Regional Immunity and Immunologic Microenvironments
The concept that many organs and tissue sites possess modifications to the classic immune response arc is called regional immunity. Regional immunity can affect all 3 phases of the response arc—afferent, processing, and effector. Regional differences in immune response occur because of differences in the immunologic microenvironments of various tissue sites. These regional differences can occur down to the level of specific locations within and around the eye (Table 3-1), such as the
cornea and sclera
anterior chamber, anterior uvea (iris and ciliary body), and vitreous
retina, retinal pigment epithelium (RPE), and choriocapillaris
A unique feature of the microenvironment of the eye is termed the ocular immune privilege. The term was introduced in 1940s by the finding that foreign antigen introduction to the anterior chamber did not elicit inflammatory response. Immune privilege is thought to be an evolutionary adaptation to protect vital structures. Traditionally, central nervous system, eyes, and testicles are considered immune-privileged organs.
Table 3-1 Comparison of Immune Microenvironments in Various Normal Ocular Sites
Excerpted from BCSC 2020-2021 series: Section 9 - Uveitis and Ocular Inflammation. For more information and to purchase the entire series, please visit https://www.aao.org/bcsc.