Study reveals function of thousands of autoantibodies in blood

The study, which appears in the April 2 edition of PLoS ONE, also notes that autoantibody profiles are unique to individuals and remarkably stable over time, and are influenced by the person's age, gender and the presence of disease.

Using human protein microarrays, the researchers examined the immune-response profiling of 166 individuals, including subject groups of Alzheimer's, Parkinson's, multiple sclerosis and breast cancer patients. Among the study's startling findings:

• Most people have more than 1,000 discrete autoantibodies present in their blood and an individual's unique autoantibody profile remains relatively consistent over time.
• Women have significantly more autoantibodies than men which may account for the higher incidence of autoimmune diseases among women.
• Increasing age is accompanied by a corresponding increase in the number of detectable autoantibodies.
• Alzheimer's, Parkinson's, multiple sclerosis and breast cancer patients all had measurably lower numbers of autoantibodies than age- and gender-matched controls.

"Our previous studies showed that it is possible to identify changes in the autoantibody profile to accurately diagnose both Alzheimer's and Parkinson's diseases," said Robert Nagele, PhD, director of the Biomarker Discovery Center at UMDNJ-SOM and the study's corresponding author. "This research supports our proposal that autoantibody profiles will be useful as diagnostic biomarkers for a wide variety of diseases."

Advances in protein microarray technology helped to make this type of research possible, but still has limits, the study's authors acknowledge. The arrays used in this study contained nearly 9,500 distinct human antigens, but that is only a fraction of the estimated size of the entire human proteome.

"Given the evidence supporting an abundance of autoantibodies, it is probable that there are even more naturally occurring autoantibodies than we were able to detect here," Nagele said. "The complex profile of autoantibodies suggests that they carry out an essential function, and the clearance of debris generated by the body on a day-to-day basis is a reasonable bet."