People exposed to high levels of asbestos may face a higher risk in the future of contracting certain autoimmune diseases like rheumatoid arthritis and multiple sclerosis. So says a study from the University of Montana.1
While the study did not make a direct connection between asbestos exposure and autoimmune disease, it did find a higher link between asbestos and autoantibody activity in a group of people, suggesting that this could serve as a basis for future disease.
Expanding on Previous Studies
Jean Pfau, PhD, a research assistant professor with the Center for Environmental Health Sciences at the university and her colleagues studied the risk in a small town in Montana. "The population in Libby, Montana provides a unique opportunity for such a study because of both occupational and environmental exposures that have occurred as a result of the mining of asbestos-contaminated vermiculite near the community," they wrote.
While previous studies have suggested increased immune activity in the blood of people exposed to asbestos, no comprehensive study has been published assessing the prevalence, specificity, or significance of autoantibodies associated with asbestos exposure, the research team wrote.
An Apparent Link
In all, 50 residents of the town were recruited for the study and were compared to 50 residents of a nearby town known to have no asbestos exposure. Blood samples were collected from each individual and tested for the presence of a specialized antibody known as antinuclear antibodies, or ANA. These are often found in people whose immune systems may be predisposed to cause inflammation against their own body tissues, similar to what is found in people with MS.2
The researchers found that the level of ANAs in the blood samples from the Libby residents were nearly 29% higher than those in the adjoining town with no asbestos exposure. Additionally, those who had been exposed to asbestos for more than five years tended to have higher concentrations of ANAs in their blood than those with less exposure.
Pfau and her team also found significantly higher levels of immunoglobulin A in the individuals exposed to asbestos versus those who were not. Immunoglobulin A (IgA) is a type of protein produced by plasma cells which makes up part of the immune system. Of the Libby residents tested, more than three-quarters also had asbestos-related lung problems, and those with more severe lung problems had higher levels of these autoantibodies.
"By demonstrating an association between asbestos exposure and measures of autoimmune responses, this study supports and augments other existing evidence that asbestos is an agent of systemic autoimmunity," Pfau's group concluded.
Significant Health Risk
Because asbestos-containing vermiculite from Libby, Montana is shipped and processed around the United States, "it remains a significant health risk" to other people both occupationally and environmentally, they wrote. Awareness of the link between asbestos and autoimmunity could have a significant effect on monitoring, testing, and treatment for exposed individuals, the investigators added.
While MS is thought to be an autoimmune disease, the researchers quickly stress that "the presence of autoantibodies does not necessarily suggest a disease process." Nonetheless, the study helps improve medical experts' understanding of the underlying processes behind autoimmune diseases "and could lead to improved interventions as an ultimate goal."
1. Pfau JC, Sentissi JJ, Weller G, Putnam EA. Assessment of autoimmune responses associated with asbestos exposure in Libby, Montana, USA. Environ Health Perspect 2005 Jan;113(1):25-30.
2. National Multiple Sclerosis Society. What Causes MS? Available at: http://www.nationalmssociety.org/What%20causes%20MS.asp. Accessed April 22, 2005.
John Martin is a long-time health journalist and an editor for Priority Healthcare. His credits include coverage of health news for the website of Fox Television's The Health Network, and articles for the New York Post and other consumer and trade publications.