BRONCHO-BRONCHIOLITIS OBLITERANS AS A COMPLICATION OF BONE-MARROW TRANSPLANTATION - A CLINICOPATHOLOGICAL STUDY OF 8 AUTOPSY CASES

We identified eight patients with bronchiolitis obliterans (BO) in the autopsies of 81 bone marrow transplant (BMT) recipients. Rapidly prog ressive dyspnoea and cough were the main presenting symptoms in all ei ght patients, associated with overinflation and/or infiltrative opacit y seen on chest X-ray and obstructive disorder revealed by pulmonary f unction tests. Early lesions were characterized by epithelial loss and an inflammatory infiltrate containing foamy histiocytes with mild lum inal narrowing. Partial or total occlusion of the bronchiolar lumina b y fibrous connective tissue was the feature of late lesions. Both chan ges were coexistent in all cases. In one case, small bronchi with cart ilage were also affected by the obstructive process, showing bronchiti s obliterans, All eight patients showed non-obstructive broncho-bronch iolitis characterized by denuding of respiratory epithelium, mural oed ema and an inflammatory infiltrate in addition to BO, and these change s were also seen in 18 patients without BO. The submucosal glands of l arge bronchi and the trachea showed mucous retention and a mild inflam matory infiltrate in four of the eight patients. Coexistent infectious processes were seen in all cases, cytomegalovirus and Aspergillus bei ng the most frequent organisms, BO probably develops as an immunopatho logical event related to graft-versus-host disease (GVHD) during the i mpaired immune status phase of the post-BMT period, possibly initiated by infection. Bronchial gland involvement in chronic GVHD is one of t he factors responsible for this abnormal immune status.