regulatory cells

Science Immunology

Nine of 10 individuals who develop systemic lupus erythematosus (SLE) are women. Furthermore, individuals with Klinefelter syndrome (47,XXY) also have increased incidence of SLE, suggesting that X chromosome dosage could be an important risk factor in SLE. Using sensitive quantification methods, Souyris et al . demonstrate that Toll-like receptor 7 ( TLR7 ) that is encoded from the X chromosome escapes X inactivation in B cells and myeloid cells in females and Klinefelter individuals. TLR7 binds single-stranded RNA and activates type I interferon signaling, a pathway that is also activated in SLE patients. On the basis of this, the authors propose that biallelic expression of TLR7 contributes to greater SLE risk in individuals with two X chromosomes.

TLR7 escapes X chromosome inactivation in immune cells