Mononuclear cell reconstitution in the lung after marrow transplantation. Lack of influence of cytomegalovirus pneumonia, irradiation, and graft-versus-host disease.

The number and types of mononuclear cells obtained by bronchoalveolar lavage from 105 marrow transplant patients with and without cytomegalovirus pneumonia were studied to determine whether: (1) CMV pneumonia was associated with local recruitment of lymphocytes and lymphocytes of particular subtypes to the lung, and (2) whether local recruitment was affected by the known risk factors for the development of CMV pneumonia, namely acute graft-versus-host disease and total body irradiation. Results showed a significant increase in the number of lymphocytes (P = 0.014) and in the number of lymphocytes marking for CD8 (P = 0.0045) and CD16 (P = 0.052) in BAL from all patients compared with BAL from normal subjects. However, no significant differences were observed in BAL cellular characteristics between patients with and without pneumonia nor between patients with CMV or other etiologies of pneumonia. There were also no significant differences in BAL characteristics when patients were analyzed for the presence of acute GVHD, the use of TBI, or the type of transplant. These results do not provide evidence for local recruitment of lymphocytes to the lung unique of patients with CMV pneumonia nor to patients with GVHD and CMV pneumonia, in contrast to what is observed in murine CMV pneumonia.