[Activated eosinophils in vernal keratoconjunctivitis].

A recent study showed that eosinophil basic proteins in eosinophil granules tend to cause severe lesions in allergic disease. Eosinophil cationic protein (ECP) (an eosinophil basic protein), released from activated eosinophils, damages the epithelial mucosa. Vernal keratoconjunctivitis (VKC) always accompanies salient eosinophil infiltrations in the conjunctiva. To evaluate the role of activated eosinophils during VKC, we studied conjunctival specimens from VKC patients, using an immunohistochemical technique with monoclonal antibody (EG2) and electron microscope. We also determined ECP content in the patient tears. Immunocytochemical study showed a significant number of activated and degranulated eosinophils in the conjunctiva (giant papilla), including its epithelia and subepithelial tissue. Electron microscopy showed that the tear mucoid layer contained a number of exfoliated conjunctival epithelial cells with eosinophil granules. ECP content in the tears of these patients was 1361.4 +/- 1053.4 ng/ml, significantly higher than that of a normal subjects (< 20.0 ng/ml) (p < 0.01). These results suggest that the activated eosinophils and ECP contribute to the development of the lesion during VKC.