The inhibition of glutamine synthetase sensitizes human sarcoma cells to L-asparaginase.

PURPOSE: To evaluate the activity of the antitumor enzyme L: -asparaginase (ASNase) on tumor cells of mesenchymal origin and the contribution of glutamine synthetase (GS) to the adaptation to the metabolic stress caused by the anti-tumor enzyme. METHODS: We studied the effects of ASNase in six human sarcoma cell lines: HT1080 (fibrosarcoma); RD (rhabdomyosarcoma); SW872 (liposarcoma); HOS, SAOS-2, and U2OS (osteosarcoma) in the absence or in the presence of the GS inhibitor methionine L: -sulfoximine (MSO). RESULTS: HT1080 and SW872 cells were highly sensitive to ASNase-dependent cytotoxicity. In contrast, RD, SAOS-2, HOS, and U2OS cells exhibited only a partial growth suppression upon treatment with the anti-tumor enzyme. In these cell lines ASNase treatment was associated with increased levels of GS. When ASNase was used together with MSO, the proliferation of the poorly sensitive cell lines was completely blocked and a significant decrease in the IC(50) for ASNase was observed. Moreover, when ASNase treatment was carried on in the presence of MSO, HOS and U2OS osteosarcoma cells exhibited a marked cytotoxicity, with increased apoptosis. CONCLUSIONS: In human sarcoma cells (1) GS markedly contributes to the metabolic adaptation of tumor cells to ASNase and (2) the inhibition of GS activity enhances the antiproliferative and cytotoxic effects of ASNase. The two-step interference with glutamine metabolism, obtained through the combined treatment with ASNase and MSO, may provide a novel therapeutic approach that should be further investigated in human tumors of mesenchymal origin.

Effects of various antireabsorptive treatments on bone mineral density in hypogonadal young women after allogeneic stem cell transplantation.

Ovarian failure after allogeneic stem cell transplant (allo-SCT) is an important risk factor for development of osteoporosis. We investigated the effects of various antiresorptive treatments in long-term surviving females with ovarian failure after allo-SCT. A total of 60 women with osteoporosis or osteopenia were divided randomly into four groups of 15 women each. Group 1 was treated with calcium and vitamin D alone, group 2 received the same treatment in combination with hormone replacement therapy (HRT), group 3 received risedronate (35 mg weekly, orally for 1 year) and group 4 zoledronic acid (3 monthly doses of 4 mg (intravenous)). All groups were similar for age, body mass index, underlying disease and time elapsed from transplant. Lumbar and femoral bone mineral density (BMD) were measured at baseline and after 12 months, together with serum osteocalcin and urinary hydroxyproline. At 12 months, a significant decrease in lumbar and femoral BMD was observed in group 1 and a milder decrease in group 2. Risedronate treatment increased significantly lumbar BMD and prevented bone loss at the femoral neck. Zoledronic acid increased significantly both lumbar and femoral BMD. In groups 3 and 4 the hydroxyproline excretion was significantly reduced, while osteocalcin mildly increased only in group 4. In conclusion, bisphosphonate administration is useful to prevent and treat bone demineralization in young adult women after allo-SCT.

Significant reduction of the hybrid BCR/ABL transcripts after induction and consolidation therapy is a powerful predictor of treatment response in adult Philadelphia-positive acute lymphoblastic leukemia.

