Precision Medicine in House Dust Mite-Driven Allergic Asthma

House dust mites (HDMs) are the allergenic sources most frequently involved in airway allergy. Nevertheless, not every sensitized patient develops respiratory symptoms upon exposure to HDM, and there is a clinical need to differentiate allergic asthmatics (AAs) from atopic non-allergic asthmatics with HDM sensitization. This differentiation sometimes requires in vivo provocations like the bronchial allergen challenge (BAC). Interestingly, recent data demonstrate that non-atopic patients with asthma can also develop positive BAC results. This novel phenotype has been termed local allergic asthma (LAA). The interest in identifying the allergic triggers of asthma resides in the possibility of administering allergen immunotherapy (AIT). AIT is a disease-modifying intervention, the clinical benefit of which persists after therapy discontinuation. Recently, new modalities of sublingual tablets of HDM immunotherapy registered as pharmaceutical products (HDM-SLIT tablets) have become commercially available. HDM-SLIT tablets have demonstrated a robust effect over critical asthma parameters (dose of inhaled corticosteroids, exacerbations, and safety), thus being recommended by international guidelines for patients with HDM-driven AA. In this review, we will summarize the current knowledge on the phenotype and endotype of HDM-driven AA, and LAA, address the difficulties for BAC implementation in the clinic, and discuss the effects of AIT in AA and LAA.This work was supported by the Instituto de Salud Carlos III of the Spanish Ministry of Science and Competitiveness (grants co-funded by the European Regional Development Fund) through the research contracts “Rio Hortega” for ATM (CM20/00160), “Juan Rodes” for IEG (JR19/00029) and “Sara Borrell” for AA (CD17/00146), the research project PI17/01410 and the program of Redes Temáticas de Investigación Colaborativa en Salud (RETICS): Asma, Reacciones Adversas y Alérgicas-ARADyAL (RD16/0006/0001, RD16/0006/0007, RD16/0006/0019 and RD16/0006/0021). This work was also supported by the Andalusian Regional Ministry of Health through the “Nicolas Monardes” program for CM (RC-0004-2016C).Ye