[1] Seoul Natl Univ, Coll Med, Div Pulm & Crit Care Med, Dept Internal Med, Seoul 110744, South Korea
[2] Seoul Natl Univ, Coll Med, Lung Inst, Med Res Ctr, Seoul 110744, South Korea
[3] Seoul Natl Univ, Coll Med, Div Rheumatol, Dept Internal Med,Med Res Ctr, Seoul 110744, South Korea