Platelet Transfusion: The transfer of blood platelets from a donor to a recipient or reinfusion to the donor.Blood Transfusion: The introduction of whole blood or blood component directly into the blood stream. (Dorland, 27th ed)Blood Platelets: Non-nucleated disk-shaped cells formed in the megakaryocyte and found in the blood of all mammals. They are mainly involved in blood coagulation.Platelet Count: The number of PLATELETS per unit volume in a sample of venous BLOOD.Thrombocytopenia: A subnormal level of BLOOD PLATELETS.Plateletpheresis: The preparation of platelet concentrates with the return of red cells and platelet-poor plasma to the donor.Erythrocyte Transfusion: The transfer of erythrocytes from a donor to a recipient or reinfusion to the donor.Platelet Aggregation: The attachment of PLATELETS to one another. This clumping together can be induced by a number of agents (e.g., THROMBIN; COLLAGEN) and is part of the mechanism leading to the formation of a THROMBUS.Blood Component Transfusion: The transfer of blood components such as erythrocytes, leukocytes, platelets, and plasma from a donor to a recipient or back to the donor. This process differs from the procedures undertaken in PLASMAPHERESIS and types of CYTAPHERESIS; (PLATELETPHERESIS and LEUKAPHERESIS) where, following the removal of plasma or the specific cell components, the remainder is transfused back to the donor.Antigens, Human Platelet: Human alloantigens expressed only on platelets, specifically on platelet membrane glycoproteins. These platelet-specific antigens are immunogenic and can result in pathological reactions to transfusion therapy.Thrombocytopenia, Neonatal Alloimmune: A condition in newborns caused by immunity of the mother to PLATELET ALLOANTIGENS on the fetal platelets. The PLATELETS, coated with maternal ANTIBODIES, are destroyed and removed by the fetal MONONUCLEAR PHAGOCYTE SYSTEM. Affected infants may have INTRACRANIAL HEMORRHAGES.Isoantibodies: Antibodies from an individual that react with ISOANTIGENS of another individual of the same species.Blood Transfusion, Intrauterine: In utero transfusion of BLOOD into the FETUS for the treatment of FETAL DISEASES, such as fetal erythroblastosis (ERYTHROBLASTOSIS, FETAL).Blood Transfusion, Autologous: Reinfusion of blood or blood products derived from the patient's own circulation. (Dorland, 27th ed)Hemorrhage: Bleeding or escape of blood from a vessel.Blood Grouping and Crossmatching: Testing erythrocytes to determine presence or absence of blood-group antigens, testing of serum to determine the presence or absence of antibodies to these antigens, and selecting biocompatible blood by crossmatching samples from the donor against samples from the recipient. Crossmatching is performed prior to transfusion.Platelet Adhesiveness: The process whereby PLATELETS adhere to something other than platelets, e.g., COLLAGEN; BASEMENT MEMBRANE; MICROFIBRILS; or other "foreign" surfaces.Blood Preservation: The process by which blood or its components are kept viable outside of the organism from which they are derived (i.e., kept from decay by means of a chemical agent, cooling, or a fluid substitute that mimics the natural state within the organism).Exchange Transfusion, Whole Blood: Repetitive withdrawal of small amounts of blood and replacement with donor blood until a large proportion of the blood volume has been exchanged. Used in treatment of fetal erythroblastosis, hepatic coma, sickle cell anemia, disseminated intravascular coagulation, septicemia, burns, thrombotic thrombopenic purpura, and fulminant malaria.Platelet Membrane Glycoproteins: Surface glycoproteins on platelets which have a key role in hemostasis and thrombosis such as platelet adhesion and aggregation. Many of these are receptors.Hematology: A subspecialty of internal medicine concerned with morphology, physiology, and pathology of the blood and blood-forming tissues.Blood Component Removal: Any procedure in which blood is withdrawn from a donor, a portion is separated and retained and the remainder is returned to the donor.Blood DonorsBlood Group Incompatibility: An antigenic mismatch between donor and recipient blood. Antibodies present in the recipient's serum may be directed against antigens in the donor product. Such a mismatch may result in a transfusion reaction in which, for example, donor blood is hemolyzed. (From Saunders Dictionary & Encyclopedia of Laboratory Medicine and Technology, 1984).Anemia, Aplastic: A form of anemia in which the bone marrow fails to produce adequate numbers of peripheral blood elements.Platelet Factor 4: A CXC chemokine that is found in the alpha granules of PLATELETS. The protein has a molecular size of 7800 kDa and can occur as a monomer, a dimer or a tetramer depending upon its concentration in solution. Platelet factor 4 has a high affinity for HEPARIN and is often found complexed with GLYCOPROTEINS such as PROTEIN C.Thrombopoietin: A humoral factor that stimulates the production of thrombocytes (BLOOD PLATELETS). Thrombopoietin stimulates the proliferation of bone marrow MEGAKARYOCYTES and their release of blood platelets. The process is called THROMBOPOIESIS.Fetofetal Transfusion: Passage of blood from one fetus to another via an arteriovenous communication or