Type I Innate Lymphoid Cells Control Leukemia Stem Cell Fate and Limit Development of Acute Myeloid Leukemia [1]

Type I innate lymphoid cells (ILC1s) are critical regulators of inflammation and immunity in mammalian tissues. However, their functional roles in cancer are largely undefined. We found that a high concentration of normal murine ILC1s induced leukemia stem cell (LSC) apoptosis. At a lower concentration, ILC1s prevented LSCs from differentiating into leukemia progenitors and promoted their differentiation into non-leukemic cells, thus blocking the production of terminal myeloid blasts. All of these effects, which required ILC1s to produce interferon-γ after cell–cell contact with LSCs, converged to suppress leukemogenesis in vivo. Conversely, ILC1s’ anti-leukemia potential waned when JAK-STAT and PI3K-AKT signaling was inhibited. The relevant anti-leukemic properties of normal ILC1s were operative in humans and impaired in AML patients. Collectively, our findings reveal crucial functions of ILC1s as anti-cancer immune cells seemingly suitable for AML immunotherapy, and provide a new potential strategy to treat AML and/or prevent relapse of the disease. Identification of the ILC1 regulatory pathways in AML