Immunology of the ocular surface/corneal graft: What happens when immune vigilance goes awry?

The eye's remarkable immune privilege has 3 components, each disrupting different aspects of the immune response. While corneal allografts are the most obvious beneficiary of immune privilege, these mechanisms also reduce inflammation in the cornea, blunting the immunopathological sequelae associated with infectious diseases of the corneal surface. Loss of immune privilege, caused by factors such as vascularisation, splenectomy, and lack of FasL may lead to graft rejection. The insights gained from studying immune privilege may have clinical applications for patients at high risk of rejecting corneal allografts, as well as for other conditions involving ocular surface immunology, including dry eye disease.