Biomedical subjects

N Carlesso

Publications and source records attributed to N Carlesso.

17 recordsLinked to original sources

PubMed2001

Alternative splicing determines the function of CYP4F3 by switching substrate specificity.

Diversity of cytochrome P450 function is determined by the expression of multiple genes, many of which have a high degree of identity. We report that the use of alternate exons, each coding for 48 amino acids, generates isoforms of human CYP4F3 that differ in substrate specificity, tissue distribution, and biological function. Both isoforms contain a total of 520 amino acids. CYP4F3A, which incorporates exon 4, inactivates LTB4 by omega-hydroxylation (Km = 0.68 microm) but has low activity for arachidonic acid (Km = 185 microm); it is the only CYP4F isoform expressed in myeloid cells in peripheral blood and bone marrow. CYP4F3B incorporates exon 3 and is selectively expressed in liver and kidney; it is also the predominant CYP4F isoform in trachea and tissues of the gastrointestinal tract. CYP4F3B has a 30-fold higher Km for LTB4 compared with CYP4F3A, but it utilizes arachidonic acid as a substrate for omega-hydroxylation (Km = 22 microm) and generates 20-HETE, an activator of protein kinase C and Ca2+/calmodulin-dependent kinase II. Homology modeling demonstrates that the alternative exon has a position in the molecule which could enable it to contribute to substrate interactions. The results establish that tissue-specific alternative splicing of pre-mRNA can be used as a mechanism for changing substrate specificity and increasing the functional diversity of cytochrome P450 genes.

Alternative Splicing↗

PubMed2001

The Wilms tumor suppressor WT1 directs stage-specific quiescence and differentiation of human hematopoietic progenitor cells.

WT1, a transcription factor implicated in both normal kidney differentiation and tumorigenesis, is also expressed in differentiating hematopoietic progenitors. Most human acute leukemias contain high levels of the wild-type transcript, while a minority have point mutations, raising the possibility that this tumor suppressor might have a paradoxical oncogenic effect in some hematopoietic cells. Using high titer retroviral infection, we demonstrate that WT1 triggers rapid growth arrest and lineage-specific differentiation in primary hematopoietic progenitors and differentiation-competent leukemia cell lines, while it induces cellular quiescence in a primitive subset of primary precursors. Growth arrest by WT1 is associated with induction of p21(CIP1), but expression of this cyclin-dependent kinase inhibitor alone is insufficient for either cellular differentiation or primitive cell preservation. The effects of WT1 are enhanced by co-expression of its naturally occurring isoforms, and are correlated with the physiological expression pattern of WT1 in vivo. Our observations suggest a role for WT1 in the differentiation of human hematopoietic cells, and provide a functional model that supports its capacity as a tumor suppressor in human acute leukemia.

Bone Marrow Cells↗

PubMed2000

Tat peptide-derivatized magnetic nanoparticles allow in vivo tracking and recovery of progenitor cells.

The ability to track the distribution and differentiation of progenitor and stem cells by high-resolution in vivo imaging techniques would have significant clinical and research implications. We have developed a cell labeling approach using short HIV-Tat peptides to derivatize superparamagnetic nanoparticles. The particles are efficiently internalized into hematopoietic and neural progenitor cells in quantities up to 10-30 pg of superparamagnetic iron per cell. Iron incorporation did not affect cell viability, differentiation, or proliferation of CD34+ cells. Following intravenous injection into immunodeficient mice, 4% of magnetically CD34+ cells homed to bone marrow per gram of tissue, and single cells could be detected by magnetic resonance (MR) imaging in tissue samples. In addition, magnetically labeled cells that had homed to bone marrow could be recovered by magnetic separation columns. Localization and retrieval of cell populations in vivo enable detailed analysis of specific stem cell and organ interactions critical for advancing the therapeutic use of stem cells.

Animals↗

PubMed1999

Notch1-induced delay of human hematopoietic progenitor cell differentiation is associated with altered cell cycle kinetics.

