Environmental Factor, July 2011, National Institute of Environmental Health Sciences
Autoimmune mysteries spark ongoing research
By Josh Zeldin
Parks' background includes her work on the Carolina Lupus Study(http://www.niehs.nih.gov/research/atniehs/labs/epi/studies/cls/index.cfm). She helped organize a workshop in September 2010 that included panels of experts evaluating the state of the science in autoimmune disease research (see story(http://www.niehs.nih.gov/news/newsletter/2010/october/science-autoimmunity.cfm)). She suggested that those interested in understanding more about autoimmune disease visit the website of the American Autoimmune Related Diseases Association(http://www.aarda.org/) , a clearinghouse for patient and advocate information. (Photo courtesy of Steve McCaw)
Among scientists attending the presentation was NIEHS biologist Xiao-Ping Yang, Ph.D., of the Institute's Cell Biology Group. (Photo courtesy of Steve McCaw)
Visitors included Pete Schubert, center, from neighboring U.S. Environmental Protection Agency. Seated in the background is DAC co-chair Sloane. (Photo courtesy of Steve McCaw)
NIEHS epidemiologist Christine Parks, Ph.D., spoke to employees and guests May 27 on "Autoimmune diseases: What we know (and don't know) about environmental risk factors and why we care." Parks' presentation addressed current knowledge surrounding environmental risk factors for the nearly 80 autoimmune diseases that affect five to eight percent of the population. She also examined why people should care about these risk factors and the impact of these chronic and incurable diseases on the workplace.
The presentation was sponsored by the NIEHS Disability Advocacy Committee (DAC) and hosted by committee co-chairs Dick Sloane and Tina Jones.
At the beginning of her talk, Parks, a research fellow with the NIEHS Chronic Disease Epidemiology Group, said her presentation would try target a general population without a science background. Despite many of the audience lacking this education, the subject of autoimmune diseases was close to the heart of attendees who have either been directly affected by autoimmune diseases or known someone who has been affected. The presentation had added appeal to attendees since Parks herself also has a family history of autoimmune diseases.
Elusive causes of autoimmune disease
After giving a brief introduction of her history and connection to autoimmune disease, Parks dove right into basic facts, subsequently defining autoimmune disease, outlining its known causes, and describing briefly its prevalence in the United States. While scientists have not been able to pinpoint a single source triggering autoimmune diseases, Parks made it clear that the problem is, in most cases, likely to be due to a mix of both genetic and environmental factors.
"The story is not yet entirely clear," Parks conceded. "Many aspects of these diseases are just not well understood."
This sentiment was echoed throughout the presentation as Parks identified known risk factors for autoimmune diseases, including being a female, family history, ethnicity, cigarette smoking, silica dust, sunlight exposure, infections, ionizing radiation, and solvents. Parks again highlighted how this list included both environmental and genetic risk factors, underscoring how the causes of these diseases may be exponentially complex and interconnected.
As with cause, the mechanisms of autoimmune disease have proven elusive. While there is research linking autoimmune diseases to T-cell regulation, the aryl hydrocarbon receptor, and toll-like receptors, scientists are still working to understand how these relate to environmental and genetic causes.
Limitations of current research and research methods
After touching on more rudimentary, technical information, Parks transitioned to a less scientific segment of her presentation to identify gaps in the research of autoimmune diseases. Parks stressed that there needs to be more exploration of potential risk factors, such as pesticides, metals, air pollution, and other forms of chemical exposures that affect immune function and inflammatory processes.
Additionally, Parks pointed to the possible influence of psychosocial factors, such as stress - a subject, according to Parks, that hasn't been given sufficient attention. She also pointed to the need for expanding research methods and tools used to investigate risk factors in human studies.
"We do need systematic methods for studying the environment," Parks explained. "We need better tools."
Among the challenges of current epidemiological studies of autoimmune diseases is the need to rely on self-report of past exposures and the lack of resources and attention given to developing validated questionnaires linking self-report to objectively verified measures. Also, according to Parks, the lack of a comprehensive registry base has hampered scientists trying to extrapolate consistent patterns to formulate reasons to explain what seems to be a rising incidence of autoimmune disease.
"Disease rates may be increasing," Parks said, "and we don't know why this is happening."
While the unknown can be challenging, Parks was optimistic about the future of autoimmune disease research - a future she hopes will be marked by more answers and clarification to address a public health problem that costs as much as $100 billion annually in direct medical expense.
"Solutions will come," Parks predicted. "It's just a matter of time, with the growing public awareness and attention of the research community."
(Josh Zeldin is a summer intern with the NIEHS Office of Communications and Public Liaison. He is a student at the University of North Carolina at Chapel Hill.)