IMMUNOHISTOCHEMICAL ANALYSIS OF THE PATHOGENESIS OF POSTERIOR POLYMORPHOUS DYSTROPHY

The pathogenesis of posterior polymorphous dystrophy was analyzed by i mmunohistologic methods. Sections of corneal buttons from two patients undergoing transplantation owing to posterior polymorphous dystrophy were stained with 2B4.14.1, a monoclonal antibody that reacts with hum an corneal endothelium, and with a cocktail of antihuman cytokeratin m onoclonal antibodies that do not react with normal corneal endothelium . Single-stained sections revealed a variegated, intermittent staining pattern of antibody reactive and nonreactive cells. Double-stained se ctions revealed some cells that stained with only one of the antibodie s and many cells that stained with both antibodies. The presence of ce lls staining positively for both 2B4.14.1 antigen and cytokeratins sup ports the hypothesis that the cytokeratin-expressing epithelial-like c ells found in corneas with posterior polymorphous dystrophy arise via a metaplastic process in which the phenotype of endothelial cells beco mes progressively abnormal.