A nested case-control study has found that rheumatoid arthritis (RA) can be predicted years before the onset of symptoms due to upregulation of the immune system. Study subjects who went on to develop RA had significantly increased concentrations of proinflammatory cytokines such as interleukin-1β, tumor necrosis factor-α, and eotaxin. Researchers reported these findings in the February issue of Arthritis & Rheumatism.

Previously, researchers have demonstrated that other antibodies such as rhuematoid factor and anti-cyclic citrullinated peptide (CCP) antibodies are also present in the years before RA symptoms develop.

Researchers observed that the inflammatory picture shifts with RA disease onset; as time draws closer to the onset of symptoms, concentrations of many factors become further elevated. However, the proinflammatory cytokine interleukin-17, while present in high levels before RA symptoms appear, begins to decrease within months of a positive RA diagnosis.

"This observation endorses the role of IL-17 in the initiating phase, and, as the pathogenesis progresses, other factors are subsequently brought into action," the study authors conclude.

While they admit certain limitations to the study, such as the potential effects of storage time on their samples, they believe that "this explorative study can help to generate an hypothesis regarding the development of [rheumatoid arthritis], particularly in terms of the role of the immune system in the initiation of the disease."

The researchers hope that the study findings will lead to further investigation on better models to predict the risk of RA and possibly prevent progression of the disease.