The investigators plan to collect blood, salivary and sputum samples in both EGPA and severe asthmatic patients (as controls) at baseline and at different timepoints after starting treatment with mepolizumab, an anti-IL-5 drug, in order to cluster patients and to analyse the effect of the therapy during treatment and assess the disease progression on three key aspects of the disease: lung function and symptoms control, vasculitis and neuropathy.
untangle the mechanisms of the disease and to characterize response to treatment, in the context of a phenotype/endotype asthma and EGPA management.
