CD40LG and B-cell chronic lymphocytic leukemia: With the aim of in vitro reproducing the microenvironment that CLL cells find in the proliferative centers in vivo, we have developed a co-culture system of primary CLL cells with the bone marrow stromal cell (BMSC) cell line UE6E7T-2, soluble CD40L, CpG ODN and anti-IgM which has been reported elsewhere21.