other shunt, in a monozygotic twin pregnancy. It results in anemia in one twin and polycythemia in the other. (Lee et al., Wintrobe's Clinical Hematology, 9th ed, p737-8)Anemia, Refractory: A severe sometimes chronic anemia, usually macrocytic in type, that does not respond to ordinary antianemic therapy.Hemostasis: The process which spontaneously arrests the flow of BLOOD from vessels carrying blood under pressure. It is accomplished by contraction of the vessels, adhesion and aggregation of formed blood elements (eg. ERYTHROCYTE AGGREGATION), and the process of BLOOD COAGULATION.Blood Loss, Surgical: Loss of blood during a surgical procedure.Bleeding Time: Duration of blood flow after skin puncture. This test is used as a measure of capillary and platelet function.Thrombasthenia: A congenital bleeding disorder with prolonged bleeding time, absence of aggregation of platelets in response to most agents, especially ADP, and impaired or absent clot retraction. Platelet membranes are deficient in or have a defect in the glycoprotein IIb-IIIa complex (PLATELET GLYCOPROTEIN GPIIB-IIIA COMPLEX).Leukemia: A progressive, malignant disease of the blood-forming organs, characterized by distorted proliferation and development of leukocytes and their precursors in the blood and bone marrow. Leukemias were originally termed acute or chronic based on life expectancy but now are classified according to cellular maturity. Acute leukemias consist of predominately immature cells; chronic leukemias are composed of more mature cells. (From The Merck Manual, 2006)Platelet Function Tests: Laboratory examination used to monitor and evaluate platelet function in a patient's blood.HLA Antigens: Antigens determined by leukocyte loci found on chromosome 6, the major histocompatibility loci in humans. They are polypeptides or glycoproteins found on most nucleated cells and platelets, determine tissue types for transplantation, and are associated with certain diseases.Platelet Glycoprotein GPIIb-IIIa Complex: Platelet membrane glycoprotein complex important for platelet adhesion and aggregation. It is an integrin complex containing INTEGRIN ALPHAIIB and INTEGRIN BETA3 which recognizes the arginine-glycine-aspartic acid (RGD) sequence present on several adhesive proteins. As such, it is a receptor for FIBRINOGEN; VON WILLEBRAND FACTOR; FIBRONECTIN; VITRONECTIN; and THROMBOSPONDINS. A deficiency of GPIIb-IIIa results in GLANZMANN THROMBASTHENIA.Platelet Activating Factor: A phospholipid derivative formed by PLATELETS; BASOPHILS; NEUTROPHILS; MONOCYTES; and MACROPHAGES. It is a potent platelet aggregating agent and inducer of systemic anaphylactic symptoms, including HYPOTENSION; THROMBOCYTOPENIA; NEUTROPENIA; and BRONCHOCONSTRICTION.Thrombopoiesis: The process of generating thrombocytes (BLOOD PLATELETS) from the pluripotent HEMATOPOIETIC STEM CELLS in the BONE MARROW via the MEGAKARYOCYTES. The humoral factor with thrombopoiesis-stimulating activity is designated THROMBOPOIETIN.Interleukin-11: A lymphohematopoietic cytokine that plays a role in regulating the proliferation of ERYTHROID PRECURSOR CELLS. It induces maturation of MEGAKARYOCYTES which results in increased production of BLOOD PLATELETS. Interleukin-11 was also initially described as an inhibitor of ADIPOGENESIS of cultured preadipocytes.Leukapheresis: The preparation of leukocyte concentrates with the return of red cells and leukocyte-poor plasma to the donor.Megakaryocytes: Very large BONE MARROW CELLS which release mature BLOOD PLATELETS.Pancytopenia: Deficiency of all three cell elements of the blood, erythrocytes, leukocytes and platelets.Hematopoietic Stem Cell Transplantation: Transfer of HEMATOPOIETIC STEM CELLS from BONE MARROW or BLOOD between individuals within the same species (TRANSPLANTATION, HOMOLOGOUS) or transfer within the same individual (TRANSPLANTATION, AUTOLOGOUS). Hematopoietic stem cell transplantation has been used as an alternative to BONE MARROW TRANSPLANTATION in the treatment of a variety of neoplasms.ABO Blood-Group System: The major human blood type system which depends on the presence or absence of two antigens A and B. Type O occurs when neither A nor B is present and AB when both are present. A and B are genetic factors that determine the presence of enzymes for the synthesis of certain glycoproteins mainly in the red cell membrane.Platelet Glycoprotein GPIb-IX Complex: Platelet membrane glycoprotein complex essential for normal platelet adhesion and clot formation at sites of vascular injury. It is composed of three polypeptides, GPIb alpha, GPIb beta, and GPIX. Glycoprotein Ib functions as a receptor for von Willebrand factor and for thrombin. Congenital deficiency of the GPIb-IX complex results in Bernard-Soulier syndrome. The platelet glycoprotein GPV associates with GPIb-IX and is also absent in Bernard-Soulier syndrome.Thrombelastography: Use of a thrombelastograph, which provides a continuous graphic record of the physical shape of a clot during fibrin formation and subsequent lysis.Neonatology: A subspecialty of Pediatrics concerned with the newborn infant.Purpura, Thrombocytopenic, Idiopathic: Thrombocytopenia occurring in the absence of toxic exposure or a disease associated with decreased platelets. It is mediated by