Question

For an organ transplant, it is an advantage to have an identical twin. Why?

Answer 1

Very often, when some human organs like heart, eye, liver, and kidney fail to function satisfactorily, transplantation is the only remedy to enable the patient to live a normal life. Then a search begins to find a suitable donor. 

Grafts from just any source-an animal, another primate, or any human beings cannot be made since the grafts would be rejected sooner or later. Tissue matching, blood group matching are essential before undertaking any graft/transplant and even after this the patient has to take immuno-suppresants all his/her life. The body is able to differentiate ‘self ’ and ‘nonself’ and the cell-mediated immune response is responsible for the graft rejection. In an identical twin, there is no chance of rejection of the transplanted organ, so it is advantageous.