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We have studied the effects of medium conditioned by the human progranulocytic leukemia cell line, HL-60, on the subsequent growth of new inocula of HL-60 cells. When HL-60 cells were cultured at high cell density, optimal growth rate occurred in liquid suspension and confluent colony growth was observed in viscous medium without the addition of conditioned medium. However, when cells were cultured at lower cell density, growth rate was reduced and colony growth was nil unless conditioned medium from HL-60 culture was added. All HL-60 populations studied, including the earliest available passage, 9, both elaborated and responded to HL-60 CM. HL-60 CM did not stimulate normal human or mouse granulocyte-monocyte colony-forming cell (CFU-GM) growth. Conditioned media from other human cell lines varied in the ability to stimulate HL-60 cell and CFU-GM proliferation. Some, such as GCT CM, stimulated both HL-60 cells and normal CFU-GM, whereas others, like HL-60 CM, stimulated only HL-60 growth. The majority of cell line CMs tested did not stimulate either HL-60 or CFU-GM. Chromatography of HL-60 CM on Ultrogel AcA54 showed a single peak of HL-60 stimulating activity of apparent molecular weight 13,000. The ability of HL-60 cells to elaborate this activity provides a possible explanation for their proliferation at higher cell densities. Autostimulation may prove to be important in the high growth potential of other cell populations that undergo unrepressed proliferation.

GCT, a human monocyte-like cell line, has been shown to release biochemically distinct colony-stimulating activities (CSAs) for mouse and human marrows. These appear to be periodate-sensitive proteins with critical disulfide bonds. One, of molecular weight 145,000 daltons, stimulates macrophagic colony growth and is related to a 30,000-dalton molecule that also stimulates mouse growth. A 30,000-dalton CSA for human marrow can be separated from the 30,000-dalton mouse CSA by isoelectric focusing and gradient polyacrylamide gel electrophoresis. This distinction agrees with our previous finding of differential neutralization with anti-human urinary CSF antibody. The 30,000-dalton CSAs stimulate neutrophil, neutrophil-monocyte, and eosinophil colony growth in human marrow but only neutrophil and neutrophil-monocyte colonies in the mouse. Subcellular fractionation of GCT cells indicates that there are pools of preformed CSAs primarily associated with the cell cytosol that have similar apparent molecular weights to their secreted counterparts.

We have determined the influence of reference particle deformability and suspending buffer tonicity on the measurement of lymphocyte volume by an electronic particle volume analyzer. When the volume analyzer was standardized with latex spherules having a shape factor (fe) of 1.5, red cell volume was 96 cu micron and lymphocyte volume was 289 cu micron. The red cell volume corresponded closely to the true red cell volume; the true lymphocyte volume, however, was 218 cu micron when measured by the lymphocytocrit/lymphocyte count and 203 cu micron by wet lymphocyte weight and density (mean approximately 210 cu micron). The difference between the electronic volume (Ve) of 289 cu micron and true lymphocyte volume of 210 cu micron was due to the influence of lymphocyte deformability (shape factor) as it traverses the sizing aperture. Since the true volume equals the Ve/fe, the red cells with a shape factor near 1.0 were sized appropriately by this method. In contrast, the lymphocyte shape factor was 1.38; thus, the true lymphocyte volume was 289 cu micron/1.38 or 210 cu micron. The tonicity of the suspending solution also influenced the measurement of particle volume when osmotically inactive standard particles (e.g., latex spherules) were used as a reference. Whereas the true lymphocyte volume was 210 cu micron at 286 mosmole/liter, it was 194 cu micron at 330 and 229 cu micron at 250 mosmole/liter. The standard counting solution, Isoton, is hyperosmolar (330 mosmole/liter) and causes an 8% shrinkage of osmotically active cells.

