Endothelial metaplasia in the iridocorneal endothelial syndrome.

ABSTRACT

PURPOSE: To test the hypothesis that the aberrant, cytokeratin-expressing cells that replace endothelium in the iridocorneal endothelial (ICE) syndrome are of endothelial origin. METHODS: Corneas from four patients with Chandler's syndrome and three with essential iris atrophy were examined by two-color immunofluorescence for simultaneous expression of cytokeratins and two markers of endothelial lineage vimentin and the antigen recognized by the antiendothelial monoclonal antibody 2B4.14.1. RESULTS: In six corneas, unequivocal endothelial staining for cytokeratins was present; in each of these, cells coexpressing cytokeratins and the two endothelial markers were clearly identifiable. In the remaining cornea, weak cytokeratin staining that colocalized with vimentin was present. CONCLUSIONS: These results lend strong support to the hypothesis that the "epithelial-like" endothelial cells in ICE syndrome are cells of endothelial lineage rather than heterotopia of epithelial cells; these cells probably arise via a metaplastic transformation of preexisting endothelium.