Blood dendritic cells in patients with chronic lymphocytic leukaemia.

Myeloid and plasmacytoid dendritic cells (MDC, PDC) play a key role in the initiation of immune responses. We found a reduction of both DC subsets in 42 patients with chronic lymphocytic leukaemia (CLL) at diagnosis (P<0.0001 and 0.0001 vs. controls, respectively), likely related to the high secretion of CCL22 and CXCL12 (P=0.04 and 0.008 vs. controls, respectively) by leukaemic cells. However, CD14+ monocytes from CLL patients could give rise to functional IL-12p70-secreting monocyte-derived DCs, capable of inducing a type 1 polarization immunostimulatory profile. These monocyte-derived DCs from CLL patients efficiently migrate in response to CCL19/MIP-3beta chemokine, suggesting that functional autologous DCs can be generated for immunotherapeutic purposes to circumvent DC defects in CLL.