Philadelphia chromosome-positive (Ph+) acute lymphoblastic leukemia (ALL) has a dismal prognosis. We prospectively evaluated minimal residual disease (MRD) by measuring BCR/ ABL levels with a quantitative real-time PCR procedure after induction and after consolidation in 45 adults with Ph+ ALL who obtained complete hematological remission after a high-dose daunorubicin induction schedule. At diagnosis, the mean BCR-ABL/GUS ratio was 1.55 +/- 1.78. A total of 42 patients evaluable for outcome analysis were operationally divided into two MRD groups: good molecular responders (GMRs; n = 28) with > 2 log reduction of residual disease after induction and > 3 log reduction after consolidation therapy, and poor molecular responders (PMRs; n = 14) who, despite complete hematological remission, had a higher MRD at both time points. In GMR, the actuarial probability of relapse-free, disease-free and overall survival at two years was 38, 27 and 48%, respectively, as compared to 0, 0 and 0% in PMR (P = 0.0035, 0.0076 and 0.0026, respectively). Salvage therapy induced a second sustained complete hematological remission in three GMR patients, but in no PMR patient. Our data indicate that, as already shown in children, adult Ph+ ALL patients have a heterogeneous sensitivity to treatment, and that early quantification of residual disease is a prognostic parameter in this disease.

The preferential interaction of L-threonine with transport system ASC in cultured human fibroblasts.

The transport of L-threonine was studied in cultured human fibroblasts. A kinetic analysis of L-threonine transport in a range of extracellular concentrations from 0.01 to 20 mM indicated that this amino acid enters cells through both Na(+)-independent and Na(+)-dependent routes. These routes are: (1) a non-saturable, Na(+)-independent route formally indistinguishable from diffusion; (2) a saturable, Na(+)-independent route inhibitable by the analog BCH and identifiable with system L; (3) a low-affinity, Na(+)-dependent component (Km = 3 mM) which can be attributed to the activity of system A since it is adaptively enhanced by amino acid starvation and suppressed by the characterizing analog MeAIB and (4) a high-affinity, Na(+)-dependent route (Km = 0.05 mM). This latter route is identifiable with system ASC since it is insensitive to adaptive regulation, uninhibited by MeAIB, trans-stimulated by intracellular substrates of system ASC, markedly stereoselective, and relatively insensitive to changes in external pH. At an external concentration of 0.05 mM more than 90% of L-threonine transport is referrable to the activity of system ASC; in these conditions, the transport of the amino acid exhibits typical ASC-features even in the absence of inhibitors of other transport agencies, and, therefore, it can be employed as a reliable indicator of the activity of transport system ASC in cultured human fibroblasts.

The relationship between sodium-dependent transport of anionic amino acids and cell proliferation.

The relationship between the transport of anionic amino acids and the proliferative status of the cell population has been studied in NIH-3T3 cells. Proliferative quiescence, verified by determinations of growth-rate quotient and incorporation of thymidine, is associated with a marked increase of the influx of L-aspartate. After 7-10 days of serum starvation, the initial influx of L-aspartate increases by 8-10-times with respect to the transport activity determined in growing cells. The operational properties of the influx of L-aspartate are similar in growing and quiescent cells; in particular, the influx of the anionic amino acid is mostly Na(+)-dependent and completely suppressed by an excess of L-glutamate and D-aspartate, but not of D-glutamate. These features suggest that, in both cases, aspartate uptake occurs through system X(-)AG. The quiescence-related increase in aspartate transport is gradual, sensitive to the inhibition of protein synthesis and referable to the enhanced maximal capacity of transport system X(-)AG. Restoration of serum concentration in the culture medium of serum-starved cells causes a decrease in aspartate transport that is maximal in correspondence to late G1/S phases. It is concluded that the X(-)AG system for anionic amino-acid uptake is sensitive to the proliferative status of the cell population and that, in particular, its transport activity is stimulated by the establishment of proliferative quiescence.

Blood cell flow cytometry in paroxysmal nocturnal hemoglobinuria: a tool for measuring the extent of the PNH clone.

