Eosinophil Cationic Protein in Nasal Secretions and Blood Serum in Grass-Pollen Allergic Rhinitis

Concentration of the Eosinophil Cationic Protein (ECP) measured in different body fluids has been demonstrated to be a good marker of eosinophilic inflammation. In allergic asthma, ECP levels in both broncho-alveolar-lavage (BAL) fluid and serum can be used to monitor disease activity. In allergic rhinitis, the value of ECP determinations in serum and nasal secretions was not directly compared, so far. In the present study, ECP levels in blood serum (Se) and nasal secretions (NS) of grass pollen allergic and healthy individuals under pollen exposure were analyzed. Forty-three grass-pollen allergic subjects and 19 healthy volunteers were included. Grass-pollen counts were measured using Burkhard traps and a symptom scoring performed. In the allergic subjects, the mean ECP concentration in nasal secretions was 789 ± 515 ng/mL compared with 12.1 ± 7.4 ng/mL in serum; in the healthy volunteers it was 29.6 ± 15.4 ng/mL in NS compared to 9.4 ± 6.9 ng/mL in Se. ECP concentration in NS was significantly higher in allergic than in healthy subjects (P < 0.001) and in both significantly higher than in Se (P < 0.01). ECP concentration in Se did not differ significantly in patients and healthy volunteers (P > 0.05). In the allergic subjects, ECP concentration in NS but not in Se was closely correlated to symptom score and pollen exposure. We conclude that ECP levels in NS are a better marker of eosinophilic inflammation in allergic rhinitis than ECP serum levels.