Long-term outcome in acute myelogenous leukemia autografted with mafosfamide-purged marrow in a single institution: adverse events and incidence of secondary myelodysplasia.

We have analyzed the long-term outcome and toxicities in 98 patients with high-risk acute myelogenous leukemia (AML) who were treated with autologous bone marrow transplantation (ABMT) and monitored for a median observation period of 11.67 years. Between 1983 and 1994, 98 patients in our institution in first or second and higher complete remission (CR) underwent total body irradiation and high-dose cyclophosphamide prior to ABMT purged with mafosfamide. Twenty-seven out of the 90 evaluable patients (30%) were alive and in continuous CR for a median of 11.67 years (range, 6.39-15.53) after ABMT and could be considered as 'cured'. Among the 90 patients, 39 were transplanted at first CR and had a significantly higher survival rate than those transplanted at > or = 2 CR. Younger patients (<40 years) had a better prognosis and patients with FAB M1-4 had a more favorable outcome than those with M5. Long-term complications included four patients with cardiac complications, two with renal insufficiency. Five developed HCV infections, four myelodysplastic syndrome. The incidence of cataract among the long-term survivors was 44.4%. Therefore, a significant number of adult patients with AML in first CR derived long-term benefit from ABMT, despite the risks of a few long-term complications and of MDS (4.4%).

Less intense conditioning with fludarabine, cyclophosphamide, idarubicin and etoposide (FCIE) followed by allogeneic unselected peripheral blood stem cell transplantation in elderly patients with leukemia.

The objective of this study was to assess toxicity and feasibility of achieving engraftment of allogeneic blood progenitor cells following nonmyeloablative conditioning according to the FCIE protocol (fludarabine 25 mg/m(2)/day, days -7 to -3; cyclophosphamide 200 mg/m(2)/day, days -7 to -3; idarubicin 12 mg/m(2)/day, days -7 to -5; etoposide 250 mg/m(2)/day, days -4 to -3) in elderly patients with leukemia. Eleven patients were included in the study: six patients with acute myeloid leukemia (AML) in complete remission (CR); three patients with refractory or relapsed AML; one patient with chronic myeloid leukemia; one patient with acute lymphoblastic leukemia. The median age of the patients was 62 years. All patients received blood progenitor cells from an HLA-identical sibling with 8.8 x 10(6) CD34(+) cells/kg (median; range 4.7 to 26.2 x 10(6)/kg) and 5.5 x 10(8) CD3(+)cells/kg (median; range 4.5 to 7.9 x 10(8)/kg). Graft-versus-host disease (GVHD) prophylaxis consisted of cyclosporine and three courses of methotrexate. The median duration of white blood cell counts <1 x 10(9)/l was 17 days and of platelet counts <50 x 10(9)/l 20 days. In two patients acute GVHD grade I occurred. Nine of 10 patients analyzed developed mixed chimerism. Of seven patients transplanted in CR, three remained in CR 19 to 31 months after transplantation. Three patients with refractory leukemia did not achieve CR, while the patient with relapsed AML achieved a 3rd CR. After a median follow-up time of 22 months, chronic GVHD was mild and limited. The data from this pilot study in elderly patients with leukemia show that the combination of primarily immunosuppressive (FC) and antileukemic (IE) drugs for nonmyeloablative conditioning has moderate nonhematological toxicity and allows engraftment of allogeneic blood progenitor cells.

Stable mixed chimerism after T cell-depleted allogeneic hematopoietic stem cell transplantation using conditioning with low-dose total body irradiation and fludarabine.

Although reduced intensity conditioning (RIC) before allografting is associated with low treatment-related morbidity and mortality, graft-versus-host disease (GVHD) remains a significant complication of hematopoietic stem cell transplantation (HSCT). T cell depletion (TCD) has been successfully used in conventional allotransplantation to reduce the incidence of GVHD, but was associated with an increased rate of engraftment failure. In a small cohort of six patients at high risk of developing GVHD we have determined whether sustained engraftment could be achieved using reduced intensity conditioning and T cell depletion in combination. All patients engrafted and 5/6 developed high levels (i.e. > or =95%) of donor chimerism, even though mismatched related or matched unrelated donors were used. Only one patient developed acute GVHD, as he received donor lymphocyte infusions (DLI) for relapse. In summary, TCD might be a useful prophylactic tool in RIC allogeneic HSCT. Although TCD after RIC might be associated with high relapse rate, as 5/6 patients are not in remission, this combined strategy might be appropriate for patients with less aggressive malignant or non-malignant diseases in which high transplant-related morbidity and mortality is not acceptable.