Hematopoiesis is a balance between proliferation and differentiation that may be modulated by environmental signals. Notch receptors and their ligands are highly conserved during evolution and have been shown to regulate cell fate decisions in multiple developmental systems. To assess whether Notch1 signaling may regulate human hematopoiesis to maintain cells in an immature state, we transduced a vesicular stomatitis virus G-protein (VSV-G) pseudo-typed bicistronic murine stem cell virus (MSCV)-based retroviral vector expressing a constitutively active form of Notch1 (ICN) and green fluorescence protein into the differentiation competent HL-60 cell line and primary cord blood-derived CD34(+) cells. In addition, we observed endogenous Notch1 expression on the surface of both HL-60 cells and primary CD34(+) cells, and therefore exposed cells to Notch ligand Jagged2, expressed on NIH3T3 cells. Both ligand-independent and ligand-dependent activation of Notch resulted in delayed acquisition of differentiation markers by HL-60 cells and cord blood CD34(+) cells. In addition, primary CD34(+) cells retained their ability to form immature colonies, colony-forming unit-mix (CFU-mix), whereas control cells lost this capacity. Activation of Notch1 correlated with a decrease in the fraction of HL-60 cells that were in G0/G1 phase before acquisition of a mature cell phenotype. This enhanced progression through G1 was noted despite preservation of the proliferative rate of the cells and the overall length of the cell cycle. These findings show that Notch1 activation delays human hematopoietic differentiation and suggest a link of Notch differentiation effects with altered cell cycle kinetics.

3T3 Cells↗

PubMed1997

Suppression of in vitro maintenance of non-promyelocytic myeloid leukemia clonogenic cells by all-trans retinoic acid: modulating effects of dihydroxylated vitamin D3, alpha interferon and 'stem cell factor'.

In a liquid culture system, all-trans retinoic acid (ATRA), alone and in combination with dihydroxylated vitamin D3 (D3) or alpha interferon (alphaIFN) at concentrations achievable in vivo, could significantly suppress the maintenance of non-promyelocytic myeloid leukemia clonogenic cells (CFU-L) in 9/20, 9/18 and 7/11 cases, respectively. That suppression was counteracted only slightly by the addition of 'stem cell factor', a cytokine which promotes CFU-L expansion in vitro. Differentiated cells slightly increased in 5/17 cases only, suggesting the prevalence of anti-proliferative rather than differentiating mechanisms. The present results extend our previous ones and suggest the possible therapeutical value of ATRA+D3 or alphaIFN, even in cases of non-promyelocytic myeloid leukemia.

Acute Disease↗

PubMed1996

PI 3-kinase activation in BCR/abl-transformed hematopoietic cells does not require interaction of p85 SH2 domains with p210 BCR/abl.

BCR/abl is a chimeric oncogene implicated in the pathogenesis of human chronic myelogenous leukemia. Expression of the BCR/abl gene induces hematologic malignancies in transgenic mice and transformation of interleukin-3-dependent hematopoietic cells. The mechanism of BCR/abl-mediated transformation of hematopoietic cells is poorly understood and involves activation of at least two signaling pathways, p21ras and PI 3-kinase. Here we report that PI 3,4-P2 and PI 3,4,5-P3, the enzymatic products of PI 3-kinase, accumulate in metabolically labeled transformed hematopoietic cells, in contrast to our previous report on the lack of accumulation of PI 3-kinase products in nontransformed NIH 3T3 fibroblasts that express p210 BCR/abl. Transformed cells also have increased PI 3-kinase activity in total cell extracts and membrane fractions. Activation of PI 3-kinase occurs by occupancy of SH2 domains of PI 3-kinase regulatory subunit, p85, by phosphorylated YXXM motifs. Therefore, we investigated whether BCR/abl binds to p85 and whether this binding is mediated by interaction of p85 SH2 domains with YXXM motif of BCR/abl. Association of p210 BCR/abl with p85 in immune complexes and with p85 SH2 domains was evident in hematopoietic cells that express the wt p210 BCR/abl. However, the binding of BCR/abl to p85 SH2 domains was abolished in cells expressing mutant, temperature-sensitive (ts) p210 BCR/abl in which the tyrosine in the YXXM motif of p210 BCR/abl was replaced by histidine. Despite lack of direct interaction with p85 SH2 domains, expression of ts p210 BCR/abl resulted in rapid, time-dependent activation of total and membrane-associated PI 3-kinase and increased PI 3-kinase activity in anti-P-tyr and anti-abl immunoprecipitates. These data suggest that BCR/abl-induced activation of PI 3-kinase in hematopoietic cells does not require binding of p85 SH2 domains to BCR/abl gene product and involves interaction with other tyrosine phosphorylated intermediate proteins.

3T3 Cells↗

PubMed1996

Bcr/Abl expression stimulates integrin function in hematopoietic cell lines.

