In the context of GVHD, what does 'host' refer to?

In the context of graft-versus-host disease (GVHD), the term 'host' specifically refers to the patient receiving the transplant. This is a crucial concept in transplantation biology, as GVHD occurs when the immune cells from the transplanted tissue (the graft) recognize the host's body as foreign and attack it.

The host's immune system is typically compromised due to pre-transplant conditioning (such as chemotherapy or radiation), making it less capable of fighting off these immune responses. As a result, the transplanted immune cells from the donor view the host’s tissues as a threat, leading to the characteristic symptoms of GVHD, which can include skin rash, liver inflammation, and gastrointestinal problems.

Understanding the roles of donor and host in GVHD is vital for managing and preventing this complication. Therefore, the answer accurately identifies the patient receiving the transplant as the 'host' in this particular context.