Extracellular deposition of eosinophil major basic protein in orbital histiocytosis X

The eye and the eosinophil

Recent work has highlighted the eosinophil's role as an effector cell in a wide array of disease entities, including parasitic infections and allergic and nonallergic diseases. The eosinophil is filled with granules containing toxic cationic proteins, capable of harming tissue when released to the extracellular space. In the eye, toxic eosinophil cationic granule proteins have been encountered in conjunctiva, cornea, tears, and contact lenses of patients suffering from ocular allergy, suggesting an effector role for the eosinophil in the ophthalmic manifestations of atopy. Laboratory investigations indicate that eosinophil granule major basic protein, the principal eosinophil granule protein, may adversely influence corneal epithelium, and promote corneal ulceration in the severest forms of ocular allergy. Further, the eosinophil may play a contributory pathophysiologic role in some nonallergic ophthalmic diseases such as Wegener's granulomatosis, orbital pseudo-tumor, and histiocytosis X. The eosinophil's morphologic, immunologic, and biochemical characteristics will be reviewed and its role in certain ophthalmic diseases thoroughly examined.

Eosinophil granule major basic protein deposition in corneal ulcers associated with vernal keratoconjunctivitis

An indirect immunofluorescence assay detected eosinophil granule major basic protein in the inflammatory debris covering deepithelialized cornea in two patients with vernal keratoconjunctivitis. A slight degree of non-specific fluorescence was present in the control autopsy corneas. High concentrations of the eosinophil granule major basic protein inhibit epithelial migration and protein synthesis, whereas low concentrations affect epithelial migration. The results suggest participation of eosinophil granule major basic protein in the ulcerative process.