IMMUNOHISTOCHEMICAL PATHOLOGY OF THE CORNEAL ENDOTHELIUM IN IRIDOCORNEAL ENDOTHELIAL SYNDROME

Purpose. To evaluate immunohistochemical staining of the endothelia of corneas from patients with clinical diagnoses of iridocorneal endothe lial (ICE) syndrome. Methods. Corneas diagnosed with ICE syndrome and removed during corneal transplantation were freshly frozen, sectioned, and stained with monoclonal antibodies to keratin subgroups, vimentin , desmin, and a series of other antibodies against intermediate filame nts. Transmission electron microscopy was performed on segments of the se corneas fixed in glutaraldehyde. Results. There was almost universa l staining of the endothelial layer with A1 and A3 keratin monoclonal antibodies and vimentin. Transmission electron microscopy of the corne as also confirmed features consistent with keratin. Conclusions. The ' 'endothelial'' cell layer in the iridocorneal endothelial syndrome has electron microscopic and immunohistochemical characteristics of epith elial-like cells, but it also cross-reacts with vimentin, suggesting t hat these cells retain or derive some endothelial staining characteris tics as well. This ''epithelialization'' of the endothelial layer may explain the progressive cellular proliferation across angle and iris s imilar to that seen in iatrogenic epithelial downgrowth and posterior polymorphous endothelial dystrophy.