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SciPinion Expert Panel on the Immunotoxicity of PFAS Compounds

Immunotoxicity is the critical endpoint used by some regulatory agencies to establish toxicity values for perfluorooctanoic acid (PFOA) and perfluorooctane sulfonate (PFOS). However, the hypothesis that exposure to certain per- and polyfluoroalkyl substances (PFAS) causes immune dysregulation is subject to much debate. An independent, international expert panel was engaged utilizing methods to reduce bias and “groupthink”.

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Key findings from the panel of international experts include:

  • There is moderate evidence from animal studies that PFOA and PFOS are immunotoxic
  • Panel members agreed that the Faroe Islands cohort data should not be used as the primary basis for deriving PFAS risk assessment values
  • The panel agreed that vaccine antibody titer is not useful as a stand-alone metric for risk assessment
  • The panel concluded that the available PFAS immune epidemiology studies suffer from weaknesses in study design that preclude their use, whereas available animal toxicity studies provide comprehensive dataset to derive points of departure (PODs) for non-immune endpoints.
  • The panel recommends accounting for potential PFAS immunotoxicity by applying a database uncertainty factor to POD values derived from animal studies for other more robustly supported critical effects.

PFAS became an important issue worldwide when it was discovered that two specific PFAS, PFOA and PFOS, have long half-lives, the time that a molecule spends in the body before being eliminated, in humans. PFOA and PFOS were removed from the marketplace in the United States nearly a decade ago. Regulatory agencies worldwide are grappling with how to set safe exposure limits for these compounds. The findings of this panel helps to reduce the uncertainties about PFAS causing immunotoxic effects and helps agencies make better scientifically supported risk assessments. . To date, there is no good evidence that PFAS compounds cause immunotoxic effects in humans.

“The work conducted by these independent scientists provides an important contribution to the ongoing assessments of immunotoxicity endpoints for PFAS. This project brought together international experts in immunology, toxicology, and epidemiology, using a deliberative process that is blind to the funding source and fosters an open and scientifically rigorous evaluation of controversial topics. A key consensus finding was that while immunotoxicity is a relevant effect endpoint to evaluate for risk assessments of PFOA and PFOS, changes in vaccine antibody titers and similar indicators of immune function are not appropriate for deriving health-based criteria at this time.”

Gregory Garvey, MSPH, SciPi Topic Lead
GSI Environmental, Inc.

In Summary

The report’s panel of international experts answered a wide range of questions, had access to hundreds of pages of scientific material, and debated each other in an online forum that provided psychological safety. This was important because PFAS have proven to be controversial.

SciPinion had complete control over all aspects of the blue ribbon panel in this academic report, relying upon our proprietary and scientifically sound methods for recruiting, selecting, engaging, and reporting to minimize sources of bias and groupthink.