Primary CLL cells in co-culture showed an increase in the expression of CD38, CD49d and CD62L (mean MFI of CD38 expression in co-culture vs. in suspension: 151.9±42.56 vs. 60.16±4.79, P<0.05; mean MFI of CD49d expression in co-culture vs. in suspension: 202.8±22.8 vs. 184.3±22.48, P<0.05; mean MFI of CD62L expression in co-culture vs. in suspension: 993.9±123.7 vs. 626.0±76.49, P=n.s). This evidence concerns the gene CD38 and B-cell chronic lymphocytic leukemia.