An evaluation of the prognostic significance of antigen CD95(Fas/APO-1) expression on the cells of patients with a myelodysplastic syndrome, acute myeloid leukemia and chronic myeloleukemia

AIM: The expression of CD95(Fas/APO-1) antigen was studied on bone marrow cells of 19 MDS patients, peripheral blood blast cells of 15 acute myeloid leukemia (AML) patients, blast cells and granulocytes of 68 patients with chronic myeloid leukemia (CML)--24 in chronic, 9 in accelerated phase and 35 in blastic crisis (BC)--by indirect surface immunofluorescence assay using flow cytometry (FACScan, Becton Dickinson, USA). RESULTS: CD95(Fas/APO-1) antigen was revealed on bone marrow cells of 8 out of 19 (36.8%) MDS patients; the percentage of antigen-positive cells was 38.1 +/- 19.2%; on 45.5 +/- 22.8% of cells in 6(45%) of 15 AML patients. Fas/APO-1 antigen was totally absent in CML chronic stage; its expression was found in 34% (12 of 35) of our patients with CML BC on peripheral blood blasts and in 56% (5 of 9) on peripheral blast cells of CML patients in acceleration phase. CONCLUSION: The data on overall survival of CD95-positive MDS patients suggest that the presence of Fas antigen is a favorable prognostic sign for patients with MDS. The patients from CD95-negative group represent a risk group both for survival and AML transformation. In CML BC group the survival does not depend upon Fas-antigen expression.     

Expression of VLA molecules on acute leukemia cells: relationship with disease characteristics

VLA molecules are involved in the adhesion of hematopoietic cells to the bone marrow stroma and play a role in the mediation of cellular interactions and migrations that are potentially important in the biology of acute leukemia (AL). We studied the expression of VLA-2 (CD49b), VLA-4 (CD49d), and VLA-5 (CD49e) by indirect immunofluorescence on leukemic cells from 67 patients with acute myelogenous leukemia (AML) and 40 patients with acute lymphoblastic leukemia (ALL). VLA-2, VLA-4, and VLA-5 were expressed, respectively, on 13 +/- 17%, 33 +/- 29%, and 36 +/- 30% of AML cells with 20, 54 and 61% positive cases and on 22 +/- 27%, 40 +/- 30%, and 39 +/- 29% of ALL cells with 29, 60, and 61% positive cases. Significant difference was neither noted between French-American-British (FAB) subtypes in AML or ALL nor between immunologic subtypes in ALL. There were highly significant correlations between the expression of the three beta 1-integrins tested in both AML and ALL. In AML, expression of both VLA-4 and VLA-5 was associated with that of CD14 (p = 0.003 and p = 0.01, respectively) and CD19 (p = 0.006 and p = 0.009, respectively). Expression of VLA-5 was correlated with that of CD15 (p = 0.004). Expression of VLA-4 was associated with both a high initial blast cell count (p = 0.01) and high percentage of bone marrow blast cell involvement (p = 0.003). In ALL, expression of VLA molecules was correlated neither with differentiation antigen nor with hematologic features. In AML, as in ALL, no significant correlation was noted between expression of VLA molecules and evolution of the disease.     

A child case of CD34+, CD33-, HLA-DR-, CD7+, CD56+ stem cell leukemia with thymic involvement

It has been reported that the CD56+/CD7+/CD3- phenotype of natural killer (NK) cells develop from the CD34+/HLA-DR- bone marrow (BM) mononuclear cell population in long-term BM culture (LTBMC). An HLA-DR-/CD33+/CD56+/CD16- myeloid/natural killer cell acute leukemia has been described. We report here a 7-year-old boy who developed stem cell acute leukemia with superior vena cava syndrome secondary to thymic involvement. Surface marker analyses revealed that the leukemia cells showed CD34+/HLA-DR-/CD33-/CD7+/CD56+ phenotype. When stimulated with phorbol ester in vitro the leukemic cells morphologically differentiated to myeloid cells developing CD13, CD15 and CD56 antigens. Our results suggest that CD34+/HLA-DR-/CD7+/CD56+ stem cell leukemia may arise from transformation of a pluripotent precursor cell, which could differentiate to both myeloid and NK cell lineages.     