immune mechanisms, in most cases IMMUNOGLOBULIN G autoantibodies which attach to platelets and subsequently undergo destruction by macrophages. The disease is seen in acute (affecting children) and chronic (adult) forms.Granulocyte Colony-Stimulating Factor: A glycoprotein of MW 25 kDa containing internal disulfide bonds. It induces the survival, proliferation, and differentiation of neutrophilic granulocyte precursor cells and functionally activates mature blood neutrophils. Among the family of colony-stimulating factors, G-CSF is the most potent inducer of terminal differentiation to granulocytes and macrophages of leukemic myeloid cell lines.Treatment Outcome: Evaluation undertaken to assess the results or consequences of management and procedures used in combating disease in order to determine the efficacy, effectiveness, safety, and practicability of these interventions in individual cases or series.Thrombin: An enzyme formed from PROTHROMBIN that converts FIBRINOGEN to FIBRIN.Time Factors: Elements of limited time intervals, contributing to particular results or situations.Retrospective Studies: Studies used to test etiologic hypotheses in which inferences about an exposure to putative causal factors are derived from data relating to characteristics of persons under study or to events or experiences in their past. The essential feature is that some of the persons under study have the disease or outcome of interest and their characteristics are compared with those of unaffected persons.Histocompatibility Testing: Identification of the major histocompatibility antigens of transplant DONORS and potential recipients, usually by serological tests. Donor and recipient pairs should be of identical ABO blood group, and in addition should be matched as closely as possible for HISTOCOMPATIBILITY ANTIGENS in order to minimize the likelihood of allograft rejection. (King, Dictionary of Genetics, 4th ed)Bone Marrow Transplantation: The transference of BONE MARROW from one human or animal to another for a variety of purposes including HEMATOPOIETIC STEM CELL TRANSPLANTATION or MESENCHYMAL STEM CELL TRANSPLANTATION.Splenectomy: Surgical procedure involving either partial or entire removal of the spleen.Leukocyte Transfusion: The transfer of leukocytes from a donor to a recipient or reinfusion to the donor.Transplantation, Autologous: Transplantation of an individual's own tissue from one site to another site.Blood Banks: Centers for collecting, characterizing and storing human blood.Leukemia, Myeloid: Form of leukemia characterized by an uncontrolled proliferation of the myeloid lineage and their precursors (MYELOID PROGENITOR CELLS) in the bone marrow and other sites.Adenosine Diphosphate: Adenosine 5'-(trihydrogen diphosphate). An adenine nucleotide containing two phosphate groups esterified to the sugar moiety at the 5'-position.Isoantigens: Antigens that exist in alternative (allelic) forms in a single species. When an isoantigen is encountered by species members who lack it, an immune response is induced. Typical isoantigens are the BLOOD GROUP ANTIGENS.Cyclophosphamide: Precursor of an alkylating nitrogen mustard antineoplastic and immunosuppressive agent that must be activated in the LIVER to form the active aldophosphamide. It has been used in the treatment of LYMPHOMA and LEUKEMIA. Its side effect, ALOPECIA, has been used for defleecing sheep. Cyclophosphamide may also cause sterility, birth defects, mutations, and cancer.Acute Disease: Disease having a short and relatively severe course.Myelodysplastic Syndromes: Clonal hematopoietic stem cell disorders characterized by dysplasia in one or more hematopoietic cell lineages. They predominantly affect patients over 60, are considered preleukemic conditions, and have high probability of transformation into ACUTE MYELOID LEUKEMIA.Disseminated Intravascular Coagulation: A disorder characterized by procoagulant substances entering the general circulation causing a systemic thrombotic process. The activation of the clotting mechanism may arise from any of a number of disorders. A majority of the patients manifest skin lesions, sometimes leading to PURPURA FULMINANS.Prospective Studies: Observation of a population for a sufficient number of persons over a sufficient number of years to generate incidence or mortality rates subsequent to the selection of the study group.Immunization: Deliberate stimulation of the host's immune response. ACTIVE IMMUNIZATION involves administration of ANTIGENS or IMMUNOLOGIC ADJUVANTS. PASSIVE IMMUNIZATION involves administration of IMMUNE SERA or LYMPHOCYTES or their extracts (e.g., transfer factor, immune RNA) or transplantation of immunocompetent cell producing tissue (thymus or bone marrow).Recombinant Proteins: Proteins prepared by recombinant DNA technology.Bone Marrow DiseasesFibrinogen: Plasma glycoprotein clotted by thrombin, composed of a dimer of three non-identical pairs of polypeptide chains (alpha, beta, gamma) held together by disulfide bonds. Fibrinogen clotting is a sol-gel change involving complex molecular arrangements: whereas fibrinogen is cleaved by thrombin to form polypeptides A and B, the proteolytic action of other enzymes yields different fibrinogen degradation products.Antineoplastic Combined