Effects of ethanol on human monocyte/macrophage lysozyme storage and release. Implications for the pathobiology of alcoholic liver disease.

The effect of ethanol on the release and/or intracellular accumulation of lysozyme (LZM) by human monocytes and monocyte-derived macrophages (mø) was investigated in vitro. A reverse haemolytic plaque assay, to detect and quantify LZM release by individual cells was combined with quantitative immunocytochemistry using LZM and the pan-macrophage monoclonal EBM/11 as markers. Ethanol had no effect on monocytes; however it reduced secretion of LZM by a mø subpopulation. Ethanol also reduced both the total number of mø immunoreactive for LZM, (but not EBM/11), and the proportion of LZM-secreting mø containing detectable LZM. The latter was correlated with an increase in the proportion of LZM-secreting mø that were not immunoreactive for this enzyme. These data suggest functional heterogeneity amongst human macrophages with a mø subpopulation which responds to ethanol exposure with a drop in both content and release of LZM. This might have implications for macrophage function in alcoholic liver disease.