1 Department of Allergy, Guy's and St Thomas' NHS Foundation Trust, London, United Kingdom; Division of Rheumatology and Clinical Immunology, Department of Medicine, Queen Mary Hospital, University of Hong Kong, Hong Kong.
2 Department of Allergy, Cambridge University Hospitals NHS Foundation Trust, Cambridge, United Kingdom.
3 Department of Respiratory Diagnostics, Medical University of Bialystok, Bialystok, Poland.
4 Department of Allergy, Guy's and St Thomas' NHS Foundation Trust, London, United Kingdom. Electronic address: chris.rutkowski@gstt.nhs.uk.