 h and, following intravenous infusion, from 0.62 to 9.07 h and appeared to increase with dose. The apparent clearance was greatest following subcutaneous injection at doses below 3 micrograms/kg, suggesting a saturable mechanism or different bioavailability. Only 0.001%-0.2% of the injected dose appeared in the urine as immunoreactive GM-CSF.

Characterization of the clinical effects after the first dose of bacterially synthesized recombinant human granulocyte-macrophage colony-stimulating factor

Bacterially synthesized recombinant human granulocyte-macrophage colony-stimulating factor (rhGM-CSF) is an agent with therapeutic potential for neutropenic states, but even at doses below the maximal tolerated dose adverse effects occur during short courses of administration. We have recognized a syndrome of hypoxia and hypotension that follows the first but not subsequent doses of rhGM-CSF. Thirteen of 42 patients receiving rhGM-CSF in phase I studies and 4 of 6 patients in a phase II study developed a reaction that occurred after the first dose of 24 of 78 cycles of rhGM-CSF therapy. The reaction was characterized by flushing (16 of 24), tachycardia (16 of 24), hypotension (14 of 24), musculoskeletal pain (13 of 24), dyspnea (12 of 24), nausea and vomiting (11 of 24), rigors (5 of 24), involuntary leg spasms (3 of 24), and syncope (3 of 24). The reaction did not occur after any of more than 600 second and subsequent consecutive rhGM-CSF doses. Oxygen saturation decreased during first-dose reactions by 8% +/- 4% as compared with 3% +/- 1% on first days without reactions (P less than .001) and 2% +/- 1% on subsequent days (P less than .001). Pulmonary dysfunction was characterized by hypoxemia (59 +/- 9 mm Hg, mean +/- SD) that was fully correctable with supplementary oxygen, decreased single-breath carbon monoxide diffusion capacity, and increased alveolar-arterial oxygen gradients (25 +/- 6 to 60 +/- 4 mm Hg, mean +/- SD), but no significant abnormalities on chest roentgenogram or lung perfusion scan. Factors predisposing to reactions were rhGM-CSF dose greater than or equal to 3 micrograms/kg (P less than .01), intravenous (IV) rather than subcutaneous (SC) administration (P less than .05), occurrence of a reaction after the first dose of a previous cycle of rhGM-CSF therapy (P less than .01), and for patients receiving 15 micrograms/kg/d by SC bolus, the presence of lung cancer (P less than .05). Administration of 15 micrograms/kg/d rhGM-CSF by 24-hour SC infusion rather than SC bolus resulted in a delayed onset of reaction from 30 +/- 8 minutes to 240 +/- 190 minutes (mean +/- SD, P less than .001), and a slower rate of initial transient decrease in neutrophil levels and a more prolonged duration of transient leukopenia. The time of onset of reactions correlated with the rate of rise of rhGM-CSF levels.(ABSTRACT TRUNCATED AT 400 WORDS)

Pharmacology of the colony-stimulating factors

Leukocyte production is influenced by a family of glycoproteins called colony-stimulating factors. Two of these have been purified, cloned and produced in quantities sufficient for clinical use. Granulocyte colony-stimulating factor (G-CSF) preferentially stimulates neutrophil production and has been shown to reduce the duration of neutropenia following chemotherapy. G-CSF therapy also has beneficial effects in a variety of other neutropenic states. Granulocyte-macrophage colony-stimulating factor (GM-CSF) stimulates neutrophil, monocyte and eosinophil production and function. GM-CSF is associated with more diverse haematological and clinical effects. George Morstyn and colleagues summarize the promising results from the early clinical trials with these new therapeutic agents.

Clinical experience with recombinant human granulocyte colony-stimulating factor and granulocyte macrophage colony-stimulating factor

Bacterially synthesized human granulocyte colony-stimulating factor (G-CSF) and granulocyte macrophage colony-stimulating factor (GM-CSF) have been studied to determine if they could prevent or reduce the neutropenia caused by chemotherapy. Our studies suggest that 10 micrograms/kg/day of G-CSF administered as a continuous subcutaneous infusion abrogates the neutropenia associated with a standard dose of melphalan. G-CSF produced a rapid increase of neutrophil levels, was well-tolerated, and was associated with only one frequent adverse effect: bone pain. GM-CSF, administered in doses ranging from 3 to 15 micrograms/kg/day subcutaneously, appeared to be useful in abrogating the neutropenia associated with chemotherapy, producing elevations in neutrophils, eosinophils, and monocytes. Although GM-CSF was relatively well-tolerated, several adverse effects, including bone pain, rashes, and fluid retention, were observed. The initial dose of GM-CSF in some patients produced a reaction that was characterized by hypoxia.

