CCL21 and B-cell chronic lymphocytic leukemia: CCR7 mRNA levels are higher in CLL (M and UM) than normal B cells (2.6 and 3.6 fold change).CCR7surface expression levels are higher in CLL (M and UM) than normal B cells (3 fold change).Total cell content is 4 and 5 times higher in CLL cells than in normal B cells.UM CLL cells showed a preferential binding and migration towards CCL21.