Cause found for lupus, which might lead to cure

US researchers have found a mechanism that causes the life-threatening disease lupus.

The process opens up avenues for more direct treatment of the disease, which affects millions of people worldwide.

Lupus is an autoimmune condition that occurs when the immune system attacks the body’s ordinary cells. There currently isn’t any cure.

“By identifying a cause for this disease, we have found a potential cure that will not have the side effects of current therapies,” says Dr Jaehyuk Choi, associate professor of dermatology at Northwestern University, US, and co-author on a paper describing the research, published today in Nature.

“Up until this point, all therapy for lupus is a blunt instrument. It’s broad immunosuppression.”

The researchers examined blood samples from lupus patients, looking for changes that differ from ordinary blood samples.

They found that many of the changes led to the underperformance of a protein called aryl hydrocarbon receptor, or AHR.

This protein helps to control cells’ responses to threats like pollutants and bacteria.

If the AHR isn’t operating properly, the body can overproduce immune cells called T peripheral helper cells which can then attack healthy cells.

“We’ve identified a fundamental imbalance in the immune responses that patients with lupus make, and we’ve defined specific mediators that can correct this imbalance to dampen the pathologic autoimmune response,” says co-author Dr Deepak Rao, an assistant professor of medicine at Harvard Medical School, US.

To test it, the researchers added AHR-activating molecules back into blood samples of lupus patients. This reduced the lupus-causing cells.

“We found that if we either activate the AHR pathway with small molecule activators or limit the pathologically excessive interferon in the blood, we can reduce the number of these disease-causing cells,” says Choi.

“If these effects are durable, this may be a potential cure.”

The researchers are now beginning to look for ways that these treatments can be safely given to people.