An immunohistochemical analysis and comparison of posterior polymorphous dystrophy with congenital hereditary endothelial dystrophy

Purpose. To evaluate the immunohistochemical profiles of the abnormal endothelial cells of posterior polymorphous dystrophy (PPMD) and congenital hereditary endothelial dystrophy (CHED). Methods. Formalin-fixed, paraffin-embedded sections of seven corneas with the diagnosis of PPMD (seven patients), six corneas with the diagnosis of CHED (four patients), and five control corneas were stained with hematoxylin-eosin. Adjacent histologic sections were stained with monoclonal antibodies that react with pancytokeratin, AE1/AE3, cytokeratin (CK) 7, CK 20, CAM 5.2, and epithelial membrane antigen. The immunoreactivity of the corneal endothelium was assessed by light microscopy. Results. The endothelial cells stained positive for pancytokeratin and CK 7 in seven of seven corneas of patients with PPMD and five of six corneas of patients with CHED; variable positivity was seen to AE1, AE3, and CAM 5.2. The endothelium was uniformly negative to staining by CK 20. The epithelium stained positive with pancytokeratin, AE1, and AE3. All control corneas were negative for pancytokeratin, CK 7, and CK 20. Conclusion. The abnormal endothelium in both PPMD and CHED expresses similar CKs, including CK 7, which is not present in normal endothelium or surface epithelium. This may indicate a shared developmental abnormality in these conditions, as previously suggested by ultrastructural studies and genetic mapping.