Analysis of treatment failure in acute nonlymphocytic leukemia patients over fifty years of age. A Southwest Oncology Group study

Fourteen participating centers registered 33 patients on a Southwest Oncology Group Study of adults with acute non-lymphocytic leukemia (ANLL). Induction consisted of cytosine arabinoside 70 mg/m2 days 1-7 by continuous intravenous (i.v.) infusion, VP-16 50 mg/m2 i.v. over 1 hour days 1-3, and daunomycin 30 mg/m2 i.v. bolus days 1-3. Twenty-five patients (median age 69 years) were evaluable for response. Eleven (44%) achieved a remission marrow but only 8 fulfilled both blood and marrow criteria for complete remission. Of the 11 patients with a remission marrow, there were no patients over 70 years of age. Major coexisting disease data were evaluated. Only 5 patients had no major coexisting disease and 4 of those 5 achieved a remission marrow. The study illustrates and underscores the following problems of remission induction in the elderly: (a) increased susceptibility to the stress of the induction period, with 6 patients (24%) dying before treatment day sixteen; (b) disease resistance to antileukemic therapy with persistent ANLL in 6 patients (24%), despite two induction courses; and (c) hematopoietic stem cell sensitivity in the elderly with marrow regeneration failure documented in 2 patients (8%) following induction. Acute nonlymphocytic leukemia in the elderly has a poor prognosis, and novel therapeutic approaches are warranted.

Characterization of human alveolar macrophage Fc gamma receptor III: a transmembrane glycoprotein that is shed under in vitro culture conditions

Three classes of Fc gamma receptors (FcR) have been identified on blood leukocytes: FcRI, FcRII, and FcRIII. Two forms of FcRIII have recently been characterized; a phosphatidylinositol linked form is found on neutrophils, whereas a transmembrane form of the molecule is found on a subset of peripheral blood lymphocytes. Peripheral blood monocytes express low levels of FcRIII on their surface, whereas FcRIII is readily expressed by tissue macrophages. The purpose of this investigation was to characterize the form of FcRIII expressed by normal human alveolar macrophages (AM) obtained from normal subjects by bronchoalveolar lavage. We found FcRIII expressed by AM has a molecular mass of 50 to 60 kD on sodium dodecyl sulfate polyacrylamide gel electrophoresis and migrates as a single band with a molecular mass of 35 kD after digestion with endoglycosidase F. Macrophage FcRIII was resistant to cleavage by phosphatidylinositol-specific phospholipase C. These results demonstrate that FcRIII expressed by AM is a transmembrane glycoprotein similar to the molecule found on peripheral blood lymphocytes. Scatchard binding analysis using 125I-labeled mAb 3G8 showed that AM express similar numbers of FcRIII as found on neutrophils (73,300 +/- 16,300 versus 69,300 +/- 8,500 receptor sites/cell, respectively; P = 0.73), whereas fewer binding sites were found on FcRIII-positive peripheral blood lymphocytes (35,300 +/- 13,900; P = 0.04). Of note, we found expression of FcRIII by AM was selectively and dramatically reduced during short term in vitro incubation at 37 degrees C. Receptor shedding as a result of proteolytic cleavage is probably responsible for the reduced expression that occurs during short-term in vitro culture.

Vascular cell adhesion molecule-1 and the integrin VLA-4 mediate adhesion of human B cell precursors to cultured bone marrow adherent cells

