Lung immune dysfunction now ranks among the health issues linked to pollution.
The immune system of the lungs might deteriorate with age, making older people more vulnerable to lung injury and serious respiratory infections.
A recent study gives one explanation for why this might occur:
Researchers publish online in Nature Medicine on November 21 that over time, inhaled pollution particle matter clogs up the system and weakens the immune system of the lungs.
Poor and marginalised groups are disproportionately affected by air pollution, which is a leading cause of sickness and early mortality worldwide (SN: 7/30/20).
Particulate matter, a type of pollution produced by burning fossil fuels and other sources such as wildfires and car exhaust, has been linked to a number of health problems, including respiratory, cardiovascular, and neurological conditions (SN: 9/19/17).
Researchers at Columbia University examined lung immune tissue from 84 organ donors who ranged in age from 11 to 93 years old for the current study.
The donors weren’t smokers or hadn’t smoked heavily in the past.
The research team discovered that the lymph nodes in the lungs, which filter foreign objects and house immune cells, became heavily loaded with particle matter as people aged, turning them a deep ebony colour.
According to Elizabeth Kovacs, a cell biologist who specialises in inflammation and injury at the University of Colorado Anschutz Medical Campus in Aurora, “If the [lymph nodes] pile up with so much stuff, then they can’t do their function.”
A wide variety of immune cells, including macrophages, are found in the lymph nodes.
These cellular Pac-Mans consume the particle matter as well as pathogens and other waste.
As they were clogged with the pollution, macrophages produced less cytokines—proteins that the cells emit to stimulate other immune cells.
The cells also demonstrated symptoms of decreased ability for further gobbling.
According to Kovacs, who was not involved in the study, the current study shows that elderly people have accumulated so much debris that “they may not be able to accumulate more,” hampering their capacity to deal with inhaled material.
The research team claims that pollution “is an ongoing and growing threat to the health and livelihood of the global population.”
Their research reveals that this hazard also has “a persistent and pervasive influence” as we get older on our respiratory immunity.