Flow cytometric analysis of BM and spleen from mice expressing Jak2V617F. (A) Dot plots demonstrate a marked increase in the Ter-119/CD71–postive populations in the spleens of heterozygous and homozygous mice compared with control (V617F/+) mice. Modest increases in Gr-1/Mac-1–positive cells in the spleen of heterozygous and homozygous Jak2V617F mice were observed. However, B-cell populations (B220-positive) were proportionately decreased in the BM and spleens of heterozygous and homozygous Jak2V617F mice compared with control animals. (B) Percentages of myeloid, erythroid, B- and T-lymphoid populations are shown in histograms as mean ± SEM. Data are presented as percentage of total cells (control, n = 11; heterozygous, n = 11; homozygous, n = 5). *Significance between control and heterozygous or between control and homozygous; **significance between control and homozygous as well as between heterozygous and homozygous; significant difference at P < .05.