Table 2.

Controlled human exposure studies in patients with obstructive airway diseases.

Study	Subject (number)	Design	Particles	Results
Gong et al [26]	Healthy volunteers (12) Patients with mild asthma (12)	Crossover	Filtered air, Fine CAPS (174 μg/m3)	CAPS induced modest and similar increases in parasympathetic stimulation of HRV in both groups
Gong et al [42]	Healthy elderly, age (6) Elderly patients with COPD (13)	Crossover	Filtered air, Fine CAPS (200 μg/m3)	Decrease in HRV in healthy elderly but not in COPD patients
Frampton et al [40]	Healthy volunteers (40), Patients with asthma (16)	Crossover	Filtered air Ultrafine carbon particles (10, 25 and 50 μg/m3)	In healthy subjects, reduced CD54 and CD18 on monocytes; decreased CD18 and CD49d on granulocytes; decreased CD25 in blood monocytes, basophils, and eosinophils; increased lymphocyte expression of CD25. In asthma, reduced CD11b on monocytes and eosinophils, CD54 on granulocytes, the percentage of CD4+ T cells, basophils, and eosinophils
Piatropaoli et al [41]	Healthy volunteers (40), Patients with asthma (16)	Crossover	Filtered air Ultrafine carbon particles (10, 25 and 50 μg/m3)	No changes in airway eNO and total cell count/differentials in induced sputum; Increased percentage macrophages in the sputum of asthmatics; No changes in IL-6 and IL-8 in the sputum
Gong et al [67]	Healthy volunteers (4) Patients with mild asthma (12)	Crossover	Filtered air Coarse CAPS (157 μg/m3)	Decrease HR and PNN50 4 hours post-exposure
Stenfors et al [43]	Healthy volunteers (25) Patients with mild asthma (15)	Single-blind randomized crossover	Filtered air Diesel exhaust (PM10, 108 μg/m3)	Increased neutrophils, IL-8 and IL-6 in BAL fluid and P-selectin and VCAM-1 in bronchial biopsy, no difference between normal and asthmatics
Gong et al [44]	Healthy volunteers (14) Patients with mild asthma (17)	Crossover	Filtered air Ultrafine CAPS (100 μg/m3 or 145,000/cm3 particle counts	Decreased O2sat, FEV1 and low frequency power; no differences between normal and asthmatics