Diminished Interleukin-7 receptor expression on T-cell subsets in tuberculosis patients

Area of Science:

• Immunology
• Infectious Diseases
• Cell Biology

Background:

• T-cell immunopathology is central to human tuberculosis.
• Previous research linked acute tuberculosis to reduced T-cell sensitivity to Interleukin-7 (IL-7) and lower IL-7 receptor α-chain (IL-7Rα) expression.
• The specific T-cell subsets affected and the impact of disease severity and treatment remain to be fully elucidated.

Purpose of the Study:

• To characterize T-cell subsets impacted by tuberculosis.
• To investigate the influence of tuberculosis disease severity and treatment response on T-cell phenotype.
• To analyze IL-7Rα expression and T-cell markers in tuberculosis patients and controls.

Main Methods:

• Multi-colour flow cytometry was used to analyze blood samples from 89 tuberculosis patients and 47 controls in Ghana.
• T-cell markers and IL-7Rα expression were quantified.
• Mycobacterium tuberculosis sputum burden was monitored during treatment.

Main Results:

• Tuberculosis patients displayed lower IL-7Rα expression on both CD4+ and CD8+ T-cells compared to controls.
• Patients had increased proportions of naïve T-cells and decreased proportions of memory CD4+ T-cells.
• A subset of CD27+ central memory T-cells (Tcm) lacking IL-7Rα expression was enriched in tuberculosis patients.

Conclusions:

• Tuberculosis is associated with generally impaired generation of memory CD4+ T-cells.
• An enrichment of IL-7Rα-negative Tcm cells occurs in tuberculosis patients.
• IL-7Rα expression patterns showed high variability and were not clearly associated with M. tuberculosis sputum burden or treatment response.