Immune cell dynamics and cytokine regulation in cornea and transplantation

Immune privilege is essential for clear vision in the cornea. It assists in maintaining a strong defense against pathogens while limiting inflammation. This advantage results from a combination of physical barriers, such as the blood-eye barrier, local anti-inflammatory molecules, T cell apoptosis, resident and infiltrating immune cells, cytokine network, and humoral factors. These dynamic processes collaborate to protect the cornea and prevent tissue damage. While the development of ocular T regulatory cells is well-known, the specific mechanisms through which they suppress immune-mediated inflammation are not fully characterized. Recent advances in imaging and molecular biology have revealed the dynamic behavior of corneal immune cells and their regulatory roles in the production of cytokines and other humoral mediators. This review summarizes existing knowledge on corneal immune cell dynamics, cytokine regulation, and the mechanisms that support immune privilege and its rejection in corneal transplantation. We highlight the continuing discussions, identifying research shortcomings, and innovative therapeutic approaches targeting these pathways to improve graft viability and address corneal inflammatory diseases.