These studies confirmed that expression of the ligands for NKG2D (ULBP-1, ULBP-2 and MICA/B) and DNAM-1 (CD112 and CD155) on CLL cell lines and primary samples was low/absent; in contrast, significant HLA-Class I expression was observed (Figure 4). This evidence concerns the gene ULBP1 and B-cell chronic lymphocytic leukemia.