An isograft is one that is transferred
**Core Concept**
An isograft refers to a type of graft that is transferred between genetically identical individuals, such as monozygotic twins or individuals with the same genetic makeup. This is in contrast to allografts, which are transplanted between genetically different individuals.
**Why the Correct Answer is Right**
Isografts have a lower risk of rejection compared to allografts because they share the same genetic makeup, reducing the likelihood of immune system recognition and activation. This results in a reduced need for immunosuppressive therapy and a lower risk of graft-versus-host disease. The lack of genetic differences also reduces the likelihood of histocompatibility complex (MHC) incompatibilities, which are a major factor in allograft rejection.
**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because isografts are not transferred between individuals with a close genetic relationship, such as family members. While family members may share some genetic similarities, they are not genetically identical.
**Option B:** This option is incorrect because autografts are transferred from one part of the body to another within the same individual, whereas isografts are transferred between genetically identical individuals.
**Option C:** This option is incorrect because xenografts are transplanted between individuals of different species, which is not relevant to the definition of an isograft.
**Clinical Pearl / High-Yield Fact**
It's essential to remember that isografts have a lower risk of rejection and may not require the same level of immunosuppressive therapy as allografts. However, they can still result in graft-versus-host disease if the donor and recipient are not genetically identical.
**Correct Answer:** D.