Cytomegalovirus antigenemia in the differential diagnosis of pulmonary infiltrates after allogeneic bone marrow transplantation

For the differential diagnosis of pulmonary infiltrates after bone marrow transplantation, cytomegalovirus (CMV) antigenemia was evaluated in 9 episodes of pneumonia which developed in 7 allogeneic marrow transplant patients between 9 and 495 days after transplant. The diagnosis of lung infiltration was made based on clinical findings including histological, cytological or microbiological examinations using bronchoalveolar lavage fluid specimens, sputum or lung tissue. The CMV antigen-positive leukocytes were detected with a direct immunoperoxidase technique using a peroxidase-labeled monoclonal antibody (HRP-C7) against CMV immediate early antigen. The episodes included 2 CMV pneumonias, 1 pneumocystis carinii pneumonia, 1 adenovirus pneumonia, 1 bacterial pneumonia, 1 bacterial and fungal pneumonia, 2 idiopathic pneumonias and 1 capillary leak syndrome associated with hyper acute GVHD. The CMV antigenemia became positive only in two patients with CMV pneumonia and the number of CMV antigen-positive leukocytes exceeded 10 per 50000 WBCs. The CMV antigenemia test required only 24 hours to obtain results. These observations suggest that the detection of CMV antigenemia is of great value in the differential diagnosis of pulmonary infiltrates in marrow transplant patients.