In preclinical lupus models, including MRL/lpr and NZB/W F1 mice, JAK inhibition has yielded beneficial effects: JAK2–STAT1 blockade reduced glomerular immune complex deposits, proteinuria, and inflammatory infiltrates; JAK1/STAT3 inhibition decreased disease severity and autoantibody levels (7). This evidence concerns the gene JAK1 and systemic lupus erythematosus.