The role of innate lymphoid cells in chronic rhinosinusitis severity in children: a cross-sectional study

Introduction: The microbiome has been identified as a significant factor in the pathogenesis of various inflammatory and autoimmune diseases, including chronic rhinosinusitis (CRS), a condition that affects up to 12% of the global population. Aim: To evaluate the role of innate lymphoid cells (ILC1, ILC2, and ILC3) and their relationship with nasal microbiota in CRS in children. Material and methods: We assessed the clinical, microbiological, and immunological characteristics of 63 children with CRS. We evaluated disease severity using the Sinus and Nasal Quality of Life Survey (SN-5) and measured ILC1, ILC2, and ILC3 levels in nasal scrapings; microbial diversity was expressed as OTU richness. Results: We found a statistically significant relationship between ILC1 levels and CRS severity, suggesting a potential role of ILC1 in the development of the disease. ILC3 levels were significantly associated with lower microbial richness. While atopy was more common in children with high levels of ILC2, the relationship was not significant. Conclusions: Our results indicate that innate lymphoid cells may play a significant role in the inflammatory processes underlying the development and severity of chronic rhinosinusitis, with ILC1 activation being particularly strongly associated with CRS severity in young children. Additionally, ILC3 may play a role in modulating the nasal microbiome in CRS patients, but the relationship is not strong enough to significantly impact the clinical characteristics.