All disease begins in the gut

As the largest immune organ in our body, the gut is a key area for the body to protect. However, due to its size and the constant influx of harmless yet foreign substances (such as food proteins), this area can be more difficult to police.

The gut immune system is continually teasing out what microbes are good and what are bad for us – it has the daily challenge of responding to pathogens while tolerating the constant influx of harmless substances. Microbes in the gut stimulate the immune system as needed, and it in turn talks back. However, the increasing disruption of these microbes, by way of lifestyle or for genetic reasons, breaks down the conversation and we begin to see misdirected immune responses to harmless substances. These are thought to contribute to the development of several inflammatory diseases including inflammatory bowel disease and food allergies.

An example of this dysfunction is when the gut barrier becomes permeable allowing the internal contents of the gut to leak into the bloodstream. As these components do not belong outside of the gut, the immune system views them as a threat and attacks them. Such dysfunctions within the gut are increasingly being linked to the chronic inflammation, which contributes to the development of diseases such as cancer, asthma and allergies.

More than two millennia ago, Hippocrates said, “all disease begins in the gut.” Only now are we beginning to realise how right he was. Further exploration of the gut immune response and how it can influence the development of inflammatory diseases is an exciting new area of immunology being investigated here at the Malaghan Institute by Dr Elizabeth Forbes-Blom and her team. It presents us with new opportunities for targeting and treating inflammatory diseases.