Longitudinal Microbiome Dynamics in Patients With Cancer and Immune-Mediated Diseases

The Byrd Lab is exploring how the human microbiome — the diverse community of microbes living in the gut — changes over time in patients undergoing cancer treatment or with other immune system diseases. Understanding these microbial dynamics can reveal important connections between the microbiome, immune system activity, and patient outcomes.

In collaboration with oncologists worldwide, including Shahneen Sandhu, MBBS, FRACP, at Peter MacCallum Cancer Centre in Melbourne, Australia, the lab contributes to the MicroMac observational trial. This study follows 150 patients with melanoma to track changes in their gut microbiomes before, during, and after treatment with medications such as antibiotics or corticosteroids. These medications are commonly prescribed to manage immune-related adverse events (irAEs) or infections that can arise during standard immunotherapy.

The Byrd Lab hypothesizes that shifts in the microbiome may occur before irAEs arise and that these microbial changes normalize once the irAEs resolve. To investigate this, the team has sequenced hundreds of stool samples collected over time, carefully pairing this data with detailed clinical information such as medication use, treatment responses, and adverse events. This integrated approach offers a unique window into the long-term interplay between the microbiome, medications, and immune responses during checkpoint inhibitor therapy.

Building on insights from cancer therapy, the Byrd Lab aims to extend this work to autoimmune diseases, including type 1 diabetes, rheumatoid arthritis and inflammatory bowel disease. In these conditions, the immune system mistakenly targets beneficial microbes, contributing to chronic inflammation and tissue damage. By tracking microbiome dynamics, the lab aims to uncover patterns that could help predict, prevent, or mitigate disease activity.

Through these studies, the Byrd Lab is advancing a deeper understanding of how the microbiome interacts with the immune system in both cancer and autoimmunity. This research brings together patients, clinicians, and scientists in a collaborative effort to uncover microbial patterns that could guide more precise, personalized approaches to treating immune system diseases.