RESUMEN
In an attempt to increase the number of macrophages available for reinfusion in immunotherapy trials, GM-CSF was injected in vivo to mobilize circulating blood monocytes in 2 cancer patients. Subsequently mononuclear cells were collected by apheresis, cultured in the presence of GM-CSF and activated with IFN-gamma. This procedure resulted in the harvesting of 1.3 to 3.1 x 10(9) (mean 2 x 10(9)) macrophages per apheresis, product which was very well tolerated at autologous reinfusion. These infusions did not induce increased levels of TNF-alpha, IL-6, soluble CD14 nor nitrates in blood plasma (or urine). The lack of TNF-alpha and IL-6 release in blood plasma could explain the good tolerance of these infusions. No in vivo anti-tumoural activity of these high numbers of infused macrophages could be observed.