Bronchiolitis obliterans with allogeneic hematopoietic cell transplantation: a 10-year experience of the Okayama BMT Group.

Bronchiolitis obliterans (BO) is a devastating complication of allogeneic hematopoietic stem cell transplantation (HSCT). We retrospectively studied 465 patients who underwent HSCT in the Okayama BMT Group between 2000 and 2009, and describe the detailed clinical features of 13 patients with BO. The 5-year cumulative incidence of BO was 3.43 %. The median time from transplantation to onset of BO was 15 months. In seven of the 13 patients, the primary symptom was only cough, indicating that cough was an important initial symptom for early diagnosis. The median duration from the onset of BO to the requirement of O2 supplementation was 13 months and the main cause of death was respiratory failure. History of chronic graft-versus-host disease was a significant risk factor. Furthermore, female recipients were at greater risk of BO than male recipients; however, no other previously reported risk factors were detected. It is currently difficult to prevent BO on the basis of the reported risk factors. A novel strategy for the early diagnosis and treatment of BO is required.