New research in cells finds that the PFAS chemical GenX suppresses the neutrophil respiratory burst—the method white blood cells known as neutrophils use to kill invading pathogens.

The study is an important first step in understanding how both legacy and emerging PFAS chemicals might affect the body’s innate immune system.

PFAS are a class of per- and polyfluoroalkyl chemicals used to make consumer and industrial products more resistant to water, stains, and grease. According to the US Environmental Protection Agency, there are more than 12,000 known PFAS, which also include fluoroethers such as GenX.

“It’s pretty well-established that PFAS are toxic to the adaptive immune system, but there hasn’t been as much research done on their effects on the innate immune system,” says Drake Phelps, a former PhD student at North Carolina State University and first author of the study.

The human immune system has two branches: adaptive and innate. The adaptive branch contains T cells and B cells that “remember” pathogens the body has encountered, but it is slow to mount a defense, acting days—sometimes weeks—after it detects a pathogen.

The innate immune system serves as the body’s first responders, and contains white blood cells that can be dispatched to the site of an invasion within hours. These white blood cells include neutrophils, which can dump reactive oxygen species—think tiny amounts of bleach or hydrogen peroxide that neutrophils manufacture inside their cells—directly onto pathogens, killing them. That process is called the respiratory burst.

Drake and the research team looked at the effect of nine environmentally relevant legacy and emerging PFAS on neutrophils from zebrafish embryos, neutrophil-like cells (cells that can be chemically treated to behave like neutrophils), and human neutrophil cells cultured from donor blood.

Emerging PFAS are chemicals, like GenX, developed to replace older, legacy PFAS that had proven toxic. All of the PFAS included in this study were detected in both the Cape Fear River in North Carolina and the blood serum of residents whose drinking water came from the Cape Fear River.

Read the full article about PFAS by Tracey Peake at Futurity.