allotransplantatsioon

Allotransplantatsioon (allogeneic transplantation) is the transplantation of an organ or tissue between individuals of the same species who are not genetically identical. It is distinguished from autotransplantatsioon (autografts) in which tissue is moved within the same person, and from isotransplantatsioon or syngeneic transplantation between genetically identical individuals, such as identical twins. In clinical practice, allotransplantation covers solid organs and various tissues.

Donors may be living or deceased. Commonly transplanted organs include the kidney, liver, heart, and lungs; tissues such as the cornea, bone, skin, and tendons may also be transplanted. Successful allotransplantation depends on donor–recipient matching and immune suppression; appropriate pairing improves graft survival and reduces rejection risk. Allocation systems prioritize compatibility, urgency, and donor availability.

Immune compatibility involves ABO blood group matching, human leukocyte antigen (HLA) matching when possible, and crossmatching to detect preformed antibodies. Even with good matches, the recipient’s immune system may reject the graft. Immunosuppressive therapy is required to prevent rejection, typically including calcineurin inhibitors (such as tacrolimus or cyclosporine), corticosteroids, and antimetabolites; induction therapy and newer targeted agents may be used in some cases.

Transplantation involves donor organ procurement, preservation, implantation, and postoperative care. Risks include surgical complications, infection, cardiovascular disease, and an increased risk of cancer due to immunosuppression. Long-term graft survival depends on adherence to medications and regular monitoring by clinicians.

Ethical considerations address informed consent, organ allocation fairness, and donor protection. Worldwide practice faces ongoing challenges from donor shortages and limited availability relative to demand.