Emerging concepts and treatments in autoinflammatory interferonopathies and monogenic systemic lupus erythematosus

Over the past two decades, the number of genetically defined autoinflammatory interferonopathies has steadily increased. Aicardi–Goutières syndrome and proteasome-associated autoinflammatory syndromes (PRAAS, also known as CANDLE) are caused by genetic defects that impair homeostatic intracellular nucleic acid and protein processing respectively. Research into these genetic defects revealed intracellular sensors that activate type I interferon production. In SAVI and COPA syndrome, genetic defects that cause chronic activation of the dinucleotide sensor stimulator of interferon genes (STING) share features of lung inflammation and fibrosis; and selected mutations that amplify interferon-α/β receptor signalling cause central nervous system manifestations resembling Aicardi–Goutières syndrome. Research into the monogenic causes of childhood-onset systemic lupus erythematosus (SLE) demonstrates the pathogenic role of autoantibodies to particle-bound extracellular nucleic acids that distinguishes monogenic SLE from the autoinflammatory interferonopathies. This Review introduces a classification for autoinflammatory interferonopathies and discusses the divergent and shared pathomechanisms of interferon production and signalling in these diseases. Early success with drugs that block type I interferon signalling, new insights into the roles of cytoplasmic DNA or RNA sensors, pathways in type I interferon production and organ-specific pathology of the autoinflammatory interferonopathies and monogenic SLE, reveal novel drug targets that could personalize treatment approaches. This Review provides a comprehensive update on dysregulated type I interferon production and signalling in autoinflammatory interferonopathies, monogenic systemic lupus erythematosus and conditions that present with broad immune dysregulation and interferon signatures. The authors provide a classification for autoinflammatory interferonopathies based on disease mechanisms of increased type I interferon production and signalling and overlapping clinical phenotypes. Key points Genetic defects impairing intracellular nucleic acid and protein processing and/or STING activation cause autoinflammatory interferonopathies, indicating that intracellular sensor-mediated type I interferon production exhibits disease-specific and disease-overlapping clinical features. Identification of the genetic causes of monogenic systemic lupus erythematosus (SLE) reveals molecular mechanisms triggered by extranuclear