Clinical and prognostic significance of cytokine receptor expression in adult acute lymphoblastic leukemia: interleukin-2 receptor alpha-chain predicts a poor prognosis.

We quantitatively assessed the expression of cytokine receptors (interleukin-2 receptor (IL-2R), IL-3R, IL-4R, IL-5R, IL-6R, IL-7R, granulocyte-macrophage colony-stimulating factor R (GM-CSFR), G-CSFR, c-fms, c-mpl, c-kit and FLT3) in cells from 211 adults with acute lymphoblastic leukemia (ALL) by flow cytometry and determined their prevalence and clinical significance. Although all cytokine receptors were expressed to various degrees, the levels of IL-3R alpha-chain (IL-3Ralpha), IL-2Ralpha, IL-2Rbeta, IL-7Ralpha, common-Rgamma(gammac), c-mpl, c-kit and FLT3 exhibited a wide spectrum > or =2000 sites/cell. Among them, IL-3Ralpha, IL-2Ralpha and FLT3 were highly expressed in B-lineage ALL, whereas IL-7Ralpha, gammac and c-kit predominated in T-lineage ALL. Higher levels of IL-3Ralpha, IL-2Ralpha, c-kit and FLT3 correlated with the expression of CD13/33. Increased IL-2Ralpha levels related to the presence of Philadelphia chromosome (Ph), leukocytosis and shorter event-free survival (EFS). C-kit preferred in male. Elevated FLT3 levels correlated with age > or =60 years. Multivariate analysis in B-lineage ALL revealed only IL-2Ralpha (P=0.028) and Ph (P=0.020) as independent factors for EFS. These findings suggest that several cytokine receptors associated with certain cellular and clinical features, but IL-2Ralpha solely had a prognostic value and should be considered as a major prognostic factor for adult ALL that is comparable with Ph.

Clinical pharmacology of 1-beta-D-arabinofuranosylcytosine-5'-stearylphosphate, an orally administered long-acting derivative of low-dose 1-beta-D-arabinofuranosylcytosine.

1-beta-D-Arabinofuranosylcytosine-5'-stearylphosphate (cytarabine ocfosfate, stearyl-ara-CMP) is a newly synthesized 5'-alkylphosphate derivative of 1-beta-D-arabinofuranosylcytosine (ara-C), which is lipophilic, resistant to inactivation by deamination, and orally active. Pharmacology of this drug was studied in patients with hematological malignancies. The concentrations of stearyl-ara-CMP, ara-C (its active metabolite), and 1-beta-D-arabinofuranosyluracil (ara-U, its inactive metabolite) were determined by radioimmunoassay. When six patients received a single p.o. dose of the drug (500 mg/m2), stearyl-ara-CMP, ara-C, and ara-U could be detected in the plasma for at least 72 h afterwards. The plasma disappearance curve of stearyl-ara-CMP corresponded to a one-compartment open model with first-order absorption kinetics. The peak plasma level (Cmax) was 322 +/- 218 nM, and the predicted time to reach Cmax (Tmax) was 6.5 +/- 4.5 h, while the elimination half-life (t1/2) was very long (32.0 +/- 8.4 h). The plasma ara-C level increased slowly to a Cmax of 26.3 +/- 12.7 nM (Tmax, 13.3 +/- 4.7 h) after stearyl-ara-CMP administration. This level was quite low compared with that achieved by low-dose s.c. ara-C therapy, but ara-C persisted longer in the plasma in the former case, and the area under the curve was similar for both regimens. For ara-U, the Cmax, Tmax, and t1/2 were 483 +/- 315 nM, 23.6 +/- 4.0 h, and 19.6 +/- 5.3 h, respectively. No stearyl-ara-CMP was detected in the urine, and only 8.0% of the administered dose was excreted as ara-C and ara-U within 72 h. The stearyl-ara-CMP concentration in the cerebrospinal fluid was below the limit of detection in three patients without meningeal involvement at 6 h. During clinical use of stearyl-ara-CMP, macrocytic anemia was observed, and some patients also developed megaloblastic change of their erythroblasts, suggesting a mild and persistent cytostatic effect. In conclusion, p.o. therapy with stearyl-ara-CMP achieved prolonged maintenance of the plasma drug level. Thus, the drug released a very low dose of ara-C over a long period in plasma and tissues and had a prolonged mild antineoplastic effect in patients with hematological malignancies.

A granulocytic population with rearranged immunogenotype in chronic myelocytic leukemia blast crisis and Philadelphia-chromosome-positive acute leukemia with cross-lineage nature.

