The observed calcium mobilization, shown as the ratio of calcium‐bound Indo‐1 to unbound Indo‐1, after BCR stimulation with different concentrations of anti‐IgM F(ab)2 was significantly increased in both CLL‐like cells or in all B cells of TCL1 × Siglecg−/− mice compared to cells of TCL1 mice in all analyzed organs (Fig 7B). The gene discussed is CD40LG; the disease is B-cell chronic lymphocytic leukemia.