Effects of cytokine stimulation and JAK2 mutation on marker expression. (A) Expression of markers in granulocytes of 3 healthy donors before and after stem cells mobilization by G-CSF. For each individual, the gene expression is shown before (–) and after (+) G-CSF administration and the corresponding values are connected by solid lines. The mRNA levels of the markers were determined by quantitative PCR. Relative gene expression is shown on a logarithmic scale (log₁₀) and the values represent the mRNA expression relative to a healthy control calibrator sample, calculated by the ΔΔC_T method. (B) Marker expression in patients with the JAK2-V617F mutation. The mRNA level of individual markers was determined in 28 healthy controls (C) and in 54 patients with PV (horizontal line) grouped according to the JAK2 genotype. Ten patients with wild-type JAK2 (GG), 21 patients heterozygous for the JAK2-V617F mutation (GT), and 23 patients homozygous for the JAK2-V617F mutation (TT) were examined. Bars with asterisks indicate statistically significant differences between groups (P < .05; Mann-Whitney U test).