ITGAM and myeloid sarcoma: To clarify the roles of microglia activation in the pathogenesis of MS, Heppner et al. induced EAE to transgenic CD11b-HSVTK mice, in which herpes simplex virus thymidine kinase expression was driven by the monocyte/macrophage/microglia CD11b promoter, with the intention to deplete microglia activation during the disease.