Prognostic value of minimal residual disease (MRD) in acute myeloid leukemia (AML) with favorable cytogenetics [t(8;21) and inv(16)].

Most patients with acute myeloid leukemia (AML) and t(8;21) or inv(16) have a good prognosis with current anthracycline- and cytarabine-based protocols. Tandem analysis with flow cytometry (FC) and real-time RT-PCR (RQ-PCR) was applied to 55 patients, 28 harboring a t(8;21) and 27 an inv(16), including one case with a novel CBFbeta/MYH11 transcript. A total of 31% (n=17) of CR patients relapsed: seven with t(8;21) and 10 with inv(16). The mean amount of minimal residual disease (MRD) detected by FC in relapsed and nonrelapsed patients was markedly different: 0.3 vs 0.08% (P=0.002) at the end of treatment. The mean number of fusion transcript copies/ ABL x 10(4) also differed between relapsed and non-relapsed patients: 2385 vs 122 (P=0.001) after induction, 56 vs 7.6 after intensification (P=0.0001) and 75 vs 3.3 (P=0.0001) at the end of chemotherapy. Relapses were more common in patients with FC MRD level >0.1% at the end of treatment than in patients with < or = 0.1%: cumulative incidence of relapse (CIR) was 67 and 21% (P=0.03), respectively. Likewise, using RQ-PCR, a cutoff level of >10 copies at the end of treatment correlated with a high risk of relapse: CIR was 75% for patients with RQ-PCR >10 compared to 21% for patients with RQ-PCR levels < or = 10 (P=0.04). Combined use of FC and RQ-PCR may improve MRD detection, and provide useful clinical information on relapse kinetics in AML patients.

Acute myeloid leukemia with MLL rearrangements: clinicobiological features, prognostic impact and value of flow cytometry in the detection of residual leukemic cells.

The MLL gene, located at 11q23 band, is frequently disrupted by different chromosomal rearrangements that occur in a variety of hematological malignancies. MLL rearrangements are associated with distinct clinical features and a poor prognosis. The aim of this study was to analyze the incidence and the prognostic significance of MLL rearrangements in a consecutive series of adult AML patients and to determine the immunophenotypic features of these cases. The identification of abnormal immunophenotypes could be used for the detection of minimal residual disease (MRD). Ninety-three adult patients with de novo acute myeloid leukemia (AML) were analyzed by Southern blot in order to detect MLL rearrangements (MLL+). RT-PCR and genomic long-range PCR were performed to further characterize MLL partial tandem duplication (PTD) in those patients in whom conventional karyotype did not show 11q23 chromosomal translocations. All the patients were homogeneously immunophenotyped at diagnosis. MLL rearrangements were detected in 13 (14%) patients. Four patients (5%) showed 11q23 translocations by karyotypic conventional analysis. Nine patients (10%) revealed PTD of MLL and one patient showed a MLL cleavage pattern. The MLL+ patients usually expressed myeloid and monocytic antigens CD33 (12/13 cases), CD13 (9/13), CD117 (9/13), CD64 (11/13) and in some cases CD14 (4/11). HLA-DR was also positive in (12/13). Eight out of 13 cases expressed the stem cell marker CD34. Only one patient revealed lymphoid marker reactivity (CD7) and CD56 was expressed in 5/13 cases. All the MLL+ patients showed at least one aberrant phenotype at diagnosis, which allowed us to set out a simple panel for the MRD studies. Twenty-seven samples from eight patients in morphologic complete remission (CR) were analyzed using the aberrant immunologic combinations detected at diagnosis. Phenotypically abnormal cells were detected in all the patients who subsequently relapsed, whereas only one patient with MRD+ remained in CR. Owing to the high level of residual leukemic cells, the MLL+ patients showed a short CR duration and a poor survival. In conclusion, immunophenotyping may be a suitable approach to investigating MRD status in AML patients with PTD of the MLL gene.

Prolactin receptor is associated with c-src kinase in rat liver.

