A cross between JAK2 V617F/+mice with Spic-EYFPCre or Csf1r-Cre or CD169-Cre mice would allow further investigation into the specific contribution of EBI macrophages on the pathophysiology of PV, as Spic, Csf1r, and CD169 are expressed by EBI macrophages but not erythroid cells (An et al., 2014; Li et al., 2019). The gene discussed is CSF1R; the disease is acquired polycythemia vera.