Monday, 30th October 2017

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Study links alcohol to TB in young

Young alcoholics living with latent and symptomless tuberculosis infections appear to face a higher risk of developing active TB, medical researchers in India and the US have said after a joint study.

By G.s. mudur
  • Published 6.08.18
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New Delhi: Young alcoholics living with latent and symptomless tuberculosis infections appear to face a higher risk of developing active TB, medical researchers in India and the US have said after a joint study.

Their study has indicated that chronic alcohol consumption enhances the production of a key immune system biochemical called interferon-alpha and mortality in laboratory mice infected with TB.

Immunologist Ramakrishna Vankayalapati at the University of Texas Health Science Centre and his co-workers also found that chronic alcohol intake increases mortality in young mice but not in old mice infected with TB.

Public health experts estimate that over two billion people worldwide are infected with Mycobacterium tuberculosis, the bacillus that causes TB, but only five to 10 per cent of infected persons develop active disease.

Multiple earlier studies have suggested that immunosuppressive conditions such as poor nutrition, diabetes and drug or alcohol abuse are among factors that increase the risk of TB activation in people with the latent infection.

The precise mechanisms through which alcohol influences TB activation, however, remained unclear.

The new study, published in the journal PLOS One this week, provides the first evidence that chronic alcohol consumption induces increased production of interferon-alpha that contributes to tissue damage and mortality in young mice infected with TB, the researchers said.

About 80 per cent of TB-infected young mice exposed to chronic alcohol in their diet died within five months, compared with only 25 per cent of TB-infected old mice also exposed to chronic alcohol consumption.

In another set of experiments to explore the relevance of the findings with mice to human TB disease, the r searchers collected blood samples from alcoholic and non-alcoholic volunteers with latent TB infections and exposed them to TB bacilli.

The interferon-alpha levels in the blood cells of the young alcoholic volunteers rose to 2.9 times their levels in the blood cells of old alcoholic volunteers and two times their levels in non-alcoholic volunteers.

"The effect on young persons was a big surprise," Satyanarayana Swamy Cheekatla, an immunologist and assistant professor of biotechnology at the Gandhi Institute of Technology and Management, Visakhapatnam, and co-author of the study, told The Telegraph.

"We would expect older individuals to be more vulnerable to developing active TB, more vulnerable to the effects of alcohol - but we observed a significantly worse effect on the young," said Cheekatla, who was earlier a post-doctoral research fellow in Vankayalapati's laboratory.

Their findings suggest that alcohol worsens the consequences of TB infection during the early stages of life compared to old age.

The researchers believe further investigations into the mechanisms of how interferon-alpha under the influence of chronic alcohol abuse worsens the outcome of TB infections may lead to new therapeutic strategies.