Linking Systemic Lupus Erythematosus and UV Sensitivity: When Immune Cells Receive Misguided Cell Education

Instead of improving their efficiency, they appear to lose competence.

Illustration by author

In systemic lupus erythematosus (SLE), the immune system mistakenly attacks the body’s cells, leading to inflammation in affected tissues.

About 70% of SLE patients experience cutaneous lupus erythematosus (CLE), where the immune system targets the skin cells, resulting in uncontrolled inflammations that manifest as skin rashes. Often, CLE occurs in areas of the skin directly exposed to ultraviolet (UV) rays, usually from sunlight or even artificial lamps.

The immune system is complex. But here’s a fraction of what happens in normal, healthy skin upon exposure to UV:

• First, UV rays (i.e., UVB) penetrate the skin and are absorbed entirely by the keratinocytes — cells that make up the epidermis (top layer of skin).
• In the keratinocytes, UVB may induce damage to the DNA and other components inside. If the damage is severe, the cells self-destruct. These dying cells then secrete inflammatory proteins (e.g., type I interferon (IFN) that call for an immune response.
• Picking up the signal, neutrophils, the first responders of the…