Platelets interact with neutrophils in HMGA2-overexpressing MDS mice. (A) Schematic of sample collection and FACS gating strategy. (B-C) Flow cytometric analysis of PB cells from indicated mice. Frequency of CD62P⁺ (P-selectin positive) platelets is shown in panel C. Data are presented as the mean ± SD. (D) Schematic of sample collection and FACS gating strategy. (E-F) Flow cytometric analysis of lung-infiltrated cells of Empty (n = 5) and RUNX1^S291fs/HMGA2 mice (n = 6). Frequency of CD41⁺ cells within CD11b⁺ lung-infiltrated cells is shown in panel F. Data are presented as the mean ± SD. The difference between the 2 groups is approximately twofold (1.95 times). (G-H) Representative immunofluorescence images of CD41⁺ Ly6G⁺ PNCs within CD11b⁺ cells obtained from the lung of RUNX1^S291fs/HMGA2 mice at 4 months after BMT. Scale bar, 5 μm. (E) Frequency of PNCs (≥100 cells per sample) from Empty (n = 5) and RUNX1^S291fs/HMGA2 mice (n = 3). Data are represented by the mean ± SD. (I-J) Annexin V flow cytometric analysis of lung-infiltrated cells of Empty (n = 5) and RUNX1^S291fs/HMGA2 mice (n = 6). Frequency of annexin V⁺ cells within lung-infiltrated neutrophils is shown in panel J. Data are presented as the mean ± SD. ∗P < .05 and ∗∗P < .01.