Passenger lymphocyte syndrome with severe hemolytic anemia due to an anti-Jk(a) after allogeneic PBPC transplantation.

BACKGROUND: After allogeneic peripheral blood progenitor cell (PBPC) transplantation, a patient developed a severe hemolytic transfusion reaction due to passenger lymphocyte syndrome. CASE REPORT: A 50-year-old woman with secondary acute myeloid leukemia transforming from a myelodysplastic syndrome received an ABO-compatible PBPC graft from her HLA-identical sister. For prophylaxis of GVHD, the patient was treated with cyclosporine and methotrexate. Eighteen days after the transplant, the patient experienced a severe hemolytic transfusion reaction due to an alloantibody (anti-Jk(a)) produced by donor lymphocytes. RESULTS: The patient was typed as group A, Jk(a+) before transplantation; the donor was typed as group A, Jk(a-). On Day 18 after transplantation, the immunohematologic screening revealed a positive DAT (C3d 3+) and an alloanti-Jk(a). Hemolysis in the patient at that time was indicated by a drop in the Hb and an increase in the LDH level (maximum, 592 IU/L on Day 23). CONCLUSION: The course of hemolysis and the time of appearance of an alloantibody in this patient meet the criteria for passenger lymphocyte syndrome. In most cases, this syndrome is triggered by ABO system antibodies. This is the first reported case of passenger lymphocyte syndrome after PBPC transplantation that was due to an alloantibody that did not belong to the ABO system.

The JAK-STAT pathway: signal transduction involved in proliferation, differentiation and transformation.

STAT proteins become activated upon tyrosine and serine phosphorylation, are subsequently translocated from the cytosol to the nucleus where they exert DNA-binding activity. Several STAT binding consensus motifs have been identified in the promoters of distinct genes. These consensus elements mediate STAT recruitment and influence the kind of STAT proteins that are bound at a specific promoter site. Recent structure function analyses have revealed conserved amino terminal sequences to be crucial for phosphatase dependent deactivation of the STAT proteins. To date an increasing amount of data is available concerning the on- and off-regulation of STAT activity. Considerable convergence as well as crosstalk has been shown between the JAK-STAT pathway and the MAPK, RAS, PI3K, PKC, and PKA involving pathways. Moreover, the nature of the genes that are regulated by STAT proteins as well as the cell functions that result from STAT activation are of great current interest. Understanding the critical functional role of STAT mediated signalling events as well as their regulation by interfering pathways provides new insights into the mechanisms involved in malignant cell proliferation.

Analysis of a regulatory element in the 5'-untranslated region of the bcl-2 gene.

The bcl-2 gene is an important antagonist of apoptosis, the programmed cell death. Bcl-2 is highly expressed in a variety of lymphomas. Lymphocytes of patients with chronic lymphocytic leukemia (CLL) express high amounts of bcl-2 even in the absence of the t(14;18) translocation, resulting in a strong resistance towards corticosteroid induced apoptosis. Within the 5'-untranslated region of the bcl-2 gene a p53 dependent negative response element has been described. Genetic alterations within this element could lead to uncontrolled overexpression of bcl-2 and subsequent resistance towards apoptosis. We therefore analyzed the mRNA from the 5'-untranslated region -279 to -85 bp of the bcl-2 gene by direct PCR sequencing from peripheral blood derived lymphocytes from patients with CLL and normal healthy donors. Compared to published sequences (Tsujimoto and Croce (1986) Proc. Natl. Acad. Sci. USA 83, 5214), we consistently found an exchange at position 1271 from A to G and at position 1284 from G to A in all CLL as well as normal donor derived samples analyzed. Thus, CLL specific alterations compared to normal cells could not be found and deregulated expression of bcl-2 in CLL cells does not appear to be due to alterations in the p53 dependent negative response element of the bcl-2 gene. However, our data add information to published sequence data of this region.

Allogeneic transplantation of positively selected peripheral blood CD34+ progenitor cells from matched related donors.

