allograaft

Allograaft, or allograft, is a tissue graft transplanted from a donor to a recipient who are members of the same species but genetically non-identical. It contrasts with autografts, which come from the same individual, and xenografts, which come from a different species.

Allografts are used to repair or replace damaged tissues in various medical fields, including orthopedics (bone and tendon grafts), dermatology (skin grafts), ophthalmology (corneal grafts), and cardiovascular and reconstructive surgery (heart valves, blood vessels, and soft tissue). The donor is typically a deceased or living donor, and tissues are obtained through tissue banks that screen for infectious diseases, assess compatibility where relevant, and obtain informed consent.

Processing and storage vary by tissue type. Some allografts are used fresh; others are cryopreserved, refrigerated, or decellularized. Sterilization methods, such as gamma irradiation or chemical sterilants, may be applied to reduce infection risk, though they can affect mechanical properties or cellular content. Immunological considerations are important: allografts carry a risk of immune rejection, which is managed differently by tissue type. Corneal and some soft-tissue allografts have relatively lower immunogenicity, while vascularized tissues may require broader immunosuppression in certain scenarios.

Regulatory and ethical oversight is provided by national health authorities and tissue banks, with emphasis on donor consent, anonymity, screening, traceability, and quality control. Outcomes depend on tissue type, donor quality, processing, and recipient factors; risks include infection, disease transmission (minimized by screening), and graft rejection or failure.