Hematopoietic stem cell transplant-related airflow obstruction

Purpose of review: Airflow obstruction is a rare but fatal complication following allogeneic hematopoietic stem cell transplantation. It is noninfectious, relatively late, and primarily affects small airways, ultimately leading to their obliteration. If airflow obstruction is consistent with obliteration histologically, the condition is often called bronchiolitis obliterans. This review of literature published recently evaluates progress made in this field. Recent findings: Changes reported in analysis of pulmonary function test results and their follow-up might be helpful to better manage bronchiolitis obliterans and to detect and treat it earlier. Graft-versus-host reaction possibly underlies the development of this fatal disease. Findings from high-resolution computed tomography might aid in the diagnostic process. Anti-inflammatory therapy, azithromycin and lung transplant might be an option to treat bronchiolitis obliterans. Summary: The pathomechanism of bronchiolitis obliterans remains unclear and it remains a fatal complication of hematopoietic stem cell transplantation. An appropriate model to study hematopoietic stem cell transplantation-related airflow obstruction, consensus diagnostic criteria, and prospective trials for treatment are necessary to overcome the challenge presented by bronchiolitis obliterans.