Asthma is a heterogeneous disease, and specifically the phenotype of non-allergic asthma is not yet well defined. Several studies describe this group of patients as having severe asthma, persistent eosinophilia and poor therapeutic response. Among the theories being considered is the role of local IgE. Objectives: 1) To perform a pilot test to validate the measurement technique and standardize the levels of total IgE and IgE specific to Dermatophagoides pteronyssinus (d1) in the induced sputum of asthmatic patients and healthy volunteers. 2) Correlate local total IgE and specific IgE levels to d1 (sputum and peripheral blood) in patients with allergic and non-allergic asthma. 3) Describe the clinical and inflammatory characteristics of patients with allergic and non-allergic asthma.

Comparative cross-sectional study. It will include 32 allergic and non-allergic asthma patients and 10 healthy volunteers. All patients will have an induced sputum, pulmonary function studies, FENO (exhaled fraction of nitric oxide), total and specific IgE measurement at d1 (the most common perennial pneumoallergen) in blood and induced sputum, as well as a prick skin test with standardized allergen extracts. Measurement of total IgE and IgE for d1 in induced sputum will be performed in the supernatant and by the ImmunoCAP (Phadia ThermoFisher Scientific) immunofluoroassay technique.

Inclusion Criteria:

• Age 18-70
• Asthma according to GEMA (spanish asthma guideline)

Exclusion Criteria:

• Pregnancy
• Active smoking
• Moderate alcohol consumption
• Atopic dermatitis
• Other respiratory disease different than asthma (COPD, bronchiectasis, cystic fibrosis, pleural disease, interstitial disease)
• Treatment with steroids or inmunodepressants
• Active malignancy.

Patients diagnosed with asthma without evidence of allergic disease.