XIST and systemic lupus erythematosus: Abnormal X-chromosome inactivation (XCI), reflected by reduced XIST RNA and H2AK119Ub enrichment at the inactive X chromosome is present in B cells of both pediatric and adult SLE patients.232 Functionally, XIST enforces X-inactivation in adult human B cells via binding to tripartite motif containing 28 (TRIM28) that mediates Pol II pausing at promoters of X-linked genes such as TLR7 in B cells.