1 Guy's Severe Asthma Centre, Guy's Hospital, Guy's & St Thomas' NHS Trust, London, United Kingdom; School of Immunology & Microbial Sciences, King's College London, United Kingdom.
2 Guy's Severe Asthma Centre, Guy's Hospital, Guy's & St Thomas' NHS Trust, London, United Kingdom.
3 Guy's Severe Asthma Centre, Guy's Hospital, Guy's & St Thomas' NHS Trust, London, United Kingdom; Department of Respiratory Medicine, St James' Hospital, Dublin, Ireland; School of Medicine, Trinity College Dublin, Dublin, Ireland.
4 Guy's Severe Asthma Centre, Guy's Hospital, Guy's & St Thomas' NHS Trust, London, United Kingdom; School of Immunology & Microbial Sciences, King's College London, United Kingdom. Electronic address: David.jackson@gstt.nhs.uk.