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Excerpt from Corneal Graft Rejection


Synonyms, Key Words, and Related Terms: penetrating keratoplasty rejection, corneal transplantation, corneal transplants, corneal tissue, cornea

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Background

Although described for more than 100 years, corneal transplantation has become increasingly common since the 1960s. Over 40,000 transplants were performed in 1990 in the United States and Canada. The 5-year failure rate for corneal grafts is approximately 35%; corneal graft rejection is the most common cause of graft failure in the late postoperative period.

Pathophysiology

The term graft rejection refers to the specific immunologic response of the host to the donor corneal tissue. As it is a specific process, it should be distinguished from other causes of graft failure that are not immune mediated. A corneal graft that has suffered this immunologic response may or may not ultimately fail. Some physicians distinguish between graft reaction, which is reversible with medical therapy, and graft rejection, in which the immunologic end stage has been reached and the process is irreversible. Other physicians simply use graft rejection to refer to this immunologic process at any stage of its development, noting that some cases will progress to graft failure because of rejection. This second terminology is used in this article since it is in line with terminology used in other types of organ transplantation. Furthermore, at the time of presentation, it is not possible to know with certainty whether an immune process is reversible.

Frequency

United States

Over 40,000 transplants were performed in 1990 in the United States and Canada. The 5-year failure rate for corneal grafts is approximately 35%.

Mortality/Morbidity

Corneal graft rejection is the most common cause of graft failure in the late postoperative period.

Race

No known difference in corneal graft rejection between different races exists.

Sex

No known sex predilection for corneal graft rejection exists.

Age

Host age may influence the risk of corneal graft rejection. Although it is not certain, some investigators have concluded that a lower risk of corneal graft rejection exists for hosts who are older than 60 years. It is generally believed that infants have higher rates of graft rejection than adults.

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