Two Chapters From Our New Book – Exclusive Preview!

Hello everybody! Today we're doing something different: an exclusive preview. We'll listen to the introduction and a chapter from the KTZ Gazar book Immune: A Journey into the Mysterious System that Keeps You Alive, written by KTZ Gazar founder and headwriter Philip Debar.

It's about the epic story of the immune system, the most important thing you don't know enough about, and it will forever change how you think about your body. Immune will be released on November the 2nd, and you can pre-order it right now. Links are in the description.

So, now get comfy for a rare audio-only experience.

Introduction

Imagine waking up tomorrow feeling a bit under the weather. An annoying pain in your throat, your nose is runny, you cough a bit— all in all, not bad enough to skip work you think as you step into the shower, pretty annoyed about how hard your life is.

While you are totally not being a whiny little baby, your immune system is not complaining. It is busy keeping you alive so you can live to whine another day. And so, while intruders roam your body, killing hundreds of thousands of your cells, your immune system is organizing complex defenses, communicating over vast distances, activating intricate defense networks, and dishing out a swift death to millions, if not billions, of enemies— all while you are standing in the shower, mildly annoyed.

But this complexity is largely hidden, which is a real shame because there are not many things that have such a crucial impact on the quality of your life as your immune system. It is all-embracing and all-encompassing, protecting you from bothersome nuisances like the common cold, scratches, and cuts to life-threatening stuff from cancer and pneumonia to deadly infections like COVID-19.

Your immune system is as indispensable as your heart or your lungs, and actually, it is one of the largest and most widespread organ systems throughout your body. Although we don't tend to think about it in these terms, for most of us, the immune system is a vague and cloud-like entity that follows strange and untransparent rules and which seems to sometimes work and sometimes not.

It is a bit like the weather; extremely hard to predict and subject to endless speculation and opinions, resulting in actions that feel random to us. Unfortunately, many people speak about the immune system with confidence but without actually understanding it. It can be hard to know which information to trust and why.

But what even is the immune system, and how does it actually work? Understanding the mechanisms that are keeping you alive as you read this is not just a nice exercise in intellectual curiosity; it is desperate needed knowledge. If you know how the immune system works, you can understand and appreciate vaccines and how they can save your life or the lives of your children and approach disease and sickness with a very different mindset and far less fear.

You become less susceptible to snake oil salesmen who offer wonder drugs that are entirely devoid of logic. You get a better grasp on the kinds of medication that might actually help you when you are sick. You get to know what you can do to boost your immune system. You can protect your kids from dangerous microbes while also not being too stressed out if they get dirty playing outside.

And in the very unlikely case of, say, a global pandemic, knowing what a virus does to you and how your body fights it might help you understand what the public health experts say. Besides all these practical and useful things, the immune system is also simply beautiful—a wonder of nature like no other.

The immune system is not a mere tool to make your cough go away; it is inextricably tied into almost all other processes in your body. And while it is centrally important to keeping you alive, it is likely that it may also be the part of your body that causes your untimely death, either by failing or by being too active.

I have been fascinated and obsessed by the incredible complexity of the human immune system for the better part of a decade now. It began in university, where I was studying information design and was looking for a semester project, and the immune system seemed like a good idea. So I got a large pile of books about immunology and began digging in.

But no matter how much I read, things just did not get less complicated. The more I learned, the more impossible it seemed to simplify the immune system, as every layer revealed more mechanisms, more exceptions, more complexity. And so, a project that was supposed to last the spring took the summer, and then the fall and the winter. The interactions of the parts of the immune system were too elegant, and the dance they danced was too beautiful to stop learning about them.

This progress fundamentally changed how I experienced and felt about my body. When I got the flu, I could no longer just complain but had to look at my body, touch my swollen lymph nodes, and visualize what my immune cells were doing right then— which part of the network was active and how T-cells killed millions of intruders to protect me.

When I cut myself while being careless in the forest, I felt gratitude for my macrophages, large immune cells hunting scared bacteria and ripping them into pieces to protect the open wound from infection. After taking a bite of the wrong granola bar and suffering an allergic shock while being rushed to the hospital, I thought about M cells and IgE antibodies and how they had almost killed me in a misguided attempt to protect me from scary foodstuffs.

When I was diagnosed with cancer at the age of 32 and had to undergo a couple of operations and then chemotherapy, my obsession with immunology became even more intense. One of the jobs of my immune system is to kill cancer. In this case, it had failed, but I somehow could not be angry or too upset, as I had learned how hard of a job this was for my immune cells and how hard cancer had to work to keep them in check.

