The following criteria is provided for health care professionals.

Inclusion Criteria:

* Subjects must have histologic or cytologic confirmation of ANY hematologic malignancy
* Allogeneic stem cell transplant is indicated as management of underlying hematologic malignancy.
* Participant has organ function (cardiac, lung and liver) considered adequate to undergo conditioning chemotherapy and allogeneic stem cell transplant in the assessment of the clinical program
* Participant has a 10/10 HLA-matched sibling donor OR has a HLA-haploidentical donor available (in the absence of a 10/10 HLA matched unrelated donor)
* The related transplant donor is willing, available and consents to undergo a second, non-mobilized leukapheresis for the procurement of donor lymphocytes
* The related transplant donor is 18 years of age or older
* Subjects must have the ability to understand and the willingness to sign a written informed consent document or provide assent.

Exclusion Criteria:

* Subject is unwilling to receive a prophylactic donor lymphocyte infusion per study protocol.
* The related donor is unwilling or unavailable to undergo a second, non- mobilized leukapheresis for the procurement of donor lymphocytes.
* Women of child-bearing potential and men must agree to use adequate contraception (double barrier method of birth control or abstinence) 4 weeks prior to study entry and for the duration of study participation. Women of child-bearing age must have documented negative pregnancy test prior to start of conditioning regimen for stem cell transplantation and a repeat negative pregnancy test prior to infusion of the lymphocyte product.
* Patients with any of the following organ function abnormalities: Left ventricular ejection fraction (LVEF) \< 45%; DLCO \<45% of expected value corrected for alveolar volume and hemoglobin; Serum Creatinine \>2 times the upper limit of normal.