Osmotic effects of ethanol on lymphocytes

The alterations in the immune system caused by ethanol appear to be a compl ex combination of direct and indirect effects. The role of ethanol as an os molyte has previously been studied in this laboratory with rat splenocytes. In the present study the osmotic effects of ethanol were investigated in l ymphocytes from human normal subjects and alcohol abusers. Mitogen-stimulat ed lymphocytes were cultured in vitro with ethanol in hyperosmotic isotonic or iso-osmotic hypotonic conditions. The former conditions mimic the physi ological situation where ethanol increases osmolality in an electrolyte-bal anced environment. Under these conditions, lymphocyte proliferation was una ffected Ethanol addition in iso-osmotic hypotonic conditions, where there i s electrolyte imbalance, was associated with inhibition of T-lymphocyte pro liferation. Hyperosmotic hypertonic solutions in the absence of ethanol als o resulted in inhibition of T-lymphocyte proliferation. Electron microscopy and measurement of cell viability and metabolic activity (lactate and ATP levels) indicated that the decreased proliferation associated with NaCl-ind uced hyperosmotic hypertonic conditions was at least partially attributable to cell death together with, and possibly caused by, detrimental effects o n mitochondria. Conversely, decreased T-lymphocyte proliferation in iso-osm otic hypotonic high ethanol solutions, appeared nor to be due to changes in cell viability, nor alterations to energy metabolism. It is proposed that ion fluxes involved in the maintenance of cell volume, in particular K+ mov ement, may be important in facilitating normal lymphocyte proliferation in the presence of ethanol in pathological conditions associated with electrol yte imbalance.