Chemotherapy Protocols: The use of two or more chemicals simultaneously or sequentially in the drug therapy of neoplasms. The drugs need not be in the same dosage form.Leukocyte Count: The number of WHITE BLOOD CELLS per unit volume in venous BLOOD. A differential leukocyte count measures the relative numbers of the different types of white cells.Infant, Newborn: An infant during the first month after birth.Transplantation, Homologous: Transplantation between individuals of the same species. Usually refers to genetically disparate individuals in contradistinction to isogeneic transplantation for genetically identical individuals.Lymphoma, Non-Hodgkin: Any of a group of malignant tumors of lymphoid tissue that differ from HODGKIN DISEASE, being more heterogeneous with respect to malignant cell lineage, clinical course, prognosis, and therapy. The only common feature among these tumors is the absence of giant REED-STERNBERG CELLS, a characteristic of Hodgkin's disease.P-Selectin: Cell adhesion molecule and CD antigen that mediates the adhesion of neutrophils and monocytes to activated platelets and endothelial cells.Antigens, CD34: Glycoproteins found on immature hematopoietic cells and endothelial cells. They are the only molecules to date whose expression within the blood system is restricted to a small number of progenitor cells in the bone marrow.Anemia: A reduction in the number of circulating ERYTHROCYTES or in the quantity of HEMOGLOBIN.Hemoglobins: The oxygen-carrying proteins of ERYTHROCYTES. They are found in all vertebrates and some invertebrates. The number of globin subunits in the hemoglobin quaternary structure differs between species. Structures range from monomeric to a variety of multimeric arrangements.Anemia, Neonatal: The mildest form of erythroblastosis fetalis in which anemia is the chief manifestation.Leukemia, Myeloid, Acute: Clonal expansion of myeloid blasts in bone marrow, blood, and other tissue. Myeloid leukemias develop from changes in cells that normally produce NEUTROPHILS; BASOPHILS; EOSINOPHILS; and MONOCYTES.Etoposide: A semisynthetic derivative of PODOPHYLLOTOXIN that exhibits antitumor activity. Etoposide inhibits DNA synthesis by forming a complex with topoisomerase II and DNA. This complex induces breaks in double stranded DNA and prevents repair by topoisomerase II binding. Accumulated breaks in DNA prevent entry into the mitotic phase of cell division, and lead to cell death. Etoposide acts primarily in the G2 and S phases of the cell cycle.Erythroblastosis, Fetal: A condition characterized by the abnormal presence of ERYTHROBLASTS in the circulation of the FETUS or NEWBORNS. It is a disorder due to BLOOD GROUP INCOMPATIBILITY, such as the maternal alloimmunization by fetal antigen RH FACTORS leading to HEMOLYSIS of ERYTHROCYTES, hemolytic anemia (ANEMIA, HEMOLYTIC), general edema (HYDROPS FETALIS), and SEVERE JAUNDICE IN NEWBORN.Hematopoietic Stem Cell Mobilization: The release of stem cells from the bone marrow into the peripheral blood circulation for the purpose of leukapheresis, prior to stem cell transplantation. Hematopoietic growth factors or chemotherapeutic agents often are used to stimulate the mobilization.Antibodies: Immunoglobulin molecules having a specific amino acid sequence by virtue of which they interact only with the ANTIGEN (or a very similar shape) that induced their synthesis in cells of the lymphoid series (especially PLASMA CELLS).Thrombosis: Formation and development of a thrombus or blood clot in the blood vessel.Neutropenia: A decrease in the number of NEUTROPHILS found in the blood.Graft Survival: The survival of a graft in a host, the factors responsible for the survival and the changes occurring within the graft during growth in the host.Leukocytes: White blood cells. These include granular leukocytes (BASOPHILS; EOSINOPHILS; and NEUTROPHILS) as well as non-granular leukocytes (LYMPHOCYTES and MONOCYTES).Postoperative Hemorrhage: Hemorrhage following any surgical procedure. It may be immediate or delayed and is not restricted to the surgical wound.Hematopoiesis: The development and formation of various types of BLOOD CELLS. Hematopoiesis can take place in the BONE MARROW (medullary) or outside the bone marrow (HEMATOPOIESIS, EXTRAMEDULLARY).von Willebrand Factor: A high-molecular-weight plasma protein, produced by endothelial cells and megakaryocytes, that is part of the factor VIII/von Willebrand factor complex. The von Willebrand factor has receptors for collagen, platelets, and ristocetin activity as well as the immunologically distinct antigenic determinants. It functions in adhesion of platelets to collagen and hemostatic plug formation. The prolonged bleeding time in VON WILLEBRAND DISEASES is due to the deficiency of this factor.Hepatic Veno-Occlusive Disease: Liver disease that is caused by injuries to the ENDOTHELIAL CELLS of the vessels and subendothelial EDEMA, but not by THROMBOSIS. Extracellular matrix, rich in FIBRONECTINS, is usually deposited around the HEPATIC VEINS leading to venous outflow occlusion and sinusoidal obstruction.Neoplasms: New abnormal growth of tissue. Malignant neoplasms show a greater degree of anaplasia and have the properties of invasion and metastasis, compared to benign neoplasms.