As the chemo melted the cancer, my thoughts again went to my immune cells invading the dying tumors and eating them up one cell after another. Disease and sickness are scary and unsettling, and I've had plenty of that in my life. But knowing how my cells—my immune system, this integral and personal part of myself—defended the entity that is me, how it fought and died, healed and restored this body I inhabit, always gave me a lot of comfort.

Learning about the immune system made my life better and more interesting, and it alleviated a lot of the anxiety that comes with being sick. Knowing about the immune system always put things in perspective. So because of this positive effect and just because of the fun of learning and reading about the immune system, it became an ongoing hobby.

As I eventually became a science communicator and explaining complex things became my purpose in life. About 8 years ago, I started KTZ Gazar. In a nutshell, a YouTube channel dedicated to making information easy to understand and beautiful while trying to be as true to the science as possible.

In early 2021, the KTZ Gazar team has grown to over 40 people working on this vision, while the channel has attracted over 14 million subscribers and reaches about 30 million viewers each month. So if this large platform exists, why go through the horrible process of writing this book?

Well, while some of our most successful videos have been about the immune system, it has always bugged me that I could not explore this wonderful topic in the depth it deserves. A 10-minute video is simply not the right medium for that. So this book is a way to turn my decade-long love affair with the immune system into something tangible that will hopefully be a helpful and entertaining way to learn about the stunning and beautiful complexity that makes it possible for you to survive each day.

Unfortunately, the immune system is very complicated— although that is not strong enough a word. The immune system is complicated in the sense that climbing Mount Everest is a nice stroll through nature. It is intuitive like reading the Chinese translation of the tax code of Germany is a fun Sunday afternoon. The immune system is the most complex biological system known to humanity other than the human brain.

The bigger the immunology textbook you read, the more layers of detail start piling on, the more exceptions to rules appear, the more intricate the system becomes, the more specific it seems to be for every possible eventuality. Every single one of its many parts has multiple jobs and functions and areas of expertise that overlap and influence each other.

Even if you make it past these challenges and still want to understand the immune system, you will encounter another problem: the humans who described it. Scientists have laid the foundation for the amazing modern world we get to enjoy today through hard work and endless curiosity, and we owe them a great deal of gratitude.

Unfortunately, though, many scientists are really bad at choosing good names and coming up with accessible language for the things they discover. The science of immunology is one of the worst culprits of any scientific discipline in this regard. An already breathtakingly complex field is spiked with words like major histocompatibility complex, class 1 and 2, gamma delta T cells, interferon alpha, beta, gamma, and kappa, and the complement system with actors named C4B2A3B complex.

None of this makes it a pleasure to pick up a textbook and learn about the immune system on your own. But even without this barrier, the complex relationships of the many different actors of the immune system, with countless exceptions and unintuitive rules, are a challenge all by themselves. Immunology is hard, even for the people working in public health, even for the people studying immunology, even for the foremost experts in the field.

All of this makes the immune system horrible to explain. If you venture too far into simplification, you deprive the learner of the beauty and wonder that lie in the evolutionary genius of the sheer endless complexity that deals with the most crucial problems of living beings. But if you include too much detail, it quickly becomes mind-numbingly hard to keep up with; listing everything—every part of the immune system— is just too much.

It would be like telling someone your whole life story on the first date; overwhelming and very likely to make them less interested in dating you. So my aim for this book is to try to carefully dance around all these problems. It will use human language and use complicated words only when necessary.

Where appropriate, processes and interactions will be simplified while staying as true to the science as possible. Complexity between chapters will go up and down, so after you are fed a lot of information, there will be more chill parts to relax a bit, and we will summarize what we learned in regular intervals.

I want this book to make it possible for everybody to understand their own immune system and have a bit of fun doing so. And since this complexity and beauty are deeply connected to your health and survival, you might actually learn something useful. And of course, the next time you are sick or have to deal with disease, you hopefully can look at your body from a different perspective.

Also, the obligatory disclaimer: I'm not an immunologist but a science communicator and immune system enthusiast. This book will not make every immunologist happy. What became obvious right from the start of the research is that there are a lot of different ideas and concepts about the details of the immune system, and there is a lot of disagreement between the scientists holding these ideas, which is how science is supposed to work.

For example, some immunologists consider certain cells useless fossils, while others think they are crucial for your defenses. So as much as possible, this book is based on conversations with scientists, the current literature that is used to teach immunology, and peer-reviewed papers. Still, at some point in the future, parts of this book will need an update, which is a good thing.

