WASHINGTON — Autoimmunity is a condition that causes the body’s immune system to react to normal components of its own cells, essentially using the body’s natural immune system against itself. A recent study led by scientists at the National Institutes of Health (NIH) reveals that autoimmunity is on the rise in the United States.
The research team found that the prevalence of antinuclear antibodies (ANA), the most common biomarker of autoimmunity conditions, has been increasing in the U.S. overall. The findings especially pertain to certain populations, such as men, non-Hispanic white people, adults over 50 years old, and teenagers. The team says their study is the first to evaluate ANA changes in a representative sample of the U.S. population over time.
“The reasons for the increases in ANA are not clear, but they are concerning and may suggest a possible increase in future autoimmune disease,” said senior author Dr. Frederick Miller in a statement. “These findings could help us understand more about the causes of these immune abnormalities and possibly learn what drives development of autoimmune diseases and how to prevent them.”
Dr. Miller is the deputy chief of the Clinical Research Branch of the National Institute of Environmental Health, a part of the NIH.
The researchers included 14,211 participants, all 12 years or older, who participated in the U.S. National Health and Nutrition Examination Survey. The researchers visualized antibodies in blood samples using immunofluorescence, which utilizes fluorescent dye. They found ANA prevalence from 1988 to 1991 was 11%. That figure rose to 11.5% between 1999 and 2004. In 2011 and 2012, the percentage had spiked to 15.9%. Extrapolating those percentages would result in 22, 27, and 41 million Americans affected, respectively.
Of the four demographics that showed significant ANA increases, the researchers were most concerned about adolescents aged 12 to 19. This group had the largest ANA increases in the study, moving from a two-fold increase in 1999-2004 to a three-fold increase in 2011-2012.
The researchers are working on learning why these changes in autoimmunity in each of these groups is accelerating, especially in teenagers. Ruling out the extremely slow process of genetic mutations, the scientists believe that changes in lifestyle or the environment could be causing ANA increases.
“These new findings may have important public health implications and will help us design studies to better understand why some people develop autoimmune diseases,” said co-author Dr. Christine Parks, staff scientist in the NIEHS Epidemiology Branch. Dr. Parks added that autoimmune disease comprises over 100 debilitating, chronic conditions.
The study was limited by the lack of clinical evaluations done on the populations studied. These evaluations help determine if the prevalence of autoimmune diseases like lupus and myositis is increasing overall. However, the researchers stress that ANA are usually seen in patients suffering from autoimmune disease.
The authors said that other studies have shown an increase in autoimmune disease prevalence, but those findings are based on incomplete data. Dr. Miller said he hopes that a national registry of autoimmune diseases can be established to examine changes in autoimmunity rates over time. This registry, they believe, will also define geographic hotspots and lead to the root cause.
The study was published in the journal Arthritis and Rheumatology.