Noninfectious pulmonary complications of hematopoietic stem cell transplant are currently more prevalent than infectious complications. Unfortunately, the pathophysiology basis is not completely understood. However, there is a string association with graft-versus-host disease for many of them. Therefore, an important component of their pathophysiology is likely an allo-immune response. There is much research that needs to be conducted to improve the less than optimal outcomes for these disorders
