Pneumonia in allogeneic stem cell transplantation recipients: a multicenter prospective study

Pneumonia is a common cause of mortality after allogeneic hematopoietic stem cell transplantation (allo-HSCT) but updated and prospective information is partial. The aim of this nationwide prospective study is to determine the current epidemiology, etiology, and outcome of pneumonia in allo-HSCT recipients. From September-2003 to November-2005, 112 episodes in 427 consecutive allo-HSCT recipients were included (incidence 52.2 per 100 allo-HSCT/yr), and 72 of them (64.3%) were microbiologically defined pneumonia. Bacterial pneumonia (44.4%) was more frequent than fungal (29.2%) and viral pneumonia (19.4%). The most frequent microorganisms in each group were: Escherichia coli (n = 7, 8.9%), Streptococcus pneumoniae (n = 4, 5.0%), cytomegalovirus (n = 12, 15.4%), and Aspergillus spp. (n = 12, 15.4%). The development of pneumonia and chronic graft-versus-host disease (GVHD) was associated with increased mortality after allo-HSCT, and the probability of survival was significantly lower in patients that had at least one pneumonia episode (p < 0.01). Pneumonia development in the first 100 d after transplantation, fungal etiology, GVHD, acute respiratory failure, and septic shock were associated with increased mortality after pneumonia. Our results show that pneumonia remains a frequent infectious complication after allo-HSCT, contributing to significant mortality, and provide a large current experience with the incidence, etiology and outcome of pneumonia in these patients.