CD40LG and B-cell chronic lymphocytic leukemia: With the aim of partially ex vivo mimicking the microenvironment found in the proliferative centers, we cultured primary CLL cells in 5 different culture conditions: in suspension, co-cultured with the BMSC cell line UE6E7T-2, with soluble CD40L, with CpG ODN and with the combination of all elements: BMSC, CD40L and CpG ODN.