Wang X et al. - The aim of this study was to conjugate methotrexate (MTX) with intravenous immunoglobulin (IVIG) and investigate whether the conjugate produce selective cytotoxicity on macrophages to provide a new strategy for the management of idiopathic thrombocytopenic purpura. The conjugate of IVIG and MTX showed potent and selective cytotoxicity to macrophages in vitro.