More Autoimmune Research

I read this latest research update from the National Institutes of Health with great interest.

A recent study conducted by NIH/National Institute of Environmental Health Sciences/University of Florida Gainesville determined that an alarming 32 million Americans have autoantibodies that target their own tissues. The study is the first of it's kind in that it looked at a nationally representative sampling of people carrying a positive ANA.

Although positive ANA titers are common in autoimmune disease, the presence of autoantibodies alone does not indicate that the person will go on to develop autoimmune disease.

The study is important in that it will serve as a baseline for future research into the causes of autoimmune disease:

"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.

The study reached these conclusions:

A multi-disciplinary team of researchers evaluated blood serum samples using a technique called immunofluorescence to detect ANA in 4,754 individuals from the 1994-2004 National Health and Nutrition Examination Survey (NHANES). The overall prevalence of ANA in the population was 13.8 percent, and was found to be modestly higher in African-Americans compared to whites. ANA generally increased with age and was higher in women than in men, with the female to male ratio peaking at 40-49 years of age and then declining in older age groups. 

"The peak of autoimmunity in females compared to males during the 40-49 age bracket is suggestive of the effects that the hormones estrogen and progesterone might be playing on the immune system," said Linda Birnbaum, Ph.D., director of NIEHS and an author on the paper. 

The paper also found that the prevalence of ANA was lower in overweight and obese individuals than persons of normal weight. "This finding is interesting and somewhat unexpected," said Edward Chan, Ph.D., an author on the study and professor of the Department of Oral Biology at the University of Florida. 

"It raises the likelihood that fat tissues can secrete proteins that inhibit parts of the immune system and prevent the development of autoantibodies, but we will need to do more research to understand the role that obesity might play in the development of autoimmune diseases," said Minoru Satoh, M.D., Ph.D., another author on the study and associate professor of rheumatology and clinical immunology at the University of Florida.

You can read the entire report here. Read more about the National Institutes of Health here, and the National Institute of Environmental Health Sciences here.