Your immune system is amazing. A physician-scientist wants you to know why

COVID turned "antibodies," "T cells" and "antigen tests" into dinner-table vocabulary, but the popular literature hasn't kept pace. Few recent books explain the immune system to general readers, in part because immunology is dense, fast-moving and has a language of its own.

Gary Koretzky '78, vice provost for research, a professor emeritus of medicine at Weill Cornell Medicine and a professor emeritus of microbiology and immunology at the College of Veterinary Medicine, has spent his career studying T cells, caring for patients with immunologic diseases and teaching medical and graduate students the intricacies of the immune system. Now, in his new book, "Your Immune System: The Amazing Science of Who You Are," published Oct. 6 by Johns Hopkins University Press, Koretzky aims to demystify immunology for laypeople.

The book moves from the fundamental biology of the immune system to allergies and vaccines to the newest forms of cancer immunotherapy, some of which are curing previously lethal diseases. Koretzky's book comes as measles cases hit a modern high and trust in public health is under strain. Koretzky, who spearheaded COVID town halls and a testing program in Ithaca, spoke about why he wrote this new book.

Question: You've been thinking about this book for about 40 years. Why now?

Answer: As a young rheumatologist, I was treating people with serious illnesses and struggled to find anything written to explain what was happening in their bodies. Then, about 15 years ago, cancer immunotherapy took off. The idea of harnessing the immune system against tumors moved from hope to reality and articles about new therapeutics began to appear regularly in the popular press. However, these short articles only scratched the surface of explaining how the underlying biology of how these new drugs worked. Then the COVID era made everyone want to understand immunology. Working with our community during COVID convinced me that there was an appetite for a book that would make immunology more easily understood.

Q: Measles cases in the U.S. are at their highest since elimination was declared in 2000. You devote three chapters to immunization. What do you want readers to take from them?

A: My concern is that people are making decisions without sufficient information. My goal was to lay out the facts, without a political point of view. I chose a historical lens, first telling the story of smallpox vaccination, which made one of history's most lethal diseases a thing of the past. I also describe the race to find a polio vaccine and then the discovery that immunization against a particular virus can prevent cervical cancers. Everyone can benefit from these miracles of modern medicine and I wanted my readers to understand the science well enough to make informed choices.

Q: Public trust in science has eroded. Can a book fix that?

A: I'd like to chip away at the mistrust by showing how science works. The book covers how science progresses step by step, but also through "A-ha" moments when paradigm-shifting discoveries are made. It also discusses missteps that set the field back and required retrenching and rethinking. Some people believe that if new evidence causes scientists to change how they think about a problem, the early explanations were untruths. That is decidedly incorrect. It just means that we have learned more.

As I was writing the book I was reminded that one of the reasons Cornell's COVID testing program worked so well is that we were deliberate about saying what we knew and what we didn't. People can handle uncertainty if you're honest about it and I tried to follow this principle throughout the book.

Q: What is an autoimmune disease, and what can it teach us about how the immune system works?

A: The immune system's job is to distinguish what is you from what is not you, and to eliminate what isn't. Autoimmune disease is what happens when that goes awry and the body turns on itself. Being "tolerant" (the phrase immunologists use to describe avoiding injuring our own organs) isn't a single step. It's a series of checkpoints, and autoimmunity can occur when any of these checkpoints fail. In the book I use lupus, rheumatoid arthritis, rheumatic fever, myasthenia gravis and other illnesses to illustrate how we came to understand some of the most important underlying principles of tolerance, discoveries that led to the current therapies physicians use to regain balance of the immune system.

Q: You describe the immune system as walking a tightrope. What do you mean?

A: You need an immune response strong enough to clear infections and cancer, but not so strong that it damages you. Autoimmunity, allergies and asthma are three examples of what happens when certain immune responses are too robust. Cancers are diagnosed when the immune system is not potent enough to identify cancerous cells when they are few in number and can still be eliminated. The immune system needs to be balanced.

Q: What discovery has surprised you most?

A: Remember, I am an immunologist and there are many discoveries that make my jaw drop. One that has recently captured the public's attention is how the microbiome, the world of microorganisms that live among us, impacts our immune system. For decades scientists knew these microorganisms were there, but they thought of them as largely inert. As it turns out, our microbiome matters enormously to our immune health, in ways that we are only beginning to understand.