Unusual pPtterns of X Chromosome Inactivation in Immune Cells (image) University of Pennsylvania Share Print E-Mail Caption Xist (in pink), an RNA molecule responsible for inactivating one of a female's two X chromosomes, is not tightly associated with the X chromosome in healthy human female lymphocytes, though it is in other cell types. This incompletely inactivation of genes on the X chromosome, including many immunity-related genes, may help explain why females are predisposed to many autoimmune conditions and also have stronger immune responses than males. Credit University of Pennsylvania Usage Restrictions In context of reporting Share Print E-Mail Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.