Acute skin exposure to ultraviolet light triggers neutrophil-mediated kidney inflammation

Significance Neutrophils are the most abundant leukocytes in circulation and the first responders to infectious and sterile inflammation, including skin exposure to ultraviolet (UV) light. We demonstrate that neutrophils not only migrate to the UV light–exposed skin but also disseminate systemically. In the kidney, neutrophils mediate inflammatory and injury responses triggered by skin exposure to UV. They had a proinflammatory phenotype: increased production of reactive oxygen species and a subpopulation of neutrophils in the kidney extravasated from UV light-exposed skin tissue. These studies demonstrate a direct link between skin inflammation by UV light and kidney injury and implicate neutrophils as pathogenic mediators, therefore providing a model by which exposure to UV light might contribute to kidney damage in lupus patients.