INCREASED SERUM LEVELS OL EOSINOPHIL CATIONIC PROTEIN AND EOSINOPHIL-DERIVED NEUROTOXIN (PROTEIN-X) IN VERNAL KERATOCONJUNCTIVITIS

Purpose: To evaluate whether the eosinophil preformed mediators, eosin ophil cationic protein X, and eosinophil-derived neurotoxin/eosinophil protein X (EDN/EPX) are detectable in serum and can be used as marker s of eosinophilic inflammation. Methods: A competitive radioimmunoassa y was used to detect serum levels of eosinophil cationic protein and E DN/EPX in 31 patients with vernal keratoconjunctivitis (VKC) and in 15 healthy controls. Results: Mean serum levels of both eosinophil catio nic protein and EDN/EPX were significantly higher in patients with VKC than in controls. There was a good correlation between serum levels o f eosinophil cationic protein and EDN/EPX. No significant difference i n mean serum eosinophil cationic protein levels was observed between p atients with positive radioallergosorbent test (RAST) results and thos e with negative RAST results who have VKC, whereas mean EDN/EPX and to tal immunoglobulin E serum levels were significantly higher in patient s with positive RAST results than in those with negative RAST results who have VKC. Serum eosinophil cationic protein, but not EDN/EPX, leve ls were significantly related to total immunoglobulin E levels. Conclu sion: The authors' data indicate that serum levels of eosinophil catio nic protein and EDN/EPX are useful markers of eosinophilic ocular infl ammation in VKC.