Adhesion of B cell precursors to accessory cells in the bone marrow microenvironment may be required for normal early B cell development. Human bone marrow B cell precursors adhere more avidly than mature B cells to bone marrow-derived fibroblasts. To determine the mechanism of this adhesion, expression of adhesion proteins on human B precursor cells and cell lines was measured by flow cytometry. The very late antigen (VLA) integrins VLA-4 and VLA-5 were the only adhesion proteins expressed at higher levels in B cell precursors than mature B cells. Antibodies to the alpha and beta chains of VLA-4, but not VLA-5, significantly blocked binding to bone marrow-derived fibroblasts of immature B cells and cell lines. Although fibronectin is a ligand for VLA-4, anti-fibronectin antibody and a soluble fibronectin fragment containing the VLA-4 binding domain did not block adhesion, suggesting that VLA-4 is involved in adhesion of B cell precursors, but not as a fibronectin receptor. Vascular cell adhesion molecule-1 (VCAM-1), the other known counterreceptor for VLA-4, was identified on bone marrow-derived fibroblasts, and anti-VCAM-1 significantly blocked adhesion of normal B cell precursors to bone marrow-derived fibroblasts, indicating that VLA-4/VCAM-1 interactions are important in adhesion of B cell precursors to the bone marrow microenvironment.

Macrophage-active colony-stimulating factors enhance human immunodeficiency virus type 1 infection in bone marrow stem cells

To define the relationship between human immunodeficiency virus type 1 (HIV-1) infection in hematopoietic stem cells and virus production by their progeny, we performed kinetic studies infecting bone marrow (BM) stem cells and culturing them in the presence of hematopoietic growth factors. CD34-positive (CD34+), CD4-negative (CD4-) BM cells were isolated and infected in vitro with the monocytotropic HIV-1JR-FL strain or the laboratory-maintained HTLV-IIIB strain at a high multiplicity of infection. The cells were susceptible to productive infection only with HIV-1JR-FL, and virus production as measured by p24 protein release was markedly increased (more than fivefold) in the presence of granulocyte-macrophage colony-stimulating factor (GM-CSF) and interleukin-3 (IL-3). Macrophage CSF (M-CSF) was less stimulatory and granulocyte CSF (G-CSF) had no effect on virus production. Virus production coincided with proliferation of mononuclear phagocytes but was not related to granulocytic proliferation in G-CSF-treated BM cultures. Although peak virus production from GM-CSF-treated macrophages occurred 2 to 3 weeks after infection, peak virus production in infected stem cells was observed 5 to 6 weeks after. Enhancement in virus production had a more rapid onset when CD34+/CD4- cells were cultured in the presence of both GM-CSF and IL-3 for 7 or 14 days. Under these conditions there was a 10-fold enhancement in virus production after 7 days of preincubation and a 50-fold enhancement after 14 days. These data indicate that while the stem cell compartment may be susceptible to infection with a monocytotropic HIV-1 strain, productive and sustained infection is realized only after macrophage differentiation. The lack of effect of G-CSF on virus production is likely because of the limited effect of this hematopoietin on mononuclear phagocyte generation and function.

Adhesive interactions of normal and leukemic human CD34+ myeloid progenitors: role of marrow stromal, fibroblast, and cytomatrix components

Adhesive interactions between CD34+ myeloid progenitors, cytomatrix components, and marrow fibroblast and stromal monolayers are described and compared to the binding interactions of the CD34+ myeloid leukemic cell lines KG1a and KG1. Both normal precursors and their leukemic counterparts showed adhesion to marrow stroma and fibroblasts. CD34+ myeloid progenitors bound to the extracellular matrices of marrow stromal cell and fibroblast monolayers and to laminin and fibronectin to a lesser extent than to cellular stromal layers. These adhesive interactions were not inhibited by polyclonal antibodies to laminin or fibronectin, nor by 1 mM Arg-Gly-Asp-Ser (RGDS)-containing peptides. Also, although both normal and leukemic cells expressed the CD18 antigen, binding of these cells to stroma was not inhibited by blocking anti-CD18 monoclonal antibodies. Finally, KG1a adhesion was not blocked in the presence of anti-CD54 (ICAM) antibody, nor was it blocked when galactosyl or mannosyl pyranosides were added. KG1a binding was trypsin sensitive and enhanced in the presence of neuraminidase. These studies serve to characterize adhesive properties of normal and leukemic myeloid progenitors and begin to establish interactions important for the lodgement of early progenitor cells in human marrow.

