It has been found that people exposed to fire smoke had noticeable changes in their immune systems, the cells of which were also more inflamed, suggesting the body was responding to stress or damage.
To understand how fire smoke impacts the human body, researchers from Harvard T.H. Chan School of Public Health conducted a detailed study looking at immune system changes on a cellular level.
They collected blood samples from two groups of people: 31 who had been exposed to fire smoke (some being firefighters) and 29 who had not, but were similar in age and sex. Using advanced tools, they were able to analyse individual immune cells to uncover subtle but significant changes caused by smoke exposure.
They found that those exposed to fire smoke had noticeable changes in their immune systems. In particular they had more of a specific type of immune cell called memory CD8+ T cells, which help the body remember and fight off infections over time.
They also found that those exposed to smoke showed changes in 133 different genes connected to disease. These were not changes to the genetic code itself, but epigenetic changes, alterations in how the genes function due to environmental influences such as smoke. Essentially, smoke exposure was turning some genes on or off in potentially harmful ways.
Additionally, immune cells from those exposed to smoke showed signs of increased activity and movement, suggesting the immune system was reacting to something harmful in the body.
The researchers also found higher levels of toxic metals, such as mercury and cadmium, inside the cells of these individuals. It was also seen that the amount of mercury found in a person’s cells was linked to how many years they had been exposed to smoke.
Kari Nadeau, John Rock Professor of Climate and Population Studies and chair of the Department of Environmental Health said: ‘We’ve known that smoke exposure causes poor respiratory, cardiac, neurological, and pregnancy outcomes, but we haven’t understood how.
‘Our study fills in this knowledge gap, so that clinicians and public health leaders are better equipped to respond to the growing threat of difficult to contain, toxic wildfires.’
Nadeau explained that the study could help inform environmental and public health policies and investments: ‘Knowing more about exactly how smoke exposure is harming the body, we may increase public health campaigns about the dangers of smoke exposure and the importance of following evacuation procedures during wildfires.’
Photo: Jarden Bellamkonda
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