Understanding Lupus Patients’ Inflammatory Response to Sun Exposure

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Sun sensitivity is a common and puzzling symptom among lupus patients, leaving researchers searching for answers for years. Dr. Michelle Kahlenberg, professor of internal medicine and dermatology at the University of Michigan, is leading Foundation-funded research to uncover why lupus patients develop sun-induced rashes.

While it has long been known that light exposure can alter cell structure, recent discoveries over the past decade have shed light on the role of interferons—proteins that help the immune system fight infections—in changing the skin’s response to UV light. Lupus patients, in particular, have abnormally high levels of these interferons.

“What happens when you have an excess of these interferons is that UV light triggers an inflammatory response that doesn’t shut off. This response is far more intense than what occurs in individuals without lupus,” explains Dr. Kahlenberg.

The research team discovered that these interferons activate a protein called Z-DNA binding protein 1 (ZBP1), which acts like a multiplier, amplifying the skin’s reaction to sun exposure. The aim is to develop therapies that target ZBP1, restoring the skin’s normal response in lupus patients without the harmful side effects of current treatments. The goal is to develop therapies that target it and turn the skin response in lupus patients back to normal without wreaking havoc on the immune system like current treatments often can.

“I think what’s really important here is that we’ve identified a target activated in the skin cells themselves. By targeting it, we hope to avoid the severe side effects, infections, and other complications patients currently endure,” says Dr. Kahlenberg.

Until more effective treatments are developed, sunscreen remains crucial in protecting lupus patients from this inflammatory reaction. However, the FDA no longer recommends chemical-based sunscreens due to concerns that they may enter the bloodstream.

“We encourage patients to use zinc and titanium-based sunscreens,” says Dr. Kahlenberg. “These formulas work instantly because they sit on the surface of the skin, preventing sunlight from penetrating, and they don’t get absorbed.”
While the research is ongoing, Dr. Kahlenberg is optimistic about the future. “Ultimately, my goal is for patients to no longer need sunscreen or hide from the sun during their children’s soccer games. Instead, they’ll be able to live their lives normally.”