Effect of Mepolizumab on Severe Eosinophilic Asthma

Two parts: A:Case-control study including 15 healthy adult donors and 15 severe adult eosinophilic asthmatics selected for treatment with mepolizumab. B: A longitudinal cohort study,where the same patients once on mepolizumab treatment are followed over time (0, 4, 16 and 32 weeks). SCOPE: response to mepolizumab in severe adult eosinophilic asthma. INCLUSION CRITERIA: Male or female, 18-75 years-old, with severe eosinophilic asthma. EXCLUSION CRITERIA: Smoking history, recent exacerbations, other pulmonary or systemic disease with eosinophilia, malignancy, pregnancy, obesity (BMI \>35). OBJECTIVES: General objective: Discovery of predictive/prognostic biomarkers of response to mepolizumab using flow cytometry, transcriptomic, and proteomic technologies. OTHER OBJECTIVES: 1.-To identify changes in surface markers of eosinophils and eosinophil subpopulations in response to treatment with mepolizumab using flow cytometry techniques. 2.-Transcriptomic analysis to identify mRNAs within the eosinophil transcriptome displaying enhanced or reduced levels in response to treatment with mepolizumab.3.-Proteomic profiling to identify proteins with differential abundance within the eosinophils in response to treatment with mepolizumab.4.-Check whether late-onset severe eosinophilic asthmatics display elevated levels of IGF-1, IGF-BP3, IGF-ALS in serum samples, if the response of mepolizumab depends on the levels of this markers, and if treatment with this biological reduces the concentration in serum of these IGF-family members. 5.-Identify proteins with differential abundance within the deep serum proteome of patients with SEA in response to treatment with mepolizumab by means of non-targeted proteomic analysis. MEASUREMENTS: Flow cytometry assays with multimarker panels 1 (regulatory), 2 (activation), and 3 eosinophil subsets. Clinical, hematological, biochemical and flow cytometry data generated at times T4, T16 and T32. Total RNA extraction from eosinophil lysates, assay