PT - JOURNAL ARTICLE AU - Jasper C A Broen AU - Ingrid L M Wolvers-Tettero AU - Lenny Geurts-van Bon AU - Madelon C Vonk AU - Marieke J H Coenen AU - Robert Lafyatis AU - Timothy R D J Radstake AU - Anton W Langerak TI - Skewed X chromosomal inactivation impacts T regulatory cell function in systemic sclerosis AID - 10.1136/ard.2010.129999 DP - 2010 Dec 01 TA - Annals of the Rheumatic Diseases PG - 2213--2216 VI - 69 IP - 12 4099 - http://ard.bmj.com/content/69/12/2213.short 4100 - http://ard.bmj.com/content/69/12/2213.full SO - Ann Rheum Dis2010 Dec 01; 69 AB - Objectives To investigate the role of X chromosomal inactivation (XCI) in systemic sclerosis (SSc) and its effects on forkhead box P3 (Foxp3) expression in T regulatory cells (Tregs). Methods 217 women with SSc and 107 healthy women (controls) were included in the study. From these subjects, DNA was isolated from total peripheral blood mononuclear cells, plasmacytoid dendritic cells, T cells, B cells, myeloid dendritic cells and monocytes after magnetic bead separation. All samples were assessed for skewed XCI patterns with the Human Androgen Receptor Assay. The outcome was assessed by linear regression. CD4+CD25+ cells were then isolated and intracellular Foxp3 expression was assessed by flow cytometry. Results Skewing was not associated with increased age in patients with SSc, in contrast to the control population (r=0.45, p<0.0001). Taking this into account, a significantly higher frequency of skewed XCI was found in patients with SSc compared with controls (p=0.001). No difference in skewing was observed between the immune cell subsets. In addition, a higher concentration of Foxp3+ cells exhibiting a lower Foxp3 mean fluorescence intensity was found in the patients with SSc, with profound XCI skewing (both p<0.001) associated with less efficient suppressive activity (p=0.012). Conclusions Skewed XCI plays a role in susceptibility to SSc, is not restricted and influences Foxp3 expression and the suppressive capacity of Tregs.