Secondary Corneal Amyloidosis Proving an Association with Lactoferrin

Abstract

Abstract: : Purpose: Secondary corneal amyloidosis rarely appears after chronic irritation from trichiasis. The origin of the amyloid protein localized in the cornea has not yet been sufficiently proven, although the precursor protein in lattice corneal dystrophy has been revealed to be mutant gelsolin. Lactoferrin is an iron-binding glycoprotein found in lacrimal fluid. We studied the association of lactoferrin with secondary corneal amyloidosis. Methods: Subepithelial nodular excrescent lesions in the lower center of the cornea were therapeutically taken from a young female patient who was clinically diagnosed with secondary corneal amyloidosis in the right eye due to trichiasis. Ocular and systemic examinations were performed. Histochemical studies and lactoferrin gene analysis were performed of the taken samples after obtaining informed consent. Results: The samples were confirmed as being amyloid with positive Congo red stain which emitted green light under polarized light, with the existence of amyloid fibrils noted under an electron microscope. No abnormalities were noted in the ocular examinations except for hyperopic astigmatism in the right eye, and there was no evidence of systemic amyloidosis either. Immunoreactivity of antibodies against human lactoferrin and serum amyloid P component was recognized. Lactoferrin gene analysis also revealed a Glu561Asp mutation. Conclusions: These results indicate that lactoferrin forms amyloid in the cornea especially in patients with lactoferrin gene mutation.

Keywords: degenerations/dystrophies • immunohistochemistry • gene/expression