Supporting this hypothesis, we observed that CLL cells activated by pretreatment with an agonist mix (CpG–ODN+sCD40L+IL-10) that upregulates the expression of multiple antiapoptotic proteins (15) displayed resistance to several proapoptotic agents including both inhibitors of Bcl-2, Mcl-1, and Bcl-xL and cytotoxic chemotherapeutic agents (Supplemental Figure 1, A–D; supplemental material available online with this article; https://doi.org/10.1172/JCI155938DS1). Here, MCL1 is linked to B-cell chronic lymphocytic leukemia.