Photosensitivity and Lymph Node Immune Responses in Lupus

Patients with systemic lupus erythematosus (SLE) are photosensitive, demonstrating an increased skin sensitivity to ultraviolet radiation (UVR) whereby even ambient exposure to sunlight can result in the development of inflammatory skin lesions. Advances have provided insight into both skin-intrinsic and immune cell-stromal contributions to photosensitivity, but, beyond the skin, photosensitive skin responses can trigger systemic disease flares, resulting in increased circulating autoantibodies which can deposit in and further injure end organs (1-3). The mechanisms by which photosensitive responses can lead to systemic disease flares are not well understood. Our long term goal is to delineate the mechanisms that connect photosensitivity with autoimmunity; as such, our goal with this proposal is to examine how SLE skin influences draining lymph node function. Interstitial fluid from skin drains via lymphatic vessels into sentinel lymph nodes where lymph fluid is channeled into a conduit system that provides the structural framework of the lymph node and is a distinct compartment from the parenchyma where T and B cells are located.