We have studied the marrow cells from a patient with acute myeloid leukemia (AML) for their responsiveness to colony-stimulating activity (CSA) in vitro. The AML cells were stimulated by CSA to rapid and extended growth in liquid culture. In the absence of CSA, the majority of cells died. CSA also stimulated the clonal growth of AML cells, and the minimum requirement for CSA was one-tenth to one-fiftieth that required to stimulate the growth of normal marrow CFU-C. CSA for AML cells was eluted from Sephacryl S-200 columns in fractions that represented an apparent molecular weight of 45,000 daltons. This fraction also produced optimal stimulation of normal human marrow. During remission, the patient's marrow cells did not grow in liquid culture and produced normal numbers of granulocytic and erythroid colonies in response to CSA and erythropoietin. Extended culture of the AML cells resulted in cell differentiation evidenced by decreasing proliferative capacity and by morphological and histochemical changes. These studies indicate that certain AML cells are extraordinarily responsive to CSA, an in vitro mediator of normal granulopoiesis.

The growth of human eosinophil progenitors (CFU-Eo) and the modulation of growth by hydrocortisone were studied as functions of the presence of lymphocytes and monocytes in marrow cells under study; and the source of colony-stimulating factors, specifically, media conditioned by macrophage-like cell line, GCT; phytohemagglutinin-stimulated mononuclear cells (PHA-LCM); or the T cell line, MO. CFU-Eo growth was greatest in marrow containing accessory cells as compared to marrow depleted of accessory cells; and in marrow treated with phytohemagglutinin-stimulated leukocyte conditioned media (PHA-LCM) or MO (T cell line)-conditioned medium (MO-CM) as compared with GCT cell- conditioned medium (GCT-CM). Hydrocortisone reproducibly inhibited eosinophil progenitor growth in unfractionated marrow stimulated by GCT- CM. This effect was abrogated by admixing irradiated mononuclear cells or T lymphocytes with the target marrow or by adding interleukin 1 or interleukin 2 (IL-1, IL-2). Inhibition by hydrocortisone did not occur when monocyte and T lymphocyte depleted marrow was studied. Unlike GCT- CM, MO-CM and PHA-LCM stimulated equal proportions of eosinophil progenitors in nondepleted and accessory cell-depleted marrow and demonstrated less hydrocortisone inhibition. However, both GCT-CM and PHA-LCM produced in the presence of hydrocortisone stimulated significantly fewer CFU-Eos in both unfractionated and accessory cell- depleted marrow target populations. These results indicate that the growth of CFU-Eo and inhibition of growth by hydrocortisone is a direct function of a monocyte-T cell interaction and probably is mediated through effects on the production/release of eosinophil colony stimulating factor (Eo-CSF).

The abnormal multimeric composition of plasma von Willebrand factor in type IIB von Willebrand's disease is transiently corrected after infusion of 1-deamino-[8-D-arginine]-vasopressin. However, the larger multimers released into the circulation disappear more rapidly in these patients than in type I von Willebrand's disease or normals. We demonstrate that the larger multimers of normal von Willebrand factor transfused into a type IIB patient are cleared from the circulation more slowly than multimers of similar size endogenously released from tissue stores. The rate of disappearance of large von Willebrand factor multimers after infusion of cryoprecipitate is similar in IIB, IIA, and severe homozygous-like von Willebrand's disease. Platelets from the IIB patient exhibited normal ristocetin-induced binding of normal von Willebrand factor. However, like normal platelets, they bound IIB von Willebrand factor at lower ristocetin concentrations than required for normal von Willebrand factor. These findings provide evidence that absence of the larger multimers from IIB plasma is related to a molecular abnormality of von Willebrand factor rather than to enhanced affinity of abnormal tissue or cellular binding sites, as is the case in the recently described “pseudo” von Willebrand's disease and “platelet-type” von Willebrand's disease.

A small quantity of extracellular calcium is required for the stimulation of lymphocytes by mitogens such as plant lectins. Lectin binding to the lymphocyte surface and early postbinding events that eventually lead to DNA synthesis are calcium dependent. Mitogenic lectins such as PHA and Con-A rapidly increase the size of an exchangeable pool of cell calcium and cause a smaller rise in intracellular ionized calcium. The increase in ionized calcium is so small (100–200 nM), however, that no increase in total cell calcium is measurable. When lymphocytes are stimulated by a lectin, the rate of calcium entry into the cell increases, but the plasma membrane calcium extrusion pump can prevent the total cell calcium from increasing measurably. The calcium ionophore A23187 is a lymphocyte mitogen and causes an increase in the exchangeable, ionized, and total cell calcium. The former two effects may be causal in mitogenesis; the latter effect is cytotoxic. With A23187 treatment, the rate of calcium influx exceeds the maximum rate of the plasma membrane extrusion pump and cell calcium increases in proportion to the concentration of A23187. The mitochondria, by virtue of their high membrane potential, provide a sink for the buffering of cytoplasmic calcium after A23187 treatment. Thus, the plasma membrane or mitochondria regulate the distribution of lymphocyte calcium when the cell is stimulated by mitogenic lectins or ionophores. The evidence strongly suggests that an alteration in calcium pools or an increase in cytoplasmic ionized calcium plays a role in the initiation of the biochemical reactions that lead to mitogen-induced lymphocyte proliferation in vitro and, perhaps, to the immune response.

