Focus on: Alcohol and the immune system.

Alcohol abuse suppresses multiple arms of the immune response, leading to an increased risk of infections. The course and resolution of both bacterial and viral infections is severely impaired in alcohol-abusing patients, resulting in greater patient morbidity and mortality. Multiple mechanisms have been identified underlying the immunosuppressive effects of alcohol. These mechanisms involve structural host defense mechanisms in the gastrointestinal and respiratory tract as well as all of the principal components of the innate and adaptive immune systems, which are compromised both through alcohol's direct effects and through alcohol-related dysregulation of other components. Analyses of alcohol's diverse effects on various components of the immune system provide insight into the factors that lead to a greater risk of infection in the alcohol-abusing population. Some of these mechanisms are directly related to the pathology found in people with infections such as HIV/AIDS, tuberculosis, hepatitis, and pneumonia who continue to use and abuse alcohol.