[1] Univ Calif San Francisco, San Francisco Gen Hosp, Dept Med, San Francisco, CA 94110 USA
[2] Univ Penn, Med Ctr, Div Pulm Allergy & Crit Care, Dept Med, Philadelphia, PA 19104 USA
[3] Duke Univ, Med Ctr, Div Pulm Allergy & Crit Care Med, Dept Med, Durham, NC 27710 USA
[4] Coalit Pulm Fibrosis, San Jose, CA 95118 USA
[5] Michaels Opin Res Inc, New York, NY 10012 USA
[6] Univ Colorado, Hlth Sci Ctr, Dept Med, Div Pulm Sci & Crit Care Med, Denver, CO 80262 USA