LOS ANGELES, July 26 (Xinhua) -- U.S. researchers identified a new gene associated with disease severity in models of rheumatoid arthritis, which could provide a new pathway for treatment and a way to measure the prognosis of patients diagnosed with the autoimmune condition.

Through a series of experiments, on synovial cells from the inner lining of joints in humans and animals, and in animal models of arthritis, researchers at the Icahn School of Medicine at Mount Sinai were able to show that the gene HIP1 is a driver in inflammatory arthritis severity.

This is the first time that HIP1 has been implicated in arthritis severity and in cell invasiveness, according to the new study, published Thursday online in Annals of the Rheumatic Diseases.

In the United States, nearly 1.3 million people have rheumatoid arthritis, a systemic disease that affects the entire body and is characterized by the inflammation of the membrane lining the joint, which causes pain, stiffness, warmth, redness and swelling. There are 2.5 times as many women as men with rheumatoid arthritis.

"There have been major advances in the treatment of rheumatoid arthritis in the past 20 years, but disease remission still remains uncommon. Most drugs today target inflammation but often that is not enough to control disease," Percio S. Gulko, senior author on the paper, said in a press release.

"At my laboratory, we have been looking for alternative strategies. In this research, we have focused on understanding the regulation of disease severity and joint damage. Our discovery led us to the synovial fibroblasts, cells inside the joint," said Dr. Gulko.

Previous work had found that increased HIP1 expression in certain cancers and correlated with worse prognosis in prostate cancer patients.

From 2013-2015, an estimated 54.4 million US adults annually had ever been told by a doctor that they had some form of arthritis, rheumatoid arthritis, gout, lupus, or fibromyalgia, according to U.S. Centers for Disease Control and Prevention (CDC).