Analysis of corneal epithelial kinetics after limbal allog raft transplantation

Purpose: To evaluate cell kinetics of corneal epithelium after limbal a! log raft transplantation, which supplies corneal stem cells for limbal dysfunction. Methods : Paracentral corneal epithelial cells collected 11 to 17 months (mean 14.8 ±6.1 ) postoperatively from 6 eyes of 6 patients (3 ocular cicatricial pemphigoid, 1 bullous keratopathy, I gelatinous dystrophy and 1 StevensJohnson syndrome) who underwent limbal al log raft transplantation using sexdifferent donor grafts were analyzed. The origin of epithelial cells was analyzed by fluorescence in situ hybridization (FISH ) method, observing X- and Ychromosome centromeres in the cells. Nine eyes of 8 patients who underwent penetrating keratoplasty using sex-different donor grafts (mean postoperative period: 12.0 ±2.0) were analyzed as controls. Results: The epithelial cells coinciding with the donor sex were observed in 3 among 6 eyes. On the other hand, non donor-derived epithelial cells were observed in three eyes that had postoperative complications; one with conjunctiva I invasion, one with persistent epithelial defect and one of bullous keratopathy in which the limbal graft was transplanted at an angle of 240 degrees of corneal limbus. The epithelial cells in the penetrating keratoplasty controls coincided with recipient sex in 8 out of 9 eyes. Conclusion: Donor-derived epithelial cells remained for a longer period in the successful cases of limbal allograft transplantation, as compared with conventional penetrating keratoplasty. It is suggested that limbal allograft transplantation functions as a transplant of corneal epithelial stem cells.