Eosinophil cationic protein in atopic dermatitis: changes of serum levels by the anti‐allergic agent ketotifen *

Abstract

AbstractBackground Eosinophil cationic protein (ECP) is a highly basic protein (pI over 11) with molecular weight ranging from 18.5 to 22 kDa, and is released upon eosinophil activation. ECP is stored in the eosinophil granules and has potent bactericidal, helminthotoxic, cytotoxic and neurotoxic effects. ECP levels in scrum and other body fluids are often elevated in allergic diseases and other inflammatory conditions and their measurement may give information regarding eosinophil involvement in a pathological process.Material and Methods We evaluated the scrum levels of eosinophil cationic protein (ECP), assayed using an ECP radioimmunoassay kit, and the effect of an anti‐allergic agent, ketotifen, which has a potent anti‐eosinophil activity, in atopic dermatitis (AD) patients. Serum ECP levels in AD patients correlated with the severity of AD as determined in clinical evaluations. Results In patients with severe and moderate AD, serum ECP levels were significantly higher (31.04 ± 3.35 μg/1, n= 32) than in non‐atopic controls (4.92 ± 1.06 μg/1, n= 16) (P < 0.001). However, no significant correlation was observed between serum ECP and IgE levels, or between serum ECP levels and peripheral eosinophil count. After a 4‐weck administration of ketotifen (1 mg; twice a day), in AD patients with serum ECP levels more than 20 μg/I (n= 14), serum ECP levels decreased significantly (from 44.17 ± 4.53 to 18.46 ± 3.35 μg/1, P < 0.05).Conclusion The results suggest that serum ECP levels are a useful indicator of AD activity and of the effect of anti‐allergic agents on eosinophil involvement in AD.