Because macrophages and monocytes of the mouse peritoneal cavity are often found in lymphoid aggregates with T cells and CD5+B220+ B1 cells, which are almost absent in lymphoid tissues, we reasoned that the CLL cells resided in niches, which prevent efficient killing by αSlamf6 or other monoclonal antibodies [42]. The gene discussed is CD5; the disease is B-cell chronic lymphocytic leukemia.