JNK1 mRNA expression after ibrutinib treatment . (A) B cells from healthy donors were isolated and stimulated with anti-IgM antibody to induce BCR activation for 1 h with and without ibrutinib treatment (2 µM). BCR activity was assessed via intracellular BTK phosphorylation. JNK1 mRNA levels were detected via TaqMan PCR and normalized to GAPDH (see Materials and methods section). The graph shows relative JNK1 transcript levels for three different blood donors. (B) CLL cells (n = 5 pts) were treated with ibrutinib 2 µM for 0.5, 1, and 48 h, and relative mRNA levels for JNK1 were assessed as described above. Controls were set to 1 for each individual patient (unpaired t test, ****P < 0.0001).