Cell adhesion to the extracellular matrix is largely mediated by adhesion molecules of the integrin family and is often diminished upon oncogenic transformation. However, we show here that the chronic myelogenous leukemia oncogene Bcr/Abl has positive effects on VLA-4 and VLA-5 integrin function. The presence of Bcr/Abl in the GM-CSF- or IL-3-dependent hematopoietic cell lines MO7e, 32D, and BaF/3 enhanced cell binding to both soluble and immobilized fibronectin. The effect was due to enhanced function of the VLA-5 integrin fibronectin receptor and not to increased surface expression. In parallel, Bcr/Abl stimulated cell adhesion to the VLA-4 integrin ligand VCAM-1. Stimulation of VLA-5 function directly correlated with induction of Bcr/Abl tyrosine kinase activity in a temperature-sensitive kinase mutant. Thus, Bcr/Abl stimulates integrin-dependent cell adhesion, by a mechanism involving increased ligand binding, with the tyrosine kinase activity of Bcr/Abl likely playing a key role. Consistent with these results, hematopoietic precursor cells from chronic myelogenous leukemia patients also showed increased adhesion to fibronectin.

Animals↗

PubMed1996

Tyrosyl phosphorylation and DNA binding activity of signal transducers and activators of transcription (STAT) proteins in hematopoietic cell lines transformed by Bcr/Abl.

Bcr/Abl is a chimeric oncogene that can cause both acute and chronic human leukemias. Bcr/Abl-encoded proteins exhibit elevated kinase activity compared to c-Abl, but the mechanisms of transformation are largely unknown. Some of the biological effects of Bcr/Abl overlap with those of hematopoietic cytokines, particularly interleukin 3 (IL-3). Such effects include mitogenesis, enhanced survival, and enhanced basophilic differentiation. Therefore, it has been suggested that p210Bcr/Abl and the IL-3 receptor may activate some common signal transduction pathways. An important pathway for IL-3 signaling involves activation of the Janus family kinases (JAKs) and subsequent tyrosyl phosphorylation of STAT proteins (signal transducers and activators of transcription). This pathway directly links growth factor receptors to gene transcription. We analyzed JAK activation, STAT protein phosphorylation, and the formation of specific DNA-binding complexes containing STAT proteins, in a series of leukemia cell lines transformed by Bcr/Abl or other oncogenes. We also examined these events in cell lines transformed by a temperature sensitive (ts) mutant of Bcr/Abl, where the kinase activity of Abl could be regulated. STAT1 and STAT5 were found to be constitutively phosphorylated in 32D, Ba/F3, and TF-1 cells transformed by Bcr/Abl, but not in the untransformed parental cell lines in the absence of IL-3. Phosphorylation of STAT1 and STAT5 was also observed in the human leukemia cell lines K562 and BV173, which express the Bcr/Abl oncogene, but not in several Bcr/Abl-negative leukemia cell lines. Phosphorylation of STAT1 and STAT5 was directly due to the tyrosine kinase activity of Bcr/Abl since it could be activated or deactivated by temperature shifting of cells expressing the Bcr/Abl ts mutant. DNA-STAT complexes were detected in all Bcr/Abl-transformed cell lines and they were supershifted by antibodies against STAT1 and STAT5. DNA-STAT complexes in 32Dp210Bcr/Abl cells were similar, but not identical, to those formed after IL-3 stimulation. It is interesting to note that JAK kinases (JAK1, JAK2, JAK3, and Tyk2) were not consistently activated in Bcr/Abl-positive cells. These data suggest that STATs can be activated directly by Bcr/Abl, possibly bypassing JAK family kinase activation. Overall, our results suggest a novel mechanism that could contribute to some of the major biological effects of Bcr/Abl transformation.

Base Sequence↗

PubMed1995

Identification of a viability domain in the granulocyte/macrophage colony-stimulating factor receptor beta-chain involving tyrosine-750.

