Current concepts of photosensitivity in cutaneous lupus erythematosus

Cutaneous lupus erythematosus (CLE) represents a complex autoimmune disease with a broad phenotypic spectrum ranging from acute to chronic destructive cutaneous lesions. Patients with CLE exhibit high photosensitivity and ultraviolet (UV) irradiation can lead to systemic flares in systemic lupus erythematosus. However, the exact mechanisms how UV irradiation enhances cutaneous inflammation in lupus are not fully understood. Recently, new molecular mechanisms of UV-driven immune responses in CLE were identified, offering potential therapeutic approaches. Especially the induction of type I interferons, central cytokines in lupus pathogenesis which are released by various skin cells, have become the focus of current research. In this review, we describe current pathogenic concepts of photosensitivity in lupus erythematosus, including UV-driven activation of intracellular nucleic acid sensors, cellular cytokine production and immune cell activation. Furthermore, we discuss activated pathways contributing to enhanced apoptosis as well as intracellular translocation of autoantigens thereby promoting CLE upon UV light exposure.

Automated summary

Cutaneous lupus erythematosus (CLE) is a complex autoimmune disease with a wide range of skin lesions. Patients with CLE are highly sensitive to sunlight and ultraviolet (UV) irradiation can trigger systemic flares of systemic lupus erythematosus. However, the exact mechanisms by which UV irradiation enhances skin inflammation in lupus are not fully understood. Recent studies have identified new molecular mechanisms of UV-driven immune responses in CLE, providing potential therapeutic targets. The induction of type I interferons, central cytokines in lupus pathogenesis, has become a major focus of current research.