Trasplante de progenitores hemopoyéticos

In the second half of the XX century, the transplant of hemopoietic progenitors ceased to be a desperate treatment with a high incidence of complications implying a high mortality, and became a curative treatment for thousands of patients with hematological neoplasias and other diseases. Since then understanding of the hemopoietic stem cells has increased, peripheral blood has replaced bone marrow as a source of progenitors, cord blood has been established as a viable source of progenitors and the realisation of unrelated transplants is a reality for many patients. The improvement of conditioning regimes and the introduction of new non-myeloablative treatments have reduced relapses. The new diagnostic techniques and the new anti-microbial treatments have reduced infectious complications and their mortality. There has been an advance in knowledge in determining minimal residual disease and the anti-tumour effect of the lymphocytes of the donor, which has made it possible to widen the indications. Besides, new understanding of the immunobiology of the transplant has, on the one hand, improved the options for controlling one of the principal complications, the graft-versus-host disease, and, on the other, a better use is made of the immunotherapeutic effect of the transplant

Measurement of prethrombotic markers in the assessment of acquired hypercoagulable states

Hypercoagulable states can be detected by measuring activation peptides, enzyme-inhibitor complexes, and fibrin/fibrinogen degradation products, which are markers of hemostatic activation. A series of these prethrombotic markers has been evaluated in the elderly, pregnancy, diabetes and acute myocardial infarction patients (n=30 in each group) as well as in hematologic malignancies (n=42). The parameters assayed were: prothrombin fragment 1+2 (F1+2), thrombin-antithrombin III complexes (TAT), fibrinopeptide A (FPA), plasmin-alpha2 antiplasmin complexes (PAP) and D-Dimer. Results were compared with those obtained in a group of 30 healthy subjects. We found a significant increase of F1+2, TAT and FPA in elderly (p<0.05), acute myocardial infarction (AMI) (p<0.01), hematologic malignancies (p<0.01), and pregnancy (p<0.0001), indicating a marked clotting activation. Diabetic patients under strict metabolic control only presented a moderate increase of TAT (p<0.05), suggesting a slight activation. We also observed a highly significant elevation of PAP and D-Dimer in elderly (p<0.001), AMI (p<0.0001), and malignancy (p<0.0001), indicating an activation of the fibrinolytic system. The combination of selected fibrinolytic and coagulation measurements is useful for the detection of a hypercoagulable state in conditions characterized by a risk of thrombosis

Emergence of Secondary Acute Leukemia in a Patient Treated for Osteosarcoma: Implications of Germline TP53 Mutations

Secondary leukemia and myelodysplastic syndromes have been reported in patients following treatment for a wide range of neoplastic disorders. However second malignancies after chemotherapy and/or irradiation for osteosarcoma are unusual. PROCEDURE: We report the case of a 15-year-old girl who developed a myelodysplastic syndrome with evolution to acute nonlymphocytic leukemia after treatment for osteosarcoma. Therapy-related acute leukemia karyotype findings such as abnormalities of chromosomes 5, 7, and 17 were found in the cytogenetic analysis. Moreover, using denaturing gradient gel electrophoresis and DNA sequencing, we detected the presence of a double germline mutation in exon 7 of the TP53 gene. CONCLUSION: This observation supports the possibility of a causal relationship between germline TP53 mutations and the development of secondary leukemia and myelodysplasi

Trasplante de homoinjertos valvulares cardiacos y vasculares

The advances in the manipulation of human tissues, the development of cryobiology, paediatric cardiac surgery, the impossibility of obtaining an ideal prosthetic cardiac valve and the surgical treatment of cardiovascular infections have revived interest in the use of homografts. The donors of these homografts can be: a) Live donors: aortic and pulmonary valve of the recipient of a heart transplant; b) Multiorgan donors with a diagnosis of death according to neurological criteria, whose heart is rejected for heart transplant; c) Cadaver donors with asystolia of less than 8 hours. Homograft cardiac valves are the substitute of choice in aortic valve endocarditis, patients with counter-indications for anticoagulation, reconstruction of the outflow tract of the right ventricle, aortic valve replacement in children and young adults through the Ross operation, and an optional indication is the aortic valve and/or rising aorta replacement in patients over 60 years of age. Although there are not sufficiently broad series of homogratfs with arterial substitutes, with respect to the number of patients and time of evolution, the results suggest that this can benefit patients with vascular infection, immunodepressed patients or complex patients whose technique during the operation might require a homograft

Clotting activation and impairment of fibrinolysis in malignancy

Different coagulation and fibrinolysis parameters were investigated in 149 patients with metastatic and non-metastatic tumours and results were compared with those obtained in a healthy population. Results showed a significant increase of thrombin-antithrombin complexes, fibrinopeptide A (FPA) and fibrin monomers in the group of patients (p less than 0.001). There was also a significant prolongation of euglobulin lysis time (p less than 0.005) and an increase of plasminogen activator inhibitor activity (p less than 0.0001), fibrinogen degradation products (p less than 0.001), and D-dimer (p less than 0.05) in the group of patients as compared to controls; FPA levels were also increased in patients with metastases (p less than 0.005). This study demonstrates clotting activation, at the level of fibrinogen to fibrin conversion, and impairment of fibrinolysis in patients with malignancy

Thrombopenic purpura induced by a monoclonal antibody directed to a 35-kilodalton surface protein (p35) expressed on murine platelets and endothelial cells