The granulocyte/macrophage colony-stimulating factor (GM-CSF) receptor (GMR) is a heterodimeric receptor expressed by myeloid lineage cells. In this study we have investigated domains of the GMR beta-chain (GMR beta) involved in maintaining cellular viability. Using a series of nested GMR beta deletion mutants, we demonstrate that there are at least two domains of GMR beta that contribute to viability signals. Deletion of amino acid residues 626-763 causes a viability defect that can be rescued with fetal calf serum (FCS). Deletion of residues 518-626, in contrast, causes a further decrement in viability that can be only partially compensated by the addition of FCS. GMR beta truncated proximal to amino acid 517 will not support long-term growth under any conditions. Site-directed mutagenesis of tyrosine-750 (Y750), which is contained within the distal viability domain, to phenylalanine eliminates all demonstrable tyrosine phosphorylation of GMR beta. Cell lines transfected with mutant GMR beta (Y750-->F) have a viability disadvantage when compared to cell lines containing wild-type GMR that is partially rescued by the addition of FCS. We studied signal transduction in mutant cell lines in an effort to identify pathways that might participate in the viability signal. Although tyrosine phosphorylation of JAK2, SHPTP2, and Vav is intact in Y750-->F mutant cell lines, Shc tyrosine phosphorylation is reduced. This suggests a potential role for Y750 and potentially Shc in a GM-CSF-induced signaling pathway that helps maintain cellular viability.

Animals↗

PubMed1995

Tyrosine phosphorylation of p95Vav in myeloid cells is regulated by GM-CSF, IL-3 and steel factor and is constitutively increased by p210BCR/ABL.

Vav is a recently described proto-oncogene expressed only in hematopoietic cells which contains an SH2 and two SH3 domains and shares homology with the Dbl GDP-GTP exchange factor and BCR. p95Vav is phosphorylated on tyrosine residues in response to stimulation of the T cell antigen receptor, cross-linking of IgE or IgM receptors and stimulation of immature hematopoietic cells by Steel factor. Monoclonal antibodies to human Vav were generated and used to examine the events which regulate tyrosine phosphorylation of p95Vav in myeloid cells. In the factor-dependent MO7e cell line, p95Vav was rapidly phosphorylated on tyrosine residues in a dose- and time-dependent manner by GM-CSF, IL-3 and Steel factor. Introduction of the BCR/ABL oncogene into this cell line resulted in factor-independent proliferation and constitutive phosphorylation of p95Vav. Tyrosine phosphorylation of p95Vav was also substantially increased by treatment of cytokine-deprived cells with the tyrosine phosphatase inhibitor sodium vanadate. Since many of the cytokines known to induce tyrosine phosphorylation of p95Vav are also known to activate JAK family tyrosine kinases, we looked for an interaction of p95Vav with JAK kinases. p95Vav co-precipitated with JAK2 in MO7e cells stimulated with GM-CSF, but not in unstimulated cells. Also, JAK2 was found to be constitutively associated with p95Vav in vivo when expressed at high levels in insect cells using baculovirus vectors. A fusion protein consisting of glutathione-S-transferase and the SH2 domain of p95Vav (GST-Vav-SH2) precipitated JAK2, suggesting that this interaction is mediated by the SH2 domain of p95Vav.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed1994

Generation of anti-tumour activity by OKT3-stimulation in multiple myeloma: in vitro inhibition of autologous haemopoiesis.

T cells in multiple myeloma (MM) patients are highly susceptible to activation with the anti-CD3 monoclonal antibody (mAb) OKT3. When short-term OKT3 stimulation is carried out on bone marrow mononuclear cells (BMMC), large numbers of CD3+ CD25+ HLA-DR+ cells are rapidly generated and autologous malignant plasma cells are killed. OKT3 may thus be exploited in autologous bone marrow transplantation (ABMT) to purge residual plasma cells and simultaneously activate T cells to induce graft-versus-leukemia-like (GVL-like) activity upon reinfusion. However, the possible impact of ex-vivo short-term OKT3 stimulation on haematological recovery is unknown. The aim of this work was to investigate the effect of OKT3 stimulation in vitro on autologous haemopoietic progenitor cells (HPC) of MM patients. Colony formation by granulocyte-macrophage progenitor cells (granulocyte-macrophage colony-forming units, CFU-GM) was highly suppressed, although supernatants of OKT3-activated T cells contained up to 2,500 pg/ml of granulocyte-macrophage colony-stimulating factor (GM-CSF). T cell depletion completely prevented this suppression. Neutralizing antibodies against TNF-alpha, TNF-beta and IFN-gamma (which are also produced by OKT3-activated MM T cells) did not prevent it, and Transwell cultures showed that cell-to-cell contact was the main mechanism involved. OKT3-activated T cells also suppressed erythroid burst-forming units (BFU-E) and CFU-GM generation from HPC responsible for long-term maintenance of in vitro myelopoiesis. When tested on normal allogeneic BM, MM supernatants of OKT3-stimulated BMMC partially suppressed the generation of day 7 CFU-GM, but had no effect on day 14 CFU-GM. These data indicate that short-term stimulation of BMMC with OKT3 can be used to generate anti-tumour effector T cells for autologous adoptive immunotherapy. It is not a feasable approach for ex-vivo purging and activation procedures in ABMT because of its potent inhibition of autologous haemopoiesis.

