Tph Cells Expanded in Primary Sjögren's Syndrome

Area of Science:

• Immunology
• Rheumatology

Background:

• Peripheral helper T (Tph) cells are CD4+ T cells involved in B-cell responses and antibody production.
• Their role in primary Sjögren's syndrome (pSS) pathogenesis remained unclear.

Purpose of the Study:

• To investigate the contribution of Tph cells in the development of pSS.
• To analyze Tph cell frequency, phenotype, and association with clinical parameters in pSS patients.

Main Methods:

• Flow cytometry was used to quantify Tph cells in blood from 60 pSS patients and 61 healthy controls.
• Expression of ICOS, MHC-II, IL-21, and chemokine receptors (CCR2, CCR5, CCR9) was analyzed on Tph cells.
• Tph cell presence and co-expression of markers were examined in labial gland biopsies.

Main Results:

• Patients with pSS exhibited significantly higher frequencies of circulating Tph cells compared to healthy controls.
• Tph cell counts correlated with disease activity scores (ESSDAI), IgG levels, ESR, IL-21, anti-SSA antibodies, and plasma cell markers.
• Tph cells in pSS patients showed increased expression of ICOS, IL-21, MHC-II, CCR2, and CCR5, and decreased CCR9 compared to Tfh cells.
• Tph cells and CCR2+/CCR5+ T cells were identified in the salivary glands of pSS patients.

Conclusions:

• Tph cells are enriched in both the peripheral blood and salivary glands of patients with pSS.
• The correlation of circulating Tph cells with disease activity suggests their significant role in the pathogenesis of pSS.