The human cell line, GCT, secretes hemopoietins into serum-free culture medium. The conditioned medium contains activities that stimulate neutrophil-monocyte, macrophage, eosinophil, and erythroid colony growth in human marrow cultures. We have used hydrophobic adsorption chromatography to separate a neutrophil-monocyte colony-stimulating factor (CSF) from the other colony-stimulating activities. This hydrophobic CSF has no eosinophil-stimulating activity and is virtually devoid of erythroid-stimulating activity.

The attachment of particle-bound IgG in a nonphagocytic system stimulates formation of a microfilament-rich, organelle-poor zone in the subjacent cytoplasm of human neutrophils. The attachment site is characterized by ruffling and invagination of the neutrophil membrane. Both IgG attachment and formation of the organelle-poor zone are inhibited by the microfilament inhibitor cytochalasin-B, but not by inhibitors of microtubules, such as colchicine or vinca alkaloids. In contrast, attachment of particle-bound complement is not inhibited by cytochalasin-B in doses known to disrupt actin filaments. There is no discernable change in the subjacent cytoplasm of the neutrophil in response to complement and the membrane attachment site is smooth, without ruffling or invagination. These studies disclose that both IgG- mediated attachment to neutrophils and its sequel, peripheral cytoplasmic reorganization, are mediated by cytochalasin-sensitive structures, possibly actin. Complement-mediated attachment to neutrophils is insensitive to high doses of cytochalasin, suggesting that actin integrity is not required.

Ten patients under 20 yr of age with the usual (adult) type of chronic myelogenous leukemia (CML) were seen at the University of Rochester Medical Center from 1970 to 1982. The mean white cell count in these 10 patients at presentation was 360,000/microliter, as compared to a mean of 137,000/microliter in 80 CML patients over 20 yr of age seen during the same time interval (p less than 0.02). Analyses of all 90 cases revealed a significant decrease in the average leukocyte count at presentation with increasing age. The childhood cases also had a significantly higher proportion of blood blasts, promyelocytes, and myelocytes than did the adult subjects (p less than 0.01). Signs of leukostasis were present in 12% of adult cases as compared to 60% of the 10 childhood cases, and in these 6 subjects, the mean white cell count was 510,000/microliter. In these 6 patients, leukapheresis and/or chemical therapy was initiated rapidly, and this was followed by complete resolution of the clinical signs of leukostasis. A review of the literature from 1960 to 1982 identified 61 childhood cases that were reported with the usual type of CML. In this group, the frequency of hyperleukocytosis and the distribution of white cell counts corresponded very closely to the 10 cases studied at the University of Rochester. Thus, the usual type of CML presenting in childhood differs from that of adults in that hyperleukocytosis, blood granulocyte immaturity, and leukostatic central nervous system, retinal, and respiratory signs are significantly more common and extreme and merit rapid cytoreductive treatment.

By exposing an established cell line of malignant mouse lymphocytic cells (L5178Y) to a culture environment low in calcium and magnesium, we have isolated and maintained in continuous culture a variant population with reduced growth requirements for the cations. The variant cells are larger, have enhanced aggregability, tend to form dispersed colonies in semisolid medium, and have increased oncogenicity. Variants and their progenitors share similar morphology, maximum proliferative rate, and stability of phenotype. The significance of these findings is discussed and an analogy suggested between the selective influence of calcium and magnesium deprivation in vitro and the evolution of thymic dysplasias in divalent cation- deprived rodents.