The mechanism of action of the pituitary hormone PRL was studied in hepatocytes of lactating rats. PRL receptor immune complexes obtained from liver lysates have an associated tyrosine kinase activity. The tyrosine kinase has been identified in isolated hepatocytes as pp60c-src. Incubation of hepatocytes with PRL induces the association of PRL receptor with pp60c-src and the resultant stimulation of its tyrosine kinase activity. Furthermore, PRL stimulates the gene expression of c-fos, c-jun, and c-src. All of these findings support the idea that the pp60c-src tyrosine kinase participates in the early steps of the PRL intracellular signaling that promotes cell growth in liver cells.

The short form of the prolactin (PRL) receptor silences PRL induction of the beta-casein gene promoter.

The PRL receptor (PRLR) is a member of the cytokine receptor superfamily. Rats and mice express two forms of PRLR, short (SPRLR) and long (LPRLR), which differ in the length and sequence of their cytoplasmic domains. We have analyzed the ability of each form of rat PRLR to transduce lactogenic signals in a bovine mammary gland epithelial cell line. The rat PRLR forms were expressed and detected by RT-PCR, indirect immunofluorescence, and cell surface ligand binding. When the biological activity of each form of PRLR was assessed by transient transfection, we found that the long form was able to activate the beta-casein gene promoter and that the short form was inactive. Interestingly, the coexpression of both forms of PRLR resulted in a block of PRL signal to the milk protein gene promoter as a function of the concentration of the SPRLR. Similar results were obtained when LPRLR was coexpressed with totally or partially inactive tyrosine mutants of either the Nb2 form or the LPRLR form. Thus, these results suggest that the SPRLR form has at least one clear biological function, i.e. to silence lactogenic signals and to contribute to a differential and acute PRL effect in rat tissues. Furthermore, the data derived from coexpression of LPRLR and PRLR mutants confirm a crucial role of the C-terminal tyrosine residue in lactogenic signaling and the dimerization of PRLRs.

Successful treatment of Curvularia sp infection in a patient with primarily resistant acute promyelocytic leukemia.

We report a young woman with acute promyelocytic leukemia who showed primary resistance to chemotherapy and who responded to ATRA treatment. During the neutropenic period she developed Curvularia sp infection and was finally successfully consolidated with autologous bone marrow transplantation.

Neurologic complications after allogeneic bone marrow transplantation.

Neurological complications are not usually considered among the most important complications that may appear after allogeneic bone marrow transplantation (BMT). We have analyzed the occurrence of neurological manifestation in 27 recipients of allogeneic BMT. Ten patients (37%) developed neurological symptoms, and 14 episodes were registered. The most frequent manifestations were due to the use of cyclosporin A or prednisone for prophylaxis or treatment of graft-versus-host disease (GVHD). Cerebrovascular events (infarction or hemorrhage) and CNS infections were the most severe complications: they represented 26% of cause of death in our series. In conclusion, neurological complications are frequent in these patients, and represent an important cause of morbidity and mortality.

Pentoxifylline, ciprofloxacin and prednisone failed to prevent transplant-related toxicities in bone marrow transplant recipients and were associated with an increased incidence of infectious complications.

TNF-alpha (Tumor necrosis factor-alpha) is involved in many immunological and inflammatory processes, and might be expected to play an important role in the development of BMT-related complications. Triple therapy (pentoxifylline, ciprofloxacin and prednisone) with known anti-TNF activity was tested in 37 patients undergoing a hematopoietic progenitor transplant (HPT). A control group of 16 patients with similar characteristics was selected among consecutive patients receiving a HTP in a neighboring center who did not receive anti-TNF prophylaxis. Major transplant-related complications were registered (VOD, acute GVHD, infectious episodes, renal failure and mucositis) and survival status. TNF plasma concentrations were determined by ELISA, and pentoxifylline plasma concentrations were determined by HPLC. Among patients treated with pentoxifylline (PTX), ciprofloxacin and steroids, no difference in the mean survival time was observed compared with the control group. The incidence of procedure-related death up to day +35 was 11% in the study group and 6% in the control group. In spite of a tendency to a lower incidence of mucositis there was a higher incidence of infections (positive blood cultures) in the study group (49%) than in the control group (16.7%) (P = 0.16). This difference achieved statistical significance in patients receiving an allogeneic HPT (P = 0.05). It is likely that the use of steroids in the early period after transplant increases infectious episodes and makes control of GVHD difficult. The combined administration of steroids with pentoxifylline and ciprofloxacin has not proved beneficial in preventing mucositis, renal failure, VOD or GVHD, or in improving patient survival.