Hematopoietic progenitor and stem cells are contained within the CD34+ cellular compartment of the bone marrow. Positively selected cytokine primed peripheral blood derived CD34+ cells have been shown to support autologous hematopoiesis after myeloablative therapy. We investigated hematologic reconstitution and incidence of graft-versus-host disease (GVHD) after transplantation of allogeneic peripheral blood CD34+ cells. CD34+ cells were selected from the peripheral blood of 10 matched related donors after treatment with rG-CSF followed by one to four apheresis procedures and biotin-avidin immune affinity purification. Ten patients with advanced hematologic malignancies were subsequently transplanted with cryopreserved allogeneic CD34+ cells after myeloablative chemotherapy. Immune affinity purification of CD34+ cells resulted in a 370-fold T cell reduction. Patients were grafted with a median number of 4.1 x 10(6) kg (1.6-6.4) CD34+ cells and 0.42 x 10(6)/kg (0.29-2.2) CD3+ cells. All patients received rG-CSF 5 micrograms/kg post-transplant and completely engrafted with neutrophils > 500/microliter after a median time of 10 days (9-15) and platelets > 20,000/microliter after 16 days (10-74). Complete donor chimerism was demonstrated by cytogenetic and molecular methods up to day +385 post-transplant. Cyclosporin A only was used for GVHD prophylaxis. Four of 10 patients developed acute GVHD with grade I (one) and II (three) which completely resolved with treatment. Two patients died from infectious complications. Three patients died from relapse or progressive disease. Five patients are alive in remission without GVHD with a median follow-up time of 254 (93-457) days and three of five are without immunosuppression. Allogeneic transplantation of positively selected peripheral blood-derived CD34+ cells is feasible and safe and leads to long-term engraftment without severe GVHD suggesting that peripheral blood-derived CD34+ cells contain pluripotent hematopoietic stem cells. The reduced number of T cells transplanted appears to be sufficient for engraftment.

Stat3 recruitment by two distinct ligand-induced, tyrosine-phosphorylated docking sites in the interleukin-10 receptor intracellular domain.

Recent work has shown that IL-10 induces activation of the JAK-STAT signaling pathway. To define the mechanism underlying signal transducer and activator of transcription (STAT) protein recruitment to the interleukin 10 (IL-10) receptor, the STAT proteins activated by IL-10 in different cell populations were first defined using electrophoretic mobility shift assays. In all cells tested, IL-10 activated Stat1 and Stat3 and induced the formation of three distinct DNA binding complexes that contained different combinations of these two transcription factors. IL-10 also activated Stat5 in Ba/F3 cells that stably expressed the murine IL-10 receptor. Using a structure-function mutagenesis approach, two tyrosine residues (Tyr427 and Tyr477) in the intracellular domain of the murine IL-10 receptor were found to be redundantly required for receptor function and for activation of Stat3 but not for Stat1 or Stat5. Twelve amino acid peptides encompassing either of these two tyrosine residues in phosphorylated form coprecipitated Stat3 but not Stat1 and blocked IL-10-induced Stat3 phosphorylation in a cell-free system. In contrast, tyrosine-phosphorylated peptides containing Tyr374 or Tyr396 did not interact with Stat3 or block Stat3 activation. These data demonstrate that Stat3 but not Stat1 or Stat5 is directly recruited to the ligand-activated IL-10 receptor by binding to specific but redundant receptor intracellular domain sequences containing phosphotyrosine. This study thus supports the concept that utilization of distinct STAT proteins by different cytokine receptors is dependent on the expression of particular ligand-activatable, tyrosine-containing STAT docking sites in receptor intracellular domains.

IL-10 induces DNA binding activity of three STAT proteins (Stat1, Stat3, and Stat5) and their distinct combinatorial assembly in the promoters of selected genes.

Interaction of IL-10 with its receptor leads to the activation of STAT transcription factors. Herein we report the IL-10 dependent simultaneous activation of three STAT transcription factors: Stat1, Stat3, and Stat5. Upon IL-10 treatment multiple Stat proteins become simultaneously activated, and bind to different promoters with equal kinetics but form distinct homo- and heterodimeric transcriptionally active complexes depending on the STAT-consensus elements of a selected gene promoter. Upon IL-10 treatment Stat1, 3, and 5 bind to the GRR of the FcgammaRI gene, activated Stat1 and 3 bind to the SIE sequence of the c-fos promoter and transcriptionally active Stat5 assembles at the PRL-STAT consensus sequence of the beta-casein gene. Thus, functionally relevant STAT dimerization is influenced by the activated cytokine receptor as well as the specific STAT consensus sequence present in a specific gene promoter.

Interleukin-10 increases Bcl-2 expression and survival in primary human CD34+ hematopoietic progenitor cells.

