All are affected in Graft versus host reaction –
**Core Concept**
The graft-versus-host disease (GVHD) is an immunological complication that occurs when donor T lymphocytes recognize the recipient's body as foreign and mount an immune response against it. This reaction is a major concern in hematopoietic stem cell transplantation and other forms of allogenic transplantation.
**Why the Correct Answer is Right**
In GVHD, the donor T cells recognize the recipient's major histocompatibility complex (MHC) molecules on the surface of recipient's cells as foreign. This recognition leads to the activation of donor T cells, which then cause a cascade of immune responses against the recipient's body. The affected organs and tissues include the skin, liver, and gut, leading to symptoms such as rash, diarrhea, and liver dysfunction. The pathophysiology of GVHD involves the activation of donor T cells, which release cytokines and other inflammatory mediators that cause tissue damage.
**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because the recipient's bone marrow is not affected in GVHD. The disease primarily involves the immune response against the recipient's skin, liver, and gut.
**Option B:** This option is incorrect because the recipient's kidneys are not typically affected in GVHD. While some patients may experience kidney dysfunction as a result of the disease, it is not a primary target of the immune response.
**Option C:** This option is incorrect because the recipient's heart is not typically affected in GVHD. While some patients may experience cardiac dysfunction as a result of the disease, it is not a primary target of the immune response.
**Clinical Pearl / High-Yield Fact**
One of the key risk factors for GVHD is the presence of donor T cells in the graft. This is why patients who receive T cell-depleted grafts have a lower risk of developing GVHD.
**Correct Answer: A, B, C. All of the above tissues can be affected in Graft versus host reaction.**