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Post-transfusion Purpura
Post-transfusion purpura (PTP) is a delayed adverse reaction to a blood transfusion or platelet transfusion that occurs when the body has produced alloantibodies to the allogeneic transfused platelets' antigens. These alloantibodies destroy the patient's platelets leading to thrombocytopenia, a rapid decline in platelet count. PTP usually presents 5–12 days after transfusion, and is a potentially fatal condition in rare cases. Approximately 85% of cases occur in women. __TOC__ Mechanism PTP is rare, but usually occurs in women who have had multiple pregnancies or in people who have undergone previous transfusions. The precise mechanism leading to PTP is unknown, but it most commonly occurs in individuals whose platelets lack the HPA-1a antigen (old name: PLA1). The patient develops antibodies to the HPA-1a antigen leading to platelet destruction. In some cases, HPA-5b has also been implicated. It is unclear why alloantibodies attack the patient's own, as well as any transfused ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Blood Transfusion
Blood transfusion is the process of transferring blood products into a person's circulation intravenously. Transfusions are used for various medical conditions to replace lost components of the blood. Early transfusions used whole blood, but modern medical practice commonly uses only components of the blood, such as red blood cells, white blood cells, plasma, clotting factors and platelets. Red blood cells (RBC) contain hemoglobin, and supply the cells of the body with oxygen. White blood cells are not commonly used during transfusion, but they are part of the immune system, and also fight infections. Plasma is the "yellowish" liquid part of blood, which acts as a buffer, and contains proteins and important substances needed for the body's overall health. Platelets are involved in blood clotting, preventing the body from bleeding. Before these components were known, doctors believed that blood was homogeneous. Because of this scientific misunderstanding, many patients died b ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Platelet Transfusion
Platelet transfusion, also known as platelet concentrate, is used to prevent or treat bleeding in people with either a low platelet count or poor platelet function. Often this occurs in people receiving cancer chemotherapy. Preventive transfusion is often done in those with platelet levels of less than 10 x 109/L. In those who are bleeding transfusion is usually carried out at less than 50 x 109/L. Blood group matching (ABO, RhD) is typically recommended before platelets are given. Unmatched platelets, however, are often used due to the unavailability of matched platelets. They are given by injection into a vein. Side effects can include allergic reactions such as anaphylaxis, infection, and lung injury. Bacterial infections are relatively more common with platelets as they are stored at warmer temperatures. Platelets can be produced either from whole blood or by apheresis. They keep for up to five to seven days. Platelet transfusions came into medical use in the 1950s and 1 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Alloantibodies
Alloimmunity (sometimes called isoimmunity) is an immune response to nonself antigens from members of the same species, which are called alloantigens or isoantigens. Two major types of alloantigens are blood group antigens and histocompatibility antigens. In alloimmunity, the body creates antibodies (called alloantibodies) against the alloantigens, attacking transfused blood, allotransplanted tissue, and even the fetus in some cases. Alloimmune (isoimmune) response results in graft rejection, which is manifested as deterioration or complete loss of graft function. In contrast, autoimmunity is an immune response to the self's own antigens. (The ''allo-'' prefix means "other", whereas the ''auto-'' prefix means "self".) Alloimmunization (isoimmunization) is the process of becoming alloimmune, that is, developing the relevant antibodies for the first time. Alloimmunity is caused by the difference between products of highly polymorphic genes, primarily genes of the major histocompati ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Blood Platelet
Platelets, also called thrombocytes (from Greek θρόμβος, "clot" and κύτος, "cell"), are a component of blood whose function (along with the coagulation factors) is to react to bleeding from blood vessel injury by clumping, thereby initiating a blood clot. Platelets have no cell nucleus; they are fragments of cytoplasm that are derived from the megakaryocytes of the bone marrow or lung, which then enter the circulation. Platelets are found only in mammals, whereas in other vertebrates (e.g. birds, amphibians), thrombocytes circulate as intact mononuclear cells. One major function of platelets is to contribute to hemostasis: the process of stopping bleeding at the site of interrupted endothelium. They gather at the site and, unless the interruption is physically too large, they plug the hole. First, platelets attach to substances outside the interrupted endothelium: ''adhesion''. Second, they change shape, turn on receptors and secrete chemical messengers: ''activation ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Antigens
In immunology, an antigen (Ag) is a molecule or molecular structure or any foreign particulate matter or a pollen grain that can bind to a specific antibody or T-cell receptor. The presence of antigens in the body may trigger an immune response. The term ''antigen'' originally referred to a substance that is an antibody generator. Antigens can be proteins, peptides (amino acid chains), polysaccharides (chains of monosaccharides/simple sugars), lipids, or nucleic acids. Antigens are recognized by antigen receptors, including antibodies and T-cell receptors. Diverse antigen receptors are made by cells of the immune system so that each cell has a specificity for a single antigen. Upon exposure to an antigen, only the lymphocytes that recognize that antigen are activated and expanded, a process known as clonal selection. In most cases, an antibody can only react to and bind one specific antigen; in some instances, however, antibodies may cross-react and bind more than one antigen. T ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Thrombocytopenia