The science of immunology is a dynamic field where a lot of amazing things are happening, and different theories and ideas are in flux with each other. The immune system is a living topic where great discoveries are still happening, which is great because it means we are learning more about ourselves and the world we live in.

Okay, before we jump in and explore what your immune system is doing, let us define the premise first, so we have solid ground to stand on. What is the immune system? What is the context it works in, and what are the tiny parts that do the actual work?

After we've covered these basics, we will explore what happens if you hurt yourself and how your immune system rushes in to defend you. Then we'll explore your most vulnerable parts and see how your body scrambles to protect from a serious infection. Lastly, we'll take a look at different immune disorders like allergies and autoimmune disease, and discuss how you can boost your immune system.

But now let us get to the very beginning of this story: What is there to defend? Before we can really learn about your intricate defense system, we should take a look at what needs to be defended—your body.

In a sense, this seems pretty straightforward: it is the entire area under and including your skin. Simple enough, right? But just like looking at a planet in space, you will never see anything remotely approaching the full picture from orbit. So before we do anything else, first we need to go on a journey together into a strange and foreign world.

Stranger than the deep sea or an alien planet, a world where no living being therein even knows that it exists, where monsters are a daily reality but nobody cares. A world billions of years old that exists within yourself, within everybody and everything, all around us—omnipresent but invisible. This is the world of the tiny, where the border between dead and alive becomes fuzzy, where biochemistry becomes life for reasons we still do not understand.

Let us zoom into you and take a look into your organs, through the tissue, to our most fundamental building blocks—your cells. Cells are extremely tiny living things, among the smallest units of life on Earth. For a single cell, your body is a planet drifting through a hostile universe. To understand the enormous dimensions of your body, we need to look at it from a cell's perspective.

At the scale of a cell, your body is an utterly gigantic structure of pipes as wide as mountains filled with oceans of fluids—rapid torrents permeating intricate cave systems stretching as far as whole countries. With the exception of the crystallized hard parts of your bones, all of the environment, all of the world really, is to a cell alive.

A cell can politely ask a wall to let it pass and then squeeze through a tiny gap that closes behind it. It can swim through channels and climb up mountains of meat to get anywhere it needs to go. If you were the size of one of your cells, the body of a human would be in the area of 60 to 100 kilometers tall, reaching into space.

If you are near a window, take a second and look into the sky—try to imagine this for a moment. A giant so large that passenger planes would crash against its lower legs, its head so far above you that you would not be able to see it. The cells of your immune system are tasked to defend all of that, especially the weak points where intruders can enter, which is mostly the borders, the outsides of the body.

When you think about your outsides, the first thing that comes to mind is, of course, your skin. The total surface area of your skin is about 2 square yards, about half the size of a pool table, and luckily is not that hard to defend since most of it is made out of a hard and thick barrier covered with its own defense system. It feels soft, but it is pretty hard to breach if it is intact.

Your real weak points to infections are your mucous membranes—the surface that lines your windpipe and lungs, eyelids, mouth and nose, your stomach and intestines, your reproductive tracts, and bladder. It is hard to give their total surface area since numbers vary so much from person to person, but on average there are about 200 square yards of mucous membranes in a healthy adult, about the same as a tennis court, most of them being your lungs and your digestive tract.

You may mistakenly think of your mucous membranes as your inside, but this is not true. Your mucous membranes are outside. If we took an honest look at what you are, you are, in a sense, nothing more than a complex tube—granted, a tube that can close both ends, also a lot wetter, slimier, and grosser.

Your reproductive organs, nostrils, and ears are extra holes, entrances to large tunnels and additional cave systems that reach through you. All of these places are your direct borders, contact points with the outside world—your body is just wrapped around them.

These outsides within your insides represent surfaces where millions of intruders are trying to enter you every day. A lot of ground to defend when you are the size of a cell! For your cells, the surface area of the mucous membranes is as big as Central Europe or the central United States are to you.

Building border walls would not do the trick for them, since they don't need to defend just the borders but the entire surface. It's not like intruders are trying to enter just at the edges; they could sort of drop in with parachutes. So your cells need to defend the entire continent— all of it. Still, it’s much easier to catch an enemy at one of these points than somewhere else.

For example, if we took all the blood vessels and capillaries from your body and laid them out in a straight line, they would be a baffling 74,000 kilometers long— three times the circumference of Earