Eficácia clínica e alterações na resposta de anticorpos sistêmicos e de mucosa após imunoterapia sublingual em crianças alérgicas a ácaros: um estudo randomizado duplo-cego, controlado com placebo

Abstract

This study aimed to evaluate the clinical efficacy and systemic/mucosal antibody response changes after sublingual immunotherapy (SLIT) using Dermatophagoides pteronyssinus (Dpt) allergens with or without bacterial extracts in mite-allergic children. One-hundred and two patients presenting allergic rhinitis with or without asthma were selected for a randomized double-blind, placebo-controlled trial and distributed into three groups: DPT (Dpt allergen extract, n=34), DPT+MRB (Dpt allergen plus mixed respiratory bacterial extracts, n=36), and Placebo (n=32). Clinical evaluation and immunological analyses were carried out before and after 12 and 18 months of treatment, including rhinitis/asthma symptom and medication scores, skin prick test (SPT) to Dpt extract, and measurements of Dpt, Der p 1, Der p 2 specific IgE, IgG4, and IgG1 in serum and specific IgA in saliva and nasal lavage fluid. Clinical results showed a significant decline in rhinitis/asthma symptom scores in all groups, but medication use decreased only in DPT group after 12 months. SPT results showed no significant changes and SLIT was generally safe, with no severe systemic reactions. SLIT using Dpt allergen alone induced increased serum IgG4 levels to Dpt, Der p 1 and Der p 2, and increased serum IgG1 and salivary IgA levels to Dpt and Der p 1. SLIT using DPT+MRB was able to decrease IgE levels to Der p 2, to increase salivary IgA levels to Der p 1, but had no changes on specific IgG4 and IgG1 levels. In conclusion, clinical improvement was observed both in the SLIT group and the control, but only active SLIT was able to modulate the mucosal/systemic antibody responses. These findings support the role of specific serum IgG4 and IgG1, in addition to salivary IgA, as probable blocking antibodies or biomarkers of tolerance that may be useful for monitoring the allergen specific immunotherapy.