Two patients with chronic myelocytic leukemia (CML) mixed crisis and one with Philadelphia-chromosome-positive (Ph1 +) acute lymphoblastic leukemia (ALL) with cross-lineage nature had a considerable number of granulocytes with monoclonally rearranged immunogenotype. The gene configurations of immunoglobulin heavy chain (IgH), T-cell receptor beta chain (TCR beta), and gamma chain (TCR gamma) in the granulocytic cells were identical to those in the blasts, indicating that both the blasts and the granulocytes were derived from common leukemic progenitors with the IgH gene rearrangements. In a colony assay of cells from in the Ph1 + ALL patient, the leukemic cells showed the potential to differentiate into granulocytes in the presence of either granulocyte-macrophage colony-stimulating factor (GM-CSF) or granulocyte-CSF (G-CSF). Interleukin 7 (IL-7) exerted synergistic effects on colony and cluster formation in cultures with these cytokines. Further, IL-3, GM-CSF, and G-CSF receptor gene expression was found in the leukemic cells. Our findings indicate that the Ph1 + common progenitors in these three patients preserved the potential for granulocytic differentiation even after the occurrence of the Ig (and TCR) gene rearrangements as the first genomic event in lymphocyte differentiation. The phenomenon of cross-lineage in leukemic cells, at least in Ph1 + leukemia, can be considered to demonstrate the potential of leukemic progenitors to differentiate in multiple directions.

Anti-Leukemia Chemotherapy of High-Risk Myelodysplastic Syndromes.

We evaluated the outcome of anti-leukemia chemotherapy on 42 patients with the high-risk myelodysplastic syndromes (MDS)-refractory anemia with excess of blasts (RAEB), 8 cases; RAEB in transformation (RAEB-T), 18 cases; chronic myelomonocytic leukemia (CMMOL), 6 cases; and leukemic transformation of MDS, 10 cases. The median age was 67 (range 20 to 84). As a remission-induction therapy, 35 patients received low-dose chemotherapy, such as low-dose cytarabine infusion, and seven patients received high-dose combination chemotherapy. The complete remission (CR) rates of the low-dose chemotherapy group and the high-dose combination chemotherapy group were 29% and 57%, respectively, and the overall CR rate was 33%. The median survival durations after induction chemotherapy of the CR group (14 cases), the partial remission (PR) group (11 cases), and non-remission (NR) group (17 cases) were 19 months, 8 months, and 3 months, respectively. As a post-remission consolidation chemotherapy, high-dose combination chemotherapy seemed to be superior to low-dose chemotherapy judging from the median CR duration (16 months versus 4 months), but a long-term disease-free survival is hardly expected, in contrast with results in cases of de novo acute myeloid leukemia.

The role of protein-tyrosine phosphorylation and gelatinase production in the migration and proliferation of smooth muscle cells.

BACKGROUND: It has been reported that matrix metalloproteinase (MMP) was expressed in coronary arterial atherosclerotic lesions. However, not much is known about the relationship between the production of MMP and the progression of atherosclerosis. PURPOSE AND METHOD: To demonstrate the association between the protein-tyrosine phosphorylation (PTP) and the activation of extracellular MMP in the proliferation and migration of vascular smooth muscle cells (VSMCs), the effect of platelet-derived growth factor (PDGF) and vanadate (an inhibitor of protein-tyrosine phosphatase and an activator of certain protein-tyrosine kinases) on mitogenesis ([3H]thymidine incorporation after 24 hours), migration, PTP (Western blot analysis using anti-phosphotyrosine antibodies), and production of MMP (gelatin zymography) was examined in cultured VSMCs. RESULTS: Both vanadate (1-5 micromol/l) and PDGF (1-10 ng/ml) caused a dose-dependent increase in thymidine incorporation and migration and produced 72-kDa type IV gelatinase (MMP-2) in VSMCs. The combination of vanadate and PDGF resulted in a dose-dependent synergistic effect on thymidine incorporation and MMP-2 production. Western blot analysis revealed that PDGF caused an increase in PTP, extracellular signal-regulated kinases (ERK1, ERK2) and PDGF receptor in VSMCs. Vanadate given together with PDGF induced a marked increase in the intensity of tyrosine phosphorylation in these proteins. Tyrosine kinase inhibitors (genistein and herbimycin A) and a synthetic inhibitor of MMP (1,10-phenanthroline) and an anti-MMP-2 neutralizing antibody inhibited the mitogenic effect induced by vanadate and/or PDGF. CONCLUSIONS: The data suggest that the proliferation and migration of cultured VSMCs was closely related to the stimulation of MMP-2 production that was induced through activation of PTK.