Effect of a vitamin D3 analog, EB1089, on hematopoietic stem cells from normal and myeloid leukemic blasts

The seco-steroid 1,25 dihydroxyvitamin D3 (1,25(OH)2D3) induces differentiation and inhibits clonal proliferation of HL-60 cells. We analyzed the effect of a novel vitamin D3 analog, EB1089, on normal myeloid and leukemic cells as well as CD34+ cells. EB1089 showed an extraordinary inhibition of clonal growth of HL-60 cells (ED50 = 5 x 10(-11) M) and AML blast cells (ED50 = 9 x 10(-10) M) compared to 1,25(OH)2D3 without suppression of growth of normal human bone marrow CFU-GM. The CD34+ cells from acute myeloid leukemia (AML) blasts were inhibited in a dose-dependent fashion by 1,25(OH)2D3 with an ED50 of 1.2 x 10(-9) M; and even more strikingly, 10(-10) M of EB1089 inhibited all clonal growth of human CD34+ leukemic colony-forming cells. In contrast, both EB1089 and 1,25(OH)2D3 (10(-8) M) showed little or only mild inhibition of CD34+ clongenic hematopoietic cells from normal human peripheral blood (PB); and in liquid culture, EB1089 stimulated the proliferation of normal human CD34+ cells about 2.5 times as compared to control cultures. In order to evaluate the potential use of EB1089 for purging leukemic cells from normal CD34+ progenitor cells for PB stem cell transplantation (PBSCT), normal human PB mononuclear cells (PBMNC) were contaminated with HL-60 cells, and then CD34+ cells purified and treated with EB1089. We found that CD34+ purification and EB1089 purging was able to eliminate approximately 100% of HL-60 leukemic cells with no toxicity to normal CD34+ hematopoietic progenitor cells. These data suggested that purification of CD34+ cells and ex vivo treatment with EB1089 might provide an effective therapeutic approach for PBSCT.     

The immunophenotype of blast transformation of chronic myelogenous leukemia: a high frequency of mixed lineage phenotype in "lymphoid" blasts and A comparison of morphologic, immunophenotypic, and molecular findings

Immunophenotypic studies have a limited role in the diagnosis of chronic myelogenous leukemia (CML) but are increasingly being used in CML blast transformation (BT). Determination of the cell lineage of CML blasts is clinically important because patients with lymphoid blast transformation have a better response to chemotherapy and longer survival than those with other lineages. We studied the morphologic, cytochemical, immunophenotypic, cytogenetic, and molecular features of 20 patients with Philadelphia chromosome-positive CML and more than 10% blast cells in peripheral blood or bone marrow. The blasts were morphologically heterogeneous. CD33 was expressed in 19 cases (95%), followed by CD13 (85%), CD11c (80%), CD36 (60%), CD117 (40%), and CD15 (30%). Seven cases (35%) had a precursor-B lymphoid immunophenotype, and 13 (65%) had a predominantly myeloid immunophenotype. Of the former group, of which only one had a pure lymphoid phenotype, terminal deoxynucleotidyl transferase (TdT) and CD19 were expressed in 100%, CD10 in 85.7%, and CD20 in 14.3%. Of the latter group, all 13 expressed from 3 to 6 myeloid antigens, with 46.2% myeloperoxidase positive and 69.2% CD61 positive. No cases were interpreted as T lineage, but the T-cell antigens CD3, CD4, CD5, and CD7 were expressed in 5.0, 40.0, 5.3. and 30.0% of all cases, respectively. In most cases, the immunophenotype of the CML blasts could not be predicted from their morphologic features. Polymerase chain reaction showed that 80.0% of the lymphoid group and 37.5% of the myeloid group had immunoglobulin heavy-chain gene rearrangements. The frequent lineage infidelity of the blast cells in CML BT seems to be related to the stem cell origin of this disorder. Such lineage infidelity, however, makes classification of many cases difficult and the significance of and criteria for biphenotypic blast crisis of CML is yet to be determined.     

