Birgitta Versluijs

13 Introduction 1 Pulmonary complications of hematopoietic cell transplantation Pulmonary complications, both infectious and non-infectious occur in 25-50% of HCT recipients and are associated with high rates of morbidity and mortality. Pulmonary com- plications thus are an important limitation for successfull HCT. Infectious lung problems can be either viral (common respiratory viruses, CMV, Ade- novirus), bacterial or fungal. Other opportunistic infections, like Pneumocystis jiroveci also need to be considered. Infections can occur throughout the HCT course because of impaired immunity due to the procedure itself or by IS therapy (long) after HCT. Because of improved diagnostic techniques and management of infectious pulmonary problems, non-infectious conditions have become relatively more important over time. 12-14 Non-infectious complications after HCT can roughly be subdivided in early and late complications (Figure 2). FIGURE 2. Schematic overviewof allo-immunemediated lung syndromes (allo-LS) in relation to HCT. Abbreviations: DAH, diffuse alveolar hemorrhage; PERDS, peri-engraftment respira- tory distress syndrome; IPS, idiopathic pneumonia syndrome; COP, cryptogenic organizing pneumonia; BOS, bronchiolitis obliterans syndrome.