[Pulmonary lesions following bone marrow graft. Study of 35 cases].

Lung biopsy of 35 patients with interstitial pneumonitis following bone marrow transplantation (BMT) have been studied histologically, ultrastructurally and by immunofluorescence. Among infectious diseases, cytomegaloviruses (CMV) are the more frequently found, whereas Pneumocystis carinii infections are more frequently found in immunocompromised hosts without BMT. CMV infections are related to severe chronic graft-versus-host disease in allogenic or mismatched BMT. Hemorrhagic pulmonary oedema and vascular damage might be the consequence of high doses of cyclosporin A or of disseminated intravascular coagulation. Granulomatous and fibrosing lesions corresponded in 2 cases to an eosinophilic pneumonitis and in 11 cases to an "idiopathic" diffuse interstitial pneumonitis. 2 patients had concomitant diffuse lung fibrosis, sclerotic plaques of the skin and Sjögren-like syndrome. The pulmonary and cutaneous scleroses had common features in the types of collagen and in the composition of the infiltrate. Both fibroses might result from a common pathogenic mechanism related to an immunologic conflict between the lymphocytes of the graft and the cells from the host tissues.