BAFF and APRIL expression in B-cell chronic lymphocytic leukemia: correlation with biological and clinical features.

B-cell activating factor (BAFF) and a proliferation-inducing ligand (APRIL) are involved in normal B cell survival and differentiation. We analyzed BAFF and APRIL plasma levels in patients with B-cell chronic lymphocytic leukemia (B-CLL). We also tested intracellular BAFF and APRIL expression in B-CLL and evaluated their prognostic relevance. The percentage of leukemic B cells with intracellular APRIL or BAFF expression correlated significantly with adverse prognostic factors such as ZAP-70 and CD38. Moreover, we found a close relationship between LPL protein expression or LPL/ADAM29 MFI ratio and proportion of B-CLL cells with intracellular BAFF or APRIL expression. Furthermore, patients with a low percentage of leukemic cells with intracellular BAFF or APRIL expression had a significantly longer overall survival than those with a high proportion of APRIL or BAFF positive leukemic cells.