IL5 and asthma: Mepolizumab is a humanized anti-IL-5 monoclonal antibody and is approved for use in severe asthma with an eosinophilic phenotype, eosinophilic granulomatosis with polyangiitis, hypereosinophilic syndrome, and chronic rhinosinusitis with nasal polyps for various age groups in many countries worldwide, including the European Union and the USA [22, 23].