CD19 and leukemia: We first infused 10,000 of second generation (2nd-gen) human anti-CD19 4-1BBζ-CAR T cells (hereafter CAR T cell, unless stated otherwise) per chip into the perfusable vessels from central sinus and quantified the count of pre-seeded leukaemia blasts on-chip (GFP-expressing Reh, unless stated otherwise) daily for over 7 days.