Firefighter Study Links PFAS to Immune Dysfunction

A new study of U.S. firefighters shows that exposure to PFAS, often called “forever chemicals,” can alter how genes are switched on and off in ways that may increase risk for autoimmune disease.

Researchers analyzed blood samples from more than 300 firefighters and found that PFAS exposure changed microRNA activity.

MicroRNAs are small molecules that regulate gene expression, essentially controlling whether genes are turned on or off. Several of the disrupted pathways were tied to immune system balance, including genes involved in lupus, rheumatoid arthritis, asthma, and other autoimmune or inflammatory conditions.

These findings add a crucial layer of evidence to decades of epidemiology showing higher autoimmune disease risk in people exposed to PFAS. By linking exposure to specific genetic mechanisms, the study helps explain why PFAS may drive immune dysfunction. This also opens the door to future treatments aimed at restoring normal gene regulation before disease develops.

Because PFAS accumulate in the body and resist natural breakdown, exposure through firefighting foam, water, food packaging, and household products could have long-lasting effects. Understanding how PFAS interfere with immune regulation is especially important for communities already affected by rising autoimmune disease rates.

Citation

Furlong, M. A., et al. (2025). Per- and polyfluoroalkyl substances (PFAS) and microRNA: An epigenome-wide association study in firefighters. Environmental research, 279(Pt 2), 121766. https://doi.org/10.1016/j.envres.2025.121766