The Future of CAR T Therapeutics to Treat Autoimmune Disorders.

The concept of chimeric antigen receptor (CAR) T cell therapy emerged from cancer immunotherapy and has been rapidly adapted and developed for the treatment of autoimmune, especially B-cell-driven, diseases since the first publication of an article featuring a patient with systemic lupus erythematosus in 2021. Phase II studies are about to start, but up to now, only case reports and small series have been published. In contrast to hemato-oncological diseases, where an aggressive response to malignant cells and long-lasting persistence of CAR T cells has been aimed at and observed in many patients, this is not the case with autoimmune diseases but might not be necessary to control disease. Future studies will focus on the optimal target but also on the optimal level of immunogenicity. The latter can be influenced by numerous modulations that affect not only cytokine release but also regulation. In addition, there are potential applications in regulatory cells such as CAR regulatory T cells (Treg). The question of toxicity reduction must also be addressed, as long-term complications such as the potential development of malignant diseases, infections, or cytopenia must be considered even more critically in the area of autoimmune diseases than is the case for patients with oncologic diseases. Alternative antibody-based therapies using the same target (e.g., CD3/CD19 bispecific targeting antibodies) have not been used in these patients and might also be considered in the future. In conclusion, CAR T cell therapy represents a promising therapeutic approach for autoimmune diseases, offering a targeted strategy to modulate immune responses and restore immune tolerance.