Co-infection with Mycobacterium tuberculosis impairs HIV-Specific CD8+ and CD4+ T cell functionality

Area of Science:

• Immunology
• Infectious Diseases
• Virology

Background:

• Polyfunctional T cells, capable of producing multiple cytokines, are crucial for controlling viral infections like HIV.
• Coinfection with Mycobacterium tuberculosis (MTB) is common in HIV-positive individuals and can affect disease progression.

Purpose of the Study:

• To investigate the impact of MTB coinfection on the function of HIV-specific CD8+ and CD4+ T cells.
• To compare T cell function in individuals with HIV mono-infection versus HIV/MTB coinfection, including active TB and latent TB infection (LTBI).

Main Methods:

• Assessed cytokine secretion (IFN-γ, IL-2, TNF-α, IL-21, IL-17) from peripheral blood mononuclear cells (PBMCs) of 34 South African adults.
• Stimulated PBMCs with HIV Gag peptides and analyzed T cell responses using polychromatic flow cytometry.

Main Results:

• MTB coinfection was associated with significantly lower HIV-specific T cell function compared to HIV mono-infection.
• T cell dysfunction was more pronounced in individuals with active TB coinfection than in those with LTBI.
• These findings suggest a correlation between mycobacterial load and the degree of T cell functional impairment.

Conclusions:

• MTB coinfection, particularly active TB, diminishes the polyfunctional capacity of HIV-specific T cells.
• Impaired T cell function due to MTB coinfection may contribute to increased HIV disease progression.
• Restoring T cell function in coinfected individuals could be a therapeutic target for improving HIV control.