Variation in allergen content in sublingual allergen immunotherapy with house dust mites

BACKGROUND Allergen immunotherapy is a treatment modality which can be applied using different vaccines. The aim of this study was to quantify and compare the allergen content of different house dust mites (HDM)' sublingual treatments and to review the evidence on their efficacy. METHODS Five sublingual allergen immunotherapy (SLIT) products were ordered and purchased at an ordinary pharmacy and masked for blinding before the study was started. Detection of Dermatophagoides pteronyssinus and Dermatophagoides farinae allergens Der p 1, Der f 1, Der p 2 and Der f 2 was carried out by immunoblotting and fluorescent multiplex. A literature search for meta-analyses and systematic reviews that included SLIT-HDM products was performed. RESULTS Der p 1 concentrations ranged from 0.6 to 14.5 μg/ml; similar figures were found for Der f 1 that ranged from 0.2 to 12.4 μg/ml. Der p 2+ Der f 2 ranged from 0.2 to 1.5 μg/ml. Data on efficacy are scarce for most of the five products. CONCLUSIONS Substantial variations regarding allergen content were found among these five SLIT-HDM products. Therefore, it can be necessary to guarantee the quality of the SLIT-HDM products and to demonstrate their effectiveness before they are marketed. It seems necessary, for the moment, to take into account these characteristics of the products before prescribing.