In order to examine the cells of the corneal epithelium in the patients who receive corneal transplantation after collagenase A assisted cultivated oral mucosa epithelium transplant (CA-COMET), we analyzed the specimens from penetrating keratoplasty with immunochemical staining.

Limbal insufficiency may cause persistent corneal erosion, turbidity, and even infection and blindness, leading to major eye damage. In patients with limbal stem cell insufficiency, due to the defect of the limbal stem cells, the new epidermal cells cannot be produced, and without the limbus as a barrier, the cells near the conjunctiva will move toward the center of the cornea, result in replacing the corneal cells and causing corneal conjunctivalization.

In recent years, many surgical methods for treating corneal stem cell defects include amniotic membrane transplantation, autologous limbal cell transplantation, and allogeneic limbal cell transplantation. However, in patients with bilateral total limbal insufficiency, there are no autologous limbal cells in the contralateral eye, and allografts may also have rejection and infection.

Cultured oral mucosa epithelium transplant is a method for treating bilateral full-limbal cell defects. The patient's own oral mucosal cells are cultured in the laboratory, and the cultured epithelium is transplanted to the patient's limbus. In the experiment, mouse cells are used as a feeder cell and transplanted to the human body, which is prone to potential problems such as rejection or infection. In order to resolve these problems, our laboratory modified the process of separating the limbal stem cells. By replacing the dispase II/trypsin-EDTA with Collagenase A, there were no needs to use a feeder cell. This experiment has been successfully completed under the national plan.

In this study, we want to investigate the cells on the ocular surface form the four patients who underwent corneal transplantation after receiving CA-COMET.

Dr.Kuan-Ting Kuo, a pathologist in NTUH, will assist us in the staining of the specimens of the cornea from four patients who underwent corneal transplantation after receiving CA-COMET. The specimens of the four patients will be stained (Immunohistochemistry) with markers of the cornea and conjunctival cells (K3, K4, K12, K13, K19, MUC5, P63).

Inclusion Criteria:

• The patients who underwent corneal transplantation after receiving CA-COMET in five years.

Exclusion Criteria:

• The patients who NEVER underwent corneal transplantation after receiving CA-COMET.

The patients who underwent corneal transplantation after receiving CA-COMET in five years.