Effects of ethanol on human monocyte IgG Fc receptors.

The IgG Fc receptor function of human monocytes (Mo) exposed to ethanol in vitro was assessed by a rosette assay in which IgG-coated sheep red blood cells were used as test particles. Pre-incubation of Mo in autologous serum with ethanol (55 mM and above) for 15 min at 37 degrees C, caused a significantly lower percentage of Mo-forming rosettes. This reduction by ethanol was not observed when Mo were preincubated with ethanol in fetal calf serum or in serum-free conditions, but was present when Mo were pre-incubated with ethanol in serum-free media to which IgG (10-150 micrograms/ml) had been added. Donor-dependent differences were observed in the reduction of Mo-forming rosettes in the presence of autologous serum and ethanol. Mo allowed to form rosettes without ethanol were exposed to ethanol during a subsequent phagocytosis process. A dose-dependent inhibition of the internalization of test particles was found in Mo from all donors.