Interleukin-21 (IL-21)- Expanded Natural Killer Cells for Induction of Acute Myeloid Leukemia

Inclusion Criteria:

Obtained within 30 days prior to beginning the lymphodepleting conditioning regimen, unless otherwise specified.

* Patients with relapsed AML, including Canadian Neurological Scale (CNS) disease or previous hematopoietic stem cell transplantation, which has failed remission to at least one cycle of standard or experimental reinduction chemotherapy, or primary refractory AML (primary AML that has failed remission to at least two cycles of induction therapy)
* Availability of a haploidentical family peripheral blood donor selected for best possible killer cell inhibitory receptor (KIR) reactivity.
* Patient age between 2 and 59 years, inclusive.
* Patient must have recovered from the treatment-related toxicities of prior cytotoxic agents received in the 4 weeks prior to beginning treatment on this protocol, with the exception of cytopenias resulting from persistent disease, and alopecia.
* "Zubrod" performance scale ≤ 2 or "Lansky" scale ≥ 60.
* Adequate renal function defined as:

  * Serum creatinine ≤2 mg/dL for adults.
  * Serum creatinine ≤2 mg/dL or ≤2 times upper limit of normal (ULN) for age (whichever is less) for children.
  * Or, if serum creatinine does not meet above criteria, patient will be eligible if 24h creatinine clearance ≥60 mL/min/1.73m2.
* Adequate liver function, defined as: Total bilirubin ≤2 mg/dL and serum glutamate pyruvate transaminase(SGPT) (ALT) ≤2.5 x ULN for age (unless Gilbert's disease or abnormal liver function due to primary disease).
* Pulmonary symptoms controlled by medication and pulse oximetry ≥ 92% room air.
* New York Heart Association classification \< III
* Negative serum test to rule out pregnancy within 2 weeks prior to registration in females of childbearing potential (non childbearing potential defined as premenarchal, greater than one year post-menopausal, or surgically sterilized).
* Sexually active males and females of childbearing potential must agree to use a form of contraception considered effective and medically acceptable by the Investigator.
* Negative serology for human immunodeficiency virus (HIV).

Exclusion Criteria:

* Failed attaining remission with any previous FLAG therapy.
* Investigational therapies in the 4 weeks prior to beginning treatment on this protocol.
* Congestive heart failure \<6 months prior to screening
* Unstable angina pectoris \<6 months prior to screening
* Myocardial infarction \<6 months prior to screening