Independent association of serum IgA levels with moderate-to-severe obstructive sleep apnea in children with adenotonsillar hypertrophy.

BACKGROUND

Adenotonsillar hypertrophy (ATH) is the leading cause of obstructive sleep apnea (OSA) in children. While the role of allergic inflammation (IgE-mediated) has been widely studied, the contribution of mucosal immunity-specifically Immunoglobulin A (IgA)-to disease severity remains unclear. This study aimed to investigate the association between serum immune markers and OSA severity and to construct a multivariate diagnostic model for moderate-to-severe disease.

METHODS

A total of 110 children diagnosed with ATH were enrolled in this cross-sectional study. Based on polysomnography (PSG) results and the 2020 Chinese Guidelines for Diagnosis and Treatment of Childhood OSA, participants were divided into a Mild/No OSA group (n = 65) and a Moderate-to-Severe OSA group (n = 45). Serum immunoglobulins (IgA, IgE, IgG, IgM) and complement components (C3c, C4) were analyzed. Logistic regression and Receiver Operating Characteristic (ROC) curve analyses were performed.

RESULTS

The Moderate-to-Severe group exhibited significantly lower lowest oxygen saturation (LSpO2) [0.85 (0.81, 0.89) vs. 0.89 (0.86, 0.91), P < 0.001], larger adenoids [A/N ratio: 0.77 (0.71, 0.80) vs. 0.65 (0.62, 0.75), P < 0.001], and a higher proportion of Grade III tonsils (28.9% vs. 12.3%, P < 0.001). Notably, serum IgA levels were significantly elevated in the Moderate-to-Severe group (2.05 ± 0.55 vs. 1.79 ± 0.75 g/L, P = 0.032), while IgE showed no significant difference. Multivariate logistic regression identified LSpO2 (OR = 0.853, P = 0.005) as a protective factor, while Tonsillar Hypertrophy (ORs 27.09-45.54) and IgA (OR = 2.520, 95% CI: 1.033-6.146, P = 0.042) were independent risk factors. A combined model incorporating these variables achieved an Area Under the Curve (AUC) of 0.852.

CONCLUSION

Elevated serum IgA is an independent associated factor of moderate-to-severe OSA in children with ATH, suggesting a potential mechanism involving chronic mucosal inflammation distinct from atopy. A combined diagnostic model involving IgA, anatomical metrics, and oximetry provides high diagnostic value.