CD40 and B-cell chronic lymphocytic leukemia: For instance, activating antibodies to CD40 (CD40 mAb) or soluble CD40L possess therapeutic potential [4,5,7], for example in the treatment of lymphoproliferative malignancies such as non-Hodgkin lymphoma [11], chronic lymphocytic leukemia [12], diffuse large B-cell lymphoma [13,14] and advanced solid tumors [15,16,17].