Chemoimmunotherapy in acute lymphoblastic leukemia.

ALL blast cells express a variety of specific antigens e.g. CD19, CD20, CD22, CD33, and CD52, which serve as targets for Monoclonal Antibodies (MoAbs). So far, the most experience is available for anti-CD20 (rituximab), which has been combined with chemotherapy for treatment of mature B-ALL/Burkitt's lymphoma. Studies with rituximab have also been completed in B-precursor ALL. Another antigen, CD19, is of great interest due to a very high rate of expression in ALL. It can be targeted by a bispecific monoclonal antibody, Blinatumomab, directed against CD19 and CD3. Smaller studies or case reports are also available for the anti CD52 antibody (Alemtuzumab), for anti CD22 (Epratuzumab) or anti CD33 (Gemtuzumab). Available data demonstrate that MoAb therapy in ALL is a highly promising targeted treatment. However, several details for an optimal treatment approach e.g. the required level of antigen expression, timing, schedule, dosage and stage of disease still need to be defined.