| Allotransplantation | |
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| Intervention | |
| MeSH | D014184 |
Allotransplantation (allo- from the Greek meaning "other") is the transplantation of cells, tissues, or organs, to a recipient from a (genetically non-identical) donor of the same species.[1] The transplant is called an allograft or allogeneic transplant or homograft. Most human tissue and organ transplants are allografts.
In contrast, a transplant from another species is a xenograft. A transplanted organ or tissue from a genetically identical donor (such as an identical twin) is an isograft. When a tissue is transplanted from one site to another on the same patient, it is an autograft. In bone marrow transplantation, a genetically identical graft is syngeneic,[2] whereas the equivalent of an autograft is termed autologous[3] transplantation.
When a host mounts an immune response against an allograft or xenograft, the process is termed rejection. An allogenic bone marrow transplant can result in an immune attack against recipient, termed Graft-versus-host disease.
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For any number of reasons, before death, a person may have decided to donate tissue from his or her body for the purpose of transplant to another who is in need. This may be accomplished through self-registration on a donor registry. Additionally, consent for donation may be given by the donor's Legal Next of Kin if the donor did not specify his or her wishes before death. Consent is obtained shortly after death, generally in-person at a hospital or through a recorded telephonic conversation.
After consent is obtained, potential donors are thoroughly screened for risk factors and medical conditions that would rule out donation, such as pathology to the organs/tissues to be donated, or risk for relevant communicable diseases such as HIV and Hepatitis B and C. This screening includes interviews with family members and/or the donor's primary care physician, evaluation of medical, hospital and coroner records, a physical assessment of the donor, and recovery of blood, spleen and/or lymph nodes for infectious disease testing. Recovery of the tissue is performed with respect for the donor using surgical techniques.
Personnel from tissue recovery agencies remove the tissue from the donor. These agencies are under the regulation of the Food and Drug Administration and must abide by the Current Good Tissue Practices rule. Once the tissue is removed, it is sent to tissue banks for processing and distribution. Each year, AATB-accredited tissue banks distribute 1.5 million bone and tissue allografts. These banks are also regulated by the Food and Drug Administration to ensure the quality of the tissue being distributed.
A variety of transplantable organs and tissues can be used for allografts. These include:
Bone and tissue allografts have many uses for patients, but overall they save lives, repair limbs, and enhance the quality of a patient’s life. Allografts may be used to replace damaged heart valves and skin; however, they are more frequently used in orthopedic surgery to replace tendons or bones as necessary.
Since 1993, the Food and Drug Administration (FDA) has regulated human tissue intended for transplants. As of May 2005, there are three new regulations that address the manufacturing activities associated with human cells, tissues, and cellular and tissue-based products (HCT/Ps). The first regulation requires companies to register with the FDA if they intend to produce and distribute HCT/Ps. The second regulation, called the “Donor Eligibility” rule, concerns the donor’s ability to meet certain criteria in order to be eligible to donate tissue. Finally, the third rule, referred to as the “Current Good Tissue Practices” rule, oversees the overall processing and distribution practices of each company. As a whole, these rules are implemented to ensure the quality of the tissue and reduce the risk of contamination or disease transmission.
Allografts are a natural alternative to synthetic and metal implants. However, unlike synthetic or metal implants, allografts incorporate into your body.
Another choice surgeons have is an autograft, which takes tissue from one part of your body for transplantation to another part. Using an allograft eliminates the need for a second surgery site — avoiding additional pain, risk and possible longer hospital stay.
Further options may include a transplant from another species (a xenograft), or a transplanted organ or tissue from a genetically identical donor, i.e., an identical twin (an isograft).
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