MedicalResearch.com Interview with:
Professor of Pediatrics Hans Bisgaard, MD, DMSc
Copenhagen Prospective Studies on Asthma in Childhood
Herlev and Gentofte Hospital,
University of Copenhagen, Denmark
Medical Research: What is the background for this study?
Prof. Bisgaard: Birth season has been reported to be a risk factor for several immune-mediated diseases, although the critical season varies depending on the disease. Autoimmune diseases are generally associated with spring births, whereas asthma and allergies are more common among subjects born in fall and winter. Because many of these diseases, such as asthma, rheumatoid arthritis, and
multiple sclerosis, have an underlying immune-mediated pathology, we hypothesized that this association might be mediated by differential changes in neonatal immune phenotype and function with birth season. We therefore sought to investigate the influence of season of birth on neonatal immunity by a combined analysis of immune cells subsets from cord blood and inflammatory mediators in the airways of neonates from the Copenhagen Prospective Study on Asthma in Childhood (COPSAC) 2010 birth cohort.
Medical Research: What are the main findings?
Prof. Bisgaard: We found a birth season–related fluctuation in neonatal immune cell subsets and in early-life airway mucosal immune function. The seasonal airway immune pattern was associated with the number of activated and regulatory T cells in cord blood whereas it was independent of concomitant presence of pathogenic airway microbes. Specifically, summer newborns presented with the lowest levels of all cell types and mediators and thereby seem to display the most quiescent immune status. Fall births presented mainly with an enhanced type 2 profile (eosinophils and IL-13), along with high TNF-a, IL-12p70, IL-10, and IL-2 levels, suggesting recent immune activation; whereas winter newborns had the highest levels of most cell types and mediators, including an anti-bacteria/ fungi–associated type 17 response (neutrophils, IL-17, and IL-1b), an antiviral response (pDCs and NK cells), increased eosinophil counts and an IL-5–mediated type 2 response. These season-linked immune profiles were similar to the known immune pathology of type 2 immune-mediated diseases associated with the fall and winter birth seasons, suggesting that immune function in early life might be biased toward the trajectory to later disease development.
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