Relationship between atopic status and nasal interleukin 10 and 11 levels in infants with respiratory syncytial virus bronchiolitis

Background: Interleukin 10 (IL-10) and IL-11 are known to have anti-inflammatory activities, and they have been implicated in the pathogenesis of respiratory syncytial virus (RSV) infection. Objectives: To determine IL-10, IL-11, and myeloperoxidase levels in nasal secretions of infants with acute RSV bronchiolitis and to investigate whether there are any differences in these levels in patients with vs without atopy. Methods: We measured IL-10, IL-11, and myeloperoxidase levels in nasal secretions of 44 infants (20 were atopic) with acute RSV bronchiolitis. The nasal secretion samples were obtained from patients at hospital admission and were stored immediately at -70degrees C until analysis. Atopy was defined as having at least 1 positive skin prick test reaction to common allergens, a history of atopic dermatitis, or a high serum IgE level compared with age-matched controls. Results: Levels of IL-10, IL-11, and myeloperoxidase increased significantly in samples from infants with acute RSV bronchiolitis. Levels of IL-10 and IL-11 were significantly lower in patients with vs without atopy (P <.05). Myeloperoxidase levels showed no significant difference in patients with vs without atopy (P =.18). Patients with severe symptoms tended to have lower IL-10 levels (P =.09), but no relationship was shown between symptom severity and IL-11 levels. Nasal myeloperoxidase levels were significantly higher in patients with severe symptoms (P <.05). Conclusions: Production of IL-10 and IL-11 was significantly lower in patients with vs without atopy during acute RSV bronchiolitis. The airway inflammation induced by RSV infection may be different in patients with vs without atopy, and this is associated with lower induction of these immunoregulatory cytokines in children with atopy.