Pathogenic role of circulating CD4⁺CXCR5⁺ cell subpopulations in patients with chronic spontaneous urticarial

Area of Science:

• Immunology
• Dermatology
• Allergy

Background:

• Circulating CD4+CXCR5+ T cells, including follicular helper T (Tfh) and follicular regulatory T (Tfr) cells, are crucial for immune homeostasis and humoral responses.
• These cells have been implicated in the pathogenesis of various autoimmune and inflammatory diseases.

Purpose of the Study:

• To investigate the correlation between the frequencies of CD4+CXCR5+ T cells, Tfh cells, Tfr cells, and the Tfh/Tfr ratio with disease activity in chronic spontaneous urticaria (CSU).

Main Methods:

• Flow cytometry was used to analyze the frequencies of CD4+CXCR5+ T cells, Tfh cells, and Tfr cells in peripheral blood mononuclear cells (PBMCs) from CSU patients and healthy controls.
• CXCR5 expression, plasma cytokine levels (IL-4, IL-6, IL-21), and total IgE levels were measured.
• Receiver operating characteristic (ROC) curve analysis was employed to assess the correlation between cell frequencies/levels and the urticaria activity score (UAS).

Main Results:

• CSU patients exhibited elevated frequencies of CD4+CXCR5+ T cells and Tfh cells, as well as higher Tfh/Tfr ratios, compared to healthy controls.
• CXCR5 expression was significantly higher in PBMCs of CSU patients.
• Plasma IL-4 and IL-6 levels were elevated in CSU patients and positively correlated with total IgE, while IL-21 levels were lower and negatively correlated with total IgE.
• The UAS showed a positive correlation with CD4+CXCR5+ T cell frequency, Tfh cell frequency, Tfh/Tfr ratio, and total IgE levels.

Conclusions:

• Circulating CD4+CXCR5+ T cells and Tfh cells are abnormally frequent in CSU patients.
• These cell populations and their ratio are positively correlated with disease severity (UAS).
• The findings suggest a potential role for these T cell subsets in the immunopathogenesis of CSU.