An Experimental Model of Idiopathic Pneumonia Syndrome After Bone Marrow Transplantation: I. The Roles

Idiopathic pneumonia syndrome (IPS) refers to diffuse, noninfectious pneumonia that occurs after allogeneic bone marrow transplantation (BMT). We have developed a model of IPS using a well-characterized murine BMT system (B1O.BR -+ CBA) in which lung injury after BMT can be induced by minor histocompatibility (H) antigenic differences between donor and hest. Lung pathology and broncho-alveolar lavage (BAL) fluid were analyzed in transplant recipients before and after both syngeneic and allogeneic BMT. At 2 weeks after BMT, no specific pathologic abnormalities were noted; at 6 weeks, both pneumonitis and mononuclear cell infiltration around vessels and bronchioles were observed only in mice receiving allogeneic BMT. This injury was associated with elevated BAL fluid levels of endotoxin (lipopolysaccharide [LPSI), neutrophils, and tumor necrosis factor a.