[The study of the relationship between serum eosinophil cationic protein and bronchial responsiveness in the patients with bronchial asthma].

Eosinophil cationic protein (ECP) has been expected as an index of eosinophilic inflammation in bronchial asthma. However, there are many questions about the clinical meaning of the serum ECP, yet. To examine that problem, we measured serum ECP levels in healthy subjects and the asthmatics patients, with and without attack. We also studied the relationship between bronchial responsiveness and serum ECP levels in the asthmatics patients without attack. Patients taking any steroids (including inhaled steroid), anti-allergic agents or cigarettes were excluded. The highest levels of ECP were found in serum sampled from the patients with asthma attack. The levels of the patients without attack were lower, and the levels of the healthy subjects were the lowest of all. To study the relationship between serum ECP and bronchial responsiveness in the asthmatics patients, who had not an asthma attack for at least one week, serum was sampled and simultaneously bronchial responsiveness (Dmin) was measured by Astograph. The serum ECP levels correlated negatively with Dmin, a threshold-type index of bronchial responsiveness (r = -0.569, p < 0.01). These data indicate that between attacks of bronchial asthma, bronchial responsiveness is related to the levels of serum ECP, and that during attacks the level of serum ECP increases further. They also suggest that abnormally high levels of serum ECP are associated with a preattack state in patients with bronchial asthma.