The membrane expression of nine glycosyl phosphatidyl inositol (GPI)-linked molecules was analyzed by flow cytometry on circulating cells from 18 patients affected by paroxysmal nocturnal hemoglobinuria (PNH). The results allowed us to select CD66b, CD14, CD59, CD24 and CD59 monoclonal antibodies as the most suitable reagents for discriminating between normal and PNH cells in PMN, monocytes, RBC and B or T lymphocytes, respectively. In order to assess whether the analysis of distinct cell populations could provide differential information on the extent of the disease, we compared the proportion of residual normal cells in RBC, monocyte and PMN populations. The mean percentage of unaffected cells was higher in RBC as compared to PMN (50.5 +/- 18.7 vs 17.7 +/- 19.7, P < 0.0001). The proportion of normal PMN was, in turn, significantly greater than that of normal monocytes (17.7 +/- 19.7 vs 8.7 +/- 11.0; P < 0.05). The percentage of CD14+ monocytes was directly related to Hb concentration and platelet (Plt) count, and inversely to percent lysis at the Ham's test. The percentage of CD66b+ PMN was directly related to Plt count and Hb level, while the percentage of CD59+ RBC was associated, in an inverse fashion, only to the Ham's test. No significant correlation was found between cell marker expression and PMN count, reticulocytosis, bilirubin and serum LDH. By dividing the patients into two groups, according to high (> 10 percent) or low (< 10 percent) percentage of CD14+ monocytes, a statistical analysis showed that the main hematological parameters were significantly different.

Characterization of two novel cell lines, DERL-2 (CD56+/CD3+/Tcry5+) and DERL-7 (CD56+/CD3-/TCRgammadelta-), derived from a single patient with CD56+ non-Hodgkin's lymphoma.

Two novel IL2-dependent cell lines, DERL-2 and DERL-7, were established from a patient with hepatosplenic gammadelta T cell lymphoma. This patient presented, at diagnosis, two discrete populations of CD56+ cells, one TCRgammadelta+, the second lacking T cell-restricted antigens. The cell lines derived displayed features corresponding to the two cellular components of the disease: DERL-2 was CD56+/CD3+/TcRgammadelta+ while DERL-7 was CD56+/CD3-/TcRgammadelta-. Along with CD56, the two cell lines shared the expression of CD7, CD2, CD158b and CD117. Karyotype analysis showed that both cell lines were near-diploid, with iso-7q and loss of one chromosome 10. In addition, DERL-2 showed 5q+ in all metaphases analyzed, while DERL-7 revealed loss of one chromosome 4. Genotypically, both cell lines shared the same STR pattern at nine loci and demonstrated an identical rearranged pattern of the T cell receptor genes beta, gamma and delta, with respect to the original tumor cells. These data indicated that both cell lines and the original neoplastic populations were T cell-derived and arose from a common ancestor. Among a large panel of cytokines tested, only SCF was able to substitute IL2 in supporting cell proliferation. Moreover, SCF and IL2 acted synergistically, dramatically enhancing cell growth. These cell lines may represent a model to further analyze the overlap area between T and NK cell malignancies, and may provide new information about the synergistic action of IL2 and SCF on normal and neoplastic T/NK cells.

JURL-MK1 (c-kit(high)/CD30-/CD40-) and JURL-MK2 (c-kit(low)/CD30+/CD40+) cell lines: 'two-sided' model for investigating leukemic megakaryocytopoiesis.

Two novel cell lines (JURL-MK1 and JURL-MK2) have been established from the peripheral blood of a patient in the blastic phase of chronic myelogenous leukemia. The cells grow in a single cell suspension with doubling times of 48 h (JURL-MK1) and 72 h (JURL-MK2). Cytogenetic analysis has shown that JURL-MK1 is hypodiploid whereas JURL-MK2 is near triploid and that both cell lines retain t(9;22). Moreover, JURL-MK1 and JURL-MK2 have a bcr/abl-fused gene with the same junction found in the patient's fresh cells, and both cell lines express the b3/a2 type of hybrid bcr/abl mRNA. The morphology and immunophenotype of these cell lines are reminiscent of megakaryoblasts. In both lines, a limited but consistent percentage of cells expresses gpIIbIIIa (CD41a), gpIIIa (CD61) and CD36, with no expression of gplb (CD42b), glycophorin A, hemoglobin and CD34. Both cell lines are clearly positive for CD33, CD43, CD45RO and CD63, while CD13, CD44, CD54, CD30 and CD40 are specific features of JURL-MK2. Among cytokine receptors, CD117/SCF-R is strongly displayed by a large fraction of JURL-MK1 cells but is hardly detectable on about 20% JURL-MK2 cells. Both cell lines are clearly positive for CD25/IL2R alpha, while a marked expression of CD116/GM-CSF-R and CDw123/IL3R alpha is restricted to JURL-MK2. Induction of cell differentiation in vitro has demonstrated that TPA is able to modulate the JURL-MK1 phenotype, causing an increased expression of platelet-associated antigens. The JURL-MK2 phenotype is easily modulated by both TPA and DMSO, which cause an increased expression of CD41a and CD117 accompanied by a decreased expression of CD30. Proliferation studies demonstrated that JURL-MK1 cell growth is enhanced by stem cell factor, while JURL-MK2 proliferation is unaffected by this cytokine. JURL-MK1 and JURL-MK2 are two novel cell lines with divergent biological features, representing a 'two-sided' model for investigating new aspects of megakaryocytopoiesis.

