We measured pSTAT1 in gated Tregs and Tconvs from ISG15lo and ISG15hi SLE patients, either untreated or after a pulsed exposure ex vivo to IFNα with two different doses and durations (102 IU mL−1 for 15 min, or 104 IU mL−1 for 25 min), recapitulating suboptimal or optimal stimulation of IFN receptors respectively. This evidence concerns the gene IFNA1 and systemic lupus erythematosus.