Long-lasting effect of sublingual immunotherapy in children with asthma due to house dust mite: a 10-year prospective study

Background Subcutaneous immunotherapy for respiratory allergy has shown a long-lasting efficacy after its discontinuation, whereas this evidence is still lacking for sublingual immunotherapy, despite the fact that it is widely used. Objective We aimed to evaluate whether a long-lasting effect of SLIT occurs, in a prospective parallel group controlled study. Methods Sixty children (mean age 8.5 years) suffering from allergic asthma/rhinitis due to mites were subdivided into two matched groups: 35 underwent a 4- to 5-year course of SLIT with standardized extract and 25 received only drug therapy. The patients were evaluated at three time points (baseline, end of SLIT and 4 to 5 years after SLIT discontinuation) regarding presence of asthma, use of anti-asthma drugs, skin prick tests and specific IgE. Results We found that in the SLIT group there was a significant difference vs. baseline for the presence of asthma (P less than or equal to 0.001) and the use of asthma medications (P less than or equal to 0.01), whereas no difference was observed in the control group. The mean peak expiratory flow result was significantly higher in the active group than in the control group after 10 years. No change was seen as far as new sensitizations were concerned. Specific IgE showed a near-significant increase (baseline vs. 10 years, P = 0.06) only in the control group. Conclusion Our study demonstrates that sublingual immunotherapy is effective in children and that it maintains the clinical efficacy for 4 to 5 years after discontinuation.