Individually adjusted prophylactic donor lymphocyte infusions after CD34-selected allogeneic peripheral blood stem cell transplantation.

T cell depletion of the graft increases graft failure and relapse rate in allogeneic PBSC transplantation. Delayed lymphocyte add-back after T cell-depleted transplants might prevent these complications. We present 22 consecutive allogeneic PBSC transplants from related histocompatible donors with positive selection of CD34+ cells. Recipients received prophylactic donor lymphocyte infusions (DLI) depending on their risk of relapse and of developing GVHD. Patients were considered at high risk of relapse with AML > first CR, ALL > second CR, and CML in accelerated or blastic phase. Patients were considered at high risk of developing GVHD if older than 35 years, or with a donor sensitized through previous pregnancy or blood transfusion. Patients at high risk of relapse and low risk of GVHD were scheduled to receive three DLI. Patients at low risk of relapse and high risk of GVHD did not receive DLI. The remaining patients were scheduled to receive two DLI. The DLI were administered on days +28 (2 x 10(5)/kg), +60 (2 x 10(5)/kg) and +90 (2 x 10(6)/kg) after transplant. G-CSF mobilized peripheral stem cells from healthy donors were positively selected by an immunomagnetic method. The mean CD34+ cells and CD3+ cells infused were 4.4 x 10(6)(range 1.9-10.6) and 0.085 x 10(5) (range 0.01-0.67). Cyclosporin A was given to prevent GVHD. All the patients engrafted. Twenty-two prophylactic DLI were performed in 12 patients: seven developed acute GVHD (one case grade III-IV) and none presented pancytopenia. At a mean follow-up of 585 days (range 89-1103), 14 patients were alive in CR, one patient was alive in relapse, four patients had died of relapse and three had died of transplant-related complication. Individually adjusted prophylactic DLI at the doses we used with an escalating schedule allowed an acceptable GVHD rate and a good engraftment of donor hematopoiesis.

Low-dose donor CD8+ cells in the CD4-depleted graft prevent allogeneic marrow graft rejection and severe graft-versus-host disease for chronic myeloid leukemia patients in first chronic phase.

Based on previous experiences in animals and humans, low doses of CD8+ lymphocytes infused together with the marrow graft seem to enhance engraftment after allogeneic T cell-depleted marrow transplantation. From April 1994 to February 1997, 12 patients with chronic myelogenous leukemia in first chronic phase receiving a bone marrow transplant (BMT) from an HLA-identical sibling were included in a pilot study of T cell subset depletion. Total depletion of CD4+ cells of the marrow graft and partial depletion of CD8+ cells was performed by immunomagnetic separation. In order to improve the engraftment rate, we infused a low fixed number of CD8+ lymphocytes (0.25 x 10(6)/kg). All the patients were at high risk of developing acute graft-versus-host disease (GVHD), with a recipient age of >30 years, and/or donor sensitized by previous pregnancies or transfusions. All of them received cyclosporin A and methotrexate post-BMT. No graft failure was observed. The grade III-IV GVHD rate was 16.6%, and the actuarial survival at 3 years is 81.8%. Immunological recovery showed persistent CD8+ HLA-DR+ lymphocytosis 8 months after transplant. Relapses were not observed. This experience shows the importance of CD8+ cells to ensure correct engraftment, decreasing the GVHD rate.

Mitoxantrone, etoposide, carboplatinum and ara-C combination therapy (MECA) in refractory and relapsed acute leukemia.

The present study was undertaken to assess the feasibility, toxicity and antileukemic activity of sequential chemotherapy including mitoxantrone, etoposide, carboplatin and intermediate-dose cytarabine in adult patients with refractory and relapsed acute myelogenous (AML) or lymphoid (ALL) leukemia. Fifty-one patients with poor-risk AML and ALL received 64 courses of MECA therapy. The overall response in the entire group was 51% (43% complete remission). The stage of the disease (relapsed or primarily refractory) and the age of the patients did not strongly affect the response rate. MECA therapy was more effective in ALL than in AML, and in those patients who presented at salvage treatment with a bone marrow infiltration lower than 25% blasts. Hematological and extra-hematological toxicities were tolerable and there were 6 deaths related to the treatment (11%). The incidence of documented infectious episodes was 71%. MECA therapy is a safe treatment and has a high antileukemic activity in relapsed and primarily refractory AML or ALL.

