Based on IGHV sequencing22, ten CLL patients with the highest IBTKα expression (CLL 2, 3, 4, 5, 11, 14, 22, 25, 26, 31) belonged to the M-CLL subtype, which might explain the lack of up-regulation of LPL, CD38 and ZAP70 genes in our CLL samples. This evidence concerns the gene ZAP70 and B-cell chronic lymphocytic leukemia.