CD4+CXCR5+ follicular helper T cells in salivary gland promote B cells maturation in patients with primary Sjogren's syndrome.

OBJECTIVE: To examine amount of CD4+CXCR5+Tfh cells and B cells subsets in salivary gland and peripheral blood from patients with primary Sjogren's syndrome (pSS) and to analyze whether the frequency of CD4+CXCR5+Tfh cells is associated with pSS pathologic process.

METHODS: The percentages of CD4+CXCR5+Tfh cells and B cell subsets were examined by flow cytometry. B-lymphocyte chemoattraetant (BLC; also called CXCL13), IL-21, IL-6 from the serum of pSS patients was assessed by polymerase chain reaction-enzyme-linked immunosorbent assay (ELISA).

RESULTS: The percentages of CD4+CXCR5+Tfh cells in peripheral blood were increased in pSS patients, but decreased after treatment with glucocorticoid and/or immunosuppressive drugs. Abnormal B cell subsets appeared in salivary and peripheral blood of pSS patients. The frequency of salivary CD4+CXCR5+Tfh cells was positively correlated with CD19+CD27+ memory B cells and CD19+CD27high plasma cells. Also increase of salivary CD19+CD27high plasma cells was positively associated with serum ANA titer of pSS patients.

CONCLUSIONS: CD4+CXCR5+Tfh cells are significantly increased in salivary and peripheral blood in pSS patients with aberrant CD19+CD27+ memory B cells and CD19+CD27high plasma cells, suggesting that CD4+CXCR5+Tfh cells may contribute to the pathogenesis of pSS by promoting the maturation of B cells.