This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Immunology, Subject name: Microbiology
Transplantation involving tissue from twin brothers possessing identical HLA genes is best described by which one of the following? 
Select and explain. 
A. Allograft: transplant from one species to the same species, B. Autograft: transplant from one region of a person to another region, C. Isograft: transplant from one person to a genetically identical person, D. Xenograft: transplant from one species to another species
C: Isograft: transplant from one person to a genetically identical person
Answer: C: Isograft: transplant from one person to a genetically identical person 
Explanation: Transplantation from one region of a person to another region of that same person is an autograft and has the best chance of succeeding. When a transplant is done between monozygotic twins, it is an isograft and has a complete MHC compatibility and a good chance of success. Allografts are between members of the same species, and xenografts are between members of different species. Both of these transplants have a high rate of rejection unless immunosuppression accompanies the transplant.