Vitamin K2 selectively induces apoptosis of blastic cells in myelodysplastic syndrome: flow cytometric detection of apoptotic cells using APO2.7 monoclonal antibody

We have previously reported that vitamin K2 (VK2) but not VK1 has a potent apoptosis-inducing effect on freshly isolated leukemia cells from patients with various types of leukemia. By multi-color flow cytometric analysis using monoclonal antibody (mAb), APO2.7, which detects mitochondrial 7A6 antigen specifically expressed by cells undergoing apoptosis, we further investigated the apoptosis-inducing effect of VK2 on minor populations of leukemic blast cells in bone marrow from patients with myelodysplastic syndrome (MDS) and overt myeloid leukemia (post-MDS AML). Limiting dilution of CD95 (anti-Fas) mAb-treated apoptotic Jurkat cells with nonapoptotic CTB-1 cells revealed that APO2.7-positive Jurkat cells were consistently detectable by flow cytometry when present at levels of at least 5% in the CTB-1 suspension. In patient samples the gating area for leukemic clone was determined using cell surface antigen-specific mAbs conjugated with either fluorescein isothionate (FITC) or phycoerythrin (PE) and subsequently the cells stained with phycoerythrin cyanine (PE-Cy5)-conjugated APO2.7 mAb were assessed within the gating area of the leukemic clone for monitoring apoptosis. Treatment of the bone marrow mononuclear cells with 3-10 microM of VK2 (menaquinone-3, -4 and -5) in vitro potently induced apoptosis of the leukemic blast cells as compared with the untreated control cells in all 15 MDS patients tested. This effect was more prominent on blastic cells than that on mature myeloid cells such as CD34-/CD33+ gated cells. In addition, VK2 performed much less effectively on CD3-positive lymphoid cells. In contrast to VK2, VK1 did not show apoptosis-inducing activity. These data suggest that VK2 may be used for treatment of patients with MDS in blastic transformation.     

Cytolytic activity of peripheral blood blast cells from patients with acute myeloid leukemia

The results of the present study demonstrate that cells with the morphologic and phenotypic characteristics of blast cells that are obtained from the peripheral blood of patients with newly-diagnosed or recurrent acute myeloid leukemia (AML) can be stimulated by gamma interferon + lipopolysaccharide (IFN/LPS) to mediate in vitro cytolysis of an NK-insensitive hepatoma cell line. The conditions of IFN/LPS induction and subsequent assessment of cytotoxicity that were employed were identical to those used conventionally to test macrophage-mediated tumor cell cytotoxicity. What was totally unexpected was that these same blast cells, in the absence of stimulation with IFN/LPS, were also found to mediate high levels of spontaneous cytotoxicity against autologous bone marrow cells and against the U937 human promonocytic leukemia cell line in vitro. This high level of spontaneous cytotoxicity against autologous bone marrow or U937 promonocytic leukemia cells was not enhanced by IFN/LPS or MCSF under conditions that stimulated cytotoxic function in normal blood monocytes and was markedly reduced by pretreatment of the blast cells with IL2 under conditions that induced potent NK/LAK-mediated cytotoxicity. Neutralizing antibodies against TNFalpha and/or IL1alpha/beta eliminated the cytolytic function of blast cells against autologous bone marrow or U937 promonocytic leukemia targets. These findings demonstrate the existence of a population of cells with the morphologic characteristics of blast cells in the peripheral blood of AML patients which has the capacity to mediate spontaneous cytolysis of autologous bone marrow cells or a promonocytic leukemia cell line. These cells may be an immature variant of normal precursors produced as a consequence of the disordered hematopoietic environment in the marrow of AML patients. Alternatively, this function may be mediated by a subset of the leukemic blasts themselves.     

