Multifunctional Analysis of CD4+ T-Cell Response as Immune-Based Model for Tuberculosis Detection

Area of Science:

• Immunology
• Infectious Diseases
• Tuberculosis Research

Background:

• Accurate detection of active tuberculosis (TB) and latent TB infection (LTBI) is crucial for disease control.
• Current diagnostic methods have limitations in differentiating active disease from latent infection.

Purpose of the Study:

• To evaluate mono- and multifunctional CD4(+) and CD8(+) T-cell responses for improved immune-based detection of active TB and LTBI.
• To assess the potential of T-cell cytokine profiles in distinguishing between TB infection states.

Main Methods:

• Flow cytometry was used to analyze cytokine production (IFN-γ, TNF-α, IL-2) by T cells stimulated with TB antigens.
• The study included 28 TB-infected subjects (18 active TB, 10 LTBI) and 10 uninfected controls.
• Single-cell cytokine analysis was performed on CD4(+) and CD8(+) T cells.

Main Results:

• CD4(+) T-cell cytokine production was significantly higher in TB-infected subjects compared to controls (P < 0.0001).
• A cut-off of >0.45% for activated CD4(+) T cells producing any of three cytokines differentiated TB-infected from uninfected individuals.
• Multifunctional CD4(+) T cells (producing all 3 cytokines) were lower in active TB than LTBI subjects (P = 0.003), allowing differentiation with a cut-off <0.182%.

Conclusions:

• Multifunctional CD4(+) T-cell responses show potential for identifying individuals without TB infection, as well as those with active or latent TB at a single time point.
• CD8(+) T-cell responses did not differ significantly between active TB and LTBI groups.
• This T-cell based assay could offer a valuable tool for TB diagnosis and management.