Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

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Query: EC:2.1.1.69 (BMT)
2,655 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Patients undergoing bone marrow transplantation are susceptible to many different bacterial, fungal and viral infections. Among the viral pathogens, cytomegalovirus (CMV), Epstein-Barr virus (EBV), and adenovirus cause the greatest morbidity and mortality and have been the most common infectious causes of death following the grafting of allogeneic marrow. This great susceptibility to viral infections is due to the immunodeficiency in cellular and humoral immune responses lasting for months to years. Contributing factors are high-dose chemo/radiotherapy, graft-versus-host disease (GVHD) prophylaxis/treatment, GVHD itself, the degree of HLA disparity between donor and recipient and the underlying disease. Defects of T cell helper and cytotoxic functions contribute to the great incidence of viral infections. We described here the kinetic of immunological reconstitution and the role of T cell immunodeficiency. At day 30 to 40 after BMT, a minority of patients had recovery of virus-specific CD8+ T-cell response. Between day 40 and day 90 recovery of deficient CD8+ and CD4+ T cell responses occurred in the majority of the recipients of HLA identical BMT but only in the minority of the recipients of HLA partially incompatible BMT. New approaches should therefore be envisaged either to preserve donor T-cell-mediate immunity or tho accelerate immune reconstitution. Add-back of unmanipulated T-cells, or virus-specific T cells could improve antimicrobial defenses after BMT.
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PMID:[Antiviral immunodeficiency: EBV, CMV, adenovirus]. 943 82

Myeloablative chemotherapy followed by transplantation of a T cell-depleted bone marrow graft from a partially mismatched related donor provides a potentially curative option for patients with leukemia and other disorders of hematopoiesis, although the patient is faced with a period of sustained immunodeficiency as well as pharmacologic immunosuppression as a result of prophylaxis against graft-versus-host disease. Thirty patients who received one to three antigen T cell-depleted mismatched grafts were evaluated for immune reconstitution. The percentage and numbers of cells expressing lymphocyte subset antigens were determined by flow cytometry at 14, 28, 60, 100, 180, 270 and 365 days post-BMT and at 6 month intervals thereafter. Lymphocyte reconstitution was characterized by the early appearance of natural killer cells and a low percentage of both T and B cells. During the first year after BMT, the number of NK cells remained constant while T and B cells gradually returned to normal numbers and proportions. Response to the lymphocyte mitogen phytohemagglutinin returned to normal over the course of 2 years, while the response to concanavalin A was slightly depressed and the response to pokeweed mitogen became supranormal at about 1.5 years and continued to increase. These data suggest the need for long-term immunophenotypic monitoring as well as prolonged infection surveillance and prophylaxis.
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PMID:Phenotypic and functional reconstitution of peripheral blood lymphocytes following T cell-depleted bone marrow transplantation from partially mismatched related donors. 953 38

BMT can both transmit and eliminate autoimmune diseases, and hence it has been suggested as an optional treatment for severe autoimmune conditions. In this communication we deal with the question of whether chronic GVHD is an autoimmune disease in itself, review the literature reports of autoimmune diseases following BMT in humans, and describe the autoimmune nature of the post-BMT state. Chronic GVHD, which is a frequent complication post-BMT, has clinical and pathogenic characteristics similar to autoimmune diseases, such as scleroderma and Sjogren's syndrome. Although the pathogenesis of chronic GVHD is not yet clear, thymic damage induced by acute GVHD may contribute to both the immunodeficiency and autoimmunity characterising chronic GVHD. A similar phenomenon is syngeneic GVHD, which results from an imbalance between autoreactive and autoregulatory lymphocytes. Additionally, other autoimmune diseases have been reported in post-BMT patients, and among these the most common are hypothyroidism, hyperthyroidism, myasthenia gravis and immune cytopenias. Although these diseases also occur also outside the post-BMT setting, they are unique with respect to pathogenesis (no association between myasthenia gravis and thymic pathology), diagnosis (symptoms of hyperthyroidism may be inadvertently related to other conditions), and prognosis (post-BMT autoimmune cytopenias may be fatal and treatment non-responsive). Nevertheless, many other autoimmune diseases have been reported after BMT, and these are mainly presented as case reports. Regarding the mechanism of post-BMT autoimmunity, the minority of cases stem from donor-related transfer of pathogenic lymphocytes or their progenitors, while most of the cases (either chronic GVHD or specific diseases) can be attributed to the immunologic imbalances characterising the post-BMT setting. The factors that may expose an individual to autoimmunity development post-BMT include genetic predisposition, an environmental factor such as CMV, and the nature of the donor who may aid in creating microchimerism and subsequently chronic GVHD and its related autoimmune manifestations.
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PMID:Autoimmune diseases and autoimmunity post-bone marrow transplantation. 982 15

