Medicina: Ematologia: Talassemie e trapianto del midollo osseo
| English |
| alloimmunization |
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| Attestation |
3
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| Part of speech |
Noun
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| Grammatical label |
Countable
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| Definition |
Individuals can develop antibodies to foreign HLA antigens when they have been exposed to exogenous blood and tissue cells through pregnancy, transfusion or transplantation. This is termed alloimmunization. Alloimmunization presents several problems in transfusion and transplantation. Patients who receive multiple transfusions often develop antibodies which target and destroy transfused cells, especially platelets. These patients become “refractory” to platelet transfusion, meaning the platelet count does not increase as expected post transfusion. If patients experience two or more post transfusion increments of <5000 platelets/µl, and there are no other obvious explanations for the poor response, HLA matched platelets are sometimes required. HLA matched platelets are collected, by apheresis, from a donor whose HLA type has been determined by special testing. The donor lacks HLA antigens to which the patient has developed antibodies. HLA alloimmunization poses another problem for transfusion recipients, in that it can cause febrile non-hemolytic transfusion reactions.
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| Definition source |
Puget Sound Blood Centre. Transfusion. HLA/Alloimmunization.
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| Context |
Alloimmunization develops much less frequently in children who begin a regular transfusion regime before the age of 12 months, suggesting that their relatively immature immune systems can become tolerant to multiple foreign red cell antigens.
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| Context source |
Mohamed, N. & Jackson, N. (1998). ‘Severe thalassemia intermedia: clinical problems in the absence of hypertransfusion’. Blood Reviews 12(3):163-70. (RISCEN83)
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| Synonym |
Isoimmunization
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| Subject field |
Haemopoiesis
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| Sub-field (level 1) |
Thalassemias
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| Sub-field (level 2) |
Therapies
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| Related concept |
Transfusional therapy
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| it |
Alloimmunizzazione
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| Reliability code |
3
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