[1] Univ Palermo, Cattedra Malattie Respiratoire, Palermo, Italy
[2] CNR, Ist Fisiopatol Respiratoria, Palermo, Italy
[3] Univ Nebraska, Med Ctr, Dept Internal Med, Omaha, NE 68182 USA
[4] McMaster Univ, Asthma Res Grp, Firestone Inst Resp Hlth, Hamilton, ON, Canada
[5] Univ Calif San Francisco, Div Pulm & Crit Care, Dept Med, San Francisco, CA 94143 USA
[6] Univ Calif San Francisco, Inst Cardiovasc Res, San Francisco, CA 94143 USA
[7] Univ Southampton, Gen Hosp, Southampton, Hants, England
[8] Leiden Univ, Med Ctr, Leiden, Netherlands