Expression of the 67-kDa laminin receptor in acute myeloid leukemia cells mediates adhesion to laminin and is frequently associated with monocytic differentiation.

Lodgement, proliferation, and migration of leukemic cells within bone marrow (BM) microenvironment involves adhesion of these cells to the BM extracellular matrix molecules fibronectin and laminin. The 67-kDa laminin receptor (67LR) is a nonintegrin protein with high affinity for laminin, which plays a critical role in basement membrane invasion and metastasis of cancer cells. By Western blotting, we documented that 67LR was strongly expressed in myelomonocytic THP1 and histiocytic U937 cells and was weakly expressed in promyelocytic HL-60 cells. In HL-60 cells, 67LR expression almost disappeared after retinoic-induced granulocytic differentiation, whereas it strongly increased after phorbol ester-induced monocytic differentiation. We did not detect 67LR expression in normal BM hematopoietic cells, in precursor-B acute lymphoblastic leukemia, in chronic lymphocytic leukemia, or in chronic myeloid leukemia in chronic phase. By contrast, we detected enhanced 67LR expression in 40% of 53 de novo acute myeloid leukemias (AMLs), which frequently exhibited monocytic or myelomonocytic morphology and expressed CD14 and CD11a (P < 0.05). Using a colorimetric assay, we found that the expression pattern of this receptor corresponded to a higher adhesion to laminin; the adhesion was specific because in vitro addition to laminin-coated wells of recombinant 37-kDa laminin receptor precursor (37LRP), which is the cytoplasmic precursor containing both laminin-binding domains of cell surface 67LR, significantly reduced laminin binding of AML cells. The expression of 67LR on AML cell surface did not correlate with other differentiation and integrin antigens such as CD7, CD13, CD33, CD34, CD11b, CD11c, CD49d, CD49e, CD45RA, and CD45RO. In contrast with 67LR behavior in solid tumors, no statistically significant difference was found between 67LR expression and any hematological characteristic of the disease at diagnosis, nor between 67LR expression and outcome of the disease as measured by complete remission rate, disease-free survival, or overall survival. In conclusion, our results indicate that 67LR expression mediates specific adhesion to laminin and that the detection of this molecule may be a valuable addition to other lineage-associated antigens in identifying monocytic-oriented AML.

Membrane proteins in paroxysmal nocturnal haemoglobinuria.

A review of recent information on the abnormalities of the blood cell membrane in paroxysmal nocturnal haemoglobinuria (PNH) is presented, with a detailed analysis of biochemical and flow cytometry findings. The complex patterns observed in the various cell lineages of which the PNH clone consists are described, and a simplified monoclonal antibody panel is defined for diagnostic purposes. Available data on in vitro culture of progenitor cells and on the recent establishment of PNH cell lines are summarized. Finally, we discuss speculative hypotheses on the growth advantage of the PNH clone.

Glycosyl phosphatidylinositol (GPI)-anchored molecules and the pathogenesis of paroxysmal nocturnal hemoglobinuria.

