The altered T cell landscape in Systemic Sclerosis patients is characterized by dysfunctional type 1 immunity

Area of Science:

• Immunology
• Autoimmunity
• T cell biology

Background:

• T cells in chronic autoimmune diseases often display dysfunction and exhaustion.
• Specific T cell subsets impacted by these changes in autoimmunity are not well understood.
• This study investigates T cell aberrations in Systemic Sclerosis (SSc) and Systemic Lupus Erythematosus (SLE) patients.

Purpose of the Study:

• To characterize T cell subset composition, phenotype, and function in SSc patients.
• To compare T cell landscapes in SSc and SLE patients against healthy controls.
• To identify specific T cell defects contributing to autoimmune pathology.

Main Methods:

• Developed a novel multidimensional flow-cytometry panel for T cell subset analysis.
• Utilized Optimized t-SNE and PhenoGraph algorithms for T cell landscape comparison.
• Assessed cytokine production via intracellular cytokine staining and performed transcriptomic analysis.

Main Results:

• Autoimmune patients showed altered T cell subset distribution and aberrant functional states.
• SSc and SLE patients had a significant deficiency in T-bet expressing CD8+ and CD4-CD8- T cells, exhibiting exhaustion.
• SSc patients displayed increased TIGIT+ Foxp3+ regulatory T cells and reduced IFN-γ production.

Conclusions:

• SSc patients possess a defective IFN-γ-producing T cell compartment.
• This defect may reduce anti-fibrotic T cell activity, promoting chronic fibrosis development.
• Findings highlight specific T cell dysfunctions in SSc relevant to disease pathogenesis.