A Novel Biomarker for Tiny Breaths: Linking Pulmonary Impedance, Wheeze Phenotypes and Atopy in Preschoolers

Background Pentraxin-3 (PTX-3) is a humoral pattern recognition receptor involved in innate immunity and inflammation regulation, but its relationship with lung function remains unclear.Objective This study investigated the association between serum PTX-3 levels and respiratory function in preschool wheezy children (CW), considering wheezing phenotypes and atopy.Methods In this cohort study, 165 preschoolers were divided into 84 wheezy children (CW) and 81 healthy controls (HC). Serum PTX-3 levels, eosinophil counts, and pulmonary function using impulse oscillometry (IOS) were assessed. IOS parameters included zR5, zR20, R5-20, zX5, zX20, Fres, and AX. Comparisons were made according to wheezing phenotype (multi-trigger vs episodic) and atopy status. Correlation analysis between PTX-3 and IOS parameters was performed.Results The CW group had higher PTX-3 levels (p = 0.010), increased IOS parameters (zR5, zR20, R5-20, Fres, AX; p < 0.05), and reduced zX5 (p < 0.001). PTX-3 positively correlated with zR5, zR20, and AX (r:0.220–0.226, p < 0.05). Multi-trigger wheezing and atopy were associated with higher R5-20 and PTX-3 (p < 0.05). Children with parental atopy also showed higher PTX-3 and airway resistance.Conclusion Elevated PTX-3 is associated with impaired lung function in preschool wheezy children and may serve as a biomarker for respiratory function, phenotype differentiation, and atopy.