Efficacy and Safety of Sublingual Immunotherapy using a Combination of Dermatophagoides Pteronyssinus and Blomia Tropicalis Extracts in Patients with Allergic Rhinitis: A Randomized, Double-Blind, Placebo-Controlled Trial

The aim of this study was to evaluate the safety and efficacy of sublingual immunotherapy (SLIT) with extracts of Dermatophagoides pteronyssinus and Blomia tropicalis in patients with moderate/severe persistent allergic rhinitis (AR). Methods: This was a double-blind, randomized, placebo-controlled trial of SLIT for the treatment of house dust mite-induced AR. A total of 65 patients, aged between 12 and 60 years, were treated for 12 months and randomized into two groups: SLIT and placebo. The SLIT group received a combination of extracts containing Dermatophagoides pteronyssinus and Blomia tropicalis allergens. All had their sensitization confirmed by skin prick test or serum-specific IgE. Total Nasal Symptom Score, RQLQ quality of life questionnaire, current treatment, and need for medication to control symptoms were recorded during the study. Total serum IgE, serum specific IgE, and IgG4 levels to Der p 1 and Blo t were assessed at baseline, 6 and 12 months after treatment. Results: There was no significant difference in the number of adverse events between groups. The SLIT group showed a significant reduction in the consumption of antihistamines to control symptoms (p < 0.0001) when compared to placebo. There was no significant change in serum total IgE, serum specific IgE, and IgG4 to both allergens when comparing the SLIT and placebo groups. Conclusion: After one year, SLIT using a dose of 1 mcg of Der p 1/day and 753 UBE of Blo t/day proved to be effective and safe in controlling AR exacerbations.