Analysis of spleen and bone marrow in a murine eosinophilic disease model induced by the F/P fusion gene. (A) Spleen weight of the same groups of mice that underwent transplantation as shown in Figure 1. Data are shown as mean ± SD and represent 10 to 12 mice per group, pooled from 3 independent experiments. **P < .01, compared with non–Tg-mock; ##P < .01, compared with IL-5Tg-mock. Histopathologic analysis of spleen (B) and bone marrow (C) was performed at 4 weeks by hematoxylin/eosin staining for sectioned tissue and Diff-Quick staining for cytospins. Representative examples (of 5-12 mice per group, pooled from 3 independent experiments) are shown in panels B-C (i: non–Tg-mock; ii: non–Tg-F/P; iii: IL-5Tg-mock; iv: IL-5Tg-F/P; optical magnification × 500). Arrows in panel C indicate eosinophils. Inset of panel B shows cytospin of IL-5Tg-F/P recipient spleen (optical magnification × 500). CD49d (α₄-integrin) expression on CD49d⁺ cells in CCR3⁺/EGFP⁺/7-AAD^– BM cells (D) and Siglec-F expression on Siglec-F⁺ cells in EGFP⁺/7-AAD^– BM cells (E) in IL-5Tg-mock (blue lines) and IL-5Tg-F/P (red lines) were analyzed by flow cytometry. Representative examples (3-12 mice per group, pooled from 2 or 3 independent experiments) are shown in panels D and E.