Component-Resolved Diagnostics for House Dust Mite Allergy: Enhancing Diagnostic Precision and Guiding Subcutaneous Immunotherapy in Children.

Introduction: House dust mite (HDM) sensitization plays a key role in allergic rhinitis (AR) and asthma, yet the clinical value of component-resolved diagnostics (CRD) and immunological markers in children undergoing subcutaneous immunotherapy (SCIT) remains unclear. This study aimed to investigate specific immunoglobulin E (sIgE) and sIgG4 profiles against HDM components to distinguish HDM-induced AR from asymptomatic sensitization and to evaluate the longitudinal changes following SCIT in symptomatic patients, exploring their potential as biomarkers for selecting candidates for SCIT.

Methods: A total of 72 HDM-sensitized participants were included: 46 symptomatic AR patients (with/without allergic asthma) and 26 asymptomatic individuals. Eight healthy children served as the controls. In the symptomatic group, 32 patients received SCIT. Blood samples were analyzed for sIgE and sIgG4 levels to HDM components, and the basophil activation test (BAT) was performed at baseline and after 18 months of SCIT. Clinical assessments were performed using the children's asthma control test (C-ACT) and visual analog scale.

Results: sIgE levels to Dermatophagoides pteronyssinus (Der p) 1, Der p 2, Dermatophagoides farinae (Der f) 1 and Der f 2 were significantly elevated in symptomatic patients. Higher sensitization to Der p 2 and Der f 2 was observed in patients with AR and allergic asthma. SCIT significantly reduced sIgE and increased sIgG4 levels for specific components, particularly Der p 1, Der p 2, Der f 1, Der f 2, and Der p 23. BAT results support these findings. No significant changes were observed in the non-SCIT group.

Conclusion: CRD and BAT are valuable tools for distinguishing between asymptomatic and symptomatic HDM-sensitized individuals. The longitudinal monitoring of sIgE, sIgG4, and BAT levels may enhance SCIT outcomes and guide treatment decisions.