BCR signaling measured by Ca2+ mobilization upon BCR stimulation with IgM showed that BCRlow RT cells (patients 12 and 63) had a lower Ca2+ flux compared to CLL, which contrasted with the higher flux observed in the BCRnormal RT cells of patient 19, concordant with its IGLV3–21R110 mutation27 (Fig. 5b, Supplementary Fig. 4a,b and Supplementary Table 25). The gene discussed is CD40LG; the disease is B-cell chronic lymphocytic leukemia.