Maturation-dependent adhesion of human B cell precursors to the bone marrow microenvironment

Murine B cell precursors can be induced to proliferate in culture if allowed to bind to bone marrow derived adherent cells prepared under specific conditions. We studied the binding of human B cell precursor subpopulations to various in vitro microenvironments to determine which conditions may potentially be suitable models for human B precursor differentiation. Using the markers CD10, CD34, and CD20, B lineage populations of increasing maturation were quantitated: CD10+/CD34+, CD10+/CD20-, CD10+/CD20+, and CD10-/CD20+ cells in marrow, and CD10-/CD20+ mature B cells in peripheral blood. The adhesion of subpopulations of blood and marrow-derived light density cells to adherent cell layers or matrix was studied following a 2-h incubation in 24-well plates. The absolute number of bound B lineage cells was determined by cell counts and flow cytometry analysis. The adherence of B lineage cells to passaged human marrow fibroblasts (BM-FB) was highest in the most immature CD10+/CD34+ cells (34.3 +/- 4.2%), decreasing steadily with each stage of maturation to the peripheral blood B cells (11.2 +/- 2.4%). Increased adhesion of CD10+ B cell precursors relative to CD10-/CD20+ marrow B cells was confirmed by adhesion studies using sorted cells. The two most immature B lineage cells (CD10+CD34+ and CD10+/CD20-) showed more adherence to BM-FB than any other cell type tested, except for monocytes. Only B lineage precursor cells, erythroid precursors and CD10-/CD34+ cells showed significantly greater binding to BM-FB than to plastic. B lineage precursors bound equally well to primary and passaged human marrow fibroblasts, but bound significantly less well to passaged human foreskin fibroblasts, primary human marrow stroma, extracellular matrix of marrow fibroblasts, or fibronectin. These results suggest that specific binding to marrow fibroblasts is part of the differentiation program of early B lineage precursors. This binding activity gradually and predictably decreases during B lineage differentiation, in contrast to expression of other binding receptors, such as LFA-1 and CD44, which increase during B lineage maturation.

Maturation-dependent adhesion of human B cell precursors to the bone marrow microenvironment

Murine B cell precursors can be induced to proliferate in culture if allowed to bind to bone marrow derived adherent cells prepared under specific conditions. We studied the binding of human B cell precursor subpopulations to various in vitro microenvironments to determine which conditions may potentially be suitable models for human B precursor differentiation. Using the markers CD10, CD34, and CD20, B lineage populations of increasing maturation were quantitated: CD10+/CD34+, CD10+/CD20-, CD10+/CD20+, and CD10-/CD20+ cells in marrow, and CD10-/CD20+ mature B cells in peripheral blood. The adhesion of subpopulations of blood and marrow-derived light density cells to adherent cell layers or matrix was studied following a 2-h incubation in 24-well plates. The absolute number of bound B lineage cells was determined by cell counts and flow cytometry analysis. The adherence of B lineage cells to passaged human marrow fibroblasts (BM-FB) was highest in the most immature CD10+/CD34+ cells (34.3 +/- 4.2%), decreasing steadily with each stage of maturation to the peripheral blood B cells (11.2 +/- 2.4%). Increased adhesion of CD10+ B cell precursors relative to CD10-/CD20+ marrow B cells was confirmed by adhesion studies using sorted cells. The two most immature B lineage cells (CD10+CD34+ and CD10+/CD20-) showed more adherence to BM-FB than any other cell type tested, except for monocytes. Only B lineage precursor cells, erythroid precursors and CD10-/CD34+ cells showed significantly greater binding to BM-FB than to plastic. B lineage precursors bound equally well to primary and passaged human marrow fibroblasts, but bound significantly less well to passaged human foreskin fibroblasts, primary human marrow stroma, extracellular matrix of marrow fibroblasts, or fibronectin. These results suggest that specific binding to marrow fibroblasts is part of the differentiation program of early B lineage precursors. This binding activity gradually and predictably decreases during B lineage differentiation, in contrast to expression of other binding receptors, such as LFA-1 and CD44, which increase during B lineage maturation.

