To determine whether the early-acting hematopoietic growth factors stem-cell factor (SCF) or interleukin-3 (IL-3), are able to overcome the bone-marrow suppressive effects of cytokines or drugs involved in the hematologic abnormalities that accompany HIV-1 infection.Design
In vitro colony formation assays of normal human bone-marrow cells exposed to the myelosuppressive drugs, zidovudine, interferon-α (IFN-α) and ganciclovir, or the myelosuppressive cytokines, tumor necrosis factor-α (TNF-α) or transforming growth factor-β (TGF-β), implicated in HIV dysmyelopoiesis.Results
SCF (10ng/ml) enhanced the numbers of erythroid (BFU-E) colonies in the presence of zidovudine or ganciclovir (P < 0.05) and myeloid [colony-forming unit granulocyte macrophage (CFU-GM)] colonies in the presence of ganciclovir or IFN-α (P < 0.05) relative to controls. IL-3 (10ng/ml) also improved erythroid colony numbers in the presence of zidovudine (P < 0.05) and CFU-CM in the presence of IFN-α (P < 0.05). Neither factor consistently altered the inhibition of TGF-β or TNF-α. The 50% inhibitory concentration (IC50) of the myelosuppressive agents was altered in only one setting, using IL-3 in the presence of zidovudine.Conclusions
These data suggest that SCF or IL-3 may have a therapeutic application in overcoming hematopoietic abnormalities associated with drugs commonly used in the care of AIDS patients. However, they may have less capacity to overcome the bone-marrow inhibitory effects of the endogenous cytokines TNF-α and TGF-β.