Antigens, Human Platelet
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Antigens, Human Platelet
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 ...
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Polymorphism (biology)
In biology, polymorphism is the occurrence of two or more clearly different morphs or forms, also referred to as alternative '' phenotypes'', in the population of a species. To be classified as such, morphs must occupy the same habitat at the same time and belong to a panmictic population (one with random mating). Ford E.B. 1965. ''Genetic polymorphism''. Faber & Faber, London. Put simply, polymorphism is when there are two or more possibilities of a trait on a gene. For example, there is more than one possible trait in terms of a jaguar's skin colouring; they can be light morph or dark morph. Due to having more than one possible variation for this gene, it is termed 'polymorphism'. However, if the jaguar has only one possible trait for that gene, it would be termed "monomorphic". For example, if there was only one possible skin colour that a jaguar could have, it would be termed monomorphic. The term polyphenism can be used to clarify that the different forms arise from the ...
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Immune Sera
In immunology, antiserum is a blood serum containing antibodies (either monoclonal or polyclonal) that is used to spread passive immunity to many diseases via blood donation (plasmapheresis). For example, convalescent serum, or passive antibody transfusion from a previous human survivor, was the only known effective treatment for Ebola infection with a high success rate of 7 out of 8 patients surviving. Antisera are widely used in diagnostic virology laboratories. The most common use of antiserum in humans is as antitoxin or antivenom to treat envenomation. Serum therapy, also known as serotherapy, describes the treatment of infectious diseases using the serum of animals that have been immunized against the specific organism or components of that organism that is causing the infection. History In 1890, Emil von Behring and Kitasato Shibasaburō published their first paper on serum therapy. Behring pioneered the technique, using guinea pigs to produce serum. Based on his obs ...
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Blood Cells
A blood cell (also called a hematopoietic cell, hemocyte, or hematocyte) is a cell produced through hematopoiesis and found mainly in the blood. Major types of blood cells include red blood cells (erythrocytes), white blood cells (leukocytes), and platelets (thrombocytes). Together, these three kinds of blood cells add up to a total 45% of the blood tissue by volume, with the remaining 55% of the volume composed of plasma, the liquid component of blood. Red blood cells Red blood cells or ''erythrocytes'' primarily carry oxygen and collect carbon dioxide through the use of hemoglobin. Hemoglobin is an iron-containing protein that gives red blood cells their color and facilitates transportation of oxygen from the lungs to tissues and carbon dioxide from tissues to the lungs to be exhaled. Red blood cells are the most abundant cell in the blood, accounting for about 40–45% of its volume. Red blood cells are circular, biconcave, disk-shaped and deformable to allow them to sque ...
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Antibodies
An antibody (Ab) or immunoglobulin (Ig) is a large, Y-shaped protein belonging to the immunoglobulin superfamily which is used by the immune system to identify and neutralize antigens such as bacteria and viruses, including those that cause disease. Each individual antibody recognizes one or more specific antigens, and antigens of virtually any size and chemical composition can be recognized. Antigen literally means "antibody generator", as it is the presence of an antigen that drives the formation of an antigen-specific antibody. Each of the branching chains comprising the "Y" of an antibody contains a paratope that specifically binds to one particular epitope on an antigen, allowing the two molecules to bind together with precision. Using this mechanism, antibodies can effectively "tag" the antigen (or a microbe or an infected cell bearing such an antigen) for attack by cells of the immune system, or can neutralize it directly (for example, by blocking a part of a viru ...
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CD61
Integrin beta-3 (β3) or CD61 is a protein that in humans is encoded by the ''ITGB3'' gene. CD61 is a cluster of differentiation found on thrombocytes. Structure and function The ITGB3 protein product is the integrin beta chain beta 3. Integrins are integral cell-surface proteins composed of an alpha chain and a beta chain. A given chain may combine with multiple partners resulting in different integrins. Integrin beta 3 is found along with the alpha IIb chain in platelets. Integrins are known to participate in cell adhesion as well as cell-surface-mediated signaling. Role in endometriosis Defectively expressed β3 integrin subunit has been correlated with presence of endometriosis, and has been suggested as a putative marker of this condition. Interactions CD61 has been shown to Protein-protein interaction, interact with PTK2, ITGB3BP, TLN1 and CIB1. See also * Glycoprotein IIb/IIIa References Further reading * * * * * * * * * * External links * IT ...
