A recent study found:

Too much alcohol dulls more than your wits. It also weakens your immune system and could make you much more vulnerable to viruses, including HIV.

To see how alcohol affects resistance to infection, Gyongyi Szabo of the University of Massachusetts Medical School in Worcester and colleagues exposed monocytes – white blood cells involved in the front-line defence against infection – to chemicals that mimic viruses and bacteria. Half of the cells were also soused in the levels of alcohol that a person might have in their blood after quaffing four or five alcoholic drinks daily for a week.

Alcohol blunted the monocytes' defences. When the over-the-limit cells were exposed to a virus mimic, they produced only a quarter as much of the virus-fighting signalling molecule called type-1 interferon as teetotal monocytes made.

"Interferon is pivotal, the first response to any viral infection," says Szabo. "There's no viral elimination without it."

Moreover:

Monocytes exposed to a bacterial chemical suffered a double blow when inebriated. Not only did they make half as much type-1 interferon as their abstemious equivalents, they also overproduced an inflammatory chemical called tumour necrosis factor-alpha. Although important for initiating inflammatory responses to bacteria, continued production of this chemical can damage tissue.

The evidence is mounting that alcohol truly is a toxic brew.

http://www.newscientist.com/article/...ne-system.html