More than 32 million people in the United States have autoantibodies, which are proteins made by the immune system that target the body's tissues and define a condition known as autoimmunity, a study shows. The first nationally representative sample looking at the prevalence of the most common type of autoantibody, known as antinuclear antibodies (ANA), found that the frequency of ANA is highest among women, older individuals, and African-Americans. The study was conducted by the National Institute of Environmental Health Sciences (NIEHS), part of the National Institutes of Health. Researchers in Gainesville at the University of Florida also participated.
Earlier studies have shown that ANA can actually develop many years before the clinical appearance of autoimmune diseases, such as type 1 diabetes, lupus, and rheumatoid arthritis. ANA are frequently measured biomarkers for detecting autoimmune diseases, but the presence of autoantibodies does not necessarily mean a person will get an autoimmune disease. Other factors, including drugs, cancer, and infections, are also known to cause autoantibodies in some people.
"Previous estimates of ANA prevalence have varied widely and were conducted in small studies not representative of the general population," said Frederick Miller, M.D., Ph.D., an author of the study and acting clinical director at NIEHS. "Having this large data set that is representative of the general U.S. population and includes nearly 5,000 individuals provides us with an accurate estimate of ANA and may allow new insights into the etiology of autoimmune diseases." The findings appear online in the Jan. 11 issue of the journal Arthritis and Rheumatism.
Miller, who studies the causes of autoimmune diseases, explains that the body's immune system makes large numbers of proteins called antibodies to help the body fight off infections. In some cases, however, antibodies are produced that are directed against one's
|Contact: Robin Mackar|
NIH/National Institute of Environmental Health Sciences