Bronchiolitis obliterans and airways obstruction associated with graft-versus-host disease.

Bronchiolitis obliterans is a nonspecific pathologic lesion seen after fume inhalation and infections, which is associated with connective tissue disorders and is a complication of organ transplantation. Bronchiolitis obliterans with organizing pneumonia is also associated with the connective tissue disorders but is usually idiopathic and has better prognosis with corticosteroid therapy. Bone marrow-related obliterative bronchiolitis is limited to patients who develop chronic graft-versus-host disease. Symptoms begin with cough in 3 to 6 months and progress to dyspnea and severe airflow obstruction. The roentgenogram is normal or shows hyperinflation. Prognosis is poor and most patients develop disabling irreversible airflow obstruction. Bronchiolitis obliterans is the most important clinical complication in heart-lung transplant recipients. It is not preceded by typical features of chronic graft-versus-host disease, but has the same clinical course of dyspnea, airflow obstruction, and poor response to therapy. Bronchiolitis obliterans in transplant recipients may represent a form of allograft rejection.