While a few Treg associated biomarkers including IL-10, IL-2R and CCL17 were found to be elevated in PV patients compared to healthy controls, c-c chemokine receptor (CCR)4, Treg cell count and the forkhead box protein (FOXP)3 transcription factor unique to Treg cells were found to be decreased. Here, CCL17 is linked to acquired polycythemia vera.