HLA-E and B-cell chronic lymphocytic leukemia: Consistent with our in vitro data, CXCR4low CD5high CLL cells that have recently egressed from the lymph nodes expressed significantly higher levels of surface HLA-E compared to CLL cells that have been in the circulation for longer; defined as CXCR4high CD5low and CXCR4intermediate CD5intermediate (Fig. 7I).