Salivary IgG4 Levels Contribute to Assessing the Efficacy of Dermatophagoides pteronyssinus Subcutaneous Immunotherapy in Children with Asthma or Allergic Rhinitis.

At present, there are no effective, non-invasive, and objective indicators to evaluate the efficacy of pediatric house dust mite (HDM)-specific allergen immunotherapy (AIT). A prospective, observational study was performed in children with Dermatophagoides pteronyssinus ( Der p ) asthma and/or allergic rhinitis (AR). Forty-four patients received subcutaneous Der p -AIT for 2 years, and eleven patients received only symptomatic treatment. The patients needed to finish their questionnaires at each visit. Serum and salivary Der p -specific IgE, IgG4, and IgE-blocking factors (IgE-BFs) were measured at 0, 4, 12, and 24 months during AIT. A correlation between them was also evaluated. Subcutaneous Der p -specific AIT improved the clinical symptoms of children with asthma and/or AR. The Der p -specific IgE-BF significantly increased at 4, 12, and 24 months after AIT treatment. Serum and salivary Der p -specific IgG4 significantly increased with the time of the AIT treatment, and significant correlations between them at different time points were observed ( p < 0.05). Furthermore, there were significant correlations (R = 0.31-0.62) between the serum Der p -specific IgE-BF and Der p -specific IgG4 at the baseline, 4, 12, and 24 months after the AIT ( p < 0.01). The salivary Der p -specific IgG4 levels also demonstrated a certain correlation with the Der p -specific IgE-BF. Der p -specific AIT is an effective treatment for children with asthma and/or AR. Its effect was associated with increased serum and salivary-specific IgG4 levels, as well as an increased IgE-BF. Non-invasive salivary-specific IgG4 may be useful for monitoring the efficacy of AIT in children.