The incidence of autoimmune diseases has been steadily rising. Concomitantly, the incidence of most infectious diseases has declined. This observation gave rise to the hygiene hypothesis, which postulates that a reduction in the frequency of infections contributes directly to the increase in the frequency of autoimmune and allergic diseases. This hypothesis is supported by robust epidemiological data, but the underlying mechanisms are unclear. Pathogens are known to be important, as autoimmune disease is prevented in various experimental models by infection with different bacteria, viruses and parasites. Gut commensal bacteria also play an important role: dysbiosis of the gut flora is observed in patients with autoimmune diseases, although the causal relationship with the occurrence of autoimmune diseases has not been established. Both pathogens and commensals act by stimulating immunoregulatory pathways. Here, I discuss the importance of innate immune receptors, in particular Toll-like receptors, in mediating the protective effect of pathogens and commensals on autoimmunity.

中文翻译：

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自身免疫中的卫生假说：病原体和共生体的作用

自身免疫性疾病的发病率一直在稳步上升。同时，大多数传染病的发病率下降了。该观察结果提出了卫生学假说，该假说假定感染频率的降低直接导致自身免疫和过敏性疾病的频率增加。强有力的流行病学数据支持了这一假设，但其潜在机制尚不清楚。众所周知，病原体很重要，因为在各种实验模型中，通过感染不同的细菌，病毒和寄生虫可以预防自身免疫性疾病。肠道共生细菌也起着重要作用：尽管尚未确定与自身免疫性疾病发生的因果关系，但在自身免疫性疾病患者中观察到肠道菌群失调。病原体和共生体均通过刺激免疫调节途径起作用。在这里，我讨论了先天性免疫受体，特别是Toll样受体在介导病原体和共生菌对自身免疫的保护作用中的重要性。