That sunlight and even artificial light can be a dangerous trigger factor for individuals with lupus erythematosus is well known. A research team has now succeeded in uncovering a link between the patients’ sensitivity to light and a dysregulation of the innate immune system.
In the autoimmune disease lupus erythematosus, the immune system gets out of control and forms antibodies against the body’s own structures. In this systemic disease, which belongs to the group of collagenoses, the skin and vascular connective tissue of the organs are affected by vasculitides and deposits of immune complexes. Photosensitivity is one of the classic skin manifestations along with butterfly erythema and oral ulcers. The underlying mechanism for the increased photosensitivity has not yet been fully elucidated. Scientists at the University Medical Center Göttingen investigated this question and came up with interesting findings. “We found that light under certain conditions stimulates neutrophil granulocytes to increase NET formation. This mechanism depends on the release of oxygen free radicals,” says Priv.-Doz. Dr. Luise Erpenbeck. It has been known for several years that the formation of so-called NETs (“Neutrophil Extracellular Traps”) is disturbed or increased in patients with lupus erythematosus. During NET formation, neutrophil granulocytes, a type of white blood cell, can throw out their genetic material like a kind of fishing net to catch bacteria, viruses or fungi. However, if this process – as in the case of lupus erythematosus – takes place increasingly and without an infection, or if the NETs released are not broken down, the immune system can form antibodies against these very NETs. The scientists recently received a research award and hope that, based on further study results, targeted therapies can be developed in the future to better control photosensitivity and the disease as a whole.
Source: “Sun and the Innate Immune System”, 10.09.2020, University Medical Center Göttingen (D).
Original publication:
- Erpenbeck L, et al: Front. Immunol 2019. https://doi.org/10.3389/fimmu.2019.02320
DERMATOLOGY PRACTICE 2020; 30(6): 21
