Graft versus host disease is initiated by which party?

Graft versus host disease (GVHD) is a condition that occurs after a transplant, particularly in hematopoietic stem cell transplants, where the donor's immune cells attack the recipient's tissues. The correct answer emphasizes that the initiating party in this immunological response is indeed the donor.

In GVHD, when the donor's immune cells are introduced into a recipient who has a different genetic makeup or human leukocyte antigen (HLA) type, the donor's immune system recognizes the recipient's cells as foreign. This recognition leads to the activation of the donor's T lymphocytes, which mount an immune response against the recipient's tissues, resulting in GVHD.

The involvement of the recipient's immune system is secondary, as the recipient does not initiate the attack; instead, they become the target of the donor's immune response. The role of a co-donor is not applicable in the context of GVHD, as the disease is defined primarily by the graft (donor tissue)'s action against the host (recipient) rather than any contribution from another donor.

Understanding GVHD is crucial in immunology and transplantation, as it highlights the complexities of immune interactions and the importance of matching donor and recipient tissue types to minimize adverse effects