Evaluation of Regulatory B10 Cells in Common Variable Immunodeficiency Patients with and without Autoimmunity

Common variable immunodeficiency disease (CVID) is the most prevalent symptomatic inborn errors of immunity, determined by defective B cell function, impaired antibody production, and susceptibility to frequent respiratory infections, enteropathy, autoimmunity, and malignancy. Due to the importance of autoimmunity in CVID and the probable role of regulatory B lymphocytes, we aimed to determine the frequency of B10 cells in CVID patients with and without autoimmunity. A total of 24 CVID patients and 12 healthy controls were enrolled in the study. Patients were divided into two equal groups, with and without autoimmunity. Peripheral blood cells were stained with monoclonal antibodies (mAbs) to identify CD24hiCD38hi B cells, CD27int CD38+ (plasmablasts), and CD24hiCD27+ B cells by flow cytometry. The percentages of B10, CD24hiCD27+ and CD27int CD38+ cells were significantly lower in total CVID patients, CVID patients with autoimmunity and CVID patients without autoimmunity compared to healthy controls (mean±standard deviation (SD) percentage of B10 cells: 6.36±9.21(total CVID), 2.81±5.00 (CVID with autoimmunity), and 3.25±3.5 (CVID without autoimmunity) vs. 13.02±12.45 (healthy controls); CD24hiCD27+ cells: 2.39±3.89, 3±5.20 and 1.78±1.94 vs. 20.38±14.27; CD27int CD38+ cells: 6.80±18.49, 7.40±20.24 and 6.20±17.45 vs. 11.84±5.71). CVID patients without autoimmunity had a higher percentage of CD24hiCD38hi cells than CVID patients with autoimmunity (4.73±4.14 vs. 2.62±5.02). The defect of regulatory B cells plays a significant role in the pathogenesis of autoimmunity in CVID. Further multicenter studies with higher sample sizes are suggested to determine the role of Breg cells in the clinical course of autoimmunity.