Safety of Modified Dust Mite Subcutaneous Immunotherapy in Severe Allergic Asthma

Abstract

The role of allergen specific immunotherapy (SIT) is a controversial issue in severe allergic asthma. Besides efficacy, safety is the major concern in such patients. The objetive of the present study is to evaluate the clinical tolerance of SIT in a subset of severe extrinsic asthmatic subjects. We selected 8 adult patients (mean age: 36 y.o.) with severe persistent allergic asthma. Mean inhaled steroids daily dose was above 1000 mcg of fluticasone propionate or 1600 mcg of budesonide. All patients were clinically sensitized to dust mites (Dermatophagoides spp.) as shown by skin prick test and/or specific IgE. Inclusion criteria required no hospital or emergency admissions for the last 2 months with no changes in their daily medication in the month prior to SIT. No pre-treatment with systemic steroids and/or antihistaminics were used. Modified standarized specific dust mites extracts were subcutaneously administered to reach a final dose of 100 DDP/ml -Der. p1: 14.4; Der. p2: 8.1 mcg/ml- over a two-week schedule. Clinical observation and lung function was strictly monitored. All patients reached the proposed allergen dose in two weeks.No significant adverse reactions were recorded, with no changes in the lung function. Minor immediate local reactions at the injections site were only observed at the maximal allergen dose in 5 patients showing good reponse to oral antihistaminics. No late adverse reactions were present. Proposed mantainance standarized allergen immunotherapy dose was successfully reached in a highly selected group of severe persistent allergic asthma. Although the current dose proved to be safe in this group further studies are needed to evaluate a putative role of immunotherapy in controlled severe allergic asthma.