INTERMEDIATE FILAMENT EXPRESSION BY NORMAL AND DISEASED HUMAN CORNEALEPITHELIUM

Cicatricial conjunctivitis may be a sequel to systemic disorders (eg, Stevens-Johnson syndrome, cicatricial pemphigoid) or local disorders s uch as chemical burns. The cicatrisation is often associated with corn eal epithelial changes that cause visual loss. These have been attribu ted to encroachment of the conjunctival epithelium over the cornea. Ho wever, the epithelial anomalies are poorly understood. We investigated the corneal epithelial changes in cicatricial conjunctivitis with an immunohistochemical study of intermediate filaments in normal and path ological specimens. Our results show that the normal corneal epitheliu m is immunoreactive for cytokeratin 3 (CK 3) but not cytokeratin 19 (C K 19), whereas normal conjunctival epithelium is Ca 3 negative and CK 19 positive. Conjunctiva artificially transposed over the cornea (afte r therapeutic conjunctival flap reconstruction) retained the normal pa ttern of conjunctival cytokeratin expression (CK 3 negative, CR 19 pos itive). Conversely, the entire corneal epithelium exhibited the normal cytokeratin pattern (CK 3 positive, CK 19 negative) in 82% of Stevens -Johnson, 80% of cicatricial pemphigoid, and 69% of chemical burns spe cimens. The findings suggest that conjunctival encroachment is not res ponsible for the changes at the corneal surface in cicatricial conjunc tivitis and that the abnormal corneal epithelium is derived from nativ e corneal cells in these diseases. Copyright (C) 1997 by W.B. Saunders Company.