Microbiota Alterations in Patients with Mucous Membrane Pemphigoid and Pemphigus Vulgaris: A Systematic Review

The human oral cavity comprises an extensive range of microorganisms, viruses, bacteria, fungi, archaea, and protozoa, each having a particular role and interacting with each other and with the host in sickness or health. Changes in the microbiome composition can be crucial in balancing health and disease, locally and systemically. Various microbial species in commensal relationships form the oral microbiota, and when this commensalism undergoes variations the immune system can be pushed towards the activation of inflammatory and autoimmune processes. Through a systematic review of the literature, we set out to investigate the role that the oral microbiota can play in the development and evolution of pemphigus vulgaris and mucous membrane pemphigoid. We performed our systematic review by searching "microbiome OR microbiota" AND "pemphigus OR pemphigoid" on Medline, ISI Web of science and Embase, and we included randomized controlled trials (RCTs), prospective comparison studies, retrospective cohort studies, case-control studies, and case series. These autoimmune diseases need a genetic basis to develop, but as multifactorial pathologies they are influenced by environmental factors and the dysbiosis of the oral microbiota can be a trigger. If the human microbiome plays a critical role in the pathogenesis and manifestation of oral autoimmune diseases, the next step could be new and promising therapeutic approaches such as probiotics or prebiotics.