WEDNESDAY, Feb. 4 (HealthDay News) -- A century-old antibiotic used to treat leprosy may prove effective as a treatment for multiple sclerosis and other autoimmune diseases, Johns Hopkins researchers say.

They screened thousands of U.S. Food and Drug Administration-approved drugs and identified clofazimine, created in the 1890s, as a drug that targets a molecular pathway that plays an important role in guiding the body's immune response.

"We never expected that an old antibiotic would hit this target that has been implicated in multiple sclerosis, psoriasis and type 1 diabetes," Jun O. Liu, a professor of pharmacology and molecular science, said in a Johns Hopkins news release. "People have been working for years and spending tens of millions of dollars on developing a drug to inhibit a specific molecular target involved in these diseases, and here we have a safe, known drug that hits that target."

The study was published in the journal PLoS One.

"Until now, clofazimine's presumed target was not human cells, but bacteria. But we discovered the drug has a tremendous effect on human immune cells that are heavily involved in both the initiation and execution of an effective immune response," Liu said.

The prolonged accumulation of calcium inside of immune cells is one of the key steps involved in turning on the body's immune response. The researchers found that clofazimine blocks the flow of calcium into immune cells and tamps down the presence of calcium in the cells, actions that short-circuit the signaling pathway involved in autoimmune diseases.

More information

The U.S. National Institute of Neurological Disorders and Stroke has more about multiple sclerosis.