• CTCAE grade 3 or higher immune reactions [ Time Frame: 6 Weeks ]
  Safety assessment will include grading any immune reactions.
• Grade I-IV acute GVHD [ Time Frame: day 180 ]
  Patients will be monitored for any graft versus host disease (GVHD) development.
• Chronic GVHD requiring immune suppressants (IS) [ Time Frame: 1 year ]
  Patients will be monitored for the development of chronic graft versus host disease (cGVHD)
• Best Overall Response (CR, PR) [ Time Frame: 6 Weeks ]
  Disease response will be assessed by Complete Remission (CR) or Partial Responses (PR) assessment.
• Leukemia free survival (LFS) [ Time Frame: 1 year ]
  Disease response will also include assessment of the leukemia free survival at one year.
• Overall survival (OS) [ Time Frame: 1 year ]
  Response assessment will also include Overall Survival (OS) at one year.

• Overall Response Rate [ Time Frame: 2 years ]
• Progression Free Survival [ Time Frame: 1 year ]
• Overall Survival Rate [ Time Frame: 1 year ]
• The incidence and severity of acute GVHD rates after CIML NK cell infusion plus IL-2 [ Time Frame: 2 years ]
• The incidence and severity of chronic GVHD rates after CIML NK cell infusion plus IL-2 [ Time Frame: 2 Years ]

This research study is a Phase I clinical trial, which tests the safety of an investigational intervention and also tries to define the appropriate dose of the investigational intervention to use for further studies. "Investigational" means that the intervention is being studied.

The U.S. Food and Drug Administration (FDA) has not approved CIML NK Cell Infusion as a treatment for relapsed disease.

• Biological: CIML NK
  CIML NK cells have enhanced ability to recognize and kill leukemia targets
• Drug: Fludarabine
  Fludarabine is a chemotherapy drug Chemotherapy is most effective at killing cells that are rapidly dividing.
• Drug: Cyclophosphamide
  Cyclophosphamide (CP), also known as cytophosphane among other names, is a medication used as chemotherapy and to suppress the immune system.

Inclusion Criteria:

• Histologically or cytologically confirmed relapse of AML, MDS or MPN (CMML or myelofibrosis or MDS/MPN with ≥5% blasts in the marrow).
• Relapse at ≥2 months after first related donor haploidentical stem cell transplantation.
• Available original donor (same donor as used for the initial stem cell transplant) that is willing and eligible for non-mobilized collection.
• Age ≥18 years.
• ECOG performance status ≤2 (Karnofsky ≥60%, see Appendix A).
• Recipient donor T cell chimerism ≥20% within the 4 weeks prior to cell infusion.
• Patient with ≤50% bone marrow involvement within 4 weeks prior to cell infusion.
• No systemic corticosteroid therapy for GVHD (≤ 5mg of prednisone or equivalent dose of systemic steroids for non-GVHD, non-autoimmune indications for at at least 4 weeks prior to cell infusion).
• No other systemic medications/treatments (e.g. ECP) for GVHD for at least 4 weeks prior to cell infusion.
• Ability to understand and the willingness to sign a written informed consent document.

• Adequate organ function as defined below:

  • Total bilirubin: ≤1.5 x institutional upper limit of normal (ULN) (except Gilbert's or disease-related hemolysis, then < 3 x ULN)
  • AST(SGOT)/ALT(SGPT): ≤3 x institutional ULN
  • creatinine clearance: ≤1.5 x institutional ULN
  • O2 saturation: ≥90% on room air
  • LVEF >40%
• Negative pregnancy test for women of childbearing potential only.
• The effects of CIML NK cells and IL-2 on the developing human fetus are unknown. For this reason, women of child-bearing potential and men must agree to use adequate contraception (hormonal or barrier method of birth control; abstinence) prior to study entry and for the duration of study participation. Should a woman become pregnant or suspect she is pregnant while she or her partner is participating in this study, she should inform her treating physician immediately. Men treated or enrolled on this protocol must also agree to use adequate contraception prior to the study, for the duration of study participation, and 4 months after the last IL-2 dose administration.

Exclusion Criteria:

• Extramedullary relapse involving immuno-privileged sites (e.g. CNS, testes, eyes). Other sites of extramedullary relapse (e.g. leukemia cutis, granulocytic sarcoma) are acceptable.
• Participants who have had anti-tumor chemotherapy or other investigational agents within 4 weeks prior to cell infusion (6 weeks for nitrosoureas or mitomycin C), or immunotherapy within 8 weeks prior, or those who have not recovered from adverse events due to agents administered more than 4 weeks prior. Use of hydroxyurea to control counts within 4 weeks prior to cell infusion is permitted.
• Prior history of treatment with anti-CTLA-4 or anti-PD-1 pathway therapy, or CD137 agonist therapy for post-transplant relapse.
• Prior history of Donor Lymphocyte Infusion (DLI).
• Prior history of severe (grade 3 or 4) acute GVHD, or ongoing active GVHD requiring systemic treatment.
• Organ transplant (allograft) recipient.
• History of allergic reactions attributed to compounds of similar chemical or biologic composition to IL-2 or other agents used in study.
• Autoimmune disease: Patients with a history of inflammatory bowel disease, including ulcerative colitis and Crohn's Disease, are excluded from this study, as are patients with a history of symptomatic disease (e.g., rheumatoid arthritis, systemic progressive sclerosis [scleroderma], systemic lupus erythematosus, autoimmune vasculitis [e.g., Wegener's Granulomatosis]) and motor neuropathy considered of autoimmune origin (e.g. Guillain-Barre Syndrome and Myasthenia Gravis). Patients with Hashimoto's thyroiditis are eligible to go on study.
• Uncontrolled intercurrent illness including, but not limited to, ongoing or active infection, symptomatic congestive heart failure, unstable angina pectoris, cardiac arrhythmia, or psychiatric illness/social situations that would limit compliance with study requirements.
• Pregnant women are excluded from this study because of the unknown teratogenic risk of CIML NK cells and IL-2 and with the potential for teratogenic or abortifacient effects by Flu/Cy chemotherapy regimen. Because there is an unknown but potential risk for adverse events in nursing infants secondary to treatment of the mother with CIML NK cells and IL-2, breastfeeding should be discontinued if the mother is treated on this study.
• HIV-positive participants are ineligible because of the potential for pharmacokinetic interactions with anti-retroviral agents used in this study. In addition, these participants are at increased risk of lethal infections when treated with marrow-suppressive therapy.
• Individuals with active uncontrolled hepatitis B or C are ineligible as they are at high risk of lethal treatment-related hepatotoxicity after HSCT