Defective monocyte chemotaxis in pulmonary tuberculosis

Area of Science:

• Immunology
• Infectious Diseases

Background:

• Mononuclear phagocytes are vital for host resistance against mycobacterial infections.
• Human monocytes play a critical role in cellular immunity.

Purpose of the Study:

• To investigate the functions of human monocytes in patients with active pulmonary tuberculosis.
• To compare monocyte pinocytosis, phagocytosis, and chemotaxis in tuberculosis patients versus healthy controls.

Main Methods:

• Studied pinocytosis, phagocytosis, and chemotaxis of human monocytes.
• Compared functions in 15 active, untreated pulmonary tuberculosis patients and 32 controls.
• Investigated the role of plasma factors in monocyte dysfunction.

Main Results:

• No significant difference was observed in the pinocytic and phagocytic activity of monocytes between tuberculosis patients and controls.
• Monocytes from tuberculosis patients demonstrated significantly depressed chemotaxis compared to control monocytes (P = 0.000001).
• Plasma from tuberculosis patients inhibited the chemotaxis of control monocytes and chemotactic agents, suggesting a plasma factor's involvement.

Conclusions:

• Active pulmonary tuberculosis is associated with impaired monocyte chemotaxis.
• A plasma factor in tuberculosis patients may contribute to this chemotactic defect.
• The observed chemotaxis defect could impact the host's immune response to mycobacterial infections.