RESUMO
BACKGROUND: Common Variable Immunodeficiency (CVID) is a primary immunodeficiency characterized by an immunologic deficiency in immunoglobulin production. Regulatory T cells (Tregs) play a key role in preventing the development allergic disorders. p-STAT5 is a known factor for the function and survival of Tregs. This study aimed to investigate the number of Tregs and their p-STAT5 expression in allergic and non-allergic CVID patients. METHODS: Peripheral blood mononuclear cells (PBMCs) were isolated from 10 healthy volunteers, 10 allergic patients, and 16 CVID patients (allergic and non-allergic) using Ficoll density centrifugation. The percentage of Tregs in PBMCs was analyzed by flow cytometry. Tregs were also isolated from participants using an immunomagnetic separation method and p-STAT5 expression was evaluated in Tregs using flow cytometry. RESULTS: The results revealed that Treg percentage was significantly lower in the CVID patients than the control groups (healthy and allergic individuals) (p<0.001). There was a significant reduction in Treg percentage in allergic patients compared to healthy subjects (p<0.05). No significant difference in Treg percentage between allergic and non-allergic CVID patients was observed. The expression of p-STAT5 in Tregs was significantly lower in CVID patients than the control groups (p<0.001). In addition, the expression of p-STAT5 in Tregs of allergic patients was significantly decreased compared to healthy subjects (p<0.001). However, the deference of p-STAT5 level was not statistically significant between allergic and non-allergic CVID patients. CONCLUSION: These findings suggest that p-STAT5 signaling defect and decreased Treg number may not participate in the development of allergy in CVID patients.