Current Practices, Evolving Techniques, and Immunologic Challenges in Living and Deceased Donor Limbal Stem Cell Transplantation.

This review focuses on allogeneic sources for restoring the ocular surface using limbal stem cell transplantation. We outline the current practices, evolving techniques, and immunologic challenges in living-related and deceased donor limbal stem cell transplantation. The diagnosis and staging guidelines for limbal stem cell deficiency are reviewed. We also explore the currently available treatment approaches, including the Cincinnati protocol for donor/recipient selection criteria and systemic immunosuppression (SI) regimen. Utilization of panel reactive antibody, HLA typing, ABO typing, and donor specific antibodies are highlighted. The traditional techniques as well as more novel variations are described. The importance of 3-agent SI protocols and patient adherence are emphasized to ensure excellent long-term outcomes. The primary immunologic challenge of allogeneic limbal stem cell transplantation, rejection, is also discussed in detail with recommended treatments, including a newer role for intravenous immunoglobulin. Other evolving practices have included a greater reliance on living-related conjunctival limbal allograft over deceased donor keratolimbal allograft due to improved outcomes, decreasing SI in older populations, and lengthening SI regimens due to the possibility of late acute rejection. Finally, we discuss the future of restoring the ocular surface via cell-based therapies, which may have the potential to decrease rejection.