Allografts

An allograft is a transplant of tissue or an organ between genetically non-identical individuals of the same species. It differs from autografts, which use a patient’s own tissue, and xenografts, which use tissue from a different species. Allografts can involve whole organs or smaller tissue grafts and are a common approach in contemporary medicine.

Common allografts include organ transplants (such as kidney, liver, heart, and lung) and tissue grafts (such as bone, tendon, skin, blood vessels, cornea, and heart valves). Skin allografts are used for temporary coverage in burn care, bone grafts support reconstruction, and corneal or heart-valve allografts restore function. Some tissues have lower antigenicity and are more likely to be accepted with less immunosuppression, while others require more intensive management.

Because donor antigens can trigger immune rejection, recipients typically receive immunosuppressive therapy. Matching of histocompatibility antigens, including HLA and ABO compatibility when feasible, improves graft survival. Rejection can be hyperacute, acute, or chronic, depending on timing and mechanism. Some sites, such as the cornea, benefit from relative immune privilege but are not entirely exempt from rejection.

Processing and regulatory practices address safety and ethics. Donor screening and consent aim to prevent transmission of infections (for example, HIV and hepatitis) and other pathogens. Allografts may be used fresh or processed and stored by tissue banks, using methods such as sterilization, de-cellularization, or cryopreservation. Oversight ensures safety, ethical sourcing, and appropriate use.

Overall, allografts provide essential options for replacing damaged or diseased tissue and organs, offering life-saving and functional benefits while requiring careful management of immunologic and infectious risks.