A group of proteins that have a role in the immune system. Certain types of histocompatibility antigens are essential for the immunological function of killer T cells (see lymphocytes). The antigens act as a guide for killer T cells to recognize and kill abnormal or foreign cells. The main group of histocompatibility antigens is the human leukocyte antigen (HLA) system, which consists of several series of antigens. A person’s tissue type (the particular set of HLAs in the body tissues) is unique, except for identical twins, who have the same set. HLA analysis has some useful applications. Comparison of HLA types may show that 2 people are related, and it has been used in paternity testing. The HLA system is also used in tissue-typing to help match recipient and donor tissues before transplant surgery. Certain HLA types occur more frequently in people with particular diseases, such as multiple sclerosis, coeliac disease, and ankylosing spondylitis. HLA testing can help to confirm the presence of such diseases and identify people at risk of developing them.
Histocompatibility antigens |
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