Evaluation of regulatory T cells in obese asthmatic children

Background: Asthma is an airway inflammatory disorder with functional and structural changes. Regulatory T (T reg) cells are important in controlling immune responses. The study was aimed to investigate the frequency of Treg cells in obese asthmatic children, in comparison to nonobese asthmatics and healthy matched controls. Methods: In addition to anthropometric and body mass index (BMI) assessment, peripheral blood samples from healthy control subjects (n = 30) and asthmatic obese (n=30) and asthmatic non-obese children (n=30) were examined for serum IgE, eosinophils counts, and flowcytometric measurement of CD4+CD25+CD127 low/neg- T cells. Pulmonary function testing was performed for asthmatic children. Results: Obese asthmatics showed significantly higher levels of serum IgE and CD4+CD25+CD127 low/neg- T cells as compared to healthy controls (p<0.001, 0.001, respectively) while comparable numbers of T reg cells were found among obese and non-obese asthmatic children. Asthmatics receiving inhaled corticosteroids (ICS) showed higher percentages of CD4+CD25+CD127 low/neg- T cells than the non-receivers (median 11.8% vs 8.8%, p <0.001). No significant correlations were found between Treg and age, eosinophil percentage, total serum IgE, pulmonary functions, or BMI and its Z score. Conclusion: Our study demonstrates an increased frequency of Treg cells in asthmatic children compared to controls with possible association with the use of ICS but not with obesity. Small sample size and lack of obese nonasthmatic group are the main points of limitation in our study.