[1] Guys Abd St Thomas NHS Fdn Trust, Royal Brompton & Harefield Clin Grp, Harefield Resp Res Grp, London, England
[2] Royal Papworth NHS Fdn Trust, Cambridge, England
[3] Guys & St Thomas NHS Fdn Trust, Interstitial Lung Dis Unit, Royal Brompton & Harefield Clin Grp, London, England
[4] Univ Southern Calif, Keck Sch Med, Hastings Ctr Pulm Res, Los Angeles, CA USA
[5] Univ Southern Calif, Keck Sch Med, Div Pulm Crit Care & Sleep Med, Los Angeles, CA USA