PPP2R2B hypermethylation causes acquired apoptosis deficiency in systemic autoimmune diseases

Chronic inflammation causes target organ damage in patients with systemic autoimmune diseases. The factors that allow this protracted response are poorly understood. We analyzed the transcriptional regulation of PPP2R2B (B55 beta), a molecule necessary for the termination of the immune response, in patients with autoimmune diseases. Altered expression of B55 beta conditioned resistance to cytokine withdrawal-induced death (CWID) in patients with autoimmune diseases. The impaired upregulation of BSS beta was caused by inflammation-driven hypermethylation of specific cytosines located within a regulatory element of PPP2R2B preventing CCCTC-binding factor binding. This phenotype could be induced in healthy T cells by exposure to TNF-alpha. Our results reveal a gene whose expression is affected by an acquired defect, through an epigenetic mechanism, in the setting of systemic autoimmunity. Because failure to remove activated T cells through CWID could contribute to autoimmune pathology, this mechanism illustrates a vicious cycle through which autoimmune inflammation contributes to its own perpetuation.