Background: There has been increasing interest in elucidating the relationship between adenoid hypertrophy (AH) and allergic rhinitis (AR). However, the impact of aeroallergen sensitization patterns on children concurrently experiencing AH and AR remains unclear. Methods: Patients aged 2-8 years (January 2019 to December 2022) with nasal symptoms were assessed for allergies, adenoid size and respiratory viral infection history. The levels of serum total immunoglobulin E (IgE) and specific IgE and flexible nasal endoscopy were performed. We analyzed the relationship between AH and sensitization patterns and lymphocyte subpopulations in adenoid samples using flow cytometry. Results: 5281 children were enrolled in our cohort. 56.5% of children was diagnosed with AR and 48.6% with AH. AR was more prevalent in AH children compared to nAR. Compared to non-sensitized, those with AR polysensitized to molds had a higher prevalence of AH (adjusted OR 1.61, 95%CI 1.32-1.96) and a greater occurrence of two or more respiratory viral infections, particularly in cases with adenoidectomy. In AH-AR children, adenoid tissues showed reduced frequencies and corrected absolute counts of regulatory T cells (Tregs), activated Tregs, class-switched memory B cells (CSMB), natural killer (NK) T cells and NK subpopulations compared to AH-nAR children. Polysensitization in AH-AR children correlated with lower CSMB frequencies. Conclusion: Polysensitivity to molds significantly increased the risk of AH in children with AR. Adenoids of AR children demonstrated less number of B cells, NK cells and Treg cells with an effector/memory phenotype, which was closely linked to sensitization models and respiratory viral infection, particularly concerning CSMB.

Background: Adenoid hypertrophy (AH) is a common comorbidity in pediatric allergic rhinitis (AR). The role of the sensitization to aeroallergens in AR children with AH is still unclear. Methods: 5307 children (2-8 years) with nasal complaints were enrolled in our study to identify the prevalence of AR and the incidence of AH complicated by AR. A smaller cohort including 2292 children was recruited for further confirmation. Basic information, serum total and specific immunoglobulin E (tIgE, sIgE) test, physical examination, and fluoroscopy evaluation were obtained for each patient. Risk factors for AH were estimated by logistic regression analysis. Results: We found that 3066 of 5307 children with nasal complaints had an elevated sIgE for at least one aeroallergen. House dust mites (HDMs) were the most common aeroallergen with a prevalence of 65.7%. Of 3066 children with AR, 1440 developed a moderate to severe AH. AR children with AH had a significantly higher tIgE level compared with those without AH (178IU/ml [interquartile range, IQR: 61.2-423.8] vs. 102IU/ml [IQR: 60.0-303.8], p<0.001). Sensitivity to Aspergillus fumigatus (Odds ratio [OR]: 1.687; 95% confidence interval [95%CI]: 1.199-2.373, p=0.003) and cockroaches (OR: 2.295, 95%CI: 1.263-4.170, p=0.006) was statistically significant in the logistic regression model after adjusting for several likely confounders. Conclusions: HDMs are the most common causes among sensitized children with nasal discomforts. AR children with higher tIgE may have higher likelihood of developing AH. AR children with AH have a distinct sensitization profile, and Aspergillus fumigatus and cockroaches could be the main triggers in urban China.