CEACAM8 and infection: As previously stated, CD66b+-isolated PBMCs met the criteria of MDSCs in their ability to suppress either T-lymphocyte cytokine/chemokine production or T-lymphocyte proliferation ex vivo (Figures 5, 6) (4, 16), although CD66b+-isolated PBMCs were not identical in their suppressive activity from acutely septic patients or late time periods after severe infection.