Regulatory T cell dysfunction in subjects with common variable immunodeficiency complicated by autoimmune disease

Area of Science:

• Immunology
• Clinical Medicine
• Cell Biology

Background:

• Common variable immunodeficiency (CVID) is a primary immunodeficiency often associated with an increased risk of autoimmune diseases, affecting approximately 25% of patients.
• The precise mechanisms linking CVID and autoimmunity remain incompletely understood, necessitating further investigation into immune dysregulation.
• Regulatory T cells (Tregs) play a critical role in maintaining immune tolerance and preventing autoimmunity.

Purpose of the Study:

• To investigate potential alterations in regulatory T cell (Treg) function and phenotype in CVID subjects.
• To determine if impaired Treg function correlates with the presence and severity of autoimmune disease in CVID patients.
• To identify specific molecular markers associated with Treg dysfunction in the context of CVID and autoimmunity.

Main Methods:

• Analysis of T cell and B cell subsets in CVID subjects and healthy controls (HC).
• Functional assessment of regulatory T cells (CD4+CD25hiCD127lo) using standard suppression assays.
• Flow cytometry was employed to quantify the expression of key Treg-associated proteins (FoxP3, Granzyme A, XCL1, pSTAT5, GITR).

Main Results:

• Treg suppressive function was significantly attenuated in CVID subjects with autoimmune disease (CVID w/ AI) compared to CVID subjects without autoimmune disease (CVID w/o AI) and HC.
• Expression levels of proteins crucial for Treg function, including FoxP3, Granzyme A, XCL1, pSTAT5, and GITR, were significantly reduced in Tregs from CVID w/ AI subjects.
• A significant correlation was observed between the intracellular mean fluorescence intensity (MFI) of FoxP3, Granzyme A, and pSTAT5 in Tregs and the degree of Treg dysfunction.

Conclusions:

• Attenuation of regulatory T cell function is demonstrably associated with autoimmune disease in CVID subjects.
• Impaired Treg suppressive capacity and altered protein expression may contribute to the pathogenesis of autoimmunity in CVID.
• These findings highlight Tregs as a potential therapeutic target for managing autoimmune complications in CVID.