CD19 and hematologic disorder: Blinatumomab, an anti-CD3/CD19 BiTE (bispecific T cell engager), was the first FDA-approved BiTE for the treatment of R/R precursor B-cell ALL (pre-B-ALL) and has also achieved remarkable curative effects.26 Over the past several decades, antibody-drug conjugates (ADCs) have been evaluated in a variety of clinical trials of hematologic malignancies.