Chronic
alcohol abuse by human beings has been shown to be associated with increased susceptibility to pulmonary
infections and severity of inflammatory responses associated with pulmonary
infection. On the basis of the higher likelihood of exposure to respiratory viruses, people who
abuse alcohol would logically be susceptible to respiratory
viral infections. To test this hypothesis, mice were provided alcohol in
drinking water for 13-16 weeks with the Meadows-Cook protocol and infected intranasally with respiratory syncytial virus. At various times after
infection, severity of
infection was determined by evaluation of cellular and
cytokine composition of bronchoalveolar lavage fluid (BALF) and histologic evaluation of
inflammation.
Infection was associated with neutrophil infiltration in both groups, but the proportion and number of neutrophils in BALF were significantly greater in the alcohol consumption group than in the control group. Concentrations of
tumor necrosis factor-alpha and
monocyte chemoattractant protein-1 in BALF in the alcohol consumption group were increased.
Interferon (IFN)-gamma concentrations were lower in the alcohol consumption group at later times of
infection.
Pulmonary inflammation was cleared by 3-5 days after
infection in the control group. In contrast,
pulmonary inflammation was evident in the alcohol consumption group after 7 days of
infection, and some mice showed severe
inflammation with
hemorrhage and
edema. IFN-alpha/beta was evident in BALF at low concentrations in the alcohol consumption group for several days after
infection, and increased
mRNA for IFN-alpha/beta was also evident in the alcohol consumption group. This was accompanied by the presence of virus in this group at these times of
infection. Chronic alcohol consumption increased severity of pulmonary
infection with a virus that naturally infects hosts by an
aerosol route.
Infection of mice that had consumed alcohol chronically was more severe in terms of increased proinflammatory
cytokine production,
inflammation, and a failure to clear the virus from the lungs.