Microbiota influences on systemic lupus erythematosus and Sjögren’s syndrome

Commensal bacteria colonizing the gut, skin, and mucus membranes have recently been implicated in the pathogenesis of systemic lupus erythematosus (SLE) and Sjögren’s syndrome. The microbiota contributes to innate and adaptive immune responses that lead to systemic autoimmunity. We review here the role of the microbiota in animal models for SLE and Sjögren’s syndrome as well as human associative and mechanistic studies. We cover host-microbial mechanisms that contribute to the pathogenesis of autoimmunity including innate triggers of toll-like receptors, translocation of live bacteria into host tissues, and cross-reactivity of conserved structures within the microbiome with human autoantigens. In summary, both innate and adaptive immunity within and outside barrier organs are elicited by the microbiota. These responses lead to systemic autoimmunity and inflammation in genetically prone hosts.