CAR T-cells in autoimmunity: game changer or stepping stone?

The advent of chimeric antigen receptor (CAR) T-cells has revolutionized the treatment landscape for hematologic malignancies, and emerging evidence suggests their potential in autoimmune diseases (AIDs). This article examines the early successes and future implications of B-cell-targeting CAR T-cell therapy in AIDs. Initial applications, particularly in refractory systemic lupus erythematosus (SLE), have demonstrated significant and durable clinical remissions, with accompanying evaluation of the immune system suggesting a so-called "reset" of innate inflammation and adaptive autoimmunity. This has generated widespread interest in expanding this therapeutic approach. CAR T-cells offer unique advantages over other treatment modalities, including very deep B-cell depletion and unique therapeutic activity within inflamed tissues and associated lymph structures. However, the field must address key concerns, including long-term toxicity, particularly the risk of secondary malignancies, and future accessibility given the higher prevalence of AIDs compared to malignancies. Technological advances in cell therapy, such as next-generation CAR T-cells, allogeneic off-the-shelf products and alternative cell types such as regulatory CAR T-cells, are being explored in AIDs to improve efficacy and safety. In addition, bispecific antibodies are emerging as potential alternatives or complements to CAR T-cells, potentially offering comparable efficacy without the need for complex logistics, lymphodepletion and the risk of insertional mutagenesis. As the field evolves, cellular therapists will play a critical role in the multidisciplinary teams managing these complex cases. The transformative potential of CAR T-cells in AIDs is undeniable, but careful consideration of safety, efficacy, and implementation is essential as this novel therapeutic approach moves forward.