In this study, investigators want to evaluation of the impact of benralizumab (Fasenra®, Astra Zeneca) on different cell populations, including basophils and innate lymphoid cells, and several biomarkers, such as miRNAs, cadena α dek receptor pra la interleukin % (IL5Rα) and soluble IL5Rα in patients with severe eosinophilic asthma. For this, basophil and innate cells type 2 (ILC2) populations will be monitored in different point-time of treatment: 8 week (V1), 6 months (V2) and 1 year (V3) in blood and sputum samples. Also, follow-up IL5Rα expression on a cell surface of eosinophils, basophils and ILC2 from peripheral blood and sputum of patients treated with or or without benralizumab. Determination of IL5Rα levels will be performed by flow cytometry

For this:

1. Investigators will monitor basophil miRNAs changes with benralizumab analyzing miRNAS profile of isolated basophil before and after benralizumab treatment.
2. Also, in vitro characterization of benralizumab effects on functionality of human basophils (isolated from allergic asthmatic patients) and human cell line KU812, measuring apoptosis, activation, degranulation and histamine release will be performed.

Inclusion Criteria:

• .It is mandatory that all patients can comprehend the study requirements and provide informed consent for their participation in MEGA.

Group A:

• Adult people (≥ 18 and ≤ 80 years old) with eosinophilic severe asthma requiring high-dose inhaled corticosteroids plus long-acting beta agonists (with or without long-acting muscarinic antagonist or Montelukast or oral corticosteroids)
• Benralizumab treatment approved.

Group B:

.Patients with allergic asthma (prick test or RAST positive).

Exclusion Criteria:

• Patients with continuous OCS treatment
• Patients with Immunosuppressive drugs
• Patients with primary or secondary immune deficiency,
• Patients with chronic or/and concomitant disease, presence of severe systemic disease or cancer,
• Patients with possible infestation by parasites.
• Patients with other acute or chronic active lung disorders Patients with significant psychiatric disorders
• Patients with biological treatment will be excludes for group B

Group A: f patients with severe eosinophilic uncontrolled asthma treated with Benralizumab Those will be patients with severe eosinophilic asthma who are being treated with benralizumab and who want to participate in a volunteer manner in the study after signing informed consent. The decision of the patients treatment with benralizumab included in the study will not come in any case influenced by their participation in the study but will be made in accordance with the clinical criteria established by the Asthma Multidisciplinary Unit (UMA).

Group B:patients with allergic asthma without indication of treatment with biological therapy.