Large granular lymphocytes in bronchoalveolar lavage fluids from immunocompromised patients with cytomegalovirus pneumonitis.

Natural killer (NK) cells activities had been demonstrated to be depressed in patients with fatal cytomegalovirus (CMV) pneumonitis. NK cells can be identified by morphologic features characteristic of large granular lymphocytes (LGLs). Bronchoalveolar lavage (BAL) cells from 16 immunocompromised patients with CMV pneumonitis were analyzed. Two different groups of patients could be distinguished depending on the course of the CMV pneumonitis: nine patients who recovered (Group A), seven patients with a fatal outcome (Group B). Except for the increase in polymorphonuclear cells (PMN) in Group B (12.4 +/- 11.6%), no significant difference in the macrophage or the total lymphocyte population was observed. A differential count excluding alveolar macrophages specified the percentage of LGLs from the total lymphocyte population. The LGLs in Group A (7.1 +/- 9.9%) were similar to those previously reported in normal lung. A significant increase in LGLs was observed in the BAL cells from patients of Group B (28.1 +/- 22%). The discrepancy between the high percentage of LGLs in patients with a fatal outcome and their expected protective effects is discussed.