Modulation of human basophil histamine release by hemopoietic growth factors

To determine what kinds of CSF modulate human basophil function, recombinant or purified hemopoietic growth factors were tested for the effect on histamine release from basophils. Both granulocyte (G)-macrophage (M) CSF and IL-3 markedly enhanced histamine release upon stimulation with anti-IgE in a dose-dependent manner (maximal enhancement 25.5% by GM-CSF and 30.8% by IL-3 as expressed as percent increase against total cellular histamine content), whereas G-CSF, M-CSF, and IL-4 had no effect. Enhancing action of these factors was still observed in the highly enriched basophil population, suggesting that this action was not via contaminating cells. Enhancement of histamine release by both factors was not necessarily IgE mediated, because they also amplified histamine release upon stimulation with FMLP and ionophore A23187. The enhancement by both factors was temperature dependent, and took place rapidly and reached plateau levels in 15 min. GM-CSF and IL-3 achieved the similar plateau level of augmentation and no additive effects were observed between them. This finding suggests that they enhance histamine release by sharing the same pathway in the release reaction.