Histology of human conjunctival transplantation

The technique of conjunctival transplantation has proven very successful in reestablishing an intact ocular surface in patients with severe ocular surface disease in whom conventional treatment has failed. We present follow-up on the histology of the transplanted conjunctival tissue in four alkali-burned patients who underwent penetrating keratoplasty 3-28 months following conjunctival transplantation. The corneal button was re-epithelialized in all patients. The fate of the transplanted tissue agreed with experimental observations made in the rabbit model, i.e., under areas of vascularization and inflammation, the transplanted tissue resembled conjunctiva with numerous goblet cells and 3-4 cell layers of nonkeratinized, stratified epithelium. In one patient, a definite "transition zone" from conjunctival to corneal appearing epithelium was seen in an area with minimal inflammation and vascularization, again confirming the animal results showing that transdifferentiation of conjunctival to corneal epithelium can occur.