During inflammation and infection, many different cells expand (7), including Monocytic Myeloid-Derived Suppressor Cells (M-MDSCs) characterized by the surface markers CD33+CD11b+HLA-DR-CD14+ and the low-density polymorphonuclear MDSCs (PMN-MDSCs) characterized by the surface markers CD33+CD11b+HLA-DR-CD66b+ (8). Here, CD33 is linked to infection.