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| Organ Transplantation |
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| Organ transplantation has become a therapeutic modality to treat patients with end - stage disease. While many types of organs have been successfully transplanted, the histocompatibility barrier between recipient and donor remains a problem. It activates immune responses leading to graft rejection. |
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| Transplantation involves the replacement of an injured or diseased tissues or organs. For e.g., skin, cornea, heart, lung, kidney. Liver, bone marrow and pancreas. The success depends upon the proper matching of the major histo compatibility complex (MHC) or Human Leucocyte Antigen (HLA) complex of the recipient and donor tissue. |
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| Usually the body recognises the proteins in the transplanted tissue or organ as foreign and produces antibodies against them. This phenomenon is known as Tissue rejection. |
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| Autografts are successful because here ones own tissues are grafted to another part of the body. |
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| Isografts are where the donor and recipient are genetically identical as in identical twins. |
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| Allograft or Homograft is the transplant between individuals of the same species, but with different MHC/HLA alleles. The success depends upon matching of MHC/HLA alleles and on administration of immuno - suppressive drugs to inhibit graft rejection. |
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| Xenograft is a transplant between animals of different species. This is used when human grafts are not available. It is mostly done in laboratory animals. |
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| Immuno - suppressive drugs, such as cyclosporin A, is used to inhibit the immunological mechanisms responsible for graft rejection. This drug is derived from a fungus, and it has largely overcome this problem. It inhibits T cells which are responsible for tissue rejection. But withdrawal of the drug may result in graft rejection. |
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