Immune cells in smokers' lungs ‘too exhausted’ to fight Tuberculosis

‘Bio energetic exhaustion’ is the term being coined by HRB-funded researchers at Trinity College Dublin and St James’s Hospital in research just published today to explain why immune cells in smokers don’t work as they should.

Macrophage engulfing tuberculosis bacteria
Macrophage engulfing tuberculosis bacteria

Dr Laura Gleeson, a HRB-funded Research Fellow at St James’s Hospital explains,

‘In healthy people, immune cells in the lungs called macrophages switch on a special energy pathway when they encounter invading bacteria like tuberculosis (TB). This switch seems to be a vital cog in allowing the body to use its own defences to fight and kill the bug’.

‘In this research project we compared these macrophages in smokers' lungs to healthy people and we found that smokers' immune cells had almost no energy available to fight infection. It was as if the smokers had ‘exhausted macrophages’ and this led to the TB being able to establish itself in their lungs’.

Professor Joe Keane, a HRB Clinician Scientist and a senior author on the paper continues,

‘This is a really exciting finding because if we can now find a way to boost smokers’ immune systems so they don’t have ‘exhausted macrophages’, then their immune system can get on with the job of eradicating the infection itself’. 

‘This personalised medicine, or immunotherapy approach, circumvents the need to develop new drugs to kill the bacteria, which we know from experience, bacteria eventually develop resistance to.

The paper Cigarette Smoking Impairs the Bioenergetic Immune Response to Mycobacterium Tuberculosis Infection is published by the America Journal of Respiratory Cell and Molecular Biology on 1 November 2018. doi:10.1165/rcmb.2018-0162OC.

Along with the HRB funding, the research was supported by the Royal City of Dublin Hospital Trust.