Paroxysmal nocturnal hemoglobinuria (PNH) is characterized by the expansion of one or more clones of stem cells producing progeny of mature blood cells deficient in the plasma membrane expression of all glycosyl phosphatidylinositol (GPI)-anchored proteins (AP). This is due to somatic mutations in the X-linked gene PIGA, encoding one of the several enzymes required for GPI anchor biosynthesis. More than 20 GPI-APs are variously expressed on hematological cells. GPI-APs may function as enzymes, receptors, complement regulatory proteins or adhesion molecules; they are often involved in signal transduction. The absence of GPI-APs may well explain the main clinical findings of PNH, i.e., hemolysis and thrombosis in the venous system. Other aspects of PNH pathophysiology such as various degrees of bone marrow failure and the dominance of the PNH clone may also be linked to the biology and function of GPI-APs. Results of in vitro and in vivo experiments on embryoid bodies and mice chimeric for nonfunctional Piga have recently demonstrated that Piga inactivation confers no intrinsic advantage to the affected hematopoietic clone under physiological conditions; thus additional factors are required to allow for the expansion of the mutated cells. A close association between PNH and aplastic anemia suggests that immune system mediated bone marrow failure creates and maintains the conditions for the expansion of GPI-AP deficient cells. In this scenario, a PIGA mutation would render GPI-AP deficient cells resistant to the cytotoxic autoimmune attack, enabling them to emerge. Even though the 'survival advantage' hypothesis may explain all the various aspects of this intriguing disease, a formal proof of this theory is still lacking.

Spleen sizing by ultrasound scan and risk of pneumococcal infection in patients with chronic GVHD: preliminary observations.

Encapsulated bacteria infections (EBI) can cause severe complications after BMT, usually occurring in patients with chronic GVHD (cGVHD) and attributed to functional hyposplenism. Using ultrasound (US) scan, we measured spleen size in 22 patients transplanted from HLA identical siblings, with or without cGVHD. No patient had received TBI, spleen irradiation or penicillin prophylaxis. Results were correlated with occurrence of EBI during a mean follow-up of 55 months (range 7-93). In the group without cGVHD, the difference between pre- and post-BMT spleen longitudinal diameters was not significant, and no patient developed EBI. In the cGVHD group, post-BMT spleen longitudinal diameters were significantly smaller than those pre-BMT (9.1+/-1.6 vs. 12.3+/-2.2; P = 0.0005). Out of four patients with cGVHD who showed a major spleen size reduction, two developed a severe infection (an overwhelming sepsis and a pneumococcal meningitis). In our small series, we found a borderline relationship between spleen size reduction and duration of cGVHD (P = 0.06), as well as an increased risk of life-threatening infection in patients with extensive cGVHD and hyposplenism as detected by US scan. We conclude that US scan may be useful to detect spleen size reduction following allogeneic BMT and that penicillin prophylaxis is to be strongly recommended in patients with extensive cGVHD and spleen size reduction, even in those who have not received total body or spleen irradiation.

Lamivudine treatment for chronic replicative hepatitis B virus infection after allogeneic bone marrow transplantation.

The risk of severe hepatic damage in patients with chronic hepatitis B virus (HBV) infection is well known; more effective treatments for this infection are needed. Lamivudine is being studied in immunocompetent and immunosuppressed HBV infected patients. We report a patient suffering from chronic replicative HBV infection after allogeneic BMT, who responded to lamivudine therapy. A 24-year-old woman with CML received an allogeneic BMT from her HLA-identical sister in June 1992. Before transplant, her HBV status demonstrated viral contact without active infection (HBsAb+, HBcAb+ IgG, HBeAb+). Four months after BMT mild chronic liver GVHD appeared, requiring immunosuppressive treatment. Antibodies to HBV completely disappeared post-transplant. Acute icteric hepatitis occurred 2 years later, with HBsAg+, high level of HBV-DNA, HBeAg+ and HBcAb IgM+. Lamivudine 100 mg/day rapidly reduced transaminase levels and effected HBV-DNA disappearance within 2 months. The treatment was well tolerated; no hematological side-effects occurred. This preliminary observation warrants further investigation of lamivudine treatment in bone marrow transplanted patients with active HBV infection.

