Fig 1: ILC2-derived IL-13 expands and activates suppressive M-MDSCs in APL. a Representative example of flow cytometry analysis of cell surface expression of the IL-13Ra1 on CD3+, CD14-, CD14+ cells in peripheral blood of an APL patient. b Frequencies of IL-13Ra1 expressing cells in the different compartments (CD3+, CD14-, CD14 + n = 11). c Representative example of flow cytometry phenotypic analysis of CD14+ cells in healthy donors (HD) and APL patients (APL). Evaluated are the expression of HLA-DR and CD33, to define phenotypic M-MDSC. d Expression of arginase-1 and e iNOS in purified CD14+ cells from HD and APL, as assessed by qPCR (n = 11). f Frequency of M-MDSCs in peripheral blood of HD and APL (n = 22). g, h Expression of arginase-1 (g) and iNOS (h) as assessed by qPCR, in purified CD14+ cells cultured in medium supplemented or not with recombinant IL-13 (rIL-13), or cultured in supernatants derived from ILC2 cell lines, activated by PDG2 and the NB4 APL cell line (SN ILC2). A blocking anti-IL-13 antibody (aIL-13) or an Ig control (Ig Ctrl) were added where indicated (n = 6, three independent experiments). i Representative example of CFSE-dilutions of CD3+ T cells co-cultured with CD14+ monocytes, or with in vitro-induced M-MDSCs (CD14+SN ILC2). j Frequencies of proliferating CD3+ T cells upon co-culture with CD14+ cells or with in vitro induced M-MDSCs (CD14+SN ILC2) (n = 6, three independent experiments). Error bars are s.e.m. Statistical analysis was performed using ANOVA test (b), t test (d–f), Kruskal-Wallis test (g, h) and Mann-Whitney test (j)