RESUMO
OBJECTIVE: This study aimed to evaluate the clinical efficacy and antibody response changes after specific immunotherapy (SIT) using Dermatophagoides pteronyssinus (Dpt) allergens with or without bacterial extracts in Brazilian mite-atopic patients. METHODS: One-hundred patients with allergic rhinitis were selected for a randomized double-blind, placebo-controlled trial and distributed into 4 groups: Dpt (Dpt allergen extract), Dpt+MRB (Dpt allergen plus mixed respiratory bacterial extracts), MRB (MRB extract only) and placebo. Rhinitis symptom and medication scores; skin prick test (SPT) to Dpt extract; and serum immunoglobulin (Ig) E, IgG4, and IgG1 levels to Dpt, Der p 1, and Der p 2 allergens were evaluated before and after a year of treatment. RESULTS: After 1 year, the SPT response was reduced in the Dpt group (P=.03), whereas IgE levels to Der p 2 decreased only in the Dpt (P = .048) and Dpt+MRB (P = .005) groups. IgG4 and IgG1 levels to Dpt and Der p 1 increased in the Dpt group (P < .05), whereas in the Dpt + MRB group the IgG1 level only increased to Dpt (P=.001) and the IgG4 only increased to Der p 1 (P=.049). IgE levels to Dpt decreased only in the MRB (P= .005) and Dpt + MRB (P= .001) groups. Rhinitis symptom and medication scores fell in all groups, including the placebo group (P<.001). CONCLUSIONS: SIT using Dpt extract alone was effective in reducing SPT response and IgE levels to Der p 2 allergen, while bacterial extracts induced decreases in IgE levels to whole Dpt extract. However, only groups receiving Dpt allergen had higher levels of IgG1 and IgG4 to Dpt and Der p 1 after a year of treatment.
