Suppression function against environmental dust exposure after Dermatophagoides pteronyssinus immunotherapy is associated with production of specific and cross‐reactive immunoglobulin G4

BACKGROUND: Whether Dermatophagoides pteronyssinus (Der-p) allergen immunotherapy (AIT) can induce Dermatophagoides farina (Der-f)-specific immunoglobulin (sIg) G4 production, and tolerance to environmental allergens has not been fully investigated. OBJECTIVE: We aimed to determine serum Der-p-sIgG4 and Der-f-sIgG4 levels in asthma and/or rhinitis patients undergoing Der-p AIT and their ability to reduce immune responses triggered by indoor dust extracts. METHODS: % changes. House dust samples were collected to analyse allergen levels. Serum levels of Der-p-sIgG4 and Der-f-sIgG4, serum inhibitory capacity against Der-p, Der-f and indoor dust extract by sIgE-facilitated allergen binding to B cells (IgE-FAB), and serum blocking indoor dust extract-induced basophil activation inhibition assays (BATI) in peripheral blood monocytes were carried out at weeks 0, 4, 12, 16, 52, 104 and 156 after the initiations of the treatments. RESULTS: Our study enrolled a total of 60 participants, with 30 patients in each group. Patients in the SCIT group had significantly improved SMS when compared with the baseline and the patients in the non-SCIT group. Median levels of Der-p 1 and Der-f 1 in indoor dust extract were 1.86 μg/g and 4.74 μg/g, respectively. Serum Der-p-sIgG4 and Der-f-IgG4 levels in SCIT patients showed a significant increase from weeks 12 to 156. Serum in these SCIT patients could significantly block Der-p, Der-f and indoor dust extract formation of allergen-sIgE complex and reduced the threshold of IgE-FAB from 16 weeks after the initiation of the treatment. The capacity to inhibit Der-p, Der-f and indoor dust extract BATI was observed in SCIT serum after 12 weeks. Der-p-sIgG4 and Der-f-sIgG4 had a significant correlation with IgE-FAB and BATI in SCIT patients at all time points. CONCLUSION: Single Der-p immunotherapy induced both Der-p-sIgG4 and Der-f-sIgG4 production, which might cross-reactively induce tolerance against environmental allergen exposure in patients with asthma and/or rhinitis.