Mechanical environment associated with rotator cuff tears

The patient is a 12-year-old boy with acute mixed lineage leukemia (AMLL) and with a rare karyotype of trisomy 6. He was referred to our hospital with gingival swelling, bleeding at the conjunctiva and huge hepatosplenomegaly. Complete blood count revealed leukocytosis with 79% blasts, anemia and thrombocytopenia. Bone marrow examination revealed 82.5% blasts which were morphologically judged as M1 according to the French-American-British classification. Immunophenotyping of leukemic cells showed the presence of CD2, CD7, CD19 and CD13 antigens, suggesting the diagnosis of AMLL. Cytogenetic analysis revealed a single abnormal karyotype of 47,XY,+6,add(15)(q22) which was successfully detected by fluorescence in situ hybridization (FISH) with the probe mapping at the alpha-satellite region of chromosome 6. Although the patient was treated with several chemotherapy regimens, he could not achieve complete remission and he died of progressive disease 11 months after admission. Fluorescence in situ hybridization analysis was very informative in assessing the residual leukemic cells in interphase during his clinical course.     

Selective cytotoxicity to human leukemic myeloblasts produced by oligodeoxyribonucleotide phosphorothioates complementary to p53 nucleotide sequences

Cells were treated in vitro with oligodeoxyribonucleotide phosphorothioates (ODNs) complementary to sites common to both wild-type and mutant p53 nucleotide sequences. Acute myelogenous leukemia (AML) blasts from peripheral blood were exposed to four different p53 ODNs and showed anti-leukemic effects in suspension culture. This effect continued after removal of the ODN from the medium. Blocking of self-renewal of the leukemic blast stem cells in secondary plating of cells from cloning assays by two of the p53 ODNs was also observed. Control ODNs had no effect on leukemic blasts. Treatment of normal bone marrow cells with the four p53 ODNs did not influence their growth, nor was there any effect by the p53 ODNs on the leukemic cell-line, HL60, that does not express p53. These data suggest that p53 ODNs are selectively toxic to primary myelogenous blasts and may be therapeutically useful in AML.     

Hopwood, affirmative action, and deaf education

Leukemic cells of B-lineage acute lymphoblastic leukemia (ALL) are regarded as the malignant counterparts of immature, physiologic B cell precursors (BCPs). To determine whether phenotypic differences exist between these corresponding cell types, we investigated samples of normal pediatric bone marrow (n=30) as well as of B-precursor ALL at diagnosis (n=53; common and pre-B subtype). Using three-color multiparameter flow cytometric analysis, we compared the leukemic populations with the physiologic BCPs of corresponding maturity with respect to the intensity with which they expressed a series of antigens. In some of these antigens, leukemia-associated aberrations were frequently observed. In particular, overexpression of CD10 was displayed by 65% of ALL samples, whereas 58% of leukemic cases aberrantly exhibited very low or no CD45RA expression. Regarding CD11a and CD44, 47% and 35% of ALL populations were aberrant as defined by either the absence or significant overexpression of the antigen. In contrast, antigen densities of CD49d, CD49e, and CD99 on leukemic cells were in the normal range of values for BCPs. Combining the patterns of frequently aberrant markers in a comprehensive analysis, we were able to identify individual phenotypic leukemic cell aberrations in up to 98% of investigated cases. CD10 and/or CD45RA were aberrant in 86% of cases overall, emphasizing the high discriminative potential of these two markers. Using comparative phenotype mapping based on quantitatively aberrant, leukemia-associated antigenic patterns, we were able to detect leukemic blasts among normal bone marrow cells at frequencies as low as 10(-5). We speculate that our approach may have a profound impact on the development of new strategies for minimal residual disease investigations in patients with BCP-ALL.     

Stem cell factor enhances the adhesion of AML cells to fibronectin and augments fibronectin-mediated anti-apoptotic and proliferative signals

