CD19 and congenital rubella syndrome: Optimizing CD8α-derived HD/TMD lengths in the CD19-BBz prototype with co-stimulatory 4-1BB and CD3ζ domains, the Ying group found that CD19-BBz(86) CAR-T cells exhibited a potent and durable antilymphoma response without inducing neurotoxicity or severe cytokine release syndrome (CRS), indicating that modifying the CAR hinge and transmembrane regions can regulate cytokine secretion and contribute to mitigating CAR-T cell-associated toxicities [115].