People Exposed to Asbestos Show Early Signs of Autoimmunity

Newswise — Exposure to toxic amphibole asbestos may contribute to autoimmunity, potentially laying the groundwork for future autoimmune diseases such as rheumatoid arthritis and multiple sclerosis, according to a study published today in the January issue of the peer-reviewed journal Environmental Health Perspectives (EHP). Researchers evaluated 50 residents from Libby, Montana—a town polluted by asbestos—and found them much more likely to have a class of autoantibodies in their blood than a control group. Presence of these biological markers, known as antinuclear antibodies (ANAs), are often found in people whose immune systems may be predisposed to cause inflammation against their own body tissues.

Researchers found that ANAs occurred 28.6% more frequently in the Libby samples than in the controls. In addition, people who had been exposed to asbestos for more than five years tended to have higher concentrations of ANAs than those with less exposure. Of the Libby residents tested, 76% had asbestos-related lung problems, and those with more severe lung problems also had higher concentrations of autoantibodies.

Virtually the entire town of Libby was designated a Superfund National Priorities List site in 2002, after decades of mining vermiculite contaminated the mine, processing sites, and many homes, buildings, and properties in the town with amphibole asbestos.

"By demonstrating an association between asbestos exposure and measures of autoimmune responses, this study supports and augments other existing evidence that, like silica, asbestos is an agent of systemic autoimmunity," the study authors write. "Asbestos-contaminated vermiculite from Libby has been shipped and processed in many sites in the United States, and this material is still used in many applications. It therefore remains a significant health risk to humans both occupationally and environmentally, and an awareness of an association with autoimmunity could impact necessary monitoring, testing, and treatment regimens for exposed individuals or populations."

Based on the results of this relatively small-scale study, the researchers intend to continue their studies of actual autoimmune diseases among the Libby population.

"Asbestos exposure has long been associated with cancers, fibrosis, and other diseases, but the link between subclinical markers of autoimmune disease and asbestos exposure is important information," says Dr. Jim Burkhart, science editor for EHP.

The authors of the study were Jean C. Pfau, Jami J. Sentissi, Greg Weller, and Elizabeth A. Putnam of the Center for Environmental Health Sciences at the University of Montana. The article is available free of charge at http://ehp.niehs.nih.gov/members/2004/7431/7431.html.

EHP is published by the National Institute of Environmental Health Sciences, part of the U.S. Department of Health and Human Services. EHP is an Open Access journal. More information is available online at http://www.ehponline.org/.