Flow Cytometry Analysis of Eosinophils in Severe Asthma Patients.

Asthma is a heterogeneous disease, characterized by reversible airflow obstruction, airway hyperresponsiveness, and airway inflammation, in which 40% of patients exhibit eosinophil-driven pathobiology.The main treatment of asthma is the use of corticosteroid, whose use induces a reduction in eosinophils that is considered a strong predictor of response to treatment. Corticosteroids have remained the mainstay treatment of asthma and reduction in eosinophils has remained the unequivocal predictor of steroid response. The prevalence of asthma, which is expected to increase, it is about 300 million people worldwide. About 5-10% of asthma patients have severe disease, which is defined as asthma that requires high-dose inhaled corticosteroids (ICSs) plus a second controller to prevent it from becoming "uncontrolled" or which remains "uncontrolled" despite this therapy. Patients with severe disease have worse quality of life, and disproportionately high morbidity, mortality, and use of health care resources when compared with their peers with well-controlled disease.The pathophysiology of asthma is complex and heterogeneous between patients, as the disease itself; however, on the basis of immune system involvement, it is possible to define 2 subtypes - or endotypes- of asthma. These endotypes are named T2 (for type 2 cells) high or low, and are defined by the levels of expression of the T2 cytokines, IL-4, IL-5, and IL-13 produced by T helper 2 lymphocytes, and innate lymphoid cell-2.T2 high endotype patients display an increase in the number of blood and sputum eosinophils, and have a better response to the current available biological therapies , such as the administration of mepolizumab (anti IL-5 antibody). Eosinophilic asthma is associated to a more severe clinical phenotype,but patients with a T2 endotype respond better to biological therapies. The hypothesis of the present proposal is that the activation status of these cells, analyzed by the expression of activatio