Figure 3.

The roles of type I and type III IFNs in the pathogenesis of SLE (systemic lupus erythematosus). Self-nucleic acid from apoptotic cells, or from neutrophil extracellular traps (NETs) released from neutrophils, are detected by autoantibodies to form immune complexes, stimulating plasmacytoid dendritic cells (pDCs) to produce type I and type III IFNs. Epithelial cells also produce type III IFNs in response to pathogen-associated molecular patterns (PAMPs). Both type I and type III IFNs stimulate myeloid DCs (mDCs) to activate T- and B-cells, which leads to the production of diverse proinflammatory cytokines and autoantibodies. Type I IFNs can also promote cytotoxicity function in macrophages and natural killer (NK) cells. Both type I and type III IFNs can contribute to a positive feedback loop of inflammation.