The chimeric autoantibody receptor (CAAR), a fusion of the antigen Dsg3 to the signaling domains of CD137 and CD3ζ, is expressed in T lymphocytes (CAAR T cells). CAAR T cells target autoreactive B lymphocytes bearing antibodies specific for Dsg3. This strategy was shown to eliminate autoantibodies specific for Dsg3, which are pathogenic in pemphigus vulgaris, in vitro and in well-designed animal models3. This innovative strategy could, in theory, be extended to T-cell-mediated autoimmune diseases, such as type 1 diabetes, in which B lymphocytes present autoantigens in the context of major histocompatibility molecules to pathogenic autoreactive CD4+ or CD8+ T lymphocytes. MHC, major histocompatibility complex.