Alveolar and peritoneal macrophages bear three distinct classes of Fc receptors for IgG

The FcR for IgG on the plasma membrane of cells of the mononuclear phagocyte system mediate a number of different biologic responses such as phagocytosis, pinocytosis, superoxide generation, and antibody-dependent cytotoxicity. In the interest of understanding the pathophysiology of these processes we have begun to characterize the FcR for IgG on two readily available sources of macrophages--the lung and the peritoneum--using antireceptor mAb. We find that all three of the distinct classes of FcR for IgG which have been described in man are present on both pulmonary and peritoneal macrophages. Most monocytes, we suggest, bear low numbers of Fc gamma RIII whereas a small subpopulation of monocytes expresses substantial numbers of Fc gamma RIII. Furthermore, we find that two different forms of Fc gamma RIII differ in their capacity to bind anti-Fc gamma RIII mab 3G8 in the presence of human IgG. Human IgG does not block the binding of mAb 3G8 to neutrophils, but it does block 3G8 binding to macrophages and large granular lymphocytes; this finding correlates with the expression of the two Fc gamma RIII genes, I and II, in man. Studies aimed at illuminating the molecular mechanisms of Fc gamma R-mediated processes in macrophages will require consideration of the receptors of all three classes.

Alveolar and peritoneal macrophages bear three distinct classes of Fc receptors for IgG

The FcR for IgG on the plasma membrane of cells of the mononuclear phagocyte system mediate a number of different biologic responses such as phagocytosis, pinocytosis, superoxide generation, and antibody-dependent cytotoxicity. In the interest of understanding the pathophysiology of these processes we have begun to characterize the FcR for IgG on two readily available sources of macrophages--the lung and the peritoneum--using antireceptor mAb. We find that all three of the distinct classes of FcR for IgG which have been described in man are present on both pulmonary and peritoneal macrophages. Most monocytes, we suggest, bear low numbers of Fc gamma RIII whereas a small subpopulation of monocytes expresses substantial numbers of Fc gamma RIII. Furthermore, we find that two different forms of Fc gamma RIII differ in their capacity to bind anti-Fc gamma RIII mab 3G8 in the presence of human IgG. Human IgG does not block the binding of mAb 3G8 to neutrophils, but it does block 3G8 binding to macrophages and large granular lymphocytes; this finding correlates with the expression of the two Fc gamma RIII genes, I and II, in man. Studies aimed at illuminating the molecular mechanisms of Fc gamma R-mediated processes in macrophages will require consideration of the receptors of all three classes.

Human alveolar macrophage FcR-mediated cytotoxicity. Heteroantibody- versus conventional antibody-mediated target cell lysis

Human alveolar macrophage have three distinct receptors for IgG: FcRI, FcRII, and FcRIII. In order to compare the ability of these receptors to mediate target cell lysis, three different assay systems were examined. First, we studied lysis of chicken E (CE) opsonized with heteroantibodies, which are synthetic antibodies composed of Fab fragments with anti-FcR activity covalently linked to Fab fragments with anti-CE activity. We found alveolar macrophage readily lysed heteroantibody-opsonized CE via each of the three FcR classes (FcRI, 20 +/- 5%; FcRII, 27 +/- 7%; and FcRIII, 13 +/- 13%, p less than 0.05). Non-FcR-dependent lysis of anti-beta 2-microglobulin x anti-CE heteroantibody-opsonized CE was not detected. Second, lysis of hybridoma cell lines bearing anti-FcR antibodies on their cell surface was examined to assess killing of "tumor-like" target cells. Whereas peripheral blood monocytes and lymphocytes were able to lyse hybridoma cell lines bearing surface anti-FcR mAb, alveolar macrophages were not. Third, activity of alveolar macrophage FcR was examined in a conventional antibody-dependent cellular cytotoxicity assay by using O+ (R1,R2) human RBC opsonized with human anti-D and anti-CD serum as target cells. We found lysis of anti-D and anti-CD opsonized human RBC was mediated exclusively via FcRI. No activity of FcRII or FcRIII was detected in these latter assays even if performed under conditions that impair FcRI activity. Thus, all three FcR present on alveolar macrophage mediate lysis of heteroantibody-opsonized CE; in contrast, with the use of a conventional antibody-dependent cellular cytotoxicity assay, only FcRI activity was detected. We were unable to demonstrate lysis of anti-FcR-bearing hybridoma cell lines by alveolar macrophages.

