The microbiome and allergic diseases

Published on January 31, 2024   36 min

Other Talks in the Series: Allergy - From Basics to Clinic

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0:00
Hello everybody. My name is Harald Renz, and I'm from the Institute of Laboratory Medicine at the Philipps University of Marburg in Germany. I'm going to talk about the microbiome and allergic diseases.
0:17
Here are my conflict of interest. Particularly, I would like to focus on my editorial activities as Associate Editor of the Journal of Allergy and Clinical Immunology.
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When we are talking about the role and the function of a microbiome, it is very important to connect the microbiome with our immune system. Our normal default program of the immune system is shown on the left-hand side of this slide, and that is the development of clinical and immunological tolerance. The development of tolerance requires antigen contact. It's an active process of the immune system. It is closely related to the development of regulatory T cells and other cell types of the adaptive immune system, which are secreting interleukin 10 and TGF-beta and other cytokines. However, if this default program cannot develop or is interrupted or is disturbed, then this gives room and space for the development of pathologic pathogenic, chronic inflammation. Again, this is inflammation controlled and directed by T lymphocytes. But in this case, these are different effector T-cell responses. We term them in the most simple classification as T helper 1 or T helper 2 type inflammatory responses. You see here on the right-hand side of this slide an example of such pathogenic inflammatory response. In this case, it is T helper 2 type inflammatory reaction, which is mainly orchestrated by the cytokines secreted by these T helper 2 cells. These T helper 2 cells are instructed by epithelial cells which have encountered pathogens, bacteria, microbes, but also allergens. Now comes the microbiome into this picture. The microbiome is actually the exposure, the qualitative and quantitative composition of the exposure of the epithelial barrier of the epithelial layers to environmental microbes and microbes which have seeded here in these cell spaces. These microbes interact very closely with our epithelial barrier, but also with the immune cells directly themselves. This close and intimate interaction actually is responsible for the education and for the training of the immune system. With the right microbes at the right time, at the right place, we are able to develop a tolerogenic type of immune response. But if we have wrong microbes at the wrong time in the wrong place, this opens way to the development of pathogenic inflammation. Now it is very important to better understand the mechanisms underlying this paradigm. Here we have made some substantial progress over the last few years, which I would like to share with you throughout my presentation. On the next slide, you see the distribution of this microbiome in our body.