February 2023—Systemic lupus erythematosus is an autoimmune disease that affects multiple organ systems and is most prevalent in women of Asian, Hispanic, and African ancestries. People with the heterogeneous disease experience major organ damage, which primarily affects the kidneys, skin, heart, and joints. Transcriptomic studies of systemic lupus erythematosus (SLE) have implicated increased type 1 interferon signaling, dysregulated lymphocyte activation, and failure of apoptotic clearance as hallmarks of the disease. Many genes are near the approximately 100 loci associated with SLE. Despite the use of flow cytometry and transcriptome profiling to characterize the role of circulating immune cells in SLE, there is not a complete census of circulating immune cells in the disease, and characterizing the genetic associations has been challenging.