Levels of Bcl-2 members increase upon venetoclax treatment. (A) Summary of Bcl-2 member expression in LN emigrants and immigrants before and after venetoclax treatment (n = 5). Venetoclax T1 and T2 represent time points 1 and 2 (ie, the first and second sampling of PB during venetoclax ramp-up; median time of 3 weeks in between time points). A paired-sample Student t test was used for statistical analyses between baseline and Venetoclax T1 or T2. (B) Western blot of PB collected from 4 patients treated with venetoclax. Samples were collected at baseline and upon 2 to 4 weeks of venetoclax treatment. Protein lysates were probed for Mcl-1, Bcl-XL, and Bcl-2; actin was used as loading control. (C) CLL cells of 2 patients were cultured on 3T3 or 3T40L for 24 hours. After detachment, cells were treated with the BH3 mimetics venetoclax (ABT199), S-63845 (S63), or A-1331852 (A13) for an additional 24 hours. Protein lysates were probed for Mcl-1, Bcl-XL, and Bcl-2; actin was used as loading control. B, baseline; ns, not significant.