Biomarkers predict rheumatoid arthritis before it develops: two elevated protein levels might signal potential trouble as much as 12 years before the condition strikes.(INTERNAL MEDICINE)

Researchers at Brigham and Women's Hospital and Harvard Medical School have detected two proteins released by the immune system that, when elevated, serve as biomarkers for future rheumatoid arthritis (RA). The findings appeared in the March 2009 issue of Arthritis Rheumatism.

Blood samples from 77 women in the Women's Health Study plus 93 women from the Nurses' Health Study were taken up to 12 years before all of them eventually developed recognizable symptoms of RA. At the time of the sample, tumor necrosis factor (TNF) and interleukin-6 (IL-6) levels were elevated, but no symptoms of RA were present. Those findings were compared to TNF and IL-6 levels in three matched control group subjects who did not develop RA for every case in which arthritis later appeared.

When the Boston team analyzed the results, they discovered a 40 percent increased risk among those with IL-6 scores in the highest 25 percent compared to those in the bottom 25 percent, and a 100 percent increased risk (between the top and bottom groups) of RA among those who had elevated TNF levels. They also measured high-sensitivity C-reactive protein levels, an indicator of inflammation, but did not find significant associations.

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"Even modest elevations in these biomarkers served as predictors up to ...