Pharmacological studies of retinol palmitate and its clinical effect in patients with acute non-lymphocytic leukemia.

The pharmacokinetics of retinol palmitate were studied, and a therapeutic trial was performed in patients with ANLL. In the pharmacokinetics study, retinol was the only metabolite that was detected in plasma, and the peak concentration was 332 micrograms/dl (about 1.2 x 10(-5) M) 2.1 h after administration of retinol palmitate. Five patients with ANLL (4 with ANLL-M3 and one with ANLL-M2) were treated with retinol palmitate. In all patients with ANLL-M3, bone marrow suspension culture studies revealed that retinol induced both morphological and functional differentiation of immature leukemic cells. During the course of the treatment with retinol palmitate, morphological differentiation of bone marrow immature leukemic cells was observed in all patients with ANLL-M3 within 3-4 days after initiation of the therapy. In three of the four patients who underwent conventional chemotherapy, the sequential treatment with retinol palmitate resulted in a complete remission: controlling residual bone marrow leukemic cells. None of the patients showed any signs of aggravation of DIC in the coagulation parameters. These findings suggest the possibility that retinol palmitate functions as salvage therapy by inducing maturation and slowing proliferation, there by clearing out the residual leukemic cells following conventional chemotherapy.

Reduction of leukemia cell growth in a patient with acute promyelocytic leukemia treated by retinol palmitate.

A 67-year-old woman with acute promyelocytic leukemia (APL) showed a marked decrease in leukemic promyelocytes with concomitant maturation of leukemic cells during treatment with retinol palmitate. A culture study in vitro revealed that retinol, which is the main metabolite of retinol palmitate detected in plasma, induced morphological and functional maturation of leukemic promyelocytes. These findings may indicate that retinol palmitate induces cell differentiation and slows proliferation of leukemic cells in vivo, and that the reduction in cell growth is the key phenomenon in the clearing of leukemic cells, rather than the maturation phenomenon itself.

Differentiation induction in non-lymphocytic leukemia cells upon treatment with mycophenolate mofetil.

Inosine 5'-monophosphate (IMP) dehydrogenase catalyzes the rate-limiting reaction of guanine nucleotide biosynthesis and has been implicated in the reaction of cell growth and differentiation. We investigated the ability of mycophenolate mofetil, a prodrug of mycophenolic acid, to induce differentiation in HL-60 and U937 leukemic cells as well as in fresh leukemia cells from patients with non-lymphocytic leukemia. Treatment with mycophenolate mofetil reduced the intracellular guanosine 5'-triphosphate (GTP) levels and induced morphologic and functional differentiation in HL-60 and U937 cells dose-dependently. HL-60 and U937 cells developed macrophage-like cytoplasm as well as the expression of CD11b and CD14 antigens and the ability to oxidize nitroblue tetrazorium (NBT). These changes became evident when the intracellular GTP levels decreased to approximately 20-30% of the untreated control level and were abrogated by the addition of guanosine. In the fresh leukemic cells, differentiation induction was shown in the cells derived from seven of 13 patients. The fresh leukemia cells responding to mycophenolate mofetil revealed significant higher positivity to CD11b, CD14, and NBT before treatment and significantly reduced intracellular GTP levels after treatment compared to the non-responding cells. These findings suggest that mycophenolate mofetil induces differentiation in HL-60 and U937 cells and some fresh leukemia cells with moderate tendency to maturation, by causing a decrease in the intracellular GTP levels. Mycophenolate mofetil could be a promising differentiation inducer in vivo.

Interleukin-2 receptor alpha chain on acute myelocytic leukemia cells is involved in cell-to-cell interactions.

Leukemic cells from 21 to 197 adult patients with de novo acute myelocytic leukemia (AML) were positive for IL-2R alpha chain (IL-2R alpha), whereas IL-2R beta chain (IL-2R beta), which is responsible for IL-2 signal transduction, was not found on leukemic cells from any of these cases tested. The expression of IL-2R alpha was closely associated with that of adhesion molecules CD4, CD11b and CD22, and endopeptidase CD10. None of the IL-2R alpha (+) AML cells responded to recombinant human IL-2. These data suggest that IL-2R alpha on AML cells may not be involved in cellular proliferation as one of growth factor receptors but may have a role in the control of cell-to-cell interactions.

