Two Fc-optimized anti-CD19 mAbs have been developed for the treatment of paediatric B-linage acute lymphoblastic leukaemia (ALL), inebilizumab (modifying the Fc-linked N-glycan) and XmAb®5574 (a version of 4G7-anitbody with SDIE modification in the human Fc-domain of IgG1) (164). The gene discussed is CD19; the disease is acute lymphoblastic leukemia.