Long-term effectiveness of autologous cultured limbal stem cell grafts in patients with limbal stem cell deficiency due to chemical burns.

Background:  Chemical burns cause depletion of limbal stem cells and eventually lead to corneal opacity and visual loss. We investigated the long-term effectiveness of autologous cultured limbal stem cell grafts in patients with limbal stem cell deficiency. Design:  Prospective , non-comparative interventional case series. Participants:  Sixteen eyes from 16 patients with severe, unilateral limbal stem cell deficiency caused by chemical burns. Methods:  Autologous ex vivo cultured limbal stem cells were grafted onto the recipient eye after superficial keratectomy. Main outcome measures:  Clinical parameters of limbal stem cell deficiency (stability/transparency of the corneal epithelium, superficial corneal vascularization, and pain/photophobia), visual acuity, cytokeratin expression on impression cytology specimens and histology on excised corneal buttons. Results:  At 12 months post-surgery, evaluation of the 16 patients showed that 10 (62.6\%) experienced complete restoration of a stable and clear epithelium and 3 (18.7\%) had partially successful outcomes (re-appearance of conjunctiva in some sectors of the cornea and instable corneal surface). Graft failure (no change in corneal surface conditions) was seen in 3 (18.7\%) patients. Penetrating keratoplasty was performed in 7 patients, with visual acuity improving up to 0.8 (best result). For 2 patients, regeneration of the corneal epithelium was confirmed by molecular marker (p63, cytokeratin 3, 12 and 19, mucin 1) analysis. Follow-up times ranged from 12 to 50 months. Conclusions:  Grafts of autologous limbal stem cells cultured onto fibrin glue discs can successfully regenerate the corneal epithelium in patients with limbal stem cell deficiency, allowing to perform successful cornea transplantation and restore vision.