CTLA-4 genotype and relapse incidence in patients with acute myeloid leukemia in first complete remission after induction chemotherapy.

The recently described single-nucleotide polymorphism CT60, located in the 3'-untranslated region of the CTLA4 (cytotoxic T-lymphocyte antigen 4 ) gene, has been associated with susceptibility to several autoimmune diseases and has also been shown to be involved in immune responses following allogeneic stem cell transplantation (SCT). However, the contribution of the CTLA4 genotype to the control of minimal residual disease in patients with acute myeloid leukemia (AML) has yet to be explored. We investigated the association between the CTLA4 CT60 A/G genotype and the incidence of leukemic relapse in 143 adult patients with AML in first complete remission after the same chemotherapy protocol (CETLAM LAM'03). The CT60 AA genotype was associated with a higher rate of leukemic relapse (56.4 vs 35.6%, P=0.004; hazard ratio (HR)=2.64, 95% confidence interval (CI)=1.36-5.14) and lower overall survival at 3 years (39.4 vs 68.4%, P=0.004; HR=2.80, 95% CI=1.39-5.64). This is the first study to report an association between polymorphisms at CTLA-4 and AML relapse.

Characterization of a mammalian homolog of the GCN2 eukaryotic initiation factor 2alpha kinase.

In eukaryotic cells, protein synthesis is regulated in response to various environmental stresses by phosphorylating the alpha subunit of the eukaryotic initiation factor 2 (eIF2alpha). Three different eIF2alpha kinases have been identified in mammalian cells, the heme-regulated inhibitor (HRI), the interferon-inducible RNA-dependent kinase (PKR) and the endoplasmic reticulum-resident kinase (PERK). A fourth eIF2alpha kinase, termed GCN2, was previously characterized from Saccharomyces cerevisiae, Drosophila melanogaster and Neurospora crassa. Here we describe the cloning of a mouse GCN2 cDNA (MGCN2), which represents the first mammalian GCN2 homolog. MGCN2 has a conserved motif, N-terminal to the kinase subdomain V, and a large insert of 139 amino acids located between subdomains IV and V that are characteristic of the known eIF2alpha kinases. Furthermore, MGCN2 contains a class II aminoacyl-tRNA synthetase domain and a degenerate kinase segment, downstream and upstream of the eIF2alpha kinase domain, respectively, and both are singular features of GCN2 protein kinases. MGCN2 mRNA is expressed as a single message of approximately 5.5 kb in a wide range of different tissues, with the highest levels in the liver and the brain. Specific polyclonal anti-(MGCN2) immunoprecipitated an eIF2alpha kinase activity and recognized a 190 kDa phosphoprotein in Western blots from either mouse liver or MGCN2-transfected 293 cell extracts. Interestingly, serum starvation increased eIF2alpha phosphorylation in MGCN2-transfected human 293T cells. This finding provides evidence that GCN2 is the unique eIF2alpha kinase present in all eukaryotes from yeast to mammals and underscores the role of MGCN2 kinase in translational control and its potential physiological significance.

Characterization of the hemin-sensitive eukaryotic initiation factor 2alpha kinase from mouse nonerythroid cells.

The heme-regulated eukaryotic initiation factor 2alpha (eIF2alpha) kinase (heme-regulated inhibitor (HRI)) is activated by heme deficiency in reticulocytes and plays an important role in translational control in these cells. Previously, HRI was cloned from rabbit reticulocytes and rat brain, but a heme-regulated eIF2alpha kinase activity has only been purified from erythroid cells. In this study, we report the purification of a heme-sensitive eIF2alpha kinase activity from both mouse liver and NIH 3T3 cell extracts. Furthermore, we have cloned and characterized this mouse liver eIF2alpha kinase (mHRI), which exhibits 83 and 94% identities to rabbit and rat HRIs, respectively. Both the purified enzyme and recombinant mHRI exhibited an autokinase and an eIF2alpha kinase activity, and both activities were inhibited in vitro by hemin. In addition, wild-type mHRI, but not the inactive mHRI-K196R mutant, was autophosphorylated in vivo when it was expressed in 293 cells. Quantitation of mHRI mRNA expression in various mouse tissues by reverse transcription-polymerase chain reaction revealed relatively high levels in liver, kidney, and testis. These results provide strong evidence that mHRI is a ubiquitous eIF2alpha kinase of mammalian cells, suggesting that it could play important roles in the translational regulation of nonerythroid tissues.

