Rejection

An immune response aimed at destroying organisms or substances that the body’s immune system recognizes as foreign. Rejection commonly refers to the nonacceptance of tissue grafts or organ transplants. To avoid rejection, donor tissues are closely matched to the recipient (see tissue-typing). Immunosuppressant drugs, corticosteroid drugs, and ciclosporin are given to organ transplant recipients to suppress rejection. (See also grafting; transplant surgery.)