ICAM1 and B-cell chronic lymphocytic leukemia: To further confirm this, we blocked α4 or αL interactions in separate TEM assays through preincubating the CLL cells of LApos and, for comparison, LAneg cases with recombinant forms of VCAM-1 (rhVCAM-1) or ICAM-1 (rhICAM-1) endothelial ligands, respectively.