Infectome: A platform to trace infectious triggers of autoimmunity
Elsevier BV -- Autoimmun Rev
DOI 10.1016/j.autrev.2012.12.005
  1. AMA, anti-mitochondrial antibody
  2. ANA, anti-nuclear antibody
  3. CMV, cytomegalovirus
  4. CSF, cerebrospinal fluid
  5. EBV, Epstein–Barr virus
  6. EWAS, environmental-wide association study
  7. FDR, first degree relatives
  8. GWAS, genome wide association study
  9. HHV6, human herpes virus 6
  10. LC–MS/MS, liquid chromatography–tandem mass spectrometry (LC–MS/MS)
  11. MS, multiple sclerosis
  12. IBS, irritable bowel syndrome
  13. PBC, primary biliary cirrhosis
  14. PCR, polymerase chain reaction
  15. PDC, pyruvate dehydrogenase complex
  16. SLE, systemic lupus erythematosus
  17. Autoantibodies
  18. Autoimmunity
  19. Autoimmune disease
  20. Environment
  21. Infection
  22. Immunity
  23. Microbiome

The “exposome” is a term recently used to describe all environmental factors, both exogenous and endogenous, which we are exposed to in a lifetime. It represents an important tool in the study of autoimmunity, complementing classical immunological research tools and cutting-edge genome wide association studies (GWAS). Recently, environmental wide association studies (EWAS) investigated the effect of environment in the development of diseases. Environmental triggers are largely subdivided into infectious and non-infectious agents. In this review, we introduce the concept of the “infectome”, which is the part of the exposome referring to the collection of an individual's exposures to infectious agents. The infectome directly relates to geoepidemiological, serological and molecular evidence of the co-occurrence of several infectious agents associated with autoimmune diseases that may provide hints for the triggering factors responsible for the pathogenesis of autoimmunity. We discuss the implications that the investigation of the infectome may have for the understanding of microbial/host interactions in autoimmune diseases with long, pre-clinical phases. It may also contribute to the concept of the human body as a superorganism where the microbiome is part of the whole organism, as can be seen with mitochondria which existed as microbes prior to becoming organelles in eukaryotic cells of multicellular organisms over time. A similar argument can now be made in regard to normal intestinal flora, living in symbiosis within the host. We also provide practical examples as to how we can characterise and measure the totality of a disease-specific infectome, based on the experimental approaches employed from the “immunome” and “microbiome” projects.