We did not observe a difference between mutated and unmutated CLL cells, possibly because in contrast to these authors we stimulated the mononuclear cell fraction instead of purified CLL cells, and in addition the anti-IgM beads we use present immobilized anti-IgM antibodies, which elicit superior BCR stimulation compared to soluble anti-IgM antibodies which are rapidly internalized by endocytosis [7], [39], [50]. Here, BCR is linked to B-cell chronic lymphocytic leukemia.