doi:10.1038/nindia.2018.99 Published online 1 August 2018
The immune mechanism behind how alcohol increases the mortality of young mice infected with the tuberculosis-causing bacterium Mycobacterium tuberculosis (Mtb) has been unravelled by a team of Indian and American researchers. This effect, not seen in old mice, is mediated by the production of a protein called interferon-alpha (IFN-α), their study has found.
Long term alcoholism changes the immune defense mechanism of individuals and increases the risk of bacterial, viral and fungal infections, including that of Mtb infection. However, limited information was available till now about the cellular mechanisms involved in this process, particularly in old individuals.
Deepak Tripathi at the University of Texas Health Science Center at Tyler (UTHCT), Texas, USA and his colleagues, researchers from Louisiana State University Health Sciences Centre, USA, and co-researchers from Bhagwan Mahavir Medical Research Center in Hyderabad, used a mouse model and human blood samples to determine the effects of chronic alcohol consumption on immune responses during Mtb infection.
Their studies showed that alcohol increased the mortality of young mice but not old mice with Mtb infection. The increased mortality in alcohol-fed Mtb-infected young mice was due to IFN-α production in the lungs by a subset of immune cells that express molecules called CD11b and Ly6G.
In human blood samples with latent tuberculosis (TB) infection, Indian collaborators led by Vijaya Lakshmi Valluri showed that peripheral blood mononuclear cells from young alcoholics produced significantly higher amounts of IFN-α than those from young non-alcoholics, old alcoholics, and old non-alcoholics.
The study also shows that young alcoholics with latent TB infection have a higher risk of developing active TB infection. According to the authors, the study could facilitate the development of therapies for alcoholics with latent and active Mtb infections.
1. Tripathi, D. et al. Alcohol enhances type 1 interferon-α production and mortality in young mice infected with Mycobacterium tuberculosis. PLoS Pathog. 14, e1007174 (2018) doi: 10.1371/journal.ppat.1007174