Circulating CD8+ T Cell Subsets in Primary Sjögren's Syndrome.

Area of Science:

• Immunology
• Autoimmune Diseases

Background:

• Primary Sjögren's syndrome (pSS) is an autoimmune disorder characterized by exocrine gland damage.
• CD8+ T lymphocytes are implicated in the pathogenesis of pSS, particularly through acinar injury.

Purpose of the Study:

• To investigate the imbalance of circulating CD8+ T cell subsets in patients with pSS.
• To analyze the relationship between CD8+ T cell subsets and clinical parameters in pSS.

Main Methods:

• Flow cytometry was used to enumerate CD8+ T cell maturation stages and 'polarized' subsets.
• Analysis included 34 pSS patients and 34 healthy controls, utilizing markers like CD62L, CD28, CD27, CD45RA, CD45, CXCR5, CCR6, CXCR3, and CCR4.

Main Results:

• pSS patients exhibited higher numbers of naive CD8+ T cells and lower proportions of effector memory CD8+ T cells compared to controls.
• A reduction in cytotoxic Tc1 CD8+ T cells and an elevation in regulatory Tc2 and Tc17 CD8+ T cells were observed in pSS patients.
• Tc1 cell subsets negatively correlated with disease markers (IgG, RF, Schirmer test, saliva flow), while Tc2 subsets showed a positive correlation.

Conclusions:

• Immune dysfunction in CD8+ T cells, specifically alterations in Tc1, Tc2, and Tc17 subsets, contributes significantly to the pathogenesis of primary Sjögren's syndrome.
• These findings highlight a potential role for CD8+ T cell subsets in pSS development and progression.