Autologous transplantation of chemotherapy-purged PBSC collections from high-risk leukemia patients: a pilot study. (1/463)

We have recently demonstrated that the combination of the alkylating agent nitrogen mustard (NM) and etoposide (VP-16) is capable of eliminating, ex vivo, leukemic cells contaminating PBSC collections and this is associated with a significant recovery of primitive and committed hematopoietic progenitor cells. Based on these data a pilot study on autologous transplantation of NM/VP-16 purged PBSC for high-risk leukemic patients was recently initiated. Twelve patients (seven females and five males) with a median age of 46 years (range 18-57) have been treated. Two patients had acute myeloblastic leukemia (AML) resistant to conventional induction treatment, four patients had secondary AML in I complete remission (CR), one patient was in II CR after failing a previous autologous BM transplantation, while two additional AML individuals were in I CR achieved after three or more cycles of induction treatment. Two patients with high-risk acute lymphoblastic leukemia (ALL) in I CR and one patient with mantle cell lymphoma and leukemic dissemination were also included. Eight patients showed karyotypic abnormalities associated with a poor clinical outcome. The mobilizing regimens included cytosine arabinoside and mitoxantrone with (n = 6) or without fludarabine (n = 3) followed by subcutaneous administration of G-CSF (5 microg/kg/day until the completion of PBSC collection) and G-CSF alone (n = 3) (15 microg/kg/day). A median of two aphereses (range 1-3) allowed the collection of 7.2 x 10(8) TNC/kg (range 3.4-11.5), 5 x 10(6) CD34+ cells/kg (range 2.1-15.3) and 9.2 x 10(4) CFU-GM/kg (0.3-236). PBSC were treated with a constant dose of 20 microg of VP-16/ml and a median individual-adjusted dose (survival < or = 5% of steady-state BM CFU-GM) of NM of 0.7 microg/ml (range 0.25-1.25). Eleven patients were reinfused after busulfan (16 mg/kg) and Cy (120 mg/kg) conditioning with a median residual dose of 0.3 x 10(4) CFU-GM/kg (0-11.5). The median time to neutrophil engraftment (>0.5 x 10(9)/l) for evaluable patients was 25 days (range 12-59); the median time to platelet transfusion independence (>20 and >50 x 10(9)/l) was 40 days (18-95) and 69 days (29-235), respectively. Hospital discharge occurred at a median of 25 days (18-58) after stem cell reinfusion. Four individuals are alive in CR (n = 3) or with residual nodal disease (n = 1 lymphoma patient) with a follow-up of 32, 26, 3 and 14 months, respectively. Seven patients died due to disease progression or relapse (n = 5) or extrahematological transplant toxicity (n = 2). Our data suggest that pharmacological purging of leukapheresis collections of leukemic patients at high-risk of relapse is feasible and ex vivo treated cells reconstitute autologous hematopoiesis.  (+info)