Bcl-2 expression has been shown in hematopoietic progenitor cells. Through the use of Bcl-2 specific antisense oligonucleotides we herein report the biologic importance of Bcl-2 expression in primary human CD34+ hematopoietic progenitor cells committed to the myeloid lineage. In bone marrow or peripheral blood derived CD34+ cells Bcl-2 specific antisense decreased cell survival and inhibited the outgrowth of mixed myeloid colonies. A short-term overnight pretreatment of CD34+ cells with 25 mumol/L of Bcl-2 antisense in liquid culture completely ablated the growth of granulocyte-macrophage colony-forming cells (GM-CFC) in a subsequent 14 days methylcellulose colony assay. Control experiments using corresponding Bcl-2 sense or nonsense oligonucleotides did not significantly impair cell survival or growth of GM-colony-forming unit. Western blot analyses revealed the Bcl-2 antisense dependent inhibition of expression of the Bcl-2 protein in CD34+ progenitor cells. Furthermore, regulation of Bcl-2 expression by various cytokines including interleukin-10 (IL-10) was studied. IL-10's effects on the formation of mixed myeloid colonies were examined in the absence or presence of Bcl-2 specific antisense. In the absence of Bcl-2 antisense IL-10 significantly extended the colony forming potential of mixed myeloid colonies to 14 days. In the presence of Bcl-2 antisense rhIL-10 completely restored GM-CSF driven colony growth. Fluorescent microscopy, Western blot analysis, and reverse transcriptase-polymerase chain reaction revealed the IL-10 dependent increase in cellular expression of Bcl-2 protein and Bcl-2 mRNA transcripts in CD34+ cells. Thus these results show that Bcl-2 expression is necessary for the formation of GM-CSF-dependent colony growth in vitro and that rhIL-10 increases Bcl-2 expression and survival in primary human CD34+ hematopoietic progenitor cells that are committed to the myeloid lineage.

Umbilical cord blood: an alternative to the transplantation of bone marrow stem cells.

Recent in vitro analyses of human UCB have demonstrated the potential of UCB as a source for haematopoietic stem and progenitor cell harvest. Clinical data have further indicated that UCB can be given in vivo to fully and partially HLA-matched siblings or non-familial recipients for marrow reconstitution in genetic disorders as well as malignancies. In comparison to adult peripheral blood, UCB displayed decreased immune responses to alloantigens and was enriched in the numbers of CD34+ progenitor cells with high proliferative and long-term marrow reconstituting potential. Cord blood banks now store large transplantable resources of UCB that are analysed with respect to immunological parameters. Cryopreserved UCB cells may fill the gap in finding a stem-cell transplant for patients who lack a matched related or unrelated donor when a bone marrow transplant is needed.

Constitutive activation of STAT proteins in primary lymphoid and myeloid leukemia cells and in Epstein-Barr virus (EBV)-related lymphoma cell lines.

Although various molecular mechanisms of STAT protein (signal transducers and activators of transcription) activation have been identified, little is known about the functional role of STAT-dependent transcriptional activation. Herein we report the constitutive nuclear localization, phosphorylation, and DNA-binding activity of STAT proteins in leukemia cells and lymphoma cell lines. With the use of oligonucleotide probes derived from the Fc gamma RI promoter, the beta-casein promoter and a STAT-binding element in the promoter of the Bci-2 gene constitutive activation of STAT proteins was detected in untreated acute T- and C/B-leukemia cells (3 of 5 and 12 of 19 patients, respectively). Supershift analyses using Stats 1-6 specific antisera showed the constitutive DNA binding activity of Stat5 in these cells. Confocal microscopy revealed the nuclear localization of Stat5 and Western blot analyses showed tyrosine phosphorylation of Stat5 in nuclear extracts of acute leukemia cells. In contrast, peripheral blood mononuclear cells did not display constitutive STAT-DNA interaction. Further studies were performed on freshly isolated acute myeloid leukemia cells as well as on cell line derived K562, lymphoblastoid cells (LCL), and Burkitt's lymphoma cells (BL). Fluorescence microscopy, gelshift, and supershift experiments showed the nuclear localization and constitutive DNA-binding activity of Stat5 in K562 cells. Stat1 and Stat3 were constitutively activated in freshly isolated AML cells (10 of 14 patients) and in Epstein Barr virus-positive or interleukin-10 expressing permanent LCL and BL cells. Thus, these data indicate a differential pattern of STAT protein activation in lymphoid or myeloid leukemia and in lymphoma cells.

STAT-related transcription factors are constitutively activated in peripheral blood cells from acute leukemia patients.

