Idiopathic interstitial pneumonia following bone marrow transplantation: The relationship with total body irradiation

Interstitial pneumonia is a frequent and often fatal complication of allogenic bone marrow transplantation. Thirty to 40 percent of such cases are of unknown etiology and have been labelled as cases of idiopathic interstitial pneumonia. Idiopathic cases are more commonly associated with the use of total body irradiation; their occurrence appears to be independent of immunosupression or graft versus host disease. Evidence is presented from the literature suggesting that the development of idiopathic interstitial pneumonia is related to the absolute absorbed dose of radiation to lung. The similarity of idiopathic pneumonia to radiation paeumonitis seen in a different clinical setting is described.