Extended Data Fig. 1: Langerhans Cell Histiocytosis mouse models.

a-f, BRAFV600E^Scl+ mice and BRAFwt^Scl+ mice were generated as described in Fig. 1a. a, Representative images of spleen, lung, and femurs at 4 weeks post tamoxifen injections. b, Liver and spleen weights. c, Absolute number of BM cells in BRAFV600E^Scl+ mice and control littermates (n = 10 mice per group). d, Hematoxylin and eosin staining and CD207 immunohistochemistry staining of tissues isolated from BRAFwt^Scl+ mice (n = 2–3 mice per group). e, Absolute numbers of lung, dermal and epidermal immune cells in BRAFV600E^Scl+ mice and control littermates. Data are representative of 3 experiments (n = 3–8). f, Percentage of immune cell populations among lung and skin infiltrating Rosa^YFP+ cells in BRAFV600E^Scl+ mice and control littermates. Data are representative of 3 experiments (n = 3–8). g, Scheme of the lentiviral vector constructs used to transduce human CD34⁺ HPC. h, Graph shows that the transduction efficiency of BRAFV600E and NGFR lentiviral constructs in human CD34⁺ HPC does not exceed 40 %. i, Western blot of BRAF and phospho-ERK performed on purified BRAFV600E^hu and NGFR^hu human CD34⁺ HPC 7 days after transduction. j, Representative flow plot showing the percentage of CD11c⁺ CD14⁺ MNP among circulating blood cells in NSG mice reconstituted with BRAFV600E^hu and NGFR^hu HPC. Graph represents the percentage of CD11c and or CD14⁺ cells among human CD45⁺ cells from NSG circulating blood (n = 2–3 mice per group). Data are represented as mean ± s.e.m; statistical significance analyzed by an unpaired two-sided t-test is indicated by *p < 0.05; **p < 0.01; ***p < 0.001; ****p < 0.0001.