OBJECTIVE: With the aim of obtaining monoclonal antibodies (mAbs) against mouse endothelial surface antigens, immunization of rats with a mouse-derived endothelial cell line (PY4.1) and subsequent hybridoma production were performed. MATERIALS AND METHODS: One of the mAbs produced by hybridoma EOL5F5 was selected for its surface binding to endothelial cell lines, and identification of the mAb-recognized antigen was performed by immunoprecipitation. Experiments were performed to analyze the effects of EOL5F5 on systemic administration to mice. RESULTS: EOL5F5-recognized antigen was a single band of 35 kDa under reducing and nonreducing conditions, features that do not match other known differentiation antigens with comparable tissue distribution. In vivo administration of purified EOL5F5 mAb to mice (n = 20) induced intense cutaneous purpura as well as severe but transient thrombocytopenia. Expression of EOL5F5-recognized antigen was detected on platelets from which it immunoprecipitated a moiety of identical electrophoretic pattern in SDS-PAGE, as the one recognized on endothelial cells. Immunohistochemically, EOL5F5-recognized antigen (p35) also was expressed on dermal capillaries, suggesting that, in addition to thrombocytopenia, damaging effects of the antibody on endothelial cells also might cause the observed purpura. CONCLUSIONS: Our results show induction of thrombocytopenic purpura in mice with an mAb against a single antigenic determinant expressed on both platelets and endothelium. EOL5F5 mAb injection sets the stage for useful experimental models that resemble immune thrombocytopenic purpura

A single prior course of BCNU-cisplatin chemotherapy has a significant deleterious effect on mobilization kinetics of otherwise untreated patients

Extensive prior treatment with cytotoxic agents is associated with impaired mobilization of hematopoietic cells. To assess the effect of a single course of standarddose chemotherapy (CT), we compared the results of filgrastim-induced mobilization among two sequential groups of grade III–IV malignant glioma patients included in a hematopoietic transplantation program. The first group (21 patients) had never been treated with CT until 2 days after surgery, when they received a course of 100 mg/m2 BCNU (IV) and 100 mg intracarotid cisplatin for cytoreduction (not for mobilization). At 1 month after this CT, they were mobilized with 12 lg/kg filgrastim. The second group (22 patients) was mobilized with the same dose of filgrastim directly after the surgery, without having ever received any prior CT. The blood level of CD34þ cells was significantly lower in the CT-treated patients, both on the fourth day of filgrastim (15 vs 36 cells 106/l; P¼0.01) and on the fifth (25 vs 58 cells 106/l; P¼0.003), as it was the number of CD34þ cells collected per apheresis (1.3 vs 3.5 106/l; Po0.0005). The toxic effect of a single course of BCNUcisplatin CT led to significant impairment of the filgrastim-induced mobilization response. Bone Marrow Transplantation advance onlin

Frequent and simultaneous epigenetic inactivation of TP53 pathway genes in acute lymphoblastic leukemia

Aberrant DNA methylation is one of the most frequent alterations in patients with Acute Lymphoblastic Leukemia (ALL). Using methylation bead arrays we analyzed the methylation status of 807 genes implicated in cancer in a group of ALL samples at diagnosis (n = 48). We found that 154 genes were methylated in more than 10% of ALL samples. Interestingly, the expression of 13 genes implicated in the TP53 pathway was downregulated by hypermethylation. Direct or indirect activation of TP53 pathway with 5-aza-29-deoxycitidine, Curcumin or Nutlin-3 induced an increase in apoptosis of ALL cells. The results obtained with the initial group of 48 patients was validated retrospectively in a second cohort of 200 newly diagnosed ALL patients. Methylation of at least 1 of the 13 genes implicated in the TP53 pathway was observed in 78% of the patients, which significantly correlated with a higher relapse (p = 0.001) and mortality (p,0.001) rate being an independent prognostic factor for disease-free survival (DFS) (p = 0.006) and overall survival (OS) (p = 0.005) in the multivariate analysis. All these findings indicate that TP53 pathway is altered by epigenetic mechanisms in the majority of ALL patients and correlates with prognosis. Treatments with compounds that may reverse the epigenetic abnormalities or activate directly the p53 pathway represent a new therapeutic alternative for patients with ALL

Preclinical activity of LBH589 alone or in combination with chemotherapy in a xenogeneic mouse model of human acute lymphoblastic leukemia.

Histone deacetylases (HDACs) have been identified as therapeutic targets due to their regulatory function in chromatin structure and organization. Here, we analyzed the therapeutic effect of LBH589, a class I-II HDAC inhibitor, in acute lymphoblastic leukemia (ALL). In vitro, LBH589 induced dose-dependent antiproliferative and apoptotic effects, which were associated with increased H3 and H4 histone acetylation. Intravenous administration of LBH589 in immunodeficient BALB/c-RAG2(-/-)γc(-/-) mice in which human-derived T and B-ALL cell lines were injected induced a significant reduction in tumor growth. Using primary ALL cells, a xenograft model of human leukemia in BALB/c-RAG2(-/-)γc(-/-) mice was established, allowing continuous passages of transplanted cells to several mouse generations. Treatment of mice engrafted with T or B-ALL cells with LBH589 induced an in vivo increase in the acetylation of H3 and H4, which was accompanied with prolonged survival of LBH589-treated mice in comparison with those receiving vincristine and dexamethasone. Notably, the therapeutic efficacy of LBH589 was significantly enhanced in combination with vincristine and dexamethasone. Our results show the therapeutic activity of LBH589 in combination with standard chemotherapy in pre-clinical models of ALL and suggest that this combination may be of clinical value in the treatment of patients with ALL