The spectrum of pediatric bone marrow transplantation has changed in recent years. Mismatched and unrelated donor transplants are common, demanding an increased vigilance to detect incipient graft failure, secondary lymphoma as well as relapse and other problems, which now are potentially treatable. To diagnose these complications it may be important to know whether blood and marrow cells are of recipient or donor origin. To evaluate the role of mixed donor-recipient chimerism in relation to clinical problems we adapted a polymerase chain-reaction technique, using fluorescent primers analyzing DNA fragment length polymorphisms, to follow prospectively 17 bone marrow grafted children. To increase the precision of chimerism analysis, immunomagnetically isolated leukocyte populations were assayed in selected cases. Five patients encountered clinical problems related to chimerism. One infant with adenosine deaminase deficiency failed to engraft stem cells, yet succumbed to graft-versus-host disease, mediated by mature donor T-cells. Three children developed significant mixed chimerism. One of these three patients died in relapse of leukemia, while the two other patients who had received T-cell depleted grafts had persistent recipient T-cells, in spite of engraftment. After 5 months, these were displaced by donor T-cells in one of the patients. In the fifth patient, also after T-cell depleted BMT, a fatal donor cell lymphoma occurred. Twelve children had stable full chimerism or in one case a low grade mixed chimerism and remain disease-free throughout follow up (median 9 months). In conclusion, the analysis of chimerism, particularly of separated leukocyte populations, offers an almost indispensable insight and a basis for therapeutic decisions in complicated situations such as grafting involving unrelated or mismatched donors, graft manipulation, adoptive immunotherapy and in immunodeficiency patients.
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PMID:Engraftment and chimerism, particularly of T- and B-cells, in children undergoing allogeneic bone marrow transplantation. 1008 48

We have studied the regeneration of T cell subsets and function after BMT in 21 children affected by combined immunodeficiency after BMT. In the first months, the striking predominance of CD4+ cells displayed the primed CD45R0+ phenotype and a high number of activated (HLA-DR+) T cells were observed. Regeneration of naive CD4+CD45RA+ cells correlated with the recovery of proliferative responses to mitogens (r = 0.64, P<0.001). Peripheral blood lymphocytes circulating after BMT undergo an increased process of in vitro cell death, resulting from two mechanisms: spontaneous apoptosis (SA), a consequence of defective production of IL-2 and down-regulation of Bcl-2 (P = 0.02 vs. healthy controls), and high susceptibility to activation-induced cell death (AICD) after restimulation with mitogens. In accordance with the role of CD95/Fas in this latter process, we have observed a high level of CD95 expression (P<0.001 vs. healthy controls), correlated with AICD (P<0.001) but not with SA, and decreasing with time after BMT (P<0.001). Both SA and AICD levels correlated with the presence of activated T cells and decreased with the progressive recovery of T cell proliferative response. Therefore, the lymphocyte hyperactivated status might explain their susceptibility to apoptosis and contribute to the genesis of immunodeficiency that follows BMT.
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PMID:Immune reconstitution after bone marrow transplantation for combined immunodeficiencies: down-modulation of Bcl-2 and high expression of CD95/Fas account for increased susceptibility to spontaneous and activation-induced lymphocyte cell death. 1010 May 58

The majority of children with lethal congenital immunodeficiencies lack histocompatible related bone marrow donors. T-cell depleted haploidentical parental bone marrow transplantation has been used successfully in selected patients with severe combined immunodeficiency (SCID), but it has not benefited most patients with other immunodeficiencies when it has been tried. For these reasons, we undertook a pilot study using closely matched unrelated donors for bone marrow transplantation of children with life-threatening primary immunodeficiencies. Unrelated donor searches were performed for 24 patients and one or more suitable donors were identified for 21 patients. Unrelated donor bone marrow transplantation (URD BMT) has been performed in 18 patients with various diagnoses: SCID (8), Wiskott-Aldrich syndrome (WAS) (2), Chediak-Higashi syndrome (CHS) (2), combined immunodeficiencies (3), Ataxia Telangiectasis (AT) (2), and one patient with combined immunodeficiency and large granular lymphocytosis (1). The overall actuarial survival rate is 59% with excellent results observed for infants with SCID and children with WAS and CHS.
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PMID:Unrelated donor bone marrow transplantation for correction of lethal congenital immunodeficiencies. 1014 43

