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Mixed Field Reaction
In transfusion medicine, mixed-field agglutination refers to mixed reactions during cell typing where two distinct cell populations are present: agglutinated cells admixed with many unagglutinated cells. The presence of two or more cell populations is known as chimerism. Mixed-field agglutination is an important cause of ABO typing and genotype discrepancies. The cause of mixed field agglutinations should be sought prior to setting up blood for transfusion. Causes False chimerism By far the most common cause of mixed-field agglutination is false chimerism. There are several causes of false chimerism; 1) Transfusion of donor red cells. For example, a blood group B individual who has received a transfusion of group O donor red cells may show mixed field agglutination with anti-B sera. His own group B red cells are agglutinated by the anti-B sera while the group O donor red cells in his circulation are unagglutinated 2) After an ABO mismatched stem cell transplant for example a blood ... [...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 don ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chimerism
A genetic chimerism or chimera ( ) is a single organism composed of cells with more than one distinct genotype. In animals, this means an individual derived from two or more zygotes, which can include possessing blood cells of different blood types, subtle variations in form (phenotype) and, if the zygotes were of differing sexes, then even the possession of both female and male sex organs. Animal chimeras are produced by the merger of two (or more) embryos. In plant chimeras, however, the distinct types of tissue may originate from the same zygote, and the difference is often due to mutation during ordinary cell division. Normally, genetic chimerism is not visible on casual inspection; however, it has been detected in the course of proving parentage. Another way that chimerism can occur in animals is by organ transplantation, giving one individual tissues that developed from a different genome. For example, transplantation of bone marrow often determines the recipient's ensuin ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Stem Cell Transplant
Hematopoietic stem-cell transplantation (HSCT) is the transplantation of multipotent hematopoietic stem cells, usually derived from bone marrow, peripheral blood, or umbilical cord blood in order to replicate inside of a patient and to produce additional normal blood cells. It may be autologous (the patient's own stem cells are used), allogeneic (the stem cells come from a donor) or syngeneic (from an identical twin). It is most often performed for patients with certain cancers of the blood or bone marrow, such as multiple myeloma or leukemia. In these cases, the recipient's immune system is usually destroyed with radiation or chemotherapy before the transplantation. Infection and graft-versus-host disease are major complications of allogeneic HSCT. HSCT remains a dangerous procedure with many possible complications; it is reserved for patients with life-threatening diseases. As survival following the procedure has increased, its use has expanded beyond cancer to autoimmune d ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Antigen
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-reactivity, cross-react and bind more tha ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
