If you and the donor are found to be eligible to take part in this study, on Day -4 (4 days before the NK cell infusion) and Day -1 (1 day before the NK cell infusion), you will have an epratuzumab infusion. The length of time this infusion will take will be different for each patient. This will be done using an indwelling catheter (a tube that remains in a vein, such as tunneled in the arm or through the chest to continuously inject or drain a part of your body). If you already have an indwelling catheter in place, you will not need to have a new one placed. However, if a new catheter is needed, you will be asked to sign a separate informed consent form for its placement.