Myeloid antigen, CD13, CD14, and/or CD33 expression is restricted to certain lymphoid neoplasms.

The authors examined the expression of myeloid antigens (MyAg): CD11b, CD13, CD14, CD15, and CD33 in 249 adults with lymphoid neoplasms using flow cytometric analysis. In this study, acute leukemia that was myeloperoxidase negative by light microscopy and had at least one lymphoid antigen was defined as acute lymphoblastic leukemia (ALL). The patients were classified as follows: 6 with unclassified ALL, 35 early B precursor ALL, 32 T-ALL, 25 B-cell chronic lymphocytic leukemia (B-CLL) and its variants, 24 B-cell non-Hodgkin's lymphoma (B-NHL), 7 plasma cell disorders, 8 T-CLL, 2 adult T-cell leukemia, and 10 T-NHL. CD11b and CD15 were present in a wide range of lymphoid disorders irrespective of B/T lineage and maturity. Unclassified ALL and phenotypically immature ALL frequently expressed CD13 and CD33, and occasionally expressed CD14. Among early B precursor ALL, CD13, and/or CD33 were significantly associated with the presence of stem cell marker CD34 and the chromosomal abnormality t(9;22). In addition, ALL with deletion of chromosome 7 commonly expressed CD13 and CD33. Taken together, CD13 and/or CD33 positive ALL may originate from a multipotential stem cell. Among mature neoplasms, CD14 was frequently, and CD13 and CD33 were occasionally expressed in B-cell, but not T-cell tumors. These results suggest that CD13, CD14, and CD33 are preferentially expressed in two types of lymphoid neoplasms, namely undifferentiated ALL and mature B-cell lymphoproliferative disorders.

Differentiation induction in non-lymphocytic leukemia cells upon treatment with mizoribine.

Inosine-5'-monophosphate (IMP) dehydrogenase catalyzes the rate-limiting reaction of guanine nucleotide biosynthesis and has been implicated in the reaction of cell growth and differentiation. We examined the ability of mizoribine, an IMP dehydrogenase inhibitor, to induce differentiation in HL-60 and U937 cells as well as in fresh leukemic blast cells from patients with non-lymphocytic leukemia. Treatment with mizoribine reduced intracellular GTP levels and induced morphologic and functional differentiation in these two cell lines in a dose-dependent manner. HL-60 and U937 cells developed polymorphic nuclei and macrophage-like cytoplasm, respectively, as well as expression of CD11b and CD14 antigens and the ability to oxidize NBT. These changes became evident when intracellular GTP levels decreased to approximately 30% of untreated controls and were abrogated by addition of guanosine to the media. However, in fresh leukemic cells, the cells showing maturation in response to mizoribine were limited in those derived from two of ten patients having non-lymphocytic leukemia. These findings suggest mizoribine could induce differentiation in HL-60 and U937 cells through a decrease of intracellular GTP levels. Further study is required to determine its clinical use in patients with acute non-lymphocytic leukemia.

Hepatic tumor rupture following effectual treatment with irinotecan in a patient with highly refractory malignant lymphoma.

We describe a patient with highly refractory malignant lymphoma who died of hepatic tumor rupture following treatment with irinotecan (CPT-11). This 60-year-old man with non-Hodgkin's lymphoma (diffuse large B-cell lymphoma) demonstrated disease recurrence in the liver and the vertebrae following high-dose chemotherapy and autologous hematopoietic stem cell transfusion. He was treated with CPT-11 at a dose of one third of the conventional dose used for non-Hodgkin's lymphoma in Japan. The tumor in the liver markedly decreased in size but then ruptured. Although pathologic hepatic tumor rupture is a rare complication in patients with malignant lymphoma of the liver, this case demonstrates that hepatic tumor rupture may occur in refractory malignant lymphomas that reveal extensive degradation by this new, effective salvage therapy.

Successful salvage treatment with irinotecan (CPT-11) of recurrent malignant lymphoma in an aged patient; and CPT-11 pharmacokinetics.

