Increased cytotoxicity against cytomegalovirus-infected target cells by bronchoalveolar lavage cells from bone marrow transplant recipients with cytomegalovirus pneumonia.

Cytotoxic activity of bronchoalveolar lavage (BAL) cells from 23 bone marrow transplant recipients against CMV-infected fibroblast target cells was evaluated to determine if responses differed between patients with and without CMV pneumonia. Responses of BAL cells were also compared with responses of peripheral blood lymphocytes (PBLs). BAL cells from patients with CMV pneumonia had greater cytotoxicity than BAL cells from patients with non-CMV pneumonia (P = .008). Cytotoxicity of BAL cells was also increased, as compared with PBLs, from patients with CMV pneumonia (P = .008). Lymphocytes, not alveolar macrophages, were found to be the cytotoxic effector cells in studies using purified BAL populations. Depletion studies using Leu 11b and complement suggested that natural killer cells were responsible for the cytotoxic activity. These studies demonstrate that BAL cells from patients with CMV pneumonia after bone marrow transplant have increased cytotoxicity against CMV-infected target cells.