Effects of bacterially synthesized recombinant human granulocyte-macrophage colony-stimulating factor in patients with advanced malignancy

STUDY OBJECTIVE

To define the clinical and hematologic effects of subcutaneously administered bacterially synthesized recombinant human granulocyte-macrophage colony-stimulating factor (rhGM-CSF).

DESIGN

Single arm nonrandomized dose escalation study.

PATIENTS

Twenty-one patients with advanced malignancy who were not receiving concurrent myelosuppressive therapy.

INTERVENTIONS

Subcutaneous administration of rhGM-CSF by once-daily injection to groups of two to four patients at doses of 0.3 to 30 micrograms/kg body weight.d for 10 consecutive days. Some patients received a second 10-day period of daily rhGM-CSF treatment after a 10-day nontreatment interval followed by alternate-day treatment. Clinical status and hematologic values were monitored frequently.

MEASUREMENTS AND MAIN RESULTS

All doses of rhGM-CSF caused an immediate transient fall of 84% to 99% in circulating neutrophils, eosinophils, and monocytes. Continued daily dosing caused a leukocytosis of up to 10-fold with increases in numbers of circulating neutrophils, eosinophils, monocytes, and lymphocytes. There appeared to be a plateau in the increase in neutrophils in the dose range 3 to 15 micrograms/kg.d. Marrow aspirates showed increased proportions of promyelocytes and myelocytes. Alternate-day injection of 15 micrograms/kg maintained a leukocytosis. At doses up to 15 micrograms/kg.d, rhGM-CSF was well tolerated but adverse effects included bone pains, myalgias, rashes, and liver dysfunction. At doses exceeding 15 micrograms/kg.d, pericarditis was a dose-limiting toxicity. Idiopathic thrombocytopenic purpura was reactivated by rhGM-CSF in one patient.

CONCLUSIONS

Bacterially synthesized rhGM-CSF induces a leukocytosis in the dose range of 3 to 15 micrograms/kg.d. These doses are appropriate for phase II studies.

Spontaneous internal carotid artery dissection presenting as hypoglossal nerve palsy

A 42-year-old man presented with right temporal headache, dysarthria, and dysphagia. On examination, he had a right hypoglossal nerve palsy. The diagnosis of right internal carotid artery dissection was suggested by magnetic resonance imaging and confirmed by carotid angiography. A dynamic computed tomogram demonstrated enlargement of the carotid artery. In carotid dissection, the hypoglossal nerve may be compromised by local factors as it passes close to the carotid artery in the neck.

Kinetics of the formation of pure and heterogeneous megakaryocyte colonies by megakaryocyte progenitor cells in vitro

The formation of pure and heterogeneous megakaryocyte colonies in vitro by megakaryocyte progenitor cells was studied using a whole plate stain for acetylcholinesterase to identify megakaryocyte colonies. In cultures of 75,000 C57BL marrow cells, maximal numbers of 11 +/- 5 (mean +/- standard deviation) pure and 6 +/- 1 heterogeneous colonies were reached after 6-7 days of incubation, after which megakaryocyte colony degeneration was marked. The ratio of pure: heterogeneous colonies remained constant at 2:1 both during the incubation period, and when different concentrations of megakaryocyte colony stimulating factor (MEG-CSF) and different numbers of cells per culture were used. The average size of both pure and heterogeneous colonies increased during the incubation period to maximal colony sizes of 15 +/- 13 cells per pure colony and 264 +/- 300 cells per heterogeneous colony. Sequential analysis of individual colonies in situ failed to demonstrate an increase in the size of individual pure colonies, but the enlargement of individual heterogeneous colonies was observed.

Regeneration of hemopoietic precursor cells in spleen organ cultures from irradiated mice: influence of genotype of cells injected and of the spleen microenvironment

The regeneration of hemopoietic precursor cells (colony-forming cells, CFC) was monitored in spleen organ cultures from lethally irradiated mice injected with 10(7) normal syngeneic or allogeneic bone marrow cells. The important role of the microenvironment in supporting hemopoiesis was confirmed by the failure of mutant S1/S1d spleens to support CFC regeneration in organ cultures. However, the extent and quality of the CFC regeneration was clearly dependent on the genetic properties of the injected cells. Evidence for this was obtained from the regeneration patterns of various CFC types in organ cultured spleens derived from different mouse donor-recipient strain combinations (CBA/CBA, CBA/C57BL, CBA/BALB/c, C57BL/C57BL, C57BL/CBA, C57BL/BALB/c) that maintained the differences in the bone marrow frequency of various CFC types characteristic of the donor strain.