Corneal amyloidosis complicated by trichiasis. Immunohistochemical identification of the amyloid light chain protein

Purpose: To identify the amyloid protein of the corneal amyloidosis complicated by trichiasis.Methods: The two patients were 41-year-old and 38-year-old women with trichiasis. They had gelatinous drop-like corneal change in the hemilateral eye. The lesion was excised and examined by light and electron microscopy. Additionally, we performed an immunohistochemical study with immunofluorescence techniques using cryosections.Results: The amyloid deposits were confirmed with light and electron microscopy. Congo red positive staining was not reduced following pretreatment with potassium permanganate. Immunohistochemically, amyloid deposits in the cornea stained positively with serum human light chain kappa and lambda. Pretreatment of the section with 0.05% Tween-20 did not decrease the staining with fluorescence. The deposits stained negatively with serum prealbumin and keratin antibodies.Conclusions: These findings indicate the protein of the corneal amyloidosis complicating trichiasis to be an amyloid light chain (AL) protein that has never been identified in this kind of corneal amyloidosis.