Defective monocyte chemotaxis in pulmonary tuberculosis.

Because mononuclear phagocytes are crucially involved in the host resistance to mycobacterial challenge, various functions of human monocytes (i.e. pinocytosis, phagocytosis and chemotaxis) were studied in 15 patients with active, untreated pulmonary tuberculosis and in 32 controls. There was no difference in the pinocytic and phagocytic activity of tuberculous and control monocytes. In contrast, tuberculosis monocytes showed depressed chemotaxis compared with control monocytes (P = 0.000001). This defect may be related to a plasma factor, since tuberculous plasma inhibited the chemotaxis of control monocytes as well as the activity of chemotactic agents.