Role of Tonsillar Chronic Inflammation and Commensal Bacteria in the Pathogenesis of Pediatric OSA

SARMIENTO VARÓN, LINDYBETH; DE ROSA, JAVIER; RODRIGUEZ, RAQUEL; FERNÁNDEZ, PABLO M.; BILLORDO, L. ARIEL; BAZ, PLÁCIDA; BECCAGLIA, GLADYS; SPADA, NICOLÁS; MENDOZA, F. TATIANA; BARBERIS, CLAUDIA M.; VAY, CARLOS; ARABOLAZA, M. ELENA; PAOLI, BIBIANA; ARANA, ELOÍSA I.

Frontiers in Immunology

Nicolas Dutzan, University of Chile, Chile

Año: 2021 vol. 12 p. 1 - 14

Immune responses at the boundary between the host and the world beyond are complexand mucosal tissue homeostasis relies on them. Obstructive sleep apnea (OSA) is asyndrome suffered by children with hypertrophied tonsils. We have previouslydemonstrated that these tonsils present a defective regulatory B cell (Breg)compartment. Here, we extend those findings by uncovering the crucial role of residentpro-inflammatory B and T cells in sustaining tonsillar hypertrophy and hyperplasia byproducing TNFa and IL17, respectively, in ex vivo cultures. Additionally, we detectedprominent levels of expression of CD1d by tonsillar stratified as well as reticular epithelium,which have not previously been reported. Furthermore, we evidenced the hypertrophy ofgerminal centers (GC) and the general hyperplasia of B lymphocytes within the tissue andthe lumen of the crypts. Of note, such B cells resulted mainly (IgG/IgM)+ cells, with someIgA+ cells located marginally in the follicles. Finally, by combining bacterial culture from thetonsillar core and subsequent identification of the respective isolates, we determined themost prevalent species within the cohort of OSA patients. Although the isolated speciesare considered normal oropharyngeal commensals in children, we confirmed theircapacity to breach the epithelial barrier. Our work sheds light on the pathologicalmechanism underlying OSA, highlighting the relevance taken by the host immunesystem when defining infection versus colonization, and opening alternatives of treatment.