Airway inflammatory response to ozone in subjects with different asthma severity

The aim of this study was to evaluate whether ozone exposure induces a simi lar airway inflammatory response in subjects with different degrees of asth ma severity, Two groups of asthmatic subjects were studied: seven with intermittent mild asthma not requiring regular treatment (group A); and seven with persisten t mild asthma requiring regular treatment with inhaled corticosteroids and long-acting beta(2)-agonists (group B), All subjects were exposed, in a ran domized cross-over design, to air or O-3 (0.26 parts per million (ppm) for 2 h with intermittent exercise); subjects in group B withdrew from regular treatment 72 h before each exposure. Before the exposure, and 1 and 2 h aft er the beginning of the exposure they performed a pulmonary function test, and a questionnaire was completed to obtain a total symptom score (TSS), Si x hours after the end of the exposure, hypertonic saline (HS) sputum induct ion was conducted, Sputum cell percentages, eosinophil cationic protein (EC P) and interleukin (IL)-8 concentrations in the sputum supernatant were mea sured. TSS significantly increased and forced vital capacity (FVC) and forced expi ratory volume in one second (FEV1) significantly decreased after O-3 exposu re in comparison with air exposure in group A, whereas no changes were obse rved in group B except for a significant decrement of FEV1 2 h after the be ginning of O-3 exposure. Sputum neutrophil percentage was significantly hig her after O-3 exposure than after air exposure in both groups (Group A: 70. 2% (28-87) versus 26.6% (8.6-73.2); Group B: 62.1% (25-82.4) versus 27.9 % (14.4-54)),IL-8 was higher in sputum supernatant collected 6 h after O-3 ex posure than after air, only in group A. No change due to O-3 has been found in sputum eosinophil percentage and ECP concentration in both groups, In conclusion, the degree of airway response to a short-term exposure to oz one is different in subjects with asthma of different severity, The availab le data do not allow elucidation of whether this difference depends on the severity of the disease or on the regular anti-inflammatory treatment.