[1] Univ Nottingham, Div Epidemiol & Publ Hlth, Nottingham NG7 2RD, England
[2] Nottingham Resp Res Unit, Nottingham, England
[3] Univ Nottingham, Div Therapeut & Mol Med, Nottingham NG7 2RD, England
[4] Nottingham Univ Hosp NHS Trust, Dept Haematol, Nottingham, England
[5] Nottingham Univ Hosp NHS Trust, Dept Radiol, Nottingham, England