Epigenetics is known to be an important mechanism in the pathogenesis of autoimmune diseases. Epigenetic variations can act as integrators of environmental and genetic exposures and propagate activated states in immune cells. Studying epigenetic alterations by means of genome-wide approaches promises to unravel novel molecular mechanisms related to disease etiology, disease progression, clinical manifestations and treatment responses. This paper reviews what we have learned in the last five years from epigenome-wide studies for three systemic autoimmune diseases, namely systemic lupus erythematosus, primary Sjögren's syndrome, and rheumatoid arthritis. We examine the degree of epigenetic sharing between different diseases and the possible mediating role of epigenetic associations in genetic and environmental risks. Finally, we also shed light into the use of epigenetic markers towards a better precision medicine regarding disease prediction, prevention and personalized treatment in systemic autoimmunity.

表观遗传学是自身免疫性疾病发病机理中的重要机制。表观遗传变异可以充当环境和遗传暴露的整合者，并在免疫细胞中传播活化状态。通过全基因组方法研究表观遗传学改变有望揭示与疾病病因，疾病进展，临床表现和治疗反应有关的新型分子机制。本文回顾了过去五年中我们从表观基因组研究中了解到的三种系统性自身免疫疾病，即系统性红斑狼疮，原发性干燥综合征和类风湿性关节炎。我们研究了不同疾病之间表观遗传共享的程度以及表观遗传关联在遗传和环境风险中的可能中介作用。最后，