Terminology
The definitions of flaps and grafts used above describe the vascular
basis of the tissue transfer and the constituents of the transferred tissue.
Most tissue transfer is from one place to another in the same person. However,
there are other forms of transfer and further terminology is needed to explain
the genetic basis of these transfers. An autograft is tissue transferred from
one location to another on the same patient. An isograft is tissue transferred
between two genetically identical individuals, such as the first successful
renal transplant that was between identical twins. An allograft is tissue
transferred between genetically different members of the same species. Most
solid organ tissue transplantation involves this type of transfer. Rejection of
the transplanted tissue will occur unless immunosuppressant drugs are used. A
xenograft is tissue transferred from a donor of one species to a recipient of
another species. Xenografts are usually small amounts of tissue rendered
acellular before implantation to prevent rejection.