CD44 participates in hemorrhage in mice with APL. (A) The outline depicts the steps of the animal experiments. (B) On day 28, the hearts, livers, spleens, and lungs of APL model mice were extracted. The expression of PML-RARA was measured. ImageJ was used to calculate the gray value. (C) Soluble CD44 levels of APL mouse models treated as described above were measured by ELISA. (D) On day 21, fibrinogen levels in the different groups of mice were evaluated. (E) Pearson correlation between the fibrinogen level and soluble CD44 concentration at day 21. (F-G) Bleeding time was recorded, and the Pearson correlation between bleeding time and soluble CD44 concentration was measured, respectively. (H-I) Platelet (Plt) counts were measured, and the correlation between the number of platelets and plasma CD44 concentration was analyzed. (J) d-dimer levels were tested before the mice underwent bleeding time assays. (K) The survival curve and median survival time (days) of transplantation of bare or CD44 knockdown NB4 cells with/without ATRA/ATO treatment. (L-M) The measurement of clot lysis time and K_s number were performed as previously described. Statistical significance was calculated by using the log-rank test and nonparametric, unpaired, two-tailed, Mann-Whitney test. *P < .05, **P < .01, #P < .05 vs the data in ATO + shRNA group in panel F. Ctrl, control; ns, not significant.