Upper‐airway dysbiosis related to frequent sweets consumption increases the risk of asthma in children with chronic rhinosinusitis.

Background: Innate immunity response to local dysbiosis seems to be one of the most important immunologic backgrounds of chronic rhinosinusitis (CRS) and concomitant asthma. We aimed to assess clinical determinants of upper‐airway dysbiosis and its effect on nasal inflammatory profile and asthma risk in young children with CRS. Methods: We recruited one hundred and thirty‐three children, aged 4‐8 years with doctor‐diagnosed CRS with or without asthma. The following procedures were performed in all participants: face‐to‐face standardized Sinus and Nasal Quality of Life questionnaire, skin prick test, taste perception testing, nasopharynx swab, and sampling of the nasal mucosa. Upper‐airway dysbiosis was defined separately by asthma‐specific microbiome composition and reduced biodiversity. Multivariate methods were used to define the risk factors for asthma and upper‐airway dysbiosis and their specific inflammatory profile of nasal mucosa. Results: The asthma‐specific upper‐airway microbiome composition reflected by the decreased ratio of Patescibacteria/Actinobacteria independently of atopy increased the risk of asthma (OR:8.32; 95%CI: 2.93‐23.6). This asthma‐specific microbiome composition was associated with ≥ 7/week sweet consumption (OR:2.64; 95%C:1.11‐6.28), reduced biodiversity (OR:3.83; 95%CI:1.65‐8.87), the presence of Staphylococcus strains in the nasopharynx (OR:4.25; 95%CI:1.12‐16.1), and lower expression of beta‐defensin 2, IL‐5, and IL‐13 in the nasal mucosa. The reduced biodiversity was associated with frequent antibiotic use and with a higher nasal expression of IL‐17 and T1R3 (sweet taste receptor). In asthmatic children, reduced sweet taste perception was observed. Conclusions: Specific upper‐airway dysbiosis related to frequent sweet consumption, frequent antibiotic courses, and altered nasal immune function increases the risk of asthma in young children with CRS. [ABSTRACT FROM AUTHOR]