Allotransplantation refers to the use of donor materials from an individual of the same species to replace or augment organs, bone, and other tissues. In an advanced technique termed composite allotransplantation, the donor material can include a mixture of tissue types for more serious injuries. This medical treatment was developed in the 20th century to treat people with conditions like organ failure, serious bone injuries, and skin damage caused by burns. Advances in the technology are ongoing in the medical and scientific community.
The best candidate for transplant material is the patient, because there is a low risk of rejection and passing on communicable diseases. Another option is a twin, who could carry disease but will have the same genetic profile, which means the patient’s body is less likely to reject the material. If neither of these options are available, a donor match needs to be found. This person may be living or dead; deceased donors are a common choice for allotransplantation materials like hearts, which cannot be given by living donors because they are critical for biological function.
In the transplant procedure, a surgeon may remove a diseased or damaged organ or leave it in place, adding the replacement material and carefully connecting it so it receives a supply of blood and nerve impulses. After allotransplantation, patients need to take medications to suppress immune activity, which limits the chance of rejecting the organ. If their immune systems were allowed to function normally, they could develop severe immune responses to the foreign tissue, and their bodies would start attacking it.
Composite allotransplantation is used in procedures like face and hand transplants. In these cases, the patient has severe injuries that require replacement of more than one tissue type; hands, for example, include bone, muscle, tendon, blood vessels, and nerves. This requires a much longer and more delicate procedure to attach the donated material and check it to determine if the graft is likely to take. Recovery times can also be longer because of the increased complexity.
Research into allotransplantation includes a number of topics, including improving donor-recipient matches, preventing rejection, and screening tissue to make sure it is safe to use. Researchers also have an interest in the possibility of growing graft materials like bone in lab environments. This would eliminate the need to take it from a donor and could allow for autotransplantation by using stem cells from the recipient. Patients would donate stem cells which could be cultivated in the lab to build tissue for transplant.