MKI67 and B-cell chronic lymphocytic leukemia: In this setting, proliferative responses, measured as increase in expression of Ki-67, were significantly observed after 48 hours in CLL cells cultured with BMSC, CD40L and CpG ODN (Figure 1A) (mean % Ki-67 positive cells: 4.41±1.41 cultured with BMSC, CD40L and CpG ODN vs. 0.42±0.10 in suspension, P<0.01) and were even higher after 72 hours when, as we had previously observed [15], the co-culture with BMSC, CD40L and CpG ODN induced a Ki-67 expression of 10.71% ± 2.51% vs. 1.18%±0.34% in suspension (P<0.001).