CAR T cells for multiple sclerosis: Engineering T cells to disrupt chronic B cell-driven neuroinflammation.

Chimeric antigen receptor (CAR) T-cell therapy is emerging as a promising approach to overcome the limitations of current B-cell-targeted treatments for multiple sclerosis (MS), particularly in progressive forms where disease-modifying therapies (DMTs) often fail to halt neuroinflammation and disability progression. By penetrating both lymphoid tissues and the central nervous system (CNS), anti-CD19 CAR T cells enable deeper and more durable depletion of autoreactive B cells than monoclonal antibodies. Preclinical studies, including experimental autoimmune encephalomyelitis (EAE) models, support their capacity to induce immune tolerance, suppress demyelinating inflammation, and modulate microglial activation. Experience from the early clinical phase -which currently includes six ongoing trials-demonstrates encouraging safety profiles, CNS trafficking of CAR T cells and evidence of pathogenic B-cell depletion in progressive MS, neuromyelitis optica spectrum disorder (NMOSD), and refractory non-relapsing phenotypes. These include the first-in-human trial CT103A (BCMA-targeted CAR T) in progressive MS and NMOSD (NCT04561557), the detection of CAR T cells in the CNS without ICANS in Anti-CD19 CAR T therapy (NCT06138132), the favorable safety in the multicenter study BMS986353 (NCT06220201), and the confirmed CNS penetration in the UCSF's KYV-101, a CD19 CAR T Cell Therapy study (NCT06451159). Next-generation CAR platforms-including regulatory CAR T cells, brain-targeted safety switches, and antigen-specific modulators-may enhance precision and mitigate neurotoxicity, a critical concern in patients with neurologically vulnerable conditions. However, key challenges remain: the absence of validated CNS-specific antigens, risks such as ICANS, delayed parkinsonian-like syndromes, or progressive multifocal leukoencephalopathy (PML), immune exhaustion within the inflamed CNS, and the logistical demands of autologous cell manufacture. This mini-review synthesizes preclinical and early clinical evidence, outlines translational barriers, and discusses strategies to optimize safety, targeting, and scalability.