Frequency of CD25^hiFoxp3⁺ in the patient cohort. (A) Whole blood was stained with anti-CD4 peridinin chlorophyll protein and anti-CD25 allophycocyanin, followed by intracellular staining using phycoerythrin-conjugated anti-Foxp3. The cells were first gated on the CD4⁺ lymphoid population in peripheral blood mononuclear cells, and the frequency of CD25^hiFoxp3⁺ cells was measured based on the shown gating strategy. (B) Percentage of CD25^hiFoxp3⁺ in the CD4⁺ population in patients before (●) and on treatment with thrombopoietic agents (■) as well as the normal healthy controls (♦). No statistical differences among the groups were seen.