A 72-year-old patient with relapsed non-Hodgkin's lymphoma (diffuse large B-cell type) in the tongue was treated with irinotecan (CPT-11) as the 4th salvage therapy. A two-thirds reduced dose of 40 mg/m2 of CPT-11 was administered, as were granulocyte-colony stimulating factor and antidiarrheal agents. Complete remission was achieved. Although grade 3 leukopenia and grade 1 diarrhea were observed, these adverse reactions did not interrupt the treatment schedule and CPT-11 was administered without interruption for a total of 12 weeks. Despite the dose reduction, the area under the concentration-time curve of SN-38, the active metabolite of CPT-11, was nearly equal to the values reported in phase I and II studies of CPT-11. The patient's ratio of SN-38 to the SN-38 glucuronide (SN-38G) was low, suggesting a low risk of diarrhea. The optimal dose modification provided a sufficient amount of the active metabolite. Supportive therapy managed therapy-related toxicities and resulted in a stable treatment schedule. This is a rare case of a patient successfully treated with CPT-11 after a 4th relapse, in which the agent was administered at the total dose of 960 mg/m2, despite the patient's advanced age.

Sequential promotion of normal and leukemic hemopoiesis by recombinant human granulocyte colony-stimulating factor during the course of myelodysplastic syndrome.

A 48-year-old man developed refractory anemia with excess of blasts in transformation. Complete response was achieved by low-dose ara-C therapy, but he relapsed 15 months later, with pancytopenia and 13.0% myeloblasts in normocellular marrow. He was treated unsuccessfully with prednisolone, metenolone, and 1-alpha-hydroxyvitamin D3 for 8 weeks. He then developed life-threatening pneumonia and was treated with recombinant human granulocyte colony-stimulating factor (rhG-CSF Filgrastim; 125 micrograms/day s.c.). The pneumonia resolved and, interestingly, he achieved a partial response, with normal blood cell counts and only a few dysmyelopoietic cells in the marrow. However, thrombocytopenia progressed when rhG-CSF administration was tapered. When the dose was increased again, leukemic blasts were found to proliferate. When rhG-CSF was discontinued, blasts rapidly decreased in the peripheral blood. Chromosomal analysis revealed a complex abnormality during the first relapse, a normal 46,XY karyotype during the partial response, and recurrence of the same complex abnormality during leukemic transformation. The stimulation index of marrow mononuclear cells cultured with rhG-CSF increased with disease progression. These findings suggest that rhG-CSF initially stimulated the selective proliferation of normal hemopoietic cells, but the evolution or selection of a leukemic clone responsive to rhG-CSF appears to have occurred subsequently.

Successful treatment of cytomegalovirus retinitis in a patient with malignant lymphoma: a case report and review of the literature.

A 52-year-old Japanese woman was diagnosed as having angioimmunoblastic T-cell lymphoma (stage IV-B). She received 6 courses of chemotherapy including cyclophosphamide, doxorubicin, vincristine, and prednisolone every two weeks (biweekly CHOP), and was considered to be in partial remission. She complained of loss of visual acuity in her right eye during her last cycle of chemotherapy. Cytomegalovirus (CMV) retinitis was suspected from the characteristic ophthalmoscopic appearance. This diagnosis was further supported by the detection of CMV DNA in blood and antigens in polymorphonuclear leukocytes, a sign of CMV reactivation. Although DNAemia and antigenemia became negative, retinitis remained slightly active despite a 4-week systemic treatment of ganciclovir. Intraocular injection of ganciclovir was started and continued until the retinitis became inactive ophthalmoscopically. The patient received high-dose chemotherapy with peripheral blood stem cell transplantation and achieved complete remission. During the after this therapy no recurrence of CMV infections was observed. This case shows that 1) a quick and accurate diagnosis of CMV retinitis was possible by applying DNAemia and antigenemia and 2) intensive treatment for the CMV infection enabled the accomplishment of cure-oriented chemotherapy of the lymphoma without the recurrence of CMV retinitis.

Torsade de pointes associated with hypokalemia after anthracycline treatment in a patient with acute lymphocytic leukemia.

Severe dose-dependent anthracycline cardiotoxicity is reported to cause myocardial damage resulting in congestive heart failure. However, torsade de pointes, a life-threatening arrhythmia caused by chronic anthracycline cardiotoxicity, has not been reported previously. A 16-year-old girl who developed torsade de pointes after 6 months of chemotherapy for acute lymphocytic leukemia (French-American-British classification L2) is described. When the patient was readmitted to the hospital because of syncope, peripheral blood and bone marrow analysis indicated a relapse. In addition, the patient was hypokalemic. Twenty-four-hour ambulatory electrocardiographic monitoring demonstrated QT prolongation and an episode of torsade de pointes. The electrocardiographic changes and arrhythmia improved after correction of the hypokalemia. An inverse correlation between leukocyte count and hypokalemia was observed. The patient died from pulmonary hemorrhage. Autopsy examination demonstrated myocardial degeneration consistent with damage induced by antineoplastic antibiotics. The cumulative dose of anthracycline and anthraquinone was less than the conventional dose limit associated with chronic cardiotoxicity, even for children who are more sensitive to anthracyclines. Torsade de pointes can occur in the setting of chronic anthracycline cardiotoxicity. Therefore, children or young adults who are more sensitive to anthracycline need careful observation that includes electrolyte monitoring, especially for potassium.

