[1] Christchurch Hosp, Dept Allergy Immunol & Rheumatol, 2 Riccarton Ave, Christchurch 8053, New Zealand
[2] Mayo Clin, Coll Med, Div Pulm & Crit Care Med, Rochester, MN USA
[3] Christchurch Hosp, Resp Dept, Christchurch, New Zealand
[4] Mayo Clin, Coll Med, Div Rheumatol, Rochester, MN USA
[5] Mayo Clin, Coll Med, Dept Hlth Sci Res, Rochester, MN USA