A restrictive platelet transfusion policy allowing long-term support of outpatients with severe aplastic anemia. (2/463)

The threshold for prophylactic platelet transfusions in patients with hypoplastic thrombopenia generally recommended in the standard literature is 20,000 platelets/microL. A more restrictive transfusion policy may be indicated in patients with chronic severe aplastic anemia (SAA) in need of long-term platelet support. We evaluated the feasibility and safety of a policy with low thresholds for prophylactic transfusions (+info)

Changes in endogenous TPO levels during mobilization chemotherapy are predictive of CD34+ megakaryocyte progenitor yield and identify patients at risk of delayed platelet engraftment post-PBPC transplant. (3/463)

Patients with delayed platelet recovery post-PBPC transplant (PBPCT) are a high-risk group for thrombocytopenic bleeding and platelet transfusion dependence. Total CD34+ cell dosage has been proposed as the most important factor influencing the rate of platelet recovery. To achieve the shortest time to platelet engraftment, a minimum leukapheresis target of 10x10(6) CD34+ cells/kg was established for 30 patients. Of the 29 evaluable patients, 62% had rapid (group I: time to platelets >20x10(9)/l < or =10 days and 50x10(9)/l < or =14 days) platelet recoveries while 38% had delayed (group II: 20x10(9)/l >10 days and 50x10(9)/l >14 days) recoveries. Groups I and II were compared for: (1) pretreatment variables; (2) mobilizing capability of CD34+ cells and subsets including megakaryocyte (Mk) progenitors; (3) infused dose of these cells at transplant; (4) changes in endogenous levels of Mpl ligand (or TPO) during mobilization and myeloablative chemotherapy. Group II patients received significantly more platelet transfusions (6 vs. 2.1, P = 0.002) post-PBPCT, had a higher proportion of patients with a prior history of BM disease (64% vs. 6%, P = 0.001), and showed a reduced ability to mobilize differentiated (CD34+/38+, CD34+/DR+) and Mk progenitors (CD34+/42a+, CD34+/61+). Only the number of Mk progenitors reinfused at transplant was significantly different between the groups (group II vs. group I: CD34+/42a+ = 1.02 vs. 2.56x10(6)/kg, P = 0.013; CD34+/61+ = 1.12 vs. 2.70x10(6)/kg, P = 0.015). The ability to mobilize Mk progenitors correlated with percentage changes in endogenous levels of TPO from baseline to platelet nadir during mobilization chemotherapy (CD34+/42a+: r = 0.684, P = 0.007; CD34+/61+: r = 0.684, P = 0.007), with group II patients experiencing lower percentage changes. An inverse trend but no correlation was observed between serial TPO levels and platelet counts. TPO levels remained elevated in group II patients throughout a prolonged period of thrombocytopenia (median days to 50x10(9)/l = 25 vs. 11 for group I), indicating that delayed engraftment was not due to a deficiency of TPO but to a lack of Mk progenitor target cells. Our results show that the number of reinfused Mk progenitors is a better predictor of platelet engraftment than total CD34+ cell dosage. Small changes in endogenous TPO levels during mobilization predict for low Mk progenitor yields.  (+info)

