Blood cell parameters. Primary (left panels) or secondary (right panels) JAK2^V617F, JAK2^WT, or empty virus-recipient mice were analyzed every 1 to 3 weeks following transplantation, and data collected each month were pooled. Details of platelet counts are indicated for the MS1 group. Depicted are hemoglobin levels (A), MCVs (B), platelet counts (C), and WBC counts (D). • indicates JAK2^V617F (MP1/MS1); ▪, JAK2^V617F (MP2/MS2); ○, JAK2^WT; and □, empty virus. MP or MS correspond to primary or secondary JAK2^V617F virus-recipient mice, respectively. Details of platelet counts are indicated for the MS1 group in panel C. The mean numbers of mice studied per determination were 7, 9, 12, and 15 mice for the MP1, MP2, MS1, and MS2 groups, respectively. Around 2 determinations per month were carried out. Similar numbers of matched controls were studied. ^*P < .05 compared with the JAK2^WT-transduced mice.