The Microbiome’s Role in IBD

Our body is home to a vast ecosystem of microorganisms—bacteria, fungi and viruses—that live on and in us. Their combined genetic material, containing millions of genes, is known as the microbiome.1

While these organisms can be found all over our bodies, the highest concentration of microbes is found in our intestines, also known as the gut. In fact, there are said to be trillions of these tiny organisms in our gut, and may weigh up to five pounds!2

Microbes play such an important role in our digestion, metabolism and the immune system that researchers call them a “microbial organ.” These microbes help us break down the food we eat, produce essential amino acids, hormones and vitamins, and protect us from bacteria and viruses.

The microbiome is varied and diverse – the ‘good’ microbes work in harmony with one another as a community and protect us from disease-causing or ‘bad’ microbes.

In people with inflammatory bowel disease (IBD), this balance is disrupted, reducing the number and diversity of the microbiome. We know that change in the microbiome and its interaction with the immune system is associated with the onset of IBD. We all have a different collection of microbes, but our understanding of what that means and what to do about it is still evolving.

There isn't a single cause for IBD.

More likely, several different factors can influence the onset of the disease. These are the "omes" of IBD.

Gut Microbiome

The types of bacteria inside our gastrointestinal tracts.3


The reactivity of the intestinal immune response.3


The contributions of DNA changes and heritability.3


Environmental factors like diet and geography.3

So how does a better understanding of the microbiome help people living with IBD?

By studying the microbiome, we can begin to understand how different people will respond to different treatments. We know that if a group of people with IBD responds to therapy, their gut bacteria may rebuild back to normal levels of diversity. The analysis and manipulation of this community of microbes, which varies from person to person, may help us understand more about personalizing IBD therapies for individual people.

In June 2018, Genentech formed a strategic collaboration with Microbiotica, a leading company in microbiome research and translation based in Cambridge UK. This collaboration will provide precision analysis of the microbiome and uncover new findings that can inform the development of future treatments for IBD patients.

“Better understanding why IBD patients might or might not respond to treatment has huge implications for the future outlook of the disease,” says Mary Keir, Senior Scientist, Biomarker Discovery. “If we can better understand the inner workings of the microbiome, our body’s own community of microorganisms, there is great potential to improve the lives of those living with a complex and severely debilitating disease.”