In WHO-HAEM5 CD5 positive cases of former B-prolymphocytic leukemia (B-PLL) defined by >15 % prolymphocytes in blood/bone marrow are now incorporated into the diagnosis of CLL, provided an appropriate phenotype and the exclusion of an CCND1 rearrangement are demonstrated [1]. Here, CD5 is linked to B-cell chronic lymphocytic leukemia.