Immunophenotyping and flow cytometry analysis FACS analyses were performed on cryopreserved samples. After thawing blood cells were incubated for 15 minutes at 4uC with conjugated monoclonal antibodies (mAbs). For intracellular labeling, cells were permeabilized with the Cytofix/Cytoperm Kit (Becton Dickinson) before incubation with specific mAbs according to the manufacturer's instructions. Samples were then washed, fixed in 2% paraformaldehyde phosphate-buffered saline (PBS/PFA 2%) and acquired using a Cyan cytofluorometer (Dako) and analyzed with FlowJo 8.7 software.