DEPRESSED PHAGOCYTOSIS AND OXIDATIVE BURST IN POLYMORPHONUCLEAR LEUKOCYTES FROM INDIVIDUALS WITH PULMONARY TUBERCULOSIS WITH OR WITHOUT HUMAN-IMMUNODEFICIENCY-VIRUS TYPE-1 INFECTION

Phagocytosis and oxidative burst in whole-blood granulocytes were asse ssed by flow cytometry with Phagotest and Bursttest kits, respectively . Seventy individuals were included in this study: 15 healthy, normal donors, 18 human immunodeficiency virus (HIV) type 1 (HIV-1)-seroposit ive patients, 19 patients with pulmonary tuberculosis (TB), and 18 pat ients co-infected with Mycobacterium tuberculosis and HIV-1 (TB-HIV). Granulocyte phagocytosis was assessed by incubating whole blood with f luorescence-labelled Escherichia coli and measuring the proportion of granulocytes with ingested bacteria and the capacity (fluorescence int ensity) of each cell to phagocytose E. coli. The percentage of granulo cytes converting nonfluorescent dihydrorhodamine to fluorescent rhodam ine 123 on production of reactive oxygen intermediates (ROIs) and the mean channel shift were assessed as a measure of oxidative burst. No d ifferences in the proportion of granulocytes that were capable of phag ocytosing or producing ROIs in response to E. coli were observed betwe en any of the study groups. Phagocytosis was significantly enhanced in granulocytes from HIV-1-infected individuals. On the other hand, gran ulocytes from individuals infected with M. tuberculosis alone or in co mbination with HIV-1 had a significantly reduced capacity to phagocyto se E. coli and to produce ROIs in response to E. coli as an agonist. T hese results provide evidence that granulocytes from individuals with pulmonary TB with or, without concomitant infection with HIV-1 have an impaired ability to phagocytose and to undergo oxidative burst, possi bly contributing to the enhanced susceptibility to opportunistic infec tions in these patients.