MSFinals-5762
A 67-year-old man, who had recently undergone a full bone marrow transplantation for acute myeloid leukaemia (AML), presented with progressive dyspnoea over the past 2 weeks. He also had a dry cough, but no fever. During examination, scattered wheeze and some expiratory high-pitched sounds were observed. The C-reactive protein (CRP) level was normal, and the Mantoux test was negative. Spirometry results showed a Forced expiratory volume in 1 second (FEV1) of 51%, Forced vital capacity (FVC) of 88%, and FEV1/FVC of 58%. What is the most likely diagnosis?