Bone Marrow Cells↗

PubMed1994

Stem cell factor improvement of proliferation and maintenance of hemopoietic progenitors in myelodysplastic syndromes.

Human recombinant stem cell factor (rSCF) was tested for its capability of improving the defective growth of hemopoietic progenitors in 28 cases of myelodysplastic syndromes (MDS). In vitro growth and response to rSCF were quite variable. However, in most cases, rSCF stimulated CFU-GM growth induced by rG-CSF, rGM-CSF, rIL-3, 5637 conditioned medium (50-1400% enhancement). rSCF effect was slightly more evident on day 14 CFU-GM and in the presence of rIL-3. BFU-E growth induced by rEPO or rIL-3 + rEPO was enhanced by rSCF in about 50% of cases, in linear correlation with the levels of patients' hemoglobin. rSCF did not increase CFU-E growth, whereas it slightly stimulated CFU-Mk in 33% of the cases. EPO, SCF and, particularly, their combination, enhanced the recovery of normal CFU-E and BFU-E after 7 days of liquid culture. This was less evident in cultures of MDS patients. Conversely, CFU-GM generation in long term liquid cultures, although highly variable, was stimulated by rSCF and, above all, by rSCF + rG-CSF, similarly to what was observed with normal bone marrow samples. SCF seems to enhance in vitro erythropoiesis only in MDS cases presenting without severe anemia. It has little effect on megakaryocytopoiesis, while it seems to be more active on CFU-GM growth and maintenance.

Cell Division↗

PubMed1994

Use of a temperature-sensitive mutant to define the biological effects of the p210BCR-ABL tyrosine kinase on proliferation of a factor-dependent murine myeloid cell line.

The Philadelphia chromosome, detected in virtually all cases of chronic myelogenous leukemia, is formed by a reciprocal translocation between chromosomes 9 and 22 that fuses BCR encoded sequences upstream of exon 2 of c-ABL. This oncogene produces a fusion protein, p210BCR-ABL, in which the ABL tyrosine kinase activity is elevated. This elevated kinase activity is essential for transformation, but the mechanisms involved are unknown. To investigate p210BCR-ABL function we constructed a model system in which the tyrosine kinase activity of p210BCR-ABL was inducible. Two amino acid substitutions, Arg to His at amino acid 457 and Tyr to His at amino acid 469 of c-abl, modeled on mutations known to render v-src temperature-sensitive for tyrosine kinase activity, were introduced into p210BCR-ABL. This mutant was characterized in an IL-3 growth factor dependent murine myeloid cell line, 32Dc13. Cell lines expressing the temperature-sensitive mutant remained factor dependent at the non-permissive temperature, but at the permissive temperature displayed a marked reduction in cell death in the absence of growth factor and an exaggerated proliferative response to low levels of IL-3. Both the kinase activity of the mutant and the levels of tyrosine phosphorylated proteins are increased in the temperature-sensitive mutant at the permissive temperature. Further, tyrosine phosphorylation of potential substrates of the p210BCR-ABL tyrosine kinase, p120 rasGAP and its associated proteins of p190 and p62, only occurs at the permissive temperature in cells expressing the temperature-sensitive mutant.

Animals↗

PubMed1992

Self-renewal inhibition of acute myeloid leukemia clonogenic cells by biological inducers of differentiation.

We analyzed the maintenance of acute myeloid leukemia clonogenic cells (AML CFU-L) in liquid culture in the presence of five potential differentiation inducers: trans-retinoic acid, 1,25-dihydroxy vitamin D3, interferon gamma, granulocyte colony-stimulating factor (G-CSF), macrophage colony-stimulating factor (M-CSF), used singly and with two combined. The culture medium contained either fetal bovine or human serum from normal donors. CFU-L recovery after 7 days was compared to that observed in control cultures. Of AML cases and HL60 cells, 11/15 displayed greater than 50% CFU-L reduction in response to one or more inducers. In 8/9 responsive cases that underwent the nitroblue tetrazolium (NBT) reduction test, an increase in the percentage of functionally mature (NBT-positive) cells was detected. The combination of retinoic acid with interferon gamma was most effective in reducing CFU-L recovering (8 responsive/15 AML cases), G-CSF and M-CSF displayed either inhibitory or stimulatory activity in different AML cases. The type of serum employed generally did not affect the response to inducers of differentiation. No significant inhibition of the recovery of granulocyte-macrophage colony-forming units was determined by the five inducers in experiments with three normal bone marrow samples. Our experiments indicate that biological differentiation inducers can reduce AML CFU-L self-renewal and increase the proportion of differentiated cells at concentrations that do not affect normal myelopoiesis and could be achieved during treatments in vivo.

