[1] Royal Prince Alfred Hosp, Dept Resp & Sleep Med, Sydney, NSW, Australia
[2] Univ Sydney, Sydney Med Sch, Sydney, NSW, Australia
[3] Royal Prince Alfred Hosp, Dept Rheumatol, Sydney, NSW, Australia
[4] Royal Prince Alfred Hosp, Dept Clin Immunol & Allergy, Sydney, NSW, Australia
[5] Princess Alexandra Hosp, Dept Resp Med, Brisbane, Qld, Australia
[6] South West Sydney Pathol Serv, Immunopathol Lab, Sydney, NSW, Australia