Mobilization of dendritic cells in cancer patients treated with granulocyte colony-stimulating factor and chemotherapy.

The number of dendritic cells (DC) circulating in the peripheral blood of cancer patients were monitored at multiple time points during chemotherapy and granulocyte colony-stimulating factor (G-CSF) support. DC were identified via the lack of expression of standard lineage markers and high expression of HLA-DR (LN-/DR+). The expression of DC-associated markers, including CD83, CD11c, IL-3Ralpha (CDw123) and CD86, within this LN-/DR+ population was also monitored. Maximal mobilization occurred during recovery on d 12, with a mean 32-fold increase in LN-/DR+ numbers. The most striking increase was observed in the LN-/DR+/CD83+ cell population: 12 d after commencement of treatment, the proportion of these cells had increased by approximately 120-fold when compared with baseline. Peripheral blood mononuclear cell (PBMC) and CD34+ cell numbers also peaked 12 d into the treatment regimen in most patients. These data suggest that it should be possible to acquire substantial numbers of DC from leukapheresis products collected from cancer patients undergoing a standard treatment regimen of chemotherapy and G-CSF. This strategy may be a feasible, low-risk means of acquiring cells for DC-based vaccine studies.