Eosinophil peroxidase: A new serum marker of atopy and bronchial hyper-responsiveness

Do markers of eosinophil activation differ in their ability to detect subjects with atopy or bronchial hyper-responsiveness (BHR)? Comparisons of serum levels of eosinophil peroxidase (S-EPO), of eosinophil cationic protein (S-ECP) and the blood eosinophil count (B-Eos) have been made between 154 subjects aged 20-44 years, participating in the European Community Respiratory Health Survey in Uppsala, Sweden. Subjects with atopy had significantly higher levels of S-EPO and S-ECP than those without atopy (P<0.001). Subjects with BHR had significantly higher levels of S-EPO (P<0.001) and B-Eos (P<0.01) than subjects without BHR. Persons reporting asthma-related symptoms had significantly higher levels of S-EPO and B-Eos than subjects without such symptoms (P<0.001 and P<0.01, respectively). Asthma symptom score correlated significantly to S-EPO (r=0.26, P<0.01), S-ECP (r=0.20, P<0.05) and B-Eos (r=0.18, P<0.05). Finally, S-EPO was significantly more sensitive than S-ECP for detecting subjects with BHR (P<0.05) and significantly more sensitive than B-Eos for detecting both subjects with BHR and subjects with a combination of atopy and BHR (P<0.05). It is concluded that S-EPO is a promising marker with a higher sensitivity for BHR than S-ECP or B-Eos. Further studies are needed to define the value of S-EPO when following disease activity.