CD19 and B-cell chronic lymphocytic leukemia: These observations underline that patients with B-CLL could benefit from GBR 401 treatment and also strengthen the rationale of developing anti-CD19 mAb therapy as an alternative or complementary strategy to circumvent the resistance to, or the failure of, anti-CD20 mAb therapies associated with low levels of CD20 expression, downregulation or expression of CD20 transcript variants [48].