Evaluation of CD4+CD25+FOXP3+ regulatory T cells function in patients with common variable immunodeficiency

• Regulatory T cells number is decreased in CVID patients.
• Regulatory T cells inhibitory function is decreased in CVID patients.
• Tregs from CVID patients produce less IL-10 than those from healthy controls.

Common variable immunodeficiency (CVID) is one of the predominant antibody disorders where abnormalities in regulatory T cells (Tregs) may result in autoimmunity and chronic inflammation. To evaluate Tegs frequency and function, 13 CVID patients and 10 age- and sex-matched healthy volunteer were enrolled. The percentages of Tregs were calculated using flow cytomety method. For assessment of Treg function, Tregs were isolated and their suppressive functions were determined using Tregs suppression assay. The levels of immunoregulatory cytokines IL-10 and TGF-β produced by Tregs were also measured. Our results revealed that Tregs frequency (P < 0.001) and their suppressive functions (P < 0.001) were impaired in CVID patients. The level of TGF-β did not differ between CVID patients and controls (p = 0.09); while the amount of IL-10 was remarkably decreased in CVID patients (P = 0.007). Our findings suggest that disturbed Tregs frequency and their functional characteristics might account for aberrant immune responses observed in CVID patients.