Subsets of CD34+ hematopoietic progenitors and platelet recovery after high dose chemotherapy and peripheral blood stem cell transplantation. (4/463)

BACKGROUND AND OBJECTIVE: Randomized clinical trials have shown that peripheral blood stem cell transplantations (PBSCT) with appropriate doses of CD34+ cells are associated with rapid, complete and sustained recovery of marrow functions. Nevertheless, in a minority af patients delayed platelet recovery may occur and it remains to be established whether analysis of transplanted CD34+ cell subsets may demonstrate correlation with this phenomenon. We studied a series of 80 consecutive transplanted patients with the aim of evaluating the effect of CD34+ stem cell numbers and, in a subgroup of 32 patients, the effect of the lineage specific subset numbers on time to platelet engraftment (i.e. time to platelet counts higher than 20x10(9)/L for two consecutive days without the need for platelet transfusions). DESIGN AND METHODS: Different clinical and paraclinical factors were examined in a multivariate analysis for effect on platelet engraftment in 80 patients. RESULTS: The number of CD34+ cells/kg infused was the most important factor predicting the time to platelet engraftment. Patients receiving more than 10x10(6) CD34+ cells/kg had prompt platelet engraftment. The majority of the patients (78%) received fewer than 10x10(3) CD34+ cells/kg and 17/62 (27%) of these patients experienced delayed platelet engraftment. In 32 patients receiving fewer than 10x10(6) CD34+ cells/kg we focused on the content of different lineage specific CD34+ subsets in the PBSC products. The most significant correlation was recognized for CD34+/CD61+ megakaryocytic cell number and platelet engraftment. An inverse correlation between the CD34+/CD38Eth subset and platelet engraftment was found, indicating that a high number of CD34+/CD38Eth in the PBSC product might increase the risk for delayed engraftment. These results were further confirmed by the observation that patients who experienced platelet engraftment after day 20 had significantly more CD34+/CD38Eth cells/kg infused than patients with fast engraftment. INTERPRETATION AND CONCLUSIONS: The number of total CD34+ cells/kg infused was the most important factor predicting time to platelet engraftment. CD34+ subset analysis in a subgroup of patients suggests that a high number of uncommitted progenitors may be associated with slower platelet recovery than transplantation with a higher fraction of more committed peripheral blood stem cells.  (+info)

Serious hazards of transfusion (SHOT) initiative: analysis of the first two annual reports. (5/463)

OBJECTIVE: To receive and collate reports of death or major complications of transfusion of blood or components. DESIGN: Haematologists were invited confidentially to report deaths and major complications after blood transfusion during October 1996 to September 1998. SETTING: Hospitals in United Kingdom and Ireland. SUBJECTS: Patients who died or experienced serious complications, as defined below, associated with transfusion of red cells, platelets, fresh frozen plasma, or cryoprecipitate. MAIN OUTCOME MEASURES: Death, "wrong" blood transfused to patient, acute and delayed transfusion reactions, transfusion related acute lung injury, transfusion associated graft versus host disease, post-transfusion purpura, and infection transmitted by transfusion. Circumstances relating to these cases and relative frequency of complications. RESULTS: Over 24 months, 366 cases were reported, of which 191 (52%) were "wrong blood to patient" episodes. Analysis of these revealed multiple errors of identification, often beginning when blood was collected from the blood bank. There were 22 deaths from all causes, including three from ABO incompatibility. There were 12 infections: four bacterial (one fatal), seven viral, and one fatal case of malaria. During the second 12 months, 164/424 hospitals (39%) submitted a "nil to report" return. CONCLUSIONS: Transfusion is now extremely safe, but vigilance is needed to ensure correct identification of blood and patient. Staff education should include awareness of ABO incompatibility and bacterial contamination as causes of life threatening reactions to blood.  (+info)

