The role of neutrophils in skin damage induced by tissue-deposited lupus IgG.

Skin injury is the second most common clinical manifestation in patients with systemic lupus erythematosus (SLE). Neutrophils are crucial effector cells in the immune system but the significance of neutrophils in the pathogenesis of SLE is not clear. This study is to explore the role of neutrophils in the skin damage of SLE. We used lupus-prone mice and a C57BL/6 mouse model of lupus serum IgG-induced skin inflammation to investigate the role of neutrophils in skin damage of SLE. We found that a few neutrophils infiltrated the inflammatory sites of skin in lupus-prone mice and the lupus-IgG-induced skin damage mouse model. Depletion of neutrophils did not affect the development of skin inflammation caused by lupus IgG, and lupus IgG can induce apoptosis of neutrophils. The apoptosis of neutrophils induced by lupus IgG is related to FcγRIII and Fas/Fas ligand pathways. Our study indicates that neutrophils are not major contributors in the skin damage caused by tissue-deposited lupus IgG but death of neutrophils caused by lupus IgG may provide a resource of a large amount of autoantigens in SLE.