In this study, we challenged Gfi1:GFP knock-in reporter mice by cecal ligation and puncture (CLP) surgery and found that the population of CD11b+Ly6GlowLy6Chigh cells in this sepsis model were heterogeneous and consisted of both monocytic and granulocytic MDSCs and that CD48 can distinguish monocytic and granulocytic MDSCs during infection. Here, GFI1 is linked to Sepsis.