Alcohol suppresses both the innate and the adaptive immune systems. Chronic alcohol use reduces the ability of white blood cells to effectively engulf and swallow harmful bacteria. Excessive drinking also disrupts the production of cytokines, causing your body to either produce too much or not enough of these chemical messengers. An abundance of cytokines can damage your tissues, whereas a lack of cytokines leaves you open to infection.
Chronic alcohol use also suppresses the development of T-cells and may impair the ability of NK cells to attack tumor cells. This reduced function makes you more vulnerable to bacteria and viruses, and less capable of destroying cancerous cells.
With a compromised immune system, chronic drinkers are more liable to contract diseases like pneumonia and tuberculosis than people who do not drink too much. There is also data linking alcohol's damage to the immune system with an increased susceptibility to contracting HIV infection. HIV develops faster in chronic drinkers who already have the virus.
Drinking a lot on a single occasion also can compromise your immune system. Drinking to intoxication can slow your body's ability to produce cytokines that ward off infections by causing inflammations.Without these inflammatory responses, your body's ability to defend itself against bacteria is significantly reduced. A recent study shows that slower inflammatory cytokine production can reduce your ability to fight off infections for up to 24 hours after getting drunk.