The transplanted tissue can replace function for the life of the patient. Any transplantation faces the possibility of rejection, this of course can lead to complete failure of the approach. While immune system repression using drugs is typically performed to avoid rejection, it is not always successful, and can also have side effects. Transplantation by definition requires donors, and for many tissues such as liver, bone marrow, and kidneys, the number of donor tissues available is an order of magnitude smaller than the number of patients in need of a transplant. Autografts can replace function of lost tissue for the life of the patient.
Autografts face no danger of rejection and require no outside donor.
Requires the removal of tissue from somewhere in the patient. Trauma is caused at the site where the autograft is taken. Skin autografting requires the creation of scar tissue elsewhere on the body to repair visible defects. Although implants cause inflammation, implanted materials cannot be destroyed by an immune response. Thus there is no rejection of implants.