Why does sunlight worsen lupus symptoms?

By examining skin from lupus patients at the single-cell level, researchers identified the role of dendritic cells and excessive interferon production in ultraviolet-triggered inflammation, a finding that could help develop new treatments.

Ambassador Arjan - Social Group: Lupus patients are always faced with worsening symptoms after exposure to sunlight. Now, by analyzing the skin at the single-cell level, researchers have found out the exact mechanism of this phenomenon; A finding that can promise new treatment methods for this disease.

The Medical Express website reported in a report:

The skin of lupus patients produces more inflammatory substances after exposure to the sun's ultraviolet light. The same issue makes these patients have to avoid sunlight, but these changes occur at the cellular level and were not well understood until now.

What is lupus and why is sunlight problematic for patients?

Lupus or systemic lupus erythematosus (SLE) is an autoimmune disease; That is, instead of attacking external factors, the body's defense system attacks its own healthy tissues.

The skin of lupus patients gets severe inflammation after being exposed to sunlight. This inflammation can appear in the form of skin lesions (rash). A rash is a red, swollen, or inflamed patch on the skin that may be itchy or painful. In some cases, this inflammation can even involve the whole body and worsen the symptoms of the disease.

What did the new research discover?

In a study published in Science Translational Medicine, Kallenberg's lab at the University of Michigan used single-cell RNA sequencing. This method means checking the activity of genes in individual cells. In this way, researchers can understand what each cell is doing.

This is the first time that researchers investigate the sensitivity of lupus to sunlight at the cellular level; That is, instead of examining the whole skin, they examine individual skin cells separately to understand which cells are activated after exposure to light and what happens.

Researchers examined the skin of lupus patients to understand what happens on the surface of the cells after being exposed to ultraviolet light. The result was this: a type of immune cell called dendritic cell is activated in the skin. These cells cause severe inflammation in lupus.

Michelle Kahlenberg, vice president of research in the Department of Internal Medicine and professor of rheumatic diseases at the University of Michigan, says: This study is the first to examine the sensitivity of lupus to sunlight at the single-cell level. This research shows that the skin with lupus after being exposed to ultraviolet light has a hyper-inflammatory response that is centered around the excessive production of interferons.

Interferon is a type of protein that activates the immune system. In lupus, its overproduction causes severe inflammation.

This discovery can help in treatment, because researchers now know which cells and which pathways are involved in skin inflammation. If these pathways can be targeted with drugs, it is possible to prevent sensitivity to sunlight and skin lesions. This issue can significantly improve the quality of life of lupus patients.

He adds: This activates blood vessels and attracts special immune cells called dendritic cells to the skin. These cells cause severe inflammation and may play an important role in the development of lupus skin lesions.

According to him, this study has identified several important pathways that can be targeted by drugs to prevent sun sensitivity, skin lesions and worsening of disease symptoms.

Kallenberg's lab researchers plan to expand their knowledge about this method to improve the care and treatment of lupus patients.