Superior cytotoxic potency of mitoxantrone in interaction with DNA: comparison with that of daunorubicin.

The mechanism of action of the anthraquinone antileukemic drug mitoxantrone (MIT) was investigated and compared with that of daunorubicin (DNR) with emphasis on the interaction with DNA to clarify the more potent cytotoxic activity of MIT than DNR in human leukemia cells. MIT showed similar characteristics to those of the anthracyclines such as DNR in that binding of MIT to DNA was associated with reduced template activity and cleavage of DNA in HL-60 human leukemia cells. However, as compared with DNR, MIT showed an increased number of binding sites on DNA, a lower inhibition constant for DNA polymerization, and a greater DNA cleavage activity. These properties may contribute to its greater potency than that of DNR, with which MIT inhibited the proliferation of HL-60 human leukemia cells.

DNA-binding characteristics of aclarubicin as compared with daunorubicin and doxorubicin.

The effect of ionic strength on aclarubicin - DNA complexes was studied in comparison with its effect on daunorubicin - or doxorubicin - DNA complexes, using the spectrophotometric method. The hypochromic shift of aclarubicin, induced by its binding to native DNA, decreased to a lesser extent by the addition of Na+ than those of daunorubicin and doxorubicin, which suggests that aclarubicin-native DNA complexes are the most stable at high ionic strength. Similar examinations were made with heat-denatured DNA and polyvinyl sulfate (PVS). Aclarubicin-denatured DNA complexes showed a greater decrease in the hypochromic shift by the addition of Na+ than the corresponding complexes with native DNA. However, for daunorubicin and doxorubicin, there were no significant differences between the complexes of anthracyclines with native and denatured DNAs. In addition, the hypochromic shift of aclarubicin-PVS complexes decreased more prominently by the addition of Na+ than those of daunorubicin - and doxorubicin - PVS complexes. These results suggest that the electrostatic interaction of aclarubicin with DNA is more labile than that of daunorubicin and doxorubicin, since anthracyclines bind to single-stranded DNA and polyelectrolytes primarily by electrostatic interaction. Therefore, the other types of interaction, which may be stronger than that of daunorubicin and doxorubicin, seem to be associated with the higher stability of aclarubicin-native DNA complexes at high ionic strength. The structural differences between aclarubicin and daunorubicin or doxorubicin are considered to contribute to the differences in DNA-binding characteristics observed in this study.

Molecular remission induced by fractionated dose-escalating donor leukocyte infusion without graft-versus-host disease in a patient with chronic myelogenous leukemia relapsed after allogeneic bone marrow transplantation.

A 39-year-old male with CML who relapsed 5 years and 8 months after allogeneic bone marrow transplantation achieved complete molecular remission following fractionated dose-escalating donor leukocyte infusions. Acute or chronic graft-versus-host disease (GVHD) did not occur and the patient remained asymptomatic throughout treatment. Since no prophylaxis against GVHD was administered, this case indicated that the graft-versus-leukemia effect is entirely separate from GVHD in certain conditions.

A novel Philadelphia chromosome-positive cell line with multipotential properties.

A novel Philadelphia chromosome-positive cell line was established from the peripheral blood of a patient with chronic myelogenous leukemia in megakaryoblastic crisis. This cell line, designated TN922 showed the positive phenotypes for myeloid, monocyte-macrophage, erythroid and megakaryocytic markers. The stimulation with phorbol 12-myristate 13-acetate (PMA) increased the expression of megakaryocytic markers including the platelet peroxidase activity, dimethylsulfoxide or transforming growth factor-beta promoted up-regulation of the erythroid markers. Stimulation with PMA, tumor necrosis factor-alpha or interleukin-6 also brought about the expression of monocytoid markers. These findings indicated that TN922 cell line has the property of acting as multipotential progenitor cells. TN922 cells showed gradual growth in the absence of growth factors but the addition of granulocyte/macrophage colony-stimulating factor (GM-CSF) promoted cell growth. The message of GM-CSF was detected in TN922 cells and the neutralizing antibody against GM-CSF receptor alpha-subunit suppressed cell growth. These results indicated that TN922 cell line proliferates in an autocrine secretion of GM-CSF.