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Press Release

Press release

How smoking stops your lungs fighting tuberculosis

24 March 2016

Tobacco smoke particles 'clog up' immune cells and literally prevent them moving towards, and hence attacking, the tuberculosis bacteria. The findings have just been published in Cell, one of the most highly rated scientific journals in the world, and are the third major breakthrough in as many weeks from this HRB-funded research team.

Graham Love, Chief Executive of the Health Research Board commented,

'Ireland is so lucky to have health researchers of the quality of Professor Keane and the team that he has gathered around him. It is imperative that Ireland continues to invest in health research, as the local and global paybacks are huge, as demonstrated by Professor Keane and his team over the past few weeks'.

Professor Joe Keane, a HRB Clinician Scientist* based at St James's Hospital and Trinity College Dublin, explains the significance,

'TB kills 4,000 people every day, and there are around eight million TB cases worldwide. Cigarette smoking is one of the biggest contributors to developing the disease. It is estimated that 15% of all cases arise from the effects of smoking, and until now we didn't really know why, or how, smoking had such a profound effect.

Our partner in this research paper, Professor Lalita Ramakrishnan and her team in the University of Cambridge, identified a very interesting finding in a zebrafish model of the disease.

Professor Ramakrishnan takes up the story.

'We found that a type of immune cell called a macrophage, which is a white blood cell that is supposed to attack and engulf foreign material that gets inside the body, was not able to travel to the TB infection after it had been exposed to particles similar to those you get in tobacco smoke. We then approached Professor Keane to see if they could discover if this same effect occurred in human lungs'.

Professor Keane continues,

'Thanks in large part to HRB-funding, we are one of only a handful of laboratories in the world who could conduct this research in human cells. We took tissue samples from smokers who attended the bronchoscopy suite in St James's Hospital and found that smokers’ lungs were full of cells that looked abnormal because material from tobacco smoke goes into the white cells and gets trapped there. The 'gunk' is basically too large to get broken down. White blood cells with this debris inside them were unable to move towards the invading TB bacteria. This migration is a necessary first step for the body to fight TB, and if it can't do that, then the person is more likely to develop the disease'. 

The findings could also have significance beyond TB and smokers and might be equally applied to people who inhale indoor air pollution.

Professor Keane again,

'More than one third of the world’s population cooks indoors without a chimney and gets exposed to an excessive amount of biomass fuel smoke. This material also makes the patient susceptible to TB (accounting for 22% of cases) which is extremely common in the developing world.
We hope that with further analysis, we can fine tune interventions that will support cigarette smokers, or persons exposed to biomass fuel, in the fight against tuberculosis’.

24 March 2016 is World TB Day. The Irish research was funded by the Health Research Board and Royal City of Dublin Hospital Trust.

Further lay information about the research is also available from the University of Cambridge press release at www.cam.ac.uk/research/news/clogged-up-immune-cells-help-explain-smoking-risk-for-tb

Ends.

For more information contact:

Brian Cummins, Communications Officer, Health Research Board
e bcummins(at)hrb.ie
m 085 887 9313

*The Clinician Scientist Award scheme is targeted at senior health practitioners and allows them to dedicate up to 50% of their time to research with the award paying for replacement clinical staff so that there is no overall loss in clinical care service levels. The award enables holders to conduct their research and mentor the next generation of research talent.

The physical space for the research was provided by the Wellcome Trust -HRB Clinical Research Facility at St James’s Hospital which is one of three such major facilities that the HRB has financed in recent years.

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