Newswise — Gene signatures, or patterns, can yield important information about the severity and frequency of systemic lupus erythematosus activity, according to research presented this week at the American College of Rheumatology Annual Scientific Meeting in San Diego.

Systemic lupus erythematosus, or lupus, is a chronic disease that causes inflammation of the joints, skin rashes, low blood counts, kidney disease, or inflammation around the heart and lungs. It affects one in every 2,000 people in the U.S., and 90% of those affected are women.

Because patients with lupus can experience a broad range of symptoms, and because predicting severity and risk to various organs based on current technology is so difficult, this research is particularly encouraging.

Researchers used gene expression microarrays " a method of determining whether key genes are turned on or off " to test blood samples of 81 patients with lupus and 41 healthy control individuals. The tests were intended to find blood markers of SLE disease activity, and correlate them with several disease activity scores commonly used by clinicians in an attempt to monitor the course of this difficult disease.

The study found 137 RNA transcripts that appeared at altered levels in the blood of patients experiencing active lupus, and thus may be indicators of disease activity. Further organization of these transcripts revealed two key groups: genes induced by interferon-alpha, which is a natural cancer and infection fighter; and a distinct immunoglobulin, or antibody, group.

When examining these two key groups, or signatures, separately, researchers found that the immunoglobulin signature occurred more often in African-American patients and correlated with other lupus indicators. The appearance of the interferon-alpha signature seemed to be a better predictor of future disease activity than of current activity.

Going one step further, researchers were able to identify 10 genes which together were the best indicators of current disease activity. That set included a representative gene from each of the two signatures. These ten genes demonstrated a much higher correlation with current disease activity than any single gene from the group; and importantly, were a better predictor of future activity than any tool currently available.

"A key finding is that the combination of gene signatures is a much better indicator of disease activity than any one signature alone. Further study and validation of these signatures may lead to new, targeted therapies for lupus." said Emily C Baechler, PhD, a researcher with the University of Minnesota in Minneapolis, where the study was conducted in the laboratory of Dr. Timothy Behrens. "The ability to measure these signatures with a simple blood test could make them a useful tool in the clinic, allowing doctors to identify patients at risk for severe disease and shape their treatment plans accordingly."

The American College of Rheumatology is the professional organization for rheumatologists and health professionals who share a dedication to healing, preventing disability and curing arthritis and related rheumatic and musculoskeletal diseases. For more information on the ACR's annual meeting, see http://www.rheumatology.org/annual.

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ACR Annual Scientific Meeting