Acute myeloid leukaemia (AML) cells express the SCF receptor c-kit (CD117) on their cell surface and demonstrate enhanced adhesion to fibronectin (FN) following exposure to stem cell factor (SCF). Increased adhesion occurs within 5 min, is dose dependent, and persists beyond 2 h. Baseline and enhanced adhesion occur through the surface FN receptor very late antigen-5 (VLA-5, CD49e/CD29) which is expressed by AML cells. Unstimulated AML cells exposed to FN undergo less apoptosis than controls (inhibition 22.5 +/- 7.0%, P = 0.02, n = 8). Exposure to SCF alone without FN also inhibits AML cell apoptosis (by 19.0 +/- 7.7% compared to controls, P = 0.06, n = 8). Simultaneous exposure to SCF and FN increases the inhibition of AML cell apoptosis to 37.8 +/- 7.9% (P = 0.005 compared to control, P = 0.04 compared to FN alone, P = 0.06 compared to SCF alone) demonstrating that SCF not only enhances the propensity of AML cells to adhere to FN, but also results in an additive survival benefit following FN contact. Some but not all the reduction in apoptosis is mediated through VLA-5. The combination of SCF and FN also affects proliferation, resulting in a synergistic enhancement of AML cell proliferation in half the cases studied. When normal CD34+ human haemopoietic progenitors were studied, FN had little effect on their apoptosis and failed to enhance the anti-apoptotic effect of SCF. It did, however, synergise with SCF in promoting CD34+ cell proliferation. Exposure of AML cells to SCF and FN, both of which can be found in high concentration in the bone marrow stroma, inhibits apoptosis. Cytokines and extracellular matrix proteins augment each others' effects since SCF enhances adhesion to fibronectin, which in turn augments the survival signal delivered by the cytokine alone. Cytokine and adhesion receptors can combine to affect cell characteristics including proliferation and survival.     

Useful panel of antibodies for the classification of acute leukemia by immunohistochemical methods in bone marrow trephine biopsy specimens

To evaluate the feasibility of acute leukemia typing on routinely processed bone marrow biopsy specimens, 72 cases of previously established acute leukemia covering the spectrum of 17 known subtypes were studied immunohistochemically. Most leukemic myeloblasts were positive for myeloperoxidase in 16 (84%) of 19 cases of acute myeloid leukemia, M1-M4, and M6. Most leukemic cells in 11 of 12 M4 and M5 cases were positive for CD68 (PG-M1). All six M6 cases stained with hemoglobin. Leukemic megakaryoblasts in three of four M7 cases were positive for factor VIII-related antigen. Almost all leukemic cells of 8 T-lineage acute lymphoblastic leukemia (ALL) and 19 B-lineage ALL cases were positive for CD3 and CD79a (HM57), respectively. Staining with CD20 (L26) was positive in the more differentiated B-lineage ALL cases and strongest in L3. Immunohistochemical typing of acute leukemia is possible for most types using this panel of cell lineage-specific antibodies.     

Prognostic value of P-glycoprotein and leukocyte differentiation antigens in chronic myeloid leukemia

P-glycoprotein (Pgp) mediated multidrug resistance is often the cause of therapy failure in some tumors. Pgp expression was shown to have prognostic value in several hematological malignancies, especially in acute myeloblastic leukemia (AML) and acute lymphoblastic leukemia (ALL). In chronic myeloid leukemia (CML) Pgp is expressed by peripheral blood (PB) cells more often in the terminal disease stages (20-50% of patients have Pgp+ phenotype). Sequential studies show that Pgp+ cells often disappear from the PB during the course of therapy. Nevertheless Pgp expression has some prognostic value in blast crisis (BC) predicting shorter BC, while CD13 has the same predictive value in BC. 10% of patients formed a distinct group with large numbers of Pgp+CD34+ blasts in the PB and also had shorter BC. Cases with inactive Pgp were found in chronic and accelerated phases of CML but not in BC.     

Antibodies TC-12 ("unique") and TH-111 (CD96) characterize T-cell acute lymphoblastic leukemia and a subgroup of acute myeloid leukemia