Serotonin increases the cAMP concentration and the phosphoenolpyruvate carboxykinase mRNA in rat kidney, small intestine, and liver.

Within 60 min of the administration of serotonin to fasted-refed rats, there was a 5-, 16-, and 20-fold stimulation of the mRNA coding for the cytosolic form of P-enolpyruvate carboxykinase in the kidney, small intestine and liver, respectively. This stimulation was 5-, 1.3-, and 2-fold higher than noted in the same tissue after 24 h of starvation. Dose- and time-response curves to serotonin in the three tissues were similar. The level of PEPCK mRNA in the liver was significantly elevated within 30 min of serotonin administration, whereas 60 min was required in the small intestine and the kidney. The direct effect of serotonin on PEPCK mRNA was also assessed in hepatocytes maintained in primary culture. Serotonin (10(-8) M to 10(-4) M) caused a dose-dependent increase in the level of PEPCK mRNA and a transient increase in cAMP concentration. Within the first min of serotonin (10(-6) M) addition to cells, cAMP concentration increased 4-fold and returned after 10 min to basal level. Therefore, these results provide functional evidence of serotonin action in the rat peripheric tissues and suggest that cAMP is involved in its intracellular signalling.

Prolactin activates tyrosyl phosphorylation of insulin receptor substrate 1 and phosphatidylinositol-3-OH kinase.

Prolactin (PRL) has been demonstrated to induce tyrosine phosphorylation and activation of the cytoplasmic tyrosine kinase JAK2. The present study represents an initial effort to identify the phosphorylation repertoire of the PRL receptor (PRLR). For this purpose we have modified the rat PRLR cDNA to encode an additional N-terminal epitope specifically designed to allow the rapid purification of the PRLR and associated proteins from transfected cells. The Flag-tagged PRLR was stably expressed in the human 293 cell line. PRL induced tyrosine phosphorylation of proteins of 85, 95, and 185 kDa from 10 to 30 min after PRL stimulation. Immunoblot analysis of immunoprecipitation indicates that p85 corresponds to the 85-kDa regulatory subunit of phosphatidylinositol (PI)-3' kinase, p95 to PRLR, and p185 to insulin receptor substrate 1 (IRS-1). Both PI-3' kinase and IRS-1 appear to associate with PRLR in a PRL-dependent manner. These results thus indicate that kinases other than JAK2, namely PI-3' kinase, are activated by PRL.

Follow-up of chimerism status after allogeneic HLA-mismatched stem cell transplantation by detection of non-shared HLA alleles.

BACKGROUND AND OBJECTIVES: Chimerism studies after allogeneic transplantation are usually performed using cytogenetic analysis, PCR-VNTR or PCR-STR. Here, we report an alternative method for following the chimerism status after an HLA-mismatched stem cell transplantation (SCT), detecting the presence of non-shared HLA alleles by reference-strand mediated conformation analysis (RSCA). DESIGN AND METHODS: We tested this new approach on allogeneic related haploidentical SCT, unrelated cord blood transplantation, and HLA-mismatched unrelated donor SCT. The quantification of the chimerism was performed by laser detection of fluorescent-labeled primers on an automated DNA sequencer. RESULTS: In all cases this technique was able to detect mixed chimeras. The technique detected above 5% of residual cells when the analysis was based on HLA-class I and above 3% for HLA-class II. This sensitivity is similar to that of the PCR-VNTR analysis. INTERPRETATION AND CONCLUSIONS: This method avoids the need to search for an informative locus (which is essential for PCR-VNTR or -STR). Moreover, we did not find the phenomenon of preferential amplification that is observed with most VNTR, thus avoiding the need for construction of standard curves to quantify mixed chimeras. We conclude that the detection of the non-shared HLA alleles by RSCA is a useful approach for chimerism follow-up after HLA-mismatched SCT.