In 1907, the Russian scientist and Nobel Laureate Ilya Ilyich Mechnikov (Elie Mechnikov) proposed that ‘many diseases which lead to chronic systemic inflammation, occurred as a result of increased gut bacterial translocation into peripheral organs’ [P., M. E. G. The Prolongation of Life: Optimistic Studies. Putnam's Sons (1907)].
Today, we still only know that gut bacterial translocation is associated with many diseases, such as liver fibrosis, inflammatory bowel disease (IBD), metabolic disease (obesity, diabetes), HIV and cancer. Yet, there is a lack of cause-effect studies.
These early hypotheses by Elie Mechnikov, combined with my previous studies and recent advances in the field of host-microbe interactions inspired me to interrogate how the gut microbiota affects the immune system of the host during health and disease.