Acute Disease↗

PubMed1992

Human recombinant stem cell factor stimulates in vitro proliferation of acute myeloid leukemia cells and expands the clonogenic cell pool.

Stem cell factor (SCF) is a new growth factor acting on early hematopoietic progenitor and stem cells. In our experiments human recombinant SCF stimulated short-term proliferation of accessory cell-depleted acute myeloid leukemia (AML) cells in 13/14 cases, as determined by 3H-thymidine (3H-TdR) incorporation and cell counts. Stimulatory activity was significantly greater than in the presence of GM-CSF and was comparable to that of granulocyte colony-stimulating factor (G-CSF), interleukin 3 (IL-3), and 5637 cell line supernatant (SN). Conversely, the ability of SCF to induce primary colony formation by AML clonogenic cells (CFU-L) was lower than that of granulocyte-macrophage colony-stimulating factor (GM-CSF) and 5637 SN in all but four cases. However, SCF potentiated the stimulatory effect of GM-CSF, G-CSF, and IL-3 on both 3H-TdR incorporation and colony formation. In a 7-day liquid culture SCF enhanced CFU-L recovery in all cases to a significantly greater extent than the other growth factors. A further increment was obtained by combinations of SCF with GM-CSF, G-CSF, or IL-3, and this was significantly more effective than 5637 SN. SCF did not induce leukemic cell differentiation. Human recombinant SCF is therefore highly efficient in stimulating AML cell proliferation and expanding the CFU-L pool. It was not, however, able to support long-term growth of AML cells (beyond 2-7 weeks) in five cases tested.

Antigens, Differentiation, Myelomonocytic↗

PubMed1991

CD9 antigen on acute non-lymphoid leukemia cells: preferential expression by promyelocytic (M3) subtype.

A monoclonal antibody (S17-12), previously described to recognize subsets of myelomonocytic cells, is demonstrated to bind CD9 antigen, a surface marker of B-cell precursors, platelets and several non-hematopoietic tissues. The proportion of S17-12, CD9-positive leukemic cells was determined in 102 patients with acute non-lymphocytic leukemia. It was found to be above 75% in 14/22 M3 cases (including 3/3 of microgranular variant) and only in 1/80 cases of different FAB subtype. Complete reactivity (greater than 95%) of leukemic clonogenic cells with CD9 MoAB was restricted to 4/18 M3 cases. Therefore, a high proportion of CD9-positive cells seems to be peculiar to M3 cases. This may help in the diagnosis of cases that lack typical morphological features.

Antibodies, Monoclonal↗

PubMedDate not supplied

MACOP-B treatment for intermediate and high-grade non-Hodgkin's lymphomas at diagnosis and in relapse.

Between October, 1984 and October, 1987 a study program was carried out to evaluate the efficacy of MACOP-B in the advanced stages of intermediate/high-grade malignancy non-Hodgkin's lymphomas (NHL). Thirty patients were treated at diagnosis: 14 with D-E-F histology (median age = 56.5 years) and 16 with G-H histology (median age = 46.5). Complete remission (CR) rate was 42.8% for the D-E-F subgroup and 81.2% for the G-H subgroup. Bone marrow involvement was the major adverse factor for CR achievement in patients with intermediate-grade NHL. Overall, disease stage, bulky presentation and the presence of systemic symptoms did not significantly affect response to therapy. Survival curves predict 73% of patients alive at 45 months (median follow-up = 30 mo.). No significant differences were seen between D-E-F (64%; median follow-up = 36 mo.) and the G-H patients (81%; median follow-up = 27 mo.). The disease-free survival curve for all patients in CR reached a plateau phase at 78% (median follow-up = 30 mo). MACOP-B was much less effective when employed in 10 patients at relapse; only 2 out of these 10 reached a durable CR, which persisted 51 and 27 mo. after MACOP-B. The remaining 8 patients had a partial response, followed closely by disease progression: 7 died, whereas 1 patient is still alive after salvage therapy with bone marrow transplant. Thus, MACOP-B proved to be effective in patients at diagnosis with G-H histology.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