IL5 and eosinophilic granulomatosis with polyangiitis: Currently, only few types of biological agents have been tried in EGPA, including the B-cell antagonist monoclonal antibody Rituximab, the humanized monoclonal antibody against interleukin-5 Mepolizumab, and the recombinant humanized monoclonal anti-immunoglobulin E antibody Omalizumab.