STAT1 and systemic lupus erythematosus: First, IFN type I and type II (as well as multiple other proinflammatory cytokines) bind to JAK receptors in order to activate intracellular signals and exert their functions.20 Second, there is growing evidence that the JAK/STAT pathway may regulate IFN- regulatory factor (IRF)-related genes.21 A study of the relation between type I–II IFN trigger activation of the JAK/STAT pathway in 22 SLE patients indicated that the overexpression of STAT1 by B-cells correlated with lupus activity.