Ocular immune privilege: therapeutic opportunities from an experiment of nature

Most higher animals require sight for survival, yet even minor distortions of the visual axis can cause blindness. For this reason, intraocular inflammation is incompatible with good vision. Nature has found a way to provide the eye with immune protection against pathogens in a manner that greatly reduces the threat of inflammation-induced vision loss. Nature's way — known as 'immune privilege' — arises from anatomical, cellular and molecular specializations of the eye and the immune system. Knowledge of these unique characteristics indicates new ways to prevent and treat autoimmune and immunopathogenic diseases of the eye, as well as other organs and tissues, and to promote acceptance of cornea and other types of solid-tissue allograft.