Expansion of CCL3-expressing basophil-like leukemia cells in CML BM. (A) CD45.1⁺ congenic mouse-derived LICs were subjected to the CML model. The proportion of Ki67⁺ cells among CD45.2⁺ recipient-derived normal KLS⁺ cells was determined in the tibial BM. Data represent mean ± SD from 4 independent experiments. *P < .05; N.S., no significant difference by Dunnett’s test. (B) WT donor-derived LICs were subjected to the CML model. Expression of basophilic phenotypic markers was determined for BCR-ABL (GFP)⁻CCL3⁺ normal cells (R1) or GFP⁺CCL3⁺ leukemia cells (R2), and CCL3-expression levels were compared between GFP⁻ and GFP⁺ basophil-phenotypic cells in the tibial BMs at 2 to 3 weeks after transplantation. Rat IgG2a was used as an isotype control. Representative results from 3 independent experiments are shown. (C) Proportion of Ly6G⁺ or FcεR1⁺ cells in normal tibial BM cells or GFP⁺ BM leukemia cells harvested from CML mice at 3 weeks after transplantation. Data represent means ± SD from 4 independent experiments. *P < .05; N.S., no significant difference by the Mann-Whitney U test. (D) Expression of Ly6G and FcεR1 on GFP⁺ leukemia cells in the tibial BM and PB at 3 weeks after transplantation. Representative results from among 4 individual animals are shown along with the percentages of Ly6G⁻FcεR1⁺ cells among GFP⁺ leukemia cells. (E) Expression of CCL3 (fast blue) and ENPP3 (fast red) in the BM biopsy specimens of patients with CML. Representative results from 5 patients with CML are shown. Images were obtained using a BX50 microscope using a ×20 objective lens. Scale bar, 20 μm. Arrows indicate CCL3⁺ENPP3⁺ cells. (F) Expression of CCL3 in FcεR1⁺ENPP3⁺ cells in the BM biopsy specimens of patients with CML. Mouse IgG2b was used as an isotype control. Each histogram represents 1 individual.