Episode 364: The Lyme Puzzle - an interview with Professor Nicole Baumgarth

Introduction

• In this episode of Tick Boot Camp, our hosts Matt Sabatello and Rich Johannesen had the opportunity to talk with the remarkable Professor Nicole Baumgarth, director of the Lyme and Tick-Borne Diseases Institute at Johns Hopkins University. Baumgarth brings a unique interdisciplinary background in veterinary medicine, immunology, microbiology, and pathology offering fresh insights into the complex world of Lyme disease and tick-borne illnesses.

Lyme Disease Research

• Baumgarth and her team are investigating why we don't mount an effective adaptive immune response to Lyme as we do with influenza (the flu).
• She reveals their interesting finding about how Borrelia may alter the host's gut microbiome to enhance its survival.
• Baumgarth and her team are currently investigating why macrophages, immune cells that gobble up pathogens outside of our cells, don't eat up Lyme bacteria as they do with other bacteria and viruses.
• They are also investigating the impact Lyme has on obliterating our lymph nodes, which are critical agents in receiving signals from our body and mounting a specified immune response with targeted B cells and T cells against things like Lyme disease, as well as deploying long term memory immune cells and plasma cells which would give us long-term immunity to Lyme.
• The Lyme and Tick-Borne Diseases Institute is focusing on investigating why mice get infected with Lyme, the infection persists, yet they never get sick from the infection.
• If the team can identify human immune system deficits causing any of the above, they could identify immune therapies to overcome these shortcomings and treat all stages of Lyme disease.
• Baumgarth and her team are also looking into the impact of tick-borne co-infections. They argue that it's critical to study these diseases together rather than in isolation.

Autoimmune Responses and Lyme Disease

• Professor Baumgarth suggests that Lyme disease may cause an autoimmune response, which can be particularly concerning for those with genetic predispositions to autoimmunity.
• She cites several studies, both in the human model and mouse model, proving that Lyme disease creates an unnecessary increase in other antibodies from our immune system that aren't Lyme-related, resulting in an autoimmunity phenomenon, increased inflammation, and potential immune system burnout.

Understanding Lyme Disease: A Veterinary Perspective

• Professor Baumgarth's veterinary background has allowed her to approach Lyme disease from a macro perspective. She emphasizes that Lyme, being a zoonotic disease, is fundamentally an infection that moves from animals to humans.
• Lyme disease is often a natural infection in animals such as small rodents and birds, where ticks can bite them and transmit the disease.

Investigating the Human Immune Response to Lyme Disease

• Our hosts discuss how humans' immune responses to Lyme vary significantly. Some people are bitten by ticks multiple times without falling ill, while others suffer from chronic Lyme after just one bite.
• This discrepancy might be due to factors such as genetic predispositions, environmental stresses, or an individual's microbial load.

The Complexity of Eradicating Lyme

• Eliminating Lyme is not as simple as wiping out a certain animal species, as the bacteria Borrelia can infect a variety of different rodents and even birds.
• Borrelia is a complex bacterium that replicates slowly and requires a tick to infect a host. It's constantly evolving and it's not a simple task to eradicate Lyme from our ecology.

The Role of Antibiotics and Their Impact

• Despite their potential long-term impact on our immune response, antibiotics are currently the most common form of treatment as soon as Lyme disease is diagnosed. Professor Baumgarth emphasizes a variety of risks when using antibiotics to treat Lyme disease.
• While antibiotics can help in the short term, their effect on our long-term immunity to future infections is still unclear and Professor Baumgarth strongly warns against prolonged use of antibiotics.

Final Thoughts

• Baumgarth is hopeful about the future of Lyme disease research. Despite the challenges and controversies, she believes that continued progress is possible with dedicated research and interdisciplinary collaboration.

Episode Wrap-up

• Professor Nicole Baumgarth's interview provides an enlightening look into the intricate world of Lyme disease and its complex interaction with our immune system. Her unique veterinary perspective coupled with her background in immunology, microbiology, and pathology as well as her research findings shed light on the challenges we face and offer hope for future breakthroughs in the fight against Lyme and tick-borne diseases.