As the presence of the STAT4 risk allele (rs7574865) has been associated with more severe clinical phenotype and significantly increased risk of vascular disease in SLE, and since type I IFNs activate STAT4, we stratified subjects based on the presence (+) or absence (−) of STAT4 risk allele which has been suggested to increase the production of and sensitivity to type I IFNs in peripheral blood mononuclear cells of SLE patients, to investigate the effect(s) of these haplotypes on the clinical and immunologic response to tofacitinib15–17. The gene discussed is STAT4; the disease is systemic lupus erythematosus.