Endogenous Interleukin-8 (IL-8) Surge in Granulocyte Colony-Stimulating Factor–Induced Peripheral Blood Stem Cell Mobilization

The relationship between stem cell mobilization with granulocyte colony-stimulating factor (G-CSF) and the endogenous production of interleukin-8 (IL-8), macrophage inflammatory protein-1alpha (MIP-1alpha), tumor necrosis factor-alpha (TNF-alpha), and interferon-gamma (IFN-gamma) was studied in normal donors for allogeneic peripheral blood stem cell (PBSC) transplantation. G-CSF was administered to 20 normal donors at a dose of 10 microg/kg/d for 5 days with aphereses on days 5 and 6 of G-CSF treatment. Cytokine serum levels were measured using an enzyme-linked immunosorbent assay (ELISA) before and during G-CSF treatment. Before treatment, the average level of IL-8 was 7.1 pg/mL, increasing to 207.0 pg/mL on day 5 and 189.1 pg/mL on day 6. Serum IL-8 levels correlated CD34(+) cell numbers (P =.0151 and P =.0005 on days 5 and 6, respectively) and colony-forming unit-granulocyte-macrophage (CFU-GM) numbers (P =.0019 and P =.0010 on days 5 and 6, respectively). Furthermore, preapheresis serum IL-8 levels correlated with the yield of CD34(+) cells (P =.0027). In contrast, before treatment, the average levels of MIP-1alpha, TNF-alpha, and IFN-gamma were 70.1, 4.03, and 3.84 pg/mL, respectively, and no significant changes in the levels of these cytokines were observed during G-CSF treatment. These studies suggest that IL-8 production may be critical to G-CSF-induced stem cell mobilization, although the underlying mechanism could not be clarified.