A new study suggests per- and polyfluoroalkyl substances, known as forever chemicals or PFAS, reduce the activity of human immune cells.
Researchers from the Helmholtz Centre for Environmental Research in Leipzig, Germany, showed PFAS can impair health by reducing this activity.
The study, recently published in Chemosphere, also featured a method that "could be used to reveal the immunomodulatory effects of other chemicals."
What happened?
Dr. Gunda Herberth, an environmental immunologist, and other scientists examined the impact of PFAS on immune cells from the blood of healthy donors.
"PFAS are poorly to hardly biodegradable — and that is a real problem," Herberth said. "They therefore accumulate in the environment — in soils and bodies of water. They can even be found in Antarctica. They can enter the human body via food, drinking water, or the air."
Herberth went on to say, "Studies have shown that PFAS can be detected in the blood of almost everyone in the world. What this means for our long-term health is not yet known."
In the study, the immune cells were exposed to PFAS mixtures for 20 hours and then stimulated before their activity was measured. The cells that were exposed to PFAS showed "significantly lower activity than untreated cells," according to the study.
"The strongest effects occurred when all six PFAS were mixed," indicating a compounding effect, Herbeth said.
Researchers documented reduced activity caused by PFAS in mucosa-associated invariant T cells and T helper cells. MAIT cells bridge innate and adaptive immunity, according to the National Institutes of Health, and T helper cells activate other immune cells, according to the Cleveland Clinic.
Why is it important?
PFAS are "water-, stain-, and grease-resistant" and "toxic at extremely low levels (i.e. parts per quadrillion)," according to the Natural Resources Defense Council.
A 2021 study in the International Journal of Environmental Research and Public Health stated that PFAS were invented in the 1930s, proliferated over the next two decades, and have been linked to "high levels of serum cholesterol, thyroid dysregulation, gestational hypertension, ulcerative colitis, and some cancers."
The study also noted children are at particular risk of health problems from exposure to PFAS, including reduced immune response after vaccinations.
"Our study clearly shows that PFAS reduce the activity of immune cells," Herberth said. "If a person is exposed to high levels of PFAS, this is likely to be reflected in their health."
"If the activity of MAIT cells is restricted," Herberth added, "it is much easier for pathogens to invade the body. T-helper cells are involved in the production of antibodies. If they are inhibited by PFAS, it is likely that fewer antibodies are produced — which could explain the reduced immune response to vaccination."
What's being done?
Other studies have looked into how to dispose of forever chemicals, including with fungus.
In March, the Environmental Protection Agency proposed establishing a standard for PFAS in drinking water.
Herberth and fellow scientists "plan to simulate in vitro PFAS mixtures and concentrations as they occur 'naturally' in human blood and determine their effects on immune cells," the study stated.
"So far, tests for immunotoxic or immunomodulatory effects are not part of the regulatory testing and assessment procedures for chemicals," Herberth said. "However, as many diseases — from allergies to cancer — can be traced back to a dysregulated immune system, we believe this is urgently needed."
"We hope that with our study and our new and practical testing method, we can help pave the way for this to happen," Herberth concluded.
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