Long-Term Outcome After Adoptive Immunotherapy With Natural Killer Cells: Alloreactive NK Cell Dose Still Matters

Recently, many reports were published supporting the clinical use of adoptivelytransferred natural killer (NK) cells as a therapeutic tool against cancer, including acutemyeloid leukemia (AML). Our group demonstrated promising clinical response usingadoptive immunotherapy with donor-derived alloreactive KIR-ligand-mismatched NK cellsin AML patients. Moreover, the antileukemic effect was correlated with the dose of infusedalloreactive NK cells (“functional NK cell dose”). Herein, we update the results of ourprevious study on a cohort of adult AML patients (median age at enrollment 64) infirstmorphological complete remission (CR), not eligible for allogeneic stem celltransplantation. After an extended median follow-up of 55.5 months, 8/16 evaluablepatients (50%) are still off-therapy and alive disease-free. Overall survival (OS) and disease-free survival (DFS) are related with the dose of infused alloreactive NK cells (≥2×105/kg)