Toxic eosinophil granule protein deposition in corneal ulcerations and scars associated with atopic...

Recurrent or persistent corneal erosions and ulcerations are typical complications of atopic keratoconjunctivitis. Toxic eosinophil granule proteins such as major basic protein (MBP) and eosinophil cationic protein (ECP) may be involved in this pathogenetic process. This study was designed to demonstrate the presence of toxic eosinophil granule proteins in corneal tissue from a patient with corneal complications of atopic keratoconjunctivitis.

Observational case report.

Three corneal buttons of a patient with atopic keratoconjunctivitis associated ulcerations or scarring were examined by light microscopy and by immunofluorescence technique.

A linear deposition of eosinophil granular substance was detected subepithelially above Bowman's membrane in all corneal buttons. Indirect immunofluorescence identified this material as MBP and ECP. The deposits were not limited to the area of ulceration, but were also found underneath intact corneal epithelium. Multiple eosinophils were present in the upper corneal stroma. Normal corneas and negative control sections of the pathologic buttons revealed only minimal nonspecific staining at the surface of the epithelium.

Both MBP and ECP are known to affect human corneal epithelial cell viability and morphology in vitro. Moreover, MBP was shown to inhibit epithelial migration and protein synthesis. These toxic eosinophil proteins may also be responsible for corneal instability, recurrent and persistent corneal epithelial defects and ulcerations in patients with atopic keratoconjunctivitis.