Anterior chamber-associated immune deviation and its impact on corneal allograft survival

PURPOSE OF REVIEW: Anterior chamber-associated immune deviation is a form of immune tolerance elicited by ocular antigens and corneal transplants. It produces antigen-specific downregulation of T-helper 1 immune responses and promotes corneal allograft survival. This review discusses recent insights in the induction of anterior chamber-associated immune deviation. RECENT FINDINGS: Although initial findings suggested that anterior chamber-associated immune deviation was a preferential activation of T-helper 2 immunity, recent findings indicate that T-helper 2 cytokines, such as interleukin-4 and interleukin-13, and T-helper 2 transcription factors are not needed. Findings indicate that ocular antigen-presenting cells migrate to the spleen and release antigenic peptides that are captured and reprocessed by splenic B cells, which present antigenic peptides to T cells on both major histocompatibility complex class I and class II molecules, leading to the generation of CD8 T-regulatory cells and CD4 T-regulatory cells. SUMMARY: Anterior chamber-associated immune deviation is a complex immunoregulatory phenomenon involving multiple cell populations and four organ systems. Anterior chamber-associated immune deviation reduces the risk for immune-mediated inflammation in the eye and promotes corneal allograft survival. Understanding the mechanisms may help improve the survival of other organ transplants that are at risk for immune rejection.