Figure 2. Splenectomized human AML xenograft mice die of BM failure.

(A) Schematic of experimental procedure. (B) Hemoglobin results at 12 weeks are shown. (C) Human AML engraftment at 12 weeks. (D) Representative spleens and tibiae from NSG-PDX and irradiated-only mice are shown on the left. NSG-PDX mice (n=15) demonstrated increased splenic weight (n = 7) (p < 0.0001, unpaired t-test). (E) Representative H&E stained spleen sections from NSG-PDX mice demonstrating the presence of increased megakaryocytes (white arrows). Red pulp expansion (red areas) is seen in splenectomized NSG-PDX mice. (F) Schematic of experimental procedure. (G) Eight weeks after transplantation, hemoglobin was determined in NSG^spln--PDX mice (10 primary AML samples, n = 50 total with 5 mice in each group, p<0.0001, 1-way ANOVA) compared to NSG^sham-PDX (n=32, 10 independent AML samples) and NSG^spln--CB-CD34⁺ mice (n=15, 3 independent CB) (H) Correlation of hemoglobin and human AML BM engraftment in NSG^spln--PDX mice color-coded to reflect individual AML samples as reported in (D) (n= 46, R²= 0.02 Pearson correlation determination, p=0.42). (I) Correlation of hemoglobin and BM engraftment in NSG^spln--CB-CD34⁺ mice (n=11, R²=0.031, p=0.60). (J) Kaplan-Meier survival curve indicating overall survival of NSG^spln- irradiated only (n=5, median survival not reached), NSG^sham-SU540 (n=5, median survival 36 weeks), NSG^spln--SU540 (n=7, median survival 9.5 weeks), and NSG^spln-CB-CD34⁺ (n=5, median survival not reached ) engrafted mice. NSG^spln-PDX mice have shortened overall survival compared to NSG^sham-PDX (p<0.0001). n.s. = not significant.