S100A9 and acquired polycythemia vera: rHMGB1 triggered inflammatory mediators associated with PV, such as: Cxcl1, Cxcl2, and Ccl20, S100a7, S100a8, S100a9, and Defb2 (defensin beta 2), IL1b and TNF, IL23A-IL17A axis cytokines IL23a, IL17a, and IL22, transcription factors (Rorc/Rorγt) and the neutrophil membrane marker Ly6g [21].