ONLINE COVER Mangled Myelin. This month’s cover depicts a normal myelin sheath wrapped around the axon of a neuron next to a damaged myelin sheath impairing nerve function. Autoreactive T cells specific for epitopes in myelin proteins trigger demyelination in human multiple sclerosis and mice with experimental autoimmune encephalomyelitis (EAE). Yi and Miller et al. report that chimeric antigen receptor (CAR) T cells displaying a complex of MHC class II and a peptide from myelin oligodendrocyte protein (MOG) selectively target pathogenic T cells for elimination in mouse EAE initiated by MOG immunization, thereby preventing and treating autoimmune symptoms. Using CAR T cells with different functional efficacy, the authors found that higher affinity autoreactive T cells are required for initiation of disease onset but lower affinity cells are sufficient to maintain ongoing disease.