Immunosuppression with mycophenolate mofetil after penetrating keratoplasty: our clinical experience

Penetrating keratoplasty (PKP) has emerged as the most common form of solid tissue transplantation over the past 30 years1.This relative success of PKP is attributable to continued advances in surgical techniques, equipment, ocular pharmacology and immunology, corneal storage, and eye banking procedures. For uncomplicated first grafts performed in avascular «low-risk» beds with only local immune suppression, success rate is as high as 90%. This success in lowrisk corneal transplantation, however, is overshadowed by the results of corneal grafts placed in «high risk» beds with rejection rates approaching 70%, even with maximal local and systemic immune suppression. So, although the cornea is classically described as possessing immunological privilege, immunologic corneal graft rejection is still the leading cause of graft failure after penetrating high-risk keratoplasty2,3. In vascularised corneas and possibly corneas that have previously rejected a graft, the «immunological privilege» breaks down and the cornea becomes as susceptible as any other vascularised tissue in the body to rejection. Although much is being learned in laboratory science about this problem, not much has changed from a clinical standpoint and corneal grafting in this high-risk corneas remains a significant challenge. It is both remarkable and sobering to remember that the rate of rejection of corneas grafted into high-risk eyes, exceeds the rate of rejection of kidney, heart and liver grafts. In 1949, when cortisone became available, it was used to prevent graft rejection improving prognosis in high-risk corneas, but it is since the introduction of short-term systemic immunosuppression with cyclosporine A (CsA) in the mid-1980s4,5, that graft prognosis in such cases has improved considerably. However, the use of CsA is limited because its side effects, especially nephrotoxicity and hepatotoxicity, alterations in glucose metabolism, hypertension, and gingival hyperplasia, which occurred in up to 41% of