Lung transplant rejection: obliterative bronchiolitis

More centers are performing lung transplants for a variety of pulmonary conditions. Chronic rejection, manifested as obliterative bronchiolitis, is the most common cause of late death (greater than 6 months after transplant) in this population.

To review published literature on obliterative bronchiolitis to determine the current terminology and definition, pathophysiology, incidence, diagnosis, treatment, and outcome of this condition.

A MEDLINE search was done using the medical subject headings of bronchiolitis obliterans and lung transplantation. Studies were selected based on sample size and reporting of obliterative bronchiolitis statistics. Sources that were not data-based discussions also were selected if they were comprehensive reviews or provided insight into relevant issues.

Obliterative bronchiolitis terminology is not used consistently in the literature. It is an obstructive defect that affects the airways, causing progressive occlusion. Diagnosis is based on clinical findings or on histological analysis; early markers are sought, to aid in diagnosis. Incidence of obliterative bronchiolitis varies from 7% to 54%, with a mortality rate of 30% to 40%. Currently, enhanced immunosuppression is the treatment of choice, although research is being carried out to evaluate methods of inhibiting growth factor activity for use in future treatment strategies.

Obliterative bronchiolitis is a common complication in lung transplant recipients, and future research will focus on treatment and early diagnosis. Efforts are under way to standardize nomenclature and reporting of incidence and mortality rates.