Human alveolar macrophage FcR-mediated cytotoxicity. Heteroantibody- versus conventional antibody-mediated target cell lysis

Human alveolar macrophage have three distinct receptors for IgG: FcRI, FcRII, and FcRIII. In order to compare the ability of these receptors to mediate target cell lysis, three different assay systems were examined. First, we studied lysis of chicken E (CE) opsonized with heteroantibodies, which are synthetic antibodies composed of Fab fragments with anti-FcR activity covalently linked to Fab fragments with anti-CE activity. We found alveolar macrophage readily lysed heteroantibody-opsonized CE via each of the three FcR classes (FcRI, 20 +/- 5%; FcRII, 27 +/- 7%; and FcRIII, 13 +/- 13%, p less than 0.05). Non-FcR-dependent lysis of anti-beta 2-microglobulin x anti-CE heteroantibody-opsonized CE was not detected. Second, lysis of hybridoma cell lines bearing anti-FcR antibodies on their cell surface was examined to assess killing of "tumor-like" target cells. Whereas peripheral blood monocytes and lymphocytes were able to lyse hybridoma cell lines bearing surface anti-FcR mAb, alveolar macrophages were not. Third, activity of alveolar macrophage FcR was examined in a conventional antibody-dependent cellular cytotoxicity assay by using O+ (R1,R2) human RBC opsonized with human anti-D and anti-CD serum as target cells. We found lysis of anti-D and anti-CD opsonized human RBC was mediated exclusively via FcRI. No activity of FcRII or FcRIII was detected in these latter assays even if performed under conditions that impair FcRI activity. Thus, all three FcR present on alveolar macrophage mediate lysis of heteroantibody-opsonized CE; in contrast, with the use of a conventional antibody-dependent cellular cytotoxicity assay, only FcRI activity was detected. We were unable to demonstrate lysis of anti-FcR-bearing hybridoma cell lines by alveolar macrophages.

Pennington Biomedical Research Center. Philanthropy refocuses nutrition thinking

Pennington Biomedical Research Center (PBRC) is a $26 million facility constructed as the initial component of a generous gift from Baton Rouge oilman and philanthropist Claude B. "Doc" Pennington. The US Department of Agriculture provided a $9.4 million grant for equipment for the center. The Louisiana Public Facilities Authority provided $4.1 million for initial operating capital, and the center received a $3.5 million grant from the US Army for military nutrition research. The Pennington Center Foundation, a non-profit support organization, has so far raised $4.6 million from individuals, corporations, and private foundations. Traditional academic funding sources such as the National Institute of Health are also providing funding for research.

Rearrangement of the T-cell receptor alpha, beta and gamma chain genes in chronic lymphocytic leukemia

Simultaneous expression of mature B-cell and T-cell markers and subsequent abrogation of expression of the T-cell surface markers by cytotoxic chemotherapy was reported earlier in a patient (TG) with chronic lymphocytic leukemia (CLL). In addition to rearrangements of the immunoglobulin (Ig) gene loci correlating with phenotypic data, the T-cell receptor (TCR) alpha, beta and gamma chain genes also displayed clonal rearrangements in peripheral blood lymphocyte DNA of TG. The present case shows that in CLL cells not only the expression of B-cell and T-cell specific differentiation antigens but also the rearrangement of Ig as well as TCR alpha, beta and gamma genes may occur simultaneously.