Major histocompatibility complex (MHC) class II deficiency is a rare form of primary combined immunodeficiency that can only be corrected by stem cell transplantation. We report a 4(1/2)-year-old girl with MHC class II deficiency who underwent a related CBT due to graft failure following T cell-depleted non-identical BMT. The patient is alive and well 2 years after the second transplant. A sustained hematopoietic engraftment and a progressive immune recovery have been detected. We conclude that cord blood may be an effective source of hematopoietic stem cells for patients with immuno- deficiency disorders including diseases with a high rate of graft failure.
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PMID:Successful related umbilical cord blood transplantation for graft failure following T cell-depleted non-identical bone marrow transplantation in a child with major histocompatibility complex class II deficiency. 1046 37

Griscelli disease (GD) is a rare disorder characterized by pigment dilution, immunodeficiency and occurrence of accelerated phase consisting of hemophagocytosis, pancytopenia and neurological manifestations. Allogeneic BMT in the early period is an important modality of treatment for GD. We carried out an alloBMT from an HLA-identical sibling donor on a 4-year-old girl who presented in accelerated phase with neurological manifestations including convulsions, strabismus, severe dysarthria, ataxia and clonus. She was treated with etoposide, methylprednisolone and intrathecal methotrexate for 8 weeks and underwent alloBMT after receiving a conditioning regimen including ATG (rabbit, 10 mg/kg x 5 days), Bu/Cy. 8 x 108/kg nucleated bone marrow cells were given. Engraftment occurred early and the post-BMT period was uneventful. Currently, she is at 18 months post BMT with sustained engraftment and with a normal neurological examination except for minimal clonus. Long-term follow-up will determine the prognosis regarding the neurological findings.
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PMID:Successful bone marrow transplantation in a case of Griscelli disease which presented in accelerated phase with neurological involvement. 1051 9

Chimerism is an exceptional immunogenetic state, characterized by the survival and collaboration of cell populations originated from two different individuals. The prerequisits to induce chimerism are immuno-suppression, myeloablation, or severe immunodeficiency of the recipients on the one side and donor originated immuno-hematopoietic cells in the graft on the other. The pathologic or special immunogenetic conditions to establish chimerism are combined with bone marrow transplantation, transfusion, and various kinds of solid organ grafting. Different types of chimerism are known including complete, mixed and mosaic, or split chimerism. There are various methods used to detect the type of chimera state, depending on the immunogenetic differences between the donor and recipient. The induction of complete or mixed chimerism is first determinated by the effect of myeloablative therapy. The chimera state seems to be one of the leading factors to influence the course of the post-transplant period, the frequency and severity of GVHD, and the rate of relapse. However, the most important contribution of the chimeric state is in development of graft versus leukemia effect. A new conditioning protocol (DBM/Ara-C/Cy) for allogeneic BMT in CML patients and its consequence on chimera state and GVL effect is demonstrated.
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PMID:Immunological importance of chimerism in transplantation: new conditioning protocol in BMT and the development of chimeric state. 1071 1

Flow cytometry laboratory plays an integral part in the evaluation of a BMT patient. Its role starts at the time of clinical presentation to assure most accurate and reproducible disease diagnosis and subclassification. This can only be achieved if the flow cytometrist is fully qualified in the diagnosis of hematolymphoid neoplasia and is able to correlate each and every case with morphologic data. Flow cytometric report, therefore, includes a standing diagnosis and goes beyond the sole description of an abnormal/atypical population. Following initial diagnosis, generated data are carefully stored and are retrieved for review whenever needed particularly during the evaluation of the remission status, response to chemotherapy, relapse, staging and detection of residual disease in marrow and apheresis product. Our laboratory performs leukemia/lymphoma assessment of approximately 150-200 samples a month in addition to 3-8 weekly apheresis procedures, 25-30 post-BMT immune monitoring samples and other isoteric assessments including CD4 counts for HIV population, HLA B27 evaluation, platelet/leukocyte antibodies, reticulated platelets, immunodeficiency disorders etc. This multidisciplinary center allowed us to develop a substantial expertise in the field, which hopefully benefits our patient, clinicians and fellow cytometrists. We are please to share our expertise at this distinguished forum.
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PMID:Flow cytometric assessment of bone marrow transplant patient. 1082 94


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