To extend the panel of monoclonal antibodies useful for immunophenotyping of acute leukemias, two new reagents, TC-12 and TH-111, were developed. TC-12 was found "unique," and TH-111 was assigned to the recently defined CD96 cluster. Both reagents show little reactivity with blood and bone marrow nucleated cells but define a major (TH-111: 78.3%) or an important (TC-12: 45.6%) subset of T-cell acute lymphoblastic leukemia (ALL). In addition, in acute myeloid leukemia (AML), the expression of TC-12 was found in 64 (20.2%) of 317 and TH-111 in 97 (29.1%) of 333 of these patients. TC-12 positivity in AML was virtually restricted to the Fab subtypes M0, M1, M2, and M6. In the group of immature AML characterized by the coexpression of CD7 as well as CD117 and CD34 positivity, leukemic blasts frequently disclosed the TC-12 and TH-111 antigen. Although the TC-12 antigen could not be determined, TH-111 immunoprecipitated the TACTILE (CD96) antigen and, when expressed, was found to be associated with the transferrin receptor. These reagents may help not only to define and dissect T-cell ALL, but also to characterize a subgroup of immature AML at the divergence of T-cell and myeloid lineage.     

Adhesion molecules in the nickel allergic reaction

Nickel is the major cause of allergic contact dermatitis, and to increase our understanding of this immune reaction we studied changes in the expression of adhesion molecules on mononuclear cells during nickel stimulation in vivo and in vitro. Nickel-induced lymphocyte cultures were used in vitro, the cells being examined with monoclonal antibodies (Mabs) and by flow cytometry. Mononuclear cells from skin biopsies of in vivo cutaneous nickel reactions were studied with Mabs and immunohistochemistry. The expression of adhesion molecules in vitro was differential: the number of cells carrying CD11c, CD29, CDw49b, CDw49d, CDw49e, CDw49f, CD54, CD56 and ELAM-1 being significantly overrepresented among the nickel-induced lymphoblasts whereas the number of blasts carrying CD44 was underrepresented and those of CD11a, CD18, CD58 and LAM-1 remained unchanged. CD4+ cells gained adhesion molecules during nickel-induced blast transformation whereas CD8+ cells lost most of their adhesion molecules. The in vivo results were in agreement with the in vitro ones except that CDw49b, CDw49f, CD56 and ELAM-1 could not be detected in a 96-hour nickel reaction in vivo. In conclusion, the nickel allergic reaction favors the expression of certain adhesion molecules, and this expression is induced on CD4+ cells while CD8+ cells tend to lose such molecules. The changes were more sensitively detected with the in vitro method.     

Defect of cell-mediated immune response against hepatitis B virus: an indication for pathogenesis of hepatitis-B-virus-associated membranous nephropathy

The purpose of this study was the discrimination of porcine bone marrow hematopoietic cell (BMHC) subpopulations and cell maturation stages by using cluster of differentiation (CD) and Swine Workshop Cluster (SWC) molecules, combined with cell size, granularity, and the capacity to generate an oxidative burst. SWC3 was the earliest myeloid marker identified in the differentiation pathways. Through SWC3/SWC8 double labeling, three populations committed to the myeloid lineage were discriminated: early myeloid progenitors, which were SWC3lowSWC8-; cells committed to the granulocytic lineage, which were SWC3+SWC8+; monocytic cells, which were SWC3+(-)SWC8-. The SWC3lowSWC8- myeloid progenitors expressed high levels of CD44 and CD49d, but no CD14. Among the SWC3+SWC8+ granulocytic cells, the most immature were CD14-CD11a/18-CD44low, an intermediate stage was CD14+CD11a/18lowCD44-, and the most mature were CD14+CD11a/18high-CD44high. Only the latter could generate a rapid oxidative burst. Moreover, during granulocytic maturation, a constant decrease in CD49d/29 expression was observed. In contrast, the SWC3+SWC8- monocytic cells were mainly CD14+ and expressed high levels of the adhesion molecules. These results define porcine hematopoietic differentiation and maturation stages. Similarities in human and porcine adhesion molecule expression have been identified, suggesting common functionalities in the regulation of hematopoiesis and the potential of the pig as a model for hematopoietic studies.     

