Pharmaceutical compositions comprising specific anti-CD19 B4 antibodies with modified variable regions in combination with chemotherapeutic agents are disclosed. The modified anti-CD19 variable region polypeptides have alterations to one or more framework regions or complementarity determining regions of the heavy chain variable region or light chain variable region, thereby to reduce a T-cell response. Moreover the specific anti-CD19 antibodies are expressed in good yields in YB2/0 cells and elicit improved ADCC.
