In a phase I clinical study with idelalisib, a consistent decrease of AKT phosphorylation, reduced secretion of stroma-derived factors (CD40L, CCL2, CXCL13, tumor necrosis factor (TNF)-α) as well as CLL-derived chemokines such as CCL3, CCL4, CCL17 and CCL22 could be observed. This evidence concerns the gene CD40LG and B-cell chronic lymphocytic leukemia.