IL5 and immunoglobulin G4-related sclerosing disease: Although the role of eosinophilia in the pathogenesis of IgG4-RD is debatable, we found that IgG4-RD patients with peripheral eosinophilia tend to be more liable to disease relapse, this raises the possibility of anti-eosinophil therapy such as monoclonal antibody to IL-5 for IgG4-RD patients with recurrent disease.