Ultrasound-guided fine needle cutting biopsy for the characterization of diffuse liver diseases in bone marrow transplant patients.

Liver disease is a frequent complication in bone marrow transplant recipients and may occur early or late in the post-transplant period. Using ultrasound-guided fine needle (1.2 mm, 18 G) cutting biopsy, we studied six patients with undefined late post-BMT liver disease. No procedure-related complications occurred and all liver biopsies were informative, leading to changes in therapeutic approach. In our small series, the most frequent cause of hepatic damage was drug toxicity. US-guided fine needle cutting biopsy is a useful and easy tool for the work-up of unexplained post-BMT liver disease.

CD34+-enriched donor lymphocyte infusions in a case of pure red cell aplasia and late graft failure after major ABO-incompatible bone marrow transplantation.

A variety of immunohematological complications may occur after ABO-incompatible BMT. We report a CML patient (blood group O) who received a BMT from an HLA-identical sibling (blood group AB). The transplant was followed by normal myeloid and megakaryocytic engraftment, but erythroblastopenia persisted for more than 200 days after BMT. By bone marrow culture studies, a complement-dependent serum inhibitor of hemopoiesis was detected, suggesting immunological inhibition of erythropoiesis. The patient was resistant to a number of treatments such as intravenous gamma-globulins, prednisolone and high-dose erythropoietin. Full engraftment with normal blood counts and marrow cellularity was achieved after two dose-escalating CD34+-enriched donor lymphocyte infusions (DLI). This experience suggests that CD34+-enriched DLI may be an effective treatment for patients with delayed engraftment or late graft failure due to major ABO-incompatibility.

Allogeneic bone marrow transplantation restores IGF-I production and linear growth in a gamma-SCID patient with abnormal growth hormone receptor signaling.

Severe combined immunodeficiency (SCID) is a heterogeneous group of disorders characterized by a severe defect of both T- and B-cell immunity, which generally require allogeneic bone marrow transplantation (BMT) within the first years of life. We previously reported a patient affected with an X-linked SCID due to L183S hemizygous missense gamma chain mutation, whose severe short stature was due to a peripheral growth hormone (GH) hyporesponsiveness associated to abnormal GH receptor (GH-R) signal transduction. In this study, we report the effect of BMT on the GH-R/insulin-like growth factor I (IGF-I) axis. After BMT, the patient showed a significant improvement in linear growth and normalization of basal- and GH-stimulated IGF-I values, which paralleled a fully competent immunological reconstitution. This suggests that cells derived from the hematopoietic stem cell may exert an unexpectedly significant role in producing IGF-I. This may also suggest that stem cell-based therapies may be useful for the correction of non-hematopoietic inherited disorders, such as those of GH-R/IGF-I axis.

Hepatitis reactivation and liver failure in haemopoietic stem cell transplants for hepatitis B virus (HBV)/hepatitis C virus (HCV) positive recipients: a retrospective study by the Italian group for blood and marrow transplantation.

Hepatitis B virus/hepatitis C virus (HBV/HCV) positive patients undergoing haemopoietic stem cell transplantation (HSCT) are at risk of hepatitis reactivation and fatal liver failure: we have conducted a retrospective study to assess the risk in 20 Italian transplant centres. A total of 90 patients infected with HBV (n=33) or HCV (n=57) receiving allogeneic (n=36) or autologous (n=54) haemotopoietic stem cell transplant (HSCT) between 1996 and 2000 were reviewed. The biochemical profiles and outcomes of infection-related liver disease were also analysed. The risk of death at 2 years was comparable when considering type of infection (3% for HBV vs 8% for HCV, P=0.6) or type of HSCT (7% for allogeneic vs 5% for autologous HHSCT, P=0.34). Hepatitis reactivation followed by resolution was more frequent in HCV+ than in HBV+ patients receiving an allograft (100% vs 16%, P=0.004). In HBV+ cases, risk of reactivation was comparable after autologous or allogeneic transplantation (66 vs 81%, P=0.3), but liver disease was more severe and occurred earlier in the autologous group. Our results indicate that HBV and HCV infection should not be taken as an absolute contraindication for HSCT and the risk of life-threatening liver complications are similar after allogeneic or autologous transplants.

