CD4+ T-cell counts in spleen showed a trend toward a higher number of Il10rb−/− CD4+ T cells compared to WT T cells per spleen (Supplementary Fig. 7A), which is likely a reflection of the bigger spleen sizes in the Il10rb−/− group, as the number of CD4+ T cells per CLL cell was reduced in these mice in comparison to the WT group (Fig. 6B). This evidence concerns the gene CD4 and B-cell chronic lymphocytic leukemia.