CD4 and B-cell chronic lymphocytic leukemia: Interestingly, PI3K-δ inhibition with idelalisib in patients with CLL has been shown to inhibit CD4+CD25+CD127- Treg proliferation and Treg-induced suppression of CD4+ and CD8+ T-cells, suggesting pre-infusion pharmacologic PI3Ki therapy may favorably augment the effects of lymphodepletion (121).