Changes in non-specific airway responsiveness and sputum cells during inhalation challenges with cleaning agents
| Positive SIC | Negative SIC | |||||
|---|---|---|---|---|---|---|
| Baseline | Postchallenge | p Value | Baseline | Postchallenge | p Value | |
| AHR to histamine | (n=17) | (n=12) | (n=27) | (n=25) | ||
| PC20, mg/mL | 1.4 (0.2–4.22) | 0.5 (0.4–3.0)* | 0.019 | 13.0 (1.4–32.0) | 16.9 (2.6–32.0) | 0.267 |
| PC20 >16 mg/mL† | 2 (12) | 0 | 13 (48) | 13 (52) | ||
| >Threefold decrease in PC20† | 5 (42) | 0 | ||||
| Sputum cell counts‡ | (n=13) | (n=13) | (n=7) | (n=7) | ||
| Total cell count, 106/mL | 0.54 (0.34–0.97) | 1.15 (0.53–2.17) | 0.041 | 0.34 (0.26–1.89) | 0.65 (0.38–1.81) | 0.735 |
| Eosinophils, 106 cells/mL | 0.02 (0.01–0.04) | 0.12 (0.02–0.39) | 0.006 | 0 (0–0.01) | 0 (0–0.01) | 0.345 |
| Eosinophils, % | 1.8 (0.8–7.2) | 10.0 (4.1–15.9) | 0.009 | 0.2 (0–2.5) | 0.8 (0.2–1.5) | 0.786 |
| Increase in eosinophils >2%† | 8 (62) | 0 | ||||
| Neutrophils, 106 cells/mL | 0.40 (0.17–0.70) | 0.71 (0.38–1.62) | 0.009 | 0.19 (0.16–1.70) | 0.34 (0.25–1.52) | 0.866 |
| Neutrophils,% | 57.3 (42.4–72.5) | 69.5 (56.9–83.0) | 0.152 | 60.3 (55.7–83.0) | 70.3 (52.5–84.0) | 0.866 |
Data are presented as median value with 25–75th IQR in parentheses unless otherwise specified.
*Histamine PC20 was measured at 7 h after the end of exposure in six participants and 24 h postexposure in six participants with positive SIC.
†Data expressed as n (% of available data).
‡Data available on participants who performed an SIC from 2006 onwards.
AHR, airway hyper-responsiveness; PC20, provocative concentration of histamine causing a 20% fall in FEV1; SIC, specific inhalation challenge.