IL5 and eosinophilic granulomatosis with polyangiitis: EGPA patients receiving mepolizumab, a monoclonal antibody to interleukin-5 (IL-5) that reduces blood eosinophil counts, as an add-on therapy to glucocorticoid treatment, resulted in more accrued weeks in remission, reductions in glucocorticoid use and a reduction in relapse rate [3].