February 6 (HealthDay News) -- The first evidence that gene therapy can ease symptoms in people with rheumatoid arthritis (RA) has been reported by American and German researchers.

The study included two postmenopausal women with advanced RA. Researchers injected the interleukin-1 receptor antagonist (IL-1Ra) gene into the women's affected joints. IL-1Ra protein blocks the actions of interleukin-1 protein, which plays a role in the breakdown of cartilage that occurs in arthritis patients.

"The idea is that by remaining in place, the new gene can continuously block the action of the interleukin-1 within the joints. In essence, the gene becomes its own little factory, continuously working to alleviate pain and swelling," principal investigator Christopher Evans, director of the Center for Advanced Orthopaedic Studies at Beth Israel Deaconess Medical Center in Boston, said in a Harvard Medical School news release.

Four weeks after IL-1Ra was injected into their affected joints, both women reported reduced pain and swelling.

"In one of the two subjects, these effects were dramatic, and the gene-treated joints remained pain-free even though other joints experienced flares," said Evans, who is also a professor of orthopedic surgery at Harvard.

The findings were published in the February issue of the journal Human Gene Therapy. The study received funding from Orthogen, a German biotechnology company.

The study "helps extend gene therapy research to nongenetic, nonlethal diseases," said Evans, who added that arthritis "is a good target for this treatment, because the joint is a closed space into which we can inject genes."

SOURCE: Harvard Medical School, news release, Jan. 27, 2009