Maturation of human myeloid cells is associated with quantitative and qualitative changes in protein kinase C (PKC) and increases in N-formyl- L-methionyl-L-leucyl-L-phenylalanine (FMLP) receptors, actin, and actin regulatory proteins. We have studied the actin responses and cell shape changes caused by FMLP and its second messenger pathways in HL60 cells undergoing neutrophilic maturation. In uninduced cells, the PKC activators 12-O-tetradecanoyl phorbol-13-acetate (TPA), bryostatin, and 1-oleyl-2-acetylglycerol (OAG) resulted in 15% to 30% decreases in F- actin, whereas FMLP had no effect. Ionomycin had no effect on actin but did cause a 10-fold increase in intracellular calcium. Cells grown for 24 hours in 1% dimethyl sulfoxide (DMSO) acquired the ability to polymerize actin in response to FMLP and ionomycin. TPA continued to cause a decrease in F-actin at 24 hours, but caused an increase in F- actin at 48 to 72 hours of maturation. The PKC inhibitor 1–5- isoquinolinesulfonyl 2-methylpiperazine (H7) partially blocked the F- actin increase caused by TPA in induced cells, but had no effect on the decrease in F-actin caused by TPA in uninduced cells or the increase in F-actin seen in FMLP-treated neutrophils. F-actin rich pseudopods developed following TPA or FMLP stimulation of induced HL60 cells; in uninduced cells neither agent caused pseudopod formation but TPA caused a dramatic loss of surface ruffles. The ability of FMLP and ionomycin to elicit a neutrophil-like actin response in HL60 cells within 24 hours after DMSO treatment shows that the actin regulatory mechanism is mature by that time. The inability of ionomycin to increase F-actin in uninduced cells supports the view that calcium increases alone are insufficient for actin polymerization. The longer maturation time required for HL60 cells to develop an actin polymerization response to TPA compared with FMLP, coupled with the inability of H7 to block the FMLP-mediated F-actin increase in neutrophils, suggests that the F- actin increase caused by FMLP is not mediated solely by PKC. Lastly, the TPA-induced F-actin decrease and shape changes in uninduced HL60 cells, and the longer time required for a “mature” response to TPA, may reflect immaturity in the PKC isoenzyme pattern rather than immaturity of the actin regulatory mechanism.

Adherent cell layers and their associated extracellular matrices form when human marrow is incubated in cultures containing hydrocortisone and horse serum. These stromal layers contain cells positive for alkaline phosphatase; secrete collagens types I and III and fibronectin, bind the anti-actin monoclonal antibodies (MoAbs) HHF and CGA-7; stain with oil red O, and express the acetylated LDL receptor. Highly purified CD34 (My10)-positive progenitor cells attach to these stromal layers, and a 16-fold enrichment of CFU-GM in both stromal attachment and semisolid agar assays was observed. Granulopoiesis persisted up to 40 days (mean duration 25 days) after passaged stroma were recharged with stromal cell-depleted target cells in a two-stage liquid marrow culture system. Although equal to marrow fibroblasts in their ability to bind CD34+ myeloid progenitors, stromal layers were better at supporting granulopoiesis. This system provides an in vitro model to characterize the components of stroma and stroma-cytomatrix that enhance marrow progenitor cell localization and maintenance.

One hundred-nine cases of autoimmune hemolysis were reviewed to determine the frequency of reticulocytopenia, the state of the erythroid marrow in reticulocytopenic cases, and the course of reticulocyte production indices with time and glucocorticoid treatment. The mean hematocrit at presentation was 24 mL/dL, but 30% of cases had an initial hematocrit less than 20 mL/dL. Median reticulocyte percentage at diagnosis was 9%, and median reticulocyte production index was 2.8 times basal. Twenty percent of cases had an initial reticulocyte count less than 4%, and 37% had an initial reticulocyte production index less than 2.0 times basal. These reticulocytopenic patients were nearly evenly distributed between warm and cold antibody- mediated cases and between primary and secondary cases. Fifty-four percent of reticulocytopenic cases had a bone marrow examination during hospitalization. Three-fourths of these marrows showed erythroid hyperplasia, and erythroid hypoplasia was seen in only one case. Eighty- eight cases had serial reticulocyte measurements, and in only 15% of patients did the reticulocyte production index remain less than 2.0 times basal. Thus, in most cases, the initially low reticulocyte production index may represent a lag in marrow responsiveness to hemolytic stress. In cases with persistent reticulocytopenia, ineffective erythropoiesis is suggested by the frequency of marrow erythroid hyperplasia. In the cases that were initially reticulocytopenic and demonstrated an increase in reticulocyte production index, the magnitude of this increase was significantly greater in glucocorticoid-treated patients than in those not so treated, indicating that a glucocorticoid sensitive component exists in the marrow erythropoietic response to hemolysis. Awareness of the frequency of an initial reticulocytopenia in cases of autoimmune hemolysis may be important in initial diagnosis and treatment.

