Micro-immunotherapy in gastroenterology

The importance of the intestines for our health goes far beyond their digestive function. As a point of surface with the outer world, they are continuously exposed to external factors, such as components of food, bacteria, viruses, and parasites, lending the gut an important function as a defence organ.

This protective system is made up of three components:

• Microbiota: This refers to the whole collection of physiological microorganisms present in the intestines. In addition to suppressing undesired germs, the intestinal flora is, among other things, involved in the maturation of the immune system and has a positive effect on immune tolerance.¹
• Intestinal mucosa: This forms a physical barrier to the external world and has the dual role of, on the one hand, allowing nutrients and fluids to pass out through the intestine walls to the blood circulatory system and, on the other hand, protecting against the invasion of undesired germs.²

• Immune system of the gastrointestinal tract: 80% of immune cells can be found in the intestinal milieu. The purpose of the immune system in the gastrointestinal tract is to efficiently combat disease pathogens found in the intestines, while tolerating normal intestinal flora and food constituents.²

Disorders of intestinal permeability (leaky gut syndrome) and intestinal flora (dysbiosis) are closely associated with the occurrence of numerous diseases, including inflammatory intestinal diseases, such as Crohn’s or ulcerative colitis, but also chronic systemic diseases such as obesity and diabetes.2 Behavioural and other neuropsychological disorders, including stress, depression and autism, have also been associated with disorders of normal intestinal function.^3,4

For intestinal diseases, micro-immunotherapy aims to modulate the inflammatory response and restore the immune tolerance of the intestines. In the context of psychoneuroimmunology, it can also make a significant contribution towards the regulation of the stress axis that can also influence the gastrointestinal system.⁵

1. Petersen, C. & Round, J. L. Defining dysbiosis and its influence on host immunity and disease. Cell. Microbiol. 16, 1024–1033 (2014).
2. Richards, J. L., Yap, Y. A., McLeod, K. H., Mackay, C. R. & Mariño, E. Dietary metabolites and the gut microbiota: an alternative approach to control inflammatory and autoimmune diseases. Clin. Transl. Immunol. 5, e82 (2016).
3. Mangiola, F. et al. Gut microbiota in autism and mood disorders. World J. Gastroenterol. 22, 361–8 (2016).
4. Dinan, T. G. & Cryan, J. F. Melancholic microbes: a link between gut microbiota and depression? Neurogastroenterol. Motil. 25, 713–719 (2013)