Peripheral glucocorticoid sensitivity in children with controlled persistent asthma

Background: Persistent asthma in children is a chronic inflammatory disease and glucocorticoids (GCs) are currently recognized as the mainstay of therapy. Clinical and in vitro steroid resistance has been demonstrated in severe asthma. However, GC insensitivity has not been studied in children with controlled persistent asthma. Objectives: To analyze peripheral blood mononuclear cell (PBMC) sensitivity to GC in children (6-15 years) with persistent asthma and healthy controls. Methods: Children with persistent asthma were selected and lung function and skin-prick tests were performed in all studied asthmatic children. PBMCs were isolated and cultured in vitro to assess mitogen-induced proliferation and cellular sensitivity to dexamethasone. Results: Fifty-seven children with persistent and controlled asthma (mean age 10 years) were recruited and divided into 3 groups (severe, moderate and mild), and compared to healthy children (n = 18). Children with asthma, regardless of the severity of disease, presented similar sensitivity to GCs when compared to healthy children. Patients with mild asthma showed significantly less sensitivity to dexamethasone and children with severe asthma had similar sensitivity to dexamethasone when compared to controls. Conclusions: In vitro insensitivity to GCs was not demonstrated in children with controlled persistent asthma, even in those with severe disease. Our findings suggest that resistance to GCs in older patients with severe asthma might be an acquired process. However, future longitudinal studies are necessary to confirm this hypothesis.