Washington, Apr 9 (IANS): Autoimmunity, a condition in which the body's immune system reacts with components of its own cells, appears to be increasing in the United States, according to a release of the US National Institutes of Health (NIH).

In a study published on Wednesday in Arthritis and Rheumatology, the researchers found that the prevalence of antinuclear antibodies (ANA), the most common biomarker of autoimmunity, was significantly increasing in the United States overall and particularly in certain groups, reported Xinhua news agency.

These groups include males, non-Hispanic whites, adults 50 years and older, and adolescents.

The study is the first to evaluate ANA changes over time in a representative sampling of the US population, according to the NIH.

"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 corresponding and senior author Frederick Miller, deputy chief of the Clinical Research Branch at the National Institute of Environmental Health Sciences (NIEHS), part of the NIH.

"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," he said.

The study included 14,211 participants, 12 years and older, in the US National Health and Nutrition Examination Survey.

The scientists used immunofluorescence, a technique that uses fluorescent dye to visualize antibodies, to examine the frequencies of ANAs in subjects from three time periods.

"Hopefully, this important study will stimulate further research on the environmental factors related to the apparent increased prevalence of autoimmune diseases," said co-author and NIEHS Scientific Director Darryl Zeldin.