T cells in systemic sclerosis: a reappraisal

Area of Science:

• Immunology
• Pathogenesis of Systemic Sclerosis (SSc)
• Fibrosis Research

Background:

• Systemic sclerosis (SSc) is an autoimmune disease marked by inflammation and excessive extracellular matrix deposition, leading to organ damage.
• T cells are implicated in SSc pathogenesis, evidenced by their presence at fibrotic sites and altered blood frequencies.

Purpose of the Study:

• To review the role of T cells in SSc pathogenesis.
• To examine profibrotic mediators secreted by Th2 cells (IL-4, IL-6, IL-13) and their interaction with fibroblasts.
• To explore therapeutic strategies targeting T-cell mediators to inhibit fibrosis.

Main Methods:

• Review of existing literature on T cell roles in SSc.
• Analysis of profibrotic cytokine functions (IL-4, IL-6, IL-13).
• Examination of T cell-fibroblast interactions in fibrosis.

Main Results:

• Th2 cells secrete key profibrotic mediators (IL-4, IL-6, IL-13) that promote extracellular matrix deposition by fibroblasts.
• IL-6 drives fibrosis and promotes the switch of regulatory T cells (Tregs) to Th17 cells, perpetuating fibrosis.
• Targeting IL-6 can limit fibrosis and suppress Treg to Th17 cell differentiation.

Conclusions:

• T cells, particularly Th2-polarized cells, and their secreted cytokines directly induce fibrosis in SSc.
• Therapeutic strategies targeting these cytokines may be effective for SSc and other inflammatory fibrotic conditions.