High burden of viruses and bacterial pathobionts drives heightened nasal innate immunity in children

• DOI: 10.1084/jem.20230911
• Publication Date: 2024-07-01T13:55:58Z
• Authors: Timothy A. Watkins; Alex B. Green; Julien A.R. Amat; Nagarjuna R. Chee...; Katrin Hänsel; Richard Lozano; Sarah N. Dudgeon; Gregory Germain; Marie L. Landry; Wade L. Schulz; Ellen F. Foxman
• Keywords: Proinflammatory cytokine

Studies during the COVID-19 pandemic showed that children had heightened nasal innate immune responses compared with adults. To evaluate role of viruses and bacteria in driving these responses, we performed cytokine profiling comprehensive, symptom-agnostic testing for respiratory bacterial pathobionts nasopharyngeal samples from tested SARS-CoV-2 2021-22 (n = 467). Respiratory and/or were highly prevalent (82% symptomatic 30% asymptomatic children; 90 49% <5 years). Virus detection load correlated interferon response biomarker CXCL10, previously reported discrepancy between viral was explained by coinfections. Bacterial a distinct proinflammatory elevated IL-1β TNF but not CXCL10. Furthermore, paired healthy 1-year-olds collected 1-2 wk apart revealed frequent virus acquisition or clearance, mucosal immunophenotype changing parallel. These findings reveal frequent, dynamic host-pathogen interactions drive activation children.