Which organ is least likely to trigger a hyperacute rejection?

The cornea is the organ least likely to trigger a hyperacute rejection response. This phenomenon occurs primarily in vascularized organs, where the recipient's immune system rapidly identifies and attacks foreign tissues due to pre-existing antibodies against the donor's antigens.

The cornea is avascular, meaning it has very few blood vessels, which reduces the likelihood of immune cells interacting with transplanted tissue. Additionally, the corneal tissue has special immune privilege properties, allowing it to evade the recipient's immune response more effectively than other organs. Because the cornea's structure and function do not rely heavily on blood supply, the typical mechanisms that lead to hyperacute rejection are less relevant.

In contrast, the kidney, heart, and liver are all highly vascularized organs. Hyperacute rejection is more common in these cases because they can rapidly be recognized by the recipient's immune system once blood flow is established, triggering immediate rejection. This stark difference in vascularization and immune privilege status helps clarify why the cornea presents a lower risk for hyperacute rejection compared to the other organs listed.