Characterization of human marrow stromal cells: role in progenitor cell binding and granulopoiesis

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.

Clonal B cell expansions in patients with essential mixed cryoglobulinaemia

In essential mixed, type II, cryoglobulinaemia (EMC) monoclonal autoantibodies with rheumatoid factor activity are synthesized at an accelerated rate by non-malignant B lymphocytes. In order to determine if the high cryoglobulin production rate is related to a clonal B cell expansion, cell surface markers of peripheral blood lymphocytes (PBL) were analysed by flow cytometry and the rearrangement of immunoglobulin (Ig) genes was investigated by Southern blot analysis of DNA extracted from the PBL of 12 EMC patients. Clonal expansion of B cells could be detected using DNA probes specific for the c kappa, c-mu, and JH genes in four out of 12 patients, two of whom also showed specific expansions of mu heavy and kappa light chain bearing cells using flow cytometry. The rearrangement of the c-myc locus was also noted in one of the patients with detectable Ig gene rearrangements. Demonstration of clonal B cell expansions in EMC patients shows that the clonal type of Ig gene rearrangements are not unique markers of malignant lymphomas but may also occur in autoimmune lymphoproliferative disorders. Since malignant B cell lymphomas can develop in a small number of EMC cases, the follow-up of these patients should be pursued indefinitely.

Structural polymorphism of the human platelet Fc gamma receptor

A variable T lymphocyte proliferative response to murine IgG1 anti-T3 monoclonal antibodies, in which most North American Caucasians respond whereas a minority do not, is well established. This is most likely the result of a genetic polymorphism manifested by 1) the inability of the monocyte 40-kDa IgG FcR of some individuals to bind murine IgG1, and 2) a distinctive trimorphic pattern on IEF of the monocyte 40-kDa FcR, one form being seen in all individuals who do not respond and another form (or a combination of both forms) being seen in those who do respond. We have evaluated the IEF patterns of the platelet 40-kDa FcR and find that in every individual tested the pattern for platelet FcR correlates with that seen for the monocyte 40-kDa FcR pattern. Furthermore, the platelets of those individuals whose "nonresponder" monocyte 40-kDa FcR did not mediate a murine IgG1 anti-T3 response did not respond with an aggregation reaction to murine IgG1 immune complexes (opsonized E). In contrast, platelets from donors possessing "responder" monocytes displayed positive "aggregation" responses to E coated with murine IgG1 antibody. However, the platelet FcR structural polymorphism described earlier did not correlate with the donor-specific variability in capacity of platelets to respond functionally to aggregated human IgG described in an earlier paper. Rather, the variation in capacity of platelets from individual donors to respond functionally to aggregated human IgG was related to the quantitative expression of platelet FcR. These data indicate that the molecular mechanisms responsible for the platelet 40-kDa FcR structural polymorphism are quite different from the mechanisms governing the variation in quantitative expression of the receptor.

Structural polymorphism of the human platelet Fc gamma receptor

A variable T lymphocyte proliferative response to murine IgG1 anti-T3 monoclonal antibodies, in which most North American Caucasians respond whereas a minority do not, is well established. This is most likely the result of a genetic polymorphism manifested by 1) the inability of the monocyte 40-kDa IgG FcR of some individuals to bind murine IgG1, and 2) a distinctive trimorphic pattern on IEF of the monocyte 40-kDa FcR, one form being seen in all individuals who do not respond and another form (or a combination of both forms) being seen in those who do respond. We have evaluated the IEF patterns of the platelet 40-kDa FcR and find that in every individual tested the pattern for platelet FcR correlates with that seen for the monocyte 40-kDa FcR pattern. Furthermore, the platelets of those individuals whose "nonresponder" monocyte 40-kDa FcR did not mediate a murine IgG1 anti-T3 response did not respond with an aggregation reaction to murine IgG1 immune complexes (opsonized E). In contrast, platelets from donors possessing "responder" monocytes displayed positive "aggregation" responses to E coated with murine IgG1 antibody. However, the platelet FcR structural polymorphism described earlier did not correlate with the donor-specific variability in capacity of platelets to respond functionally to aggregated human IgG described in an earlier paper. Rather, the variation in capacity of platelets from individual donors to respond functionally to aggregated human IgG was related to the quantitative expression of platelet FcR. These data indicate that the molecular mechanisms responsible for the platelet 40-kDa FcR structural polymorphism are quite different from the mechanisms governing the variation in quantitative expression of the receptor.