Thrombocytopenia is a condition characterized by abnormally low levels of platelets, also known as thrombocytes, in the blood. It is the most common coagulation disorder among intensive care patients and is seen in a fifth of medical patients and a third of surgical patients. A normal human platelet count ranges from 150,000 to 450,000 platelets/microliter (μl) of blood. Values outside this range do not necessarily indicate disease. One common definition of thrombocytopenia requiring emergency treatment is a platelet count below 50,000/μl. Thrombocytopenia can be contrasted with the conditions associated with an abnormally ''high'' level of platelets in the blood - thrombocythemia (when the cause is unknown), and thrombocytosis (when the cause is known). Signs and symptoms Thrombocytopenia usually has no symptoms and is picked up on a routine complete blood count. Some individuals with thrombocytopenia may experience external bleeding, such as nosebleeds or bleeding gums. S ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
HPA-1a
Human platelet antigens (HPA) are polymorphisms in platelet antigens. These can stimulate production of alloantibodies (that is, antibodies against other people's antigens) in recipients of transfused platelets from donors with different HPAs. These antibodies cause neonatal alloimmune thrombocytopenia, post-transfusion purpura, and some cases of platelet transfusion refractoriness to infusion of donor platelets. __TOC__ Overview A nomenclature was devised by International Society of Blood Transfusion (ISBT), platelet working party to overcome problems generated by many different nomenclatures in use. Since inception of this list, a greater number of antigens have been described and the molecular basis of many has been resolved. To date, 24 platelet-specific alloantigens have been defined by immune sera, of which 12 are grouped in six biallelic systems (HPA-1, -2, -3, -4, -5, -15). For the remaining 12, alloantibodies against the thetical but not the antithetical antigen have be ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
IVIG
Immunoglobulin therapy is the use of a mixture of antibodies (normal human immunoglobulin or NHIG) to treat several health conditions. These conditions include primary immunodeficiency, immune thrombocytopenic purpura, chronic inflammatory demyelinating polyneuropathy, Kawasaki disease, certain cases of HIV/AIDS and measles, Guillain-Barré syndrome, and certain other infections when a more specific immunoglobulin is not available. Depending on the formulation it can be given by injection into muscle, a vein, or under the skin. The effects last a few weeks. Common side effects include pain at the site of injection, muscle pain, and allergic reactions. Other severe side effects include kidney problems, anaphylaxis, blood clots, and red blood cell breakdown. Use is not recommended in people with some types of IgA deficiency. Use appears to be relatively safe during pregnancy. Human immunoglobulin is made from human blood plasma. It contains antibodies against many viruses. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Blackwell Publishing
Wiley-Blackwell is an international scientific, technical, medical, and scholarly publishing business of John Wiley & Sons. It was formed by the merger of John Wiley & Sons Global Scientific, Technical, and Medical business with Blackwell Publishing in 2007.About Wiley-Blackwell John Wiley & Sons, Inc. Wiley-Blackwell is now an imprint that publishes a diverse range of academic and professional fields, including , , , |
Blood Transfusion
Blood transfusion is the process of transferring blood products into a person's circulation intravenously. Transfusions are used for various medical conditions to replace lost components of the blood. Early transfusions used whole blood, but modern medical practice commonly uses only components of the blood, such as red blood cells, white blood cells, plasma, clotting factors and platelets. Red blood cells (RBC) contain hemoglobin, and supply the cells of the body with oxygen. White blood cells are not commonly used during transfusion, but they are part of the immune system, and also fight infections. Plasma is the "yellowish" liquid part of blood, which acts as a buffer, and contains proteins and important substances needed for the body's overall health. Platelets are involved in blood clotting, preventing the body from bleeding. Before these components were known, doctors believed that blood was homogeneous. Because of this scientific misunderstanding, many patients died b ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Neonatal Alloimmune Thrombocytopenia
Neonatal alloimmune thrombocytopenia (NAITP, NAIT, NATP or NAT) is a disease that affects babies in which the platelet count is decreased because the mother's immune system attacks her fetus' or newborn's platelets. A low platelet count increases the risk of bleeding in the fetus and newborn. If the bleeding occurs in the brain, there may be long-term effects. Platelet antigens are inherited from both mother and father. is caused by antibodies specific for platelet antigens inherited from the father but which are absent in the mother. Fetomaternal transfusions (or fetomaternal hemorrhage) results in the recognition of these antigens by the mother's immune system as non-self, with the subsequent generation of allo-reactive antibodies which cross the placenta. , hence, is caused by transplacental passage of maternal platelet-specific alloantibody and rarely human leukocyte antigen () allo-antibodies (which are expressed by platelets) to fetuses whose platelets express the corre ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Transfusion Medicine
Transfusion medicine (or transfusiology) is the branch of medicine that encompasses all aspects of the transfusion of blood and blood components including aspects related to hemovigilance. It includes issues of blood donation, immunohematology and other laboratory testing for transfusion-transmitted diseases, management and monitoring of clinical transfusion practices, patient blood management, therapeutic apheresis, stem cell collections, cellular therapy, and coagulation. Laboratory management and understanding of state and federal regulations related to blood products are also a large part of the field. Overview In most countries, immunohematology and transfusion medicine specialists provide expert opinion on massive transfusions, difficult/incompatible transfusions and rational use of specialised blood product therapy like irradiated blood/ leukodepleted/washed blood products. The blood donor center is the facility that collects blood components from screened blood dono ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
