EOSINOPHIL CATIONIC PROTEIN (ECP) AND EOSINOPHIL PROTEIN-X (EPX) CONCENTRATIONS IN SERUM AND BRONCHIAL LAVAGE FLUID IN ASTHMA - EFFECT OF PREDNISOLONE TREATMENT

Background Eosinophil granule proteins may contribute to bronchial hyp erresponsiveness in asthma. Objective To measure eosinophil cationic p rotein (ECP) and eosinophil protein X (EPX) in serum and bronchial lav age fluid from 20 asthmatics and 16 control subjects. To assess the ef fect on these eosinophil proteins of corticosteroid treatment of asthm a. To determine whether serum ECP and EPX measured weekly in a longitu dinal study for 10 weeks reflected changes in lung function. Methods E osinophil granule proteins were measured by radioimmunoassay of bronch ial wash (BW), bronchoalveolar lavage (BAL) and serum. Results Eosinop hils were elevated in BAL (P < 0.01), BW (P < 0.01) and blood (P < 0.0 1) from asthmatics compared with control subjects. Eosinophil cationic protein concentration was significantly elevated in BAI, (P < 0.05) a nd BW from asthmatics (P < 0.01) and EPX was increased in BAL (P < 0.0 5) and BW (P < 0.01). These changes were also reflected in elevated se rum ECP (P < 0.01) and EPX (P < 0.01) concentrations in asthmatic subj ects. There was no significant difference between subjects receiving p rednisolone and the placebo group, but there was a fall in ECP in BW ( P < 0.05) and serum (P < 0.01) and in EPX in BW (P < 0.01) and serum ( P < 0.01) within the group receiving prednisolone. In the longitudinal study there was only a significant difference between ECP values asso ciated with highest and lowest peak expiratory flow rate (PEFR) (P < 0 .05). Conclusion These data confirm a role for eosinophil activation i n the airway in asthma pathogenesis, and add some support to the hypot hesis that corticosteroids may inhibit eosinophil activation in asthma .