Application of CD19-CAR T cell therapy in autoimmune diseases

Autoimmune diseases represent a broad group of chronic conditions characterized by loss of immune tolerance, autoreactive lymphocyte activation, and pathogenic autoantibody production. CD19-directed chimeric antigen receptor (CAR) T-cell therapy, originally developed for hematologic malignancies, has emerged as a promising strategy to directly eliminate autoreactive B cells and reprogram immune function. CD19-CAR T infusion can induce rapid remission, reduce autoantibody levels, and sustain drug-free disease control. Despite these encouraging results, current evidence is limited to small patient cohorts with short follow-up, leaving uncertainties regarding long-term safety, durability of remission, and the stability of immune reconstitution. Most studies implicitly assume that quantitative B-cell recovery equates to restored immune health, yet the functional resilience of the post-CAR-T immune system—its ability to protect against infection, respond to vaccines, and maintain durable tolerance—remains unexplored. To address this gap, we propose an integrated framework for evaluating the functional competence of immune reconstitution following CAR T-cell therapy and for designing next-generation targeting strategies. Functional recovery should be assessed not only by quantitative B-cell repopulation but also by vaccine responsiveness, infection surveillance, and immune repertoire diversity. Vaccine challenge studies and infection monitoring can reveal whether protective immunity is restored, while sequencing-based profiling of B- and T-cell repertoires can clarify whether regulatory balance and clonal diversity are re-established. In parallel, translational innovations such as dual-target CAR constructs (e.g., CD19 + BAFF-R) and chimeric autoantibody receptor (CAAR) T cells offer complementary solutions to broaden target coverage and improve selectivity. Moreover, Epstein–Barr virus (EBV)–mediated immortalization of patient-derived autoreactive B cells provides a feasible ex vivo platform for generating physiologically relevant antigenic stimuli during CAR engineering. This approach could yield T cells that are functionally “educated” to eliminate pathogenic clones while preserving protective immunity, thereby addressing the central challenge of rebuilding a resilient and tolerant immune system.