Effect of age and season on respiratory mucosal immune marker profiles

Abstract

BackgroundThe upper respiratory tract is continuously exposed to microorganisms and noxious elements, leading to local immune responses and the secretion of immune markers. While several studies describe immune marker profiles in respiratory mucosal samples in defined patient cohorts, mucosal immune profiles from the general population during the different seasons are lacking. Such baseline profiles are essential to understand the impact of various exposures to the mucosal immune system throughout life. ObjectivesTo establish baseline, local upper respiratory mucosal immune profiles in the general population, and assess these profiles in regard to age, sex, seasonality, and basic health and lifestyle factors. MethodsWe measured the concentrations of 35 immune markers involved in a broad range of immunological processes at the mucosa in nasopharyngeal swab samples from 951 individuals from a nationwide study, aged 0-86 years. ResultsClustering analysis shows that the immune marker profiles clearly reflect immunological functions, such as tissue regeneration and antiviral responses. The concentrations of the immune markers changed strongly with seasonality and age -with the most profound changes occurring in the first 25 years of life- and also associated with sex, BMI, smoking, mild symptoms of airway infection, and chronic asthma and hay fever. ConclusionWe show that immunological analyses of non-invasive mucosal samples provide insight into mucosal immune responses to microbial and noxious element exposure in the general population. These data provide a baseline for future studies on respiratory mucosal immune responses and for the development of mucosal immune-based diagnostics.