Correlation of cytokine elaboration with mononuclear cell adhesion to platelet storage bag plastic polymers: a pilot study. (6/463)

The basis for many febrile nonhemolytic transfusion reactions associated with platelet transfusion therapy is cytokine elaboration and accumulation in the storage bag, which correlate with the leukocyte content and the length of platelet storage. We propose that a possible additional variable in the elaboration and accumulation of cytokines is the differential adhesion of mononuclear cells to the plastic substrate of the platelet storage bag. We hypothesize that mononuclear cell adhesion-induced cytokine release is greater in random-donor platelet bags composed of the polyolefin polymer compared to the single-donor apheresis platelet bags composed of the polyvinyl chloride polymer with the tri-(2-ethylhexyl) trimellitate (TEHTM) plasticizer. For four blood donors, we demonstrate preferential mononuclear cell adhesion, in vitro, to discs of polyolefin polymer versus discs of polyvinyl chloride polymer with the TEHTM plasticizer. Scanning electron microscopy corroborates this. In addition, proinflammatory cytokine (interleukin 1beta [IL-1beta] and tumor necrosis factor alpha [TNF-alpha]) levels are greater in culture wells containing discs of polyolefin polymer than in those containing discs of polyvinyl chloride polymer with the TEHTM plasticizer, and even more so in storage bags containing polyolefin polymer versus polyvinyl chloride polymer with the TEHTM plasticizer (IL-1beta, TNF-alpha, IL-6, and IL-8). This study suggests, for the first time, that differential plastic substrate mononuclear cell adhesion may contribute to cytokine release during platelet storage. This may represent an additional variable in the pathophysiology of febrile nonhemolytic transfusion reactions in patients receiving stored platelet units.  (+info)

Immunoglobulin therapy for severe thrombocytopenia complicating falciparum malaria. (7/463)

A 12-year-old Saudi boy with falciparum malaria developed profound thrombocytopenia with associated significant bleeding. Immunoglobulin was used to treat this case.  (+info)

Sickle cell disease and aortic valve replacement: use of cardiopulmonary bypass, partial exchange transfusion, platelet sequestration, and continuous hemofiltration. (8/463)

Sickle cell disease in patients undergoing open heart procedures presents a multitude of challenges to the medical staff. With improved techniques of cardiopulmonary bypass, surgery, and anesthesia for treating patients with sickle cell disease, perfusionists will likely encounter patients with this genetic disorder on a more frequent basis. A 40-year-old black woman was admitted to our institution with recurrent Staphylococcus epidermidis and sepsis. She underwent transesophageal echocardiography and cardiac catheterization and was subsequently diagnosed with severe aortic insufficiency. The aortic valve was replaced. Herein, we report our experience in the preoperative, perioperative, and postoperative management of this patient. We present a concise update on the current literature and techniques used by others in similar cases, and we provide a brief section on future considerations to assist fellow practitioners in recognizing this disease and meeting the accompanying challenges.  (+info)

  • In September 2007, Verax received FDA clearance to market the Platelet PGD(R) test as an adjunct test to detect bacteria in leukocyte-reduced, apheresis platelets following culture testing by an FDA-cleared test. (science20.com)
  • Although considerable advances have been made in platelet transfusion therapy in the last 40 years, some areas continue to provoke debate, especially concerning the use of prophylactic platelet transfusions for the prevention of thrombocytopenic bleeding. (ox.ac.uk)
  • Search methods We searched for randomised controlled trials (RCTs) in the Cochrane Central Register of Controlled Trials (CENTRAL) (Cochrane Library 2015, Issue 6, 23 July 2015), MEDLINE (from 1946), Embase (from 1974), CINAHL (from 1937), the Transfusion Evidence Library (from 1950), and ongoing trial databases to 23 July 2015. (ox.ac.uk)
  • At that time, AABB intends to promulgate an interim standard to require enhanced methods of bacterial detection in WBD platelets-either by specifically prohibiting the use of less sensitive methods such as pH or glucose, or by establishing a minimum sensitivity level for methods used to detect bacteria. (science20.com)