Long-lasting decrease of marrow and circulating long-term culture initiating cells after allogeneic bone marrow transplant.

We investigated bone marrow (BM) and circulating (PB) hematopoietic progenitor cells in 37 normal donors and in 25 patients 1 to 8 years after successful allogeneic bone marrow transplant. At the time of testing, transplanted patients had normal blood counts and bone marrow cellularity. By flow cytometry, BM CD34+ cells were found to be three- to four-fold decreased in transplanted patients compared to normal donors, while the number of PB CD34+ cells was the same as in normal donors. Using a methylcellulose colony assay, primary BM colony-forming cells (CFU-GM) were decreased 2.1-fold, whereas PB CFU-GM were only marginally decreased. In a long-term culture initiating cell (LTC-IC) assay, an eight-fold decrease of early progenitor cells was observed in the marrow of transplanted patients compared to normal donors, and a five-fold decrease was documented in peripheral blood. We found that the BM LTC-IC cell number correlated with concurrently determined BM CD34+ cells and committed progenitor cell number (measured as CFU-GM) and with PB LTC-IC number, but not with PB CFU-GM and CD34+ cells. We conclude that marrow and circulating early stem cell compartments, as measured by the LTC-IC assay, are greatly and permanently depressed following bone marrow transplant. The correlation between BM and PB LTC-IC indicates that the enumeration of circulating LTC-IC can be used as a measure of the stem cell compartment in the bone marrow after transplant. It seems that the deficiency of the most immature progenitor cells persists forever after successful bone marrow transplant; this means that a complete hematopoietic reconstitution can be sustained by a reduced stem cell pool.

Prognostic factors of patients with acute myeloid leukemia (AML) allografted in first complete remission: an analysis of the EORTC-GIMEMA AML 8A trial. The European Organization for Research and Treatment of Cancer (EORTC) and the Gruppo Italiano Malattie Ematologiche Maligne dell' Adulto (GIMEMA) Leukemia Cooperative Groups.

The Leukemia Cooperative Groups of the EORTC and the GIMEMA conducted a prospective randomized phase III trial, in order to assess the value of autologous BMT (ABMT) vs a second intensive consolidation course (IC2), following a common intensive consolidation course (IC1) for patients with AML. Patients with an HLA-identical sibling donor were not randomized, but were included in an allogeneic BMT (alloBMT) program. This is an analysis of prognostic factors which influence the outcome of treatment after alloBMT in first complete remission (CR). The study included 730 patients < 46 years of age in CR, 270 having a histocompatible sibling donor. In 169 of these patients alloBMT was performed in first CR. Early remitters (122 patients achieving CR with one course of treatment) had a DFS at 3 years of 67%, significantly longer than that of 44% for late remitters (47 patients achieving CR after more than one course of treatment) (P = 0.006). The relapse risk for early vs late remitters was 16 and 40% at 3 years (P = 0.001) and the treatment-related mortality (TRM) at 2 years was 21 vs 27%. Age appeared to be a prognostic factor for TRM, WBC for DFS, whereas the FAB classification was not of prognostic importance. Patients with poor risk cytogenetic abnormalities showed a trend towards a higher relapse risk. Patients transplanted shortly after achieving CR appeared to have a worse prognosis than those transplanted further into remission. Overall, the number of courses of induction therapy needed to achieve CR was the most important prognostic factor for outcome after allogeneic BMT.