CD4 and acquired polycythemia vera: Through this quantitative experiment, we demonstrated that the mRNA levels of GATA3, IL-4, and IL-13 are elevated in CD4+ T cells from patients with PV, compared with those from healthy control subjects (1.359 ± 0.113 vs. 1.000 ± 0.048, p = 0.001; 3.282 ± 0.383 vs. 1.000 ± 0.388, p < 0.001; 4.602 ± 1.053 vs. 1.000 ± 0.249, p = 0.008, respectively; Figure 2).