In contrast to our findings, in a rheumatoid arthritis cohort, tofacitinib did not cause significant suppression of total STAT1 and STAT3 levels in peripheral blood monocytes, T cells, and B cells.19 However, they did show that responders to tofacitinib expressed higher baseline pSTAT1, pSTAT3, and pSTAT5 levels in peripheral blood monocytes compared with non-responders to tofacitinib, which was not found for total STAT1 and STAT 3 levels. Here, STAT3 is linked to rheumatoid arthritis.