Two experimental treatments show promise in the fight against lupus, researchers reported at the American College of Rhematology’s annual meeting.

The first involves high doses of vitamin D. In a study of 24 people with lupus, injections of 100,000 IUs of vitamin D once a week for four weeks, followed by the same amount once a month for 6 months, were found to boost activity among patients’ good immune cells while dampening activity of those cells believed to play a role in lupus.

The second experimental treatment is a potential vaccine against a specific immune system protein, interferon alpha. In this study, 28 people with lupus were given four doses of the vaccine. The patients’ immune systems then made antibodies against their own interferon alpha proteins.

Experts say larger clinical trials are needed to confirm these findings.

Lupus is a chronic disease in which the body’s own immune system attacks healthy cells throughout the body. It can affect different areas of the body: skin, joints, kidneys, lungs, nervous system and other organs, according to the U.S. Department of Health and Human Services. An estimated 1.5 million Americans suffer from lupus.

Research has focused on trying to find the specific immune cells involved in causing the disease, and then finding a way to slow them down or destroy them without damaging the rest of the immune system.