CD19 and congenital rubella syndrome: In the case of anti-CD19 CAR T cells, CRS is initiated by the activation and proliferation of CAR T-cells after CD19+ target cell recognition, leading to production of inflammatory cytokines (such as IL-6, IFN-γ, IL-10, etc. [70]), ultimately causing a plethora of symptoms such as fever, vomiting, seizures, and even organ failure.