The percentage of B cells, the highest expressors of XIST in patients with SLE, was similar in PBMCs from patients and controls (7.8% vs. 10.7%, P = 0.16), as was the percentage of monocytes (15.23% vs. 10.8%, P = 0.34), and the percentage of T cells was significantly lower in patient PBMCs compared with healthy controls (32.7% vs. 59.8%, P < 0.0001; Supplemental Figure 3D). Here, XIST is linked to systemic lupus erythematosus.