A signal transduction pathway activated by many cytokines has recently been elaborated. The JAK kinases and the signal transducers and activators of transcription (STAT) factors have been found to be essential components. In this report, we describe the presence of constitutively activated STAT factors in peripheral blood cells from patients with acute leukemia. We used oligonucleotide probes from the beta-casein and IRF-1 gene promoters and the ISRE probe to detect STAT proteins in nuclear extracts from acute leukemia cells in bandshift assays. Specific DNA protein complex formation was observed with the probes from the beta-casein and IRF-1 gene promoters, but not with the ISRE oligonucleotide probe, when cell extracts from acute lymphoblastic leukemia (ALL) and acute myeloid leukemia (AML) were investigated. We used nonradioactive oligonucleotides as competitors to show the specificity of the complex formation. Specific antibodies directed against the individual STAT proteins were used in supershift experiments. STAT5- and STAT1-related factors were detected in ALL and STAT1-, STAT3-, and STAT5-related proteins were present in nuclear cell extracts from AML. Since the cells were not treated with cytokines before the nuclear proteins were extracted, we conclude that these factors are constitutively activated in vivo. It is likely that the constitutive activation of STAT proteins is a part of the events of leukemogenesis.

Hematopoietic cell proliferation and hematopoietic growth factors.

In vivo studies using hematopoietic growth factors in humans have more clearly defined the ability of these molecules to accelerate hematopoietic cell proliferation in postchemotherapy aplasia and constitutive marrow deficiency states. Studies applying combinations of two growth factors have been added. Investigation of negative regulators of hematopoietic cell proliferation has opened new approaches to protect against damage or loss of candidate stem cells in vitro or in vivo, as well as to selectively recruit malignant cell populations into cell cycle while protecting benign cells. New insights into the synergism of positive regulators of hematopoietic cell proliferation have come from a panoply of in vitro studies, underscoring the value of growth factors previously not associated with effects on hematopoietic cells that have now been found to confer significant synergism with known hematopoietic regulators.

Interleukin 12 signaling in T helper type 1 (Th1) cells involves tyrosine phosphorylation of signal transducer and activator of transcription (Stat)3 and Stat4.

Interleukin 12 (IL-12) initiates the differentiation of naive CD4+ T cells to T helper type 1 (Th1) cells critical for resistance to intracellular pathogens such as Leishmania major. To explore the basis of IL-12 action, we analyzed induction of nuclear factors in Th1 cells. IL-12 selectively induced nuclear DNA-binding complexes that contained Stat3 and Stat4, recently cloned members of the family of signal transducers and activators of transcription (STATs). While Stat3 participates in signaling for several other cytokines, Stat4 was not previously known to participate in the signaling pathway for any natural ligand. The selective activation of Stat4 provides a basis for unique actions of IL-12 on Th1 development. Thus, this study presents the first identification of the early events in IL-12 signaling in T cells and of ligand activation of Stat4.

Lipopolysaccharide-dependent induction of IL-10 receptor expression on murine fibroblasts.

Although various biologic activities of IL-10 have been identified, little is known about IL-10's molecular mechanism of action. Herein we report the characterization of IL-10R on different murine cell lines and demonstrate the LPS inducibility of this protein. With the use of purified recombinant murine IL-10 and labeled IL-10-specific mAb, IL-10Rs were detected by flow cytometry. Radioligand binding analyses showed that RAW264.7 cells expressed 238 +/- 87 receptors per cell and bound ligand with a single affinity of 8.3 +/- 2.4 x 10(9) M-1. Similar studies documented IL-10R expression on murine B cells (CH27) and CD4+ Th1 cells but not murine Th2 cells, L929 or WA-17 fibroblasts, or fibrosarcoma cells. Exposure of fibroblasts to LPS-induced cellular IL-10 binding activity in a dose- and time-dependent manner. Radioligand binding analyses performed on LPS-treated fibroblasts showed cellular expression of 325 +/- 59 IL-10 binding sites and a binding affinity of Ka = 7.5 +/- 2.5 x 10(8) M-1. RT-PCR analysis confirmed the induction of the IL-10R. Functional analyses of IL-10R-expressing cells revealed that IL-10 activated a cellular transcription factor in RAW264.7 cells that bound a DNA probe containing the IFN-gamma response region from the Fc gamma RI gene. In contrast, IL-10 did not induce gamma response region binding activity in L929 fibroblasts either treated with LPS or transfected with the murine IL-10R cDNA. These results thus indicate that cellular responses to IL-10 may be influenced by both the external environment and the presence of additional signaling components within the cell.