COMBINATIONS AND USES THEREOF

1 - 2 . (canceled)

3 . A method for treating non-Hodgkin's lymphoma, chronic lymphocytic leukemia and/or acute lymphoblastic leukemia in a subject, said method comprising administering to the subject fludarabine and an antibody specific for CD19, wherein the antibody comprises an HCDR1 region of sequence SYVMH (SEQ ID NO: 1), an HCDR2 region of sequence NPYNDG (SEQ ID NO: 2), an HCDR3 region of sequence GTYYYGTRVFDY (SEQ ID NO: 3), an LCDR1 region of sequence RSSKSLQNVNGNTYLY (SEQ ID NO: 4), an LCDR2 region of sequence RMSNLNS (SEQ ID NO: 5), and an LCDR3 region of sequence MQHLEYPIT (SEQ ID NO: 6).

4 . The method of claim 3 , wherein the antibody comprises a variable heavy chain of the sequence EVQLVESGGGLVKPGGSLKLSCAASGYTFTSYVMHWVRQAPGKGLEWIGYINPY NDGTKYNEKFQGRVTISSDKSISTAYMELSSLRSEDTAMYYCARGTYYYGTRVFDY WG QGTLVTVSS (SEQ ID NO: 10) and a variable light chain of the sequence

(SEQ ID NO: 11)

DIVMTQSPATLSLSPGERATLSCRSSKSLQNVNGNTYLYWFQQKPGQSPQ

LLIYRMSNLNSGVPDRFSGSGSGTEFTLTISSLEPEDFAVYYCMQHLEYP

ITFGAGTKLEIK.

5 . The method of claim 3 , wherein the antibody comprises a heavy chain constant domain of the sequence

(SEQ ID NO: 12)

ASTKGPSVFPLAPSSKSTSGGTAALGCLVKD YFPEPVTVSWNSGALTSG

VHTFPAVLQSSGLYSLSSSTVPSSSLGTQTYICNVNHKPSNTKVDKKVEP

KSCDKTHTCPPCPAPELLGGPDVFLFPPKPKDTLMISRTPEVTCVVVDVS

HEDPEVQFNWYVDGVEVHNAKTKPREEQFNSTFRVVSVLTVVHQDWLNGK

EYKCKVSNKALPAPEEKTISKTKGQPREPQVYTLPPSREEMTKNQVSLTC

LVKGFYPSDIAVEWESNGQPENNYKTTPPMLDSDGSFFLYSKLTVDKSRW

QQGNVFSCSVMHEALHNHYTQKSLSLSPGK.

6 . The method of claim 3 , wherein said antibody specific for CD19 and fludarabine are administered separately.

7 . The method of claim 3 , wherein fludarabine is, administered prior to administration of the antibody specific for CD19.

8 . The method of claim 3 , wherein administration of fludarabine and said antibody specific for CD19 mediates killing of MEC-1 cells by ADCC in the presence of isolated human PBMCs with an at least two-fold better efficacy than fludarabine alone.

9 . The method of claim 10 , wherein the non-Hodgkin's lymphoma is selected from the group consisting of follicular lymphoma, small lymphocytic lymphoma, mucosa-associated lymphoid tissue, marginal zone, diffuse large B cell, Burkitt's, and mantle cell.

10 . The method of claim 3 , wherein the subject has non-Hodgkin's lymphoma.

11 . The method of claim 3 , wherein administration of fludarabine and said antibody specific for CD19 exhibits a synergistic level with a combination index (CI) of less than or equal to 0.3 in cell killing of MEC-1 leukemia cells, wherein the CI is calculated according to the CI-isobol method of Chou-Talalay.