The prognosis for patients with chronic myelogenous leukemia (CML) has improved only for patients who can receive marrow transplantation from a histocompatible sibling. The timing of the marrow transplant is made difficult by the high peritransplant mortality of 20% to 35% and a group of patients with a prolonged chronic phase of CML, which can be identified on the basis of prognostic indexes (age, percent blood myeloblasts, spleen size, and platelet count). We have developed a mathematic model and computer program that consider age, prognostic index, and projected survival rate by transplantation to balance the risk of peritransplant mortality against the risk of delaying the transplantation of patients with Philadelphia chromosome-positive CML. The computation assesses the risk of delaying transplantation; it does not offer the option of avoiding transplantation, since long-term survival ultimately requires transplantation. Three prognostic groups were considered as described by Sokal and co-workers (Blood 63:789, 1984) (I, best; II, intermediate; III, worst prognosis). The computation used the projected survival rates of transplantation from the Seattle experience and from the International Bone Marrow Transplant Registry. As an example of the model's utility, we have determined the ratio of the calculated life expectancy to the normal life expectancy for hypothetical patients up to 50 years of age in each of the three prognostic categories. A value of 20% is used for patients who successfully receive transplants after the onset of the accelerated phase. The analysis allows assessment of the risk of delaying transplantation for a finite time in patients with CML. The importance of the method rests in its consideration of multiple variables, including the peritransplant mortality, transplant projected survival before and upon entering the accelerated phase, age, prognostic group, and other risk factors. The program permits a change in these parameters as new information or advances in treatment occur. This analysis does not replace the diagnostic deliberations of the clinician. Rather, it provides a numeric framework for prognosis based on the currently available data. The physician in conjunction with the patient, not the algorithm, makes the decisions of whether and when to transplant.

Neutrophils were examined for their ability to recognize and ingest beads coated with amino-derivatives of glucose, mannose, and galactose. Radioactive or fluorescent beads coated with any of the three sugars were ingested to an extent three times that observed with albumin- coated beads. Enhancement of ingestion of sugar-coated beads was much more evident when examined by electron micrographic studies. Inclusion of glucose or mannose in the medium with glucose- or mannose-coated beads caused a dose-dependent reduction of ingestion to control levels, but ingestion of galactose-coated beads was poorly inhibited. Similarly, galactose or fucose (6-deoxy-galactose) markedly inhibited ingestion of galactose-coated beads, but caused only a slight decrease in ingestion of glucose- or mannose-coated beads. Thus, neutrophils possess carbohydrate-binding membrane structures that can mediate recognition and ingestion of sugar-coated beads. Such carbohydrate recognition systems may underlie certain interactions of neutrophils and other surfaces.

We have established two human cell lines which elaborate colony- stimulating activity (CSA) for at least four species: man, mouse, rabbit, and dog. One, GCT, was isolated from a lung metastasis of a fibrous histiocytoma; the other, RC4, from a monocyte-enriched fraction of normal blood. Medium conditioned by either GCT or RC4 cells was more potent in stimulating human marrow growth in vitro than was monocyte-conditioned medium or human leukocyte feeder layers. Fractionation of cell-line-conditioned medium by Sephacryl S-200 chromatography indicated that the maximum activity of the CSA for human marrow cells is eluted within the range of 30,000–40,000 daltons. These cells lines provide a continuous source of large quantities of conditioned medium for purification of CSA. Moreover, the invariable growth-supporting activity for all species tested and the high potency of cell-line CSA facilitates studies of its elaboration and biologic effects.