Essential thrombocythemia in transformation to smouldering megakaryoblastic leukemia with myelofibrosis

Leukemic transformation in essential thrombocythemia (ET) is rare. We describe a patient with ET which transformed to megakaryoblastic leukemia with myelofibrosis after treatment with melphalan for 8 years. His course after transformation smouldered for 20 months without antileukemic chemotherapy. A 61-year-old man was referred by a local doctor to Niigata University Hospital due to nasal bleeding in June 1984. Complete blood count (CBC) was as follows; hemoglobin 12.4 g/dl, platelets 268.8 x 10(4)/microliters, and white blood cells 11,900/microliters, with differentials of 39% PMN, 1% basophils, 2% eosinophils, 4% monocytes, and 13% lymphocytes. Bone marrow examination revealed hyperplasia of megakaryocytes without increase of reticulin fibers. Neutrophil alkaline phosphatase activity and karyotype of marrow cells were normal. ET was diagnosed. He was followed up by local doctor. The platelet count was controlled at a level of approximately 40 x 10(4)/microliters with melphalan for eight years. In January 1992 he developed pain in his lower extremities. He was admitted to our hospital on May 29, 1992. CBC was as follows; hemoglobin 8.9 g/dl, platelets 14.3 x 10(4)/microliters, and white blood cells 3,500/microliters, with differentials of 25% PMN, 5% monocytes, 28% lymphocytes, and 24% blasts. Bone marrow aspiration was unsuccessful and bone marrow biopsy revealed increases in fibroblasts and collagen fibers. Circulating blasts were positive for CD4, CD7, CD25, CD13, CD33, CD34, and HLA-DR and partly positive for CD41 and CD36. In ultrastructural cytochemistry blasts were positive for platelet peroxidase but negative for myeloperoxidase. Cytogenetic study revealed 46, XY, +der (1) t(1:7) (p11;q11) in all of five metaphases. He was diagnosed with megakaryoblastic leukemia accompanied by myelofibrosis.(ABSTRACT TRUNCATED AT 250 WORDS)     

Comparison of simultaneously obtained arterial and capillary blood gases in pediatric intensive care unit patients

In the present study the migration of human monocytes towards the supernatants of five different human myeloid leukemic cell lines, four different human lymphatic leukemic cell lines and blasts derived from three different patients with acute myeloid leukemia (AML) was studied and the role of monocyte chemoattractant protein (MCP)-1 was established with an ELISA assay. Large differences in migration of monocytes towards the leukemic cell supernatants were shown (variation of approximately 10 to 150% compared to positive control), but high amounts of monocyte migration was always restricted to myeloid leukemic cells (cell lines or patient blasts). MCP-1 turned out to play a major role in the migration, firstly since there was a direct correlation between the amount of migration and the concentration of MCP-1 in the supernatants, and secondly since the addition of anti-hMCP-1 was able to inhibit migration to background level in all cases. Cytotoxicity experiments with a MTT test using MCP-1-stimulated monocytes against two human myeloid leukemic cell lines showed no increase in cell death compared to unstimulated monocytes. It is concluded that monocyte migration towards leukemic cells is restricted to the myeloid lineage and is regulated by MCP-1, which is produced in different amounts by the leukemic cells. Besides, MCP-1 does not increase the direct toxic effects of monocytes on leukemic cells.     

Testicular extramedullary myeloid cell tumor in a patient with myelodysplastic syndrome

We report herein a case of extramedullary myeloid tumor arising bilaterally in the testes of a 66-year-old man, who had previously been diagnosed with myelodysplastic syndrome. Light microscopy of the testicular neoplasm demonstrated a tumor composed of large, slightly polygonal cells with pale blue to weakly eosinophilic cytoplasm. The tumor cells were immunoreactive for CD45, myeloperoxidase, lysozyme, CD43, and MB2. Many of the cells also expressed chloroacetate esterase. Peripheral blood and bone marrow findings were consistent with chronic myelomonocytic leukemia (FAB-CMML), particularly in the most recent material, which showed clear cellular dysplasia and an increase in the percentage of blasts in the bone marrow (15% to 20% of all nucleated cells). This case of extramedullary myeloid tumor is unusual in view of the patient's age and the testicular location. It emphasizes the importance of including extramedullary myeloid tumor in the differential diagnosis of histologically undifferentiated large-cell tumors, as well as a need to use a broad panel of immunohistochemical stains in such cases.