Expression of IgG Fc receptors in myeloid leukemic cell lines. Effect of colony-stimulating factors and cytokines

Three classes of FcR have been defined on human myeloid cells by their reactivity with mAb; FcRI (mAb 32); FcRII (mAb IV3); and FcRIII (mAb 3G8). We have quantitated the expression of each FcR on human myeloid leukemia cells and cell lines (KG-1, HL-60, U937, and K562). Detailed analysis of FcR surface expression is provided for the U937 cell line after exposure to CSF and cytokines. Increased expression of FcRI and FcRII occurred at 72 h in cells exposed to GCT or Mo cell line-conditioned medium as well as to medium from PHA-treated mononuclear cells. The augmentation of FcRII required protein synthesis and was diminished by a neutralizing antibody to granulocyte-macrophage CSF. We also show that fractions containing natural granulocyte CSF or granulocyte-macrophage CSF as well as r-granulocyte and r-granulocyte-macrophage CSF are capable of inducing FcRII on these cells, whereas other cytokines such as IL-1 and IL-2, TNF-alpha, INF-gamma and macrophages CSF failed to do so.

Expression of IgG Fc receptors in myeloid leukemic cell lines. Effect of colony-stimulating factors and cytokines

Three classes of FcR have been defined on human myeloid cells by their reactivity with mAb; FcRI (mAb 32); FcRII (mAb IV3); and FcRIII (mAb 3G8). We have quantitated the expression of each FcR on human myeloid leukemia cells and cell lines (KG-1, HL-60, U937, and K562). Detailed analysis of FcR surface expression is provided for the U937 cell line after exposure to CSF and cytokines. Increased expression of FcRI and FcRII occurred at 72 h in cells exposed to GCT or Mo cell line-conditioned medium as well as to medium from PHA-treated mononuclear cells. The augmentation of FcRII required protein synthesis and was diminished by a neutralizing antibody to granulocyte-macrophage CSF. We also show that fractions containing natural granulocyte CSF or granulocyte-macrophage CSF as well as r-granulocyte and r-granulocyte-macrophage CSF are capable of inducing FcRII on these cells, whereas other cytokines such as IL-1 and IL-2, TNF-alpha, INF-gamma and macrophages CSF failed to do so.

Hu-ets-1 gene in congenital leukemia with t(11;19)(q23;p13)

Cytogenetic analysis of the leukemic cells from a 1-day-old baby with an acute myelomonocytic leukemia revealed them to contain a chromosome change of t(11;19)(q23;p13). Molecular studies using a 980 bp HindIII/HpaI digested v-ets probe showed no DNA rearrangements, deletions, or amplification in the leukemic cells, including the JH immunoglobulin and T-cell receptor (alpha or beta) genes. The findings indicate that the leukemic cells with t(11;19)(q23;p13) appear not to contain a transposition or rearrangement of the protooncogene Hu-ets-1 located at 11q23, as previously described in leukemic cells with t(4;11)(q21;q23) and t(9;11)(p22;q23). The leukemic cases with t(11;19)(q23;p13) studied by us showed a phenotype compatible with their myelomonocytic nature, although it is possible that other cases may have a lymphoid phenotype.