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Single-nucleotide Polymorphism
In genetics and bioinformatics, a single-nucleotide polymorphism (SNP ; plural SNPs ) is a germline substitution of a single nucleotide at a specific position in the genome. Although certain definitions require the substitution to be present in a sufficiently large fraction of the population (e.g. 1% or more), many publications do not apply such a frequency threshold. For example, a Guanine, G nucleotide present at a specific location in a reference genome may be replaced by an Adenine, A in a minority of individuals. The two possible nucleotide variations of this SNP – G or A – are called alleles. SNPs can help explain differences in susceptibility to a wide range of diseases across a population. For example, a common SNP in the Factor H, CFH gene is associated with increased risk of age-related macular degeneration. Differences in the severity of an illness or response to treatments may also be manifestations of genetic variations caused by SNPs. For example, two ...
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Antithetical
Antithesis (: antitheses; Greek for "setting opposite", from "against" and "placing") is used in writing or speech either as a proposition that contrasts with or reverses some previously mentioned proposition, or when two opposites are introduced together for contrasting effect. Antithesis can be defined as "a figure of speech involving a seeming contradiction of ideas, words, clauses, or sentences within a balanced grammatical structure. Parallelism of expression serves to emphasize opposition of ideas". An antithesis must always contain two ideas within one statement. The ideas may not be structurally opposite, but they serve to be functionally opposite when comparing two ideas for emphasis. According to Aristotle, the use of an antithesis makes the audience better understand the point the speaker is trying to make. Further explained, the comparison of two situations or ideas makes choosing the correct one simpler. Aristotle states that antithesis in rhetoric is similar to ...
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Alloantibody
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 ...
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Nomenclature
Nomenclature (, ) is a system of names or terms, or the rules for forming these terms in a particular field of arts or sciences. (The theoretical field studying nomenclature is sometimes referred to as ''onymology'' or ''taxonymy'' ). The principles of naming vary from the relatively informal conventions of everyday speech to the internationally agreed principles, rules, and recommendations that govern the formation and use of the specialist terminology used in scientific and any other disciplines. Naming "things" is a part of general human communication using words and language: it is an aspect of everyday taxonomy as people distinguish the objects of their experience, together with their similarities and differences, which observers identify, name and classify. The use of names, as the many different kinds of nouns embedded in different languages, connects nomenclature to theoretical linguistics, while the way humans mentally structure the world in relation to word meanings a ...
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Platelet
Platelets or thrombocytes () are a part of blood whose function (along with the coagulation#Coagulation factors, coagulation factors) is to react to bleeding from blood vessel injury by clumping to form a thrombus, blood clot. Platelets have no cell nucleus; they are fragments of cytoplasm from megakaryocytes which reside in bone marrow or Lung, lung tissue, and then enter the circulation. Platelets are found only in mammals, whereas in other vertebrates (e.g. birds, amphibians), thrombocytes circulate as intact agranulocyte, mononuclear cells. One major function of platelets is to contribute to hemostasis: the process of stopping bleeding at the site where the lining of vessels (endothelium) has been interrupted. Platelets 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 (medicine), adhesion''. Second, they change shape, turn on receptors and secret ...
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Platelet Transfusion Refractoriness
Platelet transfusion refractoriness is the repeated failure to achieve the desired level of blood platelets in a patient following a platelet transfusion. The cause of refractoriness may be either immune or non-immune. Among immune-related refractoriness, antibodies against HLA antigens are the primary cause. Non-immune causes include splenomegaly (enlargement of the spleen), fever, and sepsis. Cause Platelet refractoriness can be due to immune causes or non-immune causes. Non-immune causes account for over 80% of cases of platelet refractoriness, and sepsis is one of the most common non-immune causes. HLA alloimmunization is the commonest immune cause of platelet refractoriness. Non-immune causes Patient-related * Sepsis * Fever * Disseminated intravascular coagulation * Splenomegaly * Treatment of infection, antibiotics (vancomycin), antifungals (amphotericin B) * Graft-versus-host disease * Hepatic veno-occlusive disease * Bleeding Platelet component-related * Age of pl ...
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