IL21 and B-cell chronic lymphocytic leukemia: In a subsequent experiment, we compared CLL cells co-cultured on HS5-CD40L-IL4 vs. HS5-CD40L-IL4-IL21 cells (n = 4 CLL), revealing 2057 significantly changed mRNAs (Padj < 0.05; Fig. 2E, Supplementary Tables 9 and 10) including genes associated with interleukin signaling (Supplementary Fig. 2D).