There are more than 100 different types of arthritis with which people can be diagnosed. While some of them are related to aging and wear and tear on the joints, such as osteoarthritis, others are directly related to the immune system. Rheumatoid arthritis, one of the most common types of arthritis, is one such disease in which the immune system malfunctions and causes problems in the joints and elsewhere.

In people without rheumatoid arthritis, healthy immune cells called macrophages fight off infection and then die themselves. But in people with rheumatoid arthritis, the immune system is basically always "on," not shutting down after fighting infection. The macrophages stay alive and produce noxious materials that build up in the joints, bones and cartilage.

One researcher thinks he may have the solution to the problem of these destructive macrophages. Harris Perlman, associate professor of medicine at Northwestern University's Feinberg School of Medicine, discovered that the rogue immune cells in rheumatoid arthritis patients are lacking in a particular molecule that causes normal immune cells to die after attacking bacteria. Feinberg created a facsimile of this molecule and injected it into mice, causing the macrophages to act normally and self destruct in 75 percent of the mice. The arthritic mice experienced less joint swelling and bone damage. The molecule was shown to not only put rheumatoid arthritis into a state of remission; it also was shown to prevent the disease in the first place.

Although right now the team is working with mice, Perlman says that the  "goal eventually is to proceed to patients," explaining that scientists are still five to 10 years away from that due to toxicity issues involving the molecule. The mice were given the molecule therapy for only a week and a half with no apparent toxic effects, but humans would need to receive it for several months, which could cause some toxic effects. "You don't want to shut down the immune system so much that patients can be susceptible to infection," Perlman says. Current treatments for rheumatoid arthritis, including low-level chemotherapy and steroids, are not always effective and may carry side effects.


Northwestern University