CD19 and acute lymphoblastic leukemia: Such MAbs are targeting CD20 (Rituximab), are antibody–drug conjugates targeting CD22 (inotuzumab ozogamicin), bispecific antibodies (Blinatumomab) and CD19 chimeric antigen receptor T cell therapy (tisagenlecleucel—the first CAR-T cell-based product approved by the FDA in august 2017 for relapsed/refractory ALL for children and AYA up to 25 years old).