Diminished IL-10 production in subjects with allergy after infection with influenza A virus

Background: Recent studies have documented a link between respiratory viral infections and the expression of asthma and other allergic disorders. Results from other studies have suggested that diminished production of IL-10, an anti-inflammatory cytokine, may contribute to the pathophysiologic features of these diseases. Objective: The objective of this study was to determine whether diminished IL-10 production and T-H2 cytokine skewing occur in allergic, as compared with nonallergic, subjects after experimental infection with the influenza A virus. Methods: PBMCs were isolated from 11 subjects with allergy and 14 subjects with no allergy before and after influenza A infection and stimulated with either mitogen (PHA) or antigen (influenza A). Supernatants were assayed for IL-10, IL-4, and IFN-gamma by ELISA. Results: PBMC IL-10 production was significantly diminished in subjects with allergy, as compared with subjects with no allergy, after experimental infection with influenza A virus. However, significant T-H2 skewing and enhanced airway symptoms were not observed in these same subjects. Conclusions: These data provide further support that subjects with allergy have an intrinsic inability to upregulate IL-10 production in response to inflammatory stimuli and extend this observation to include respiratory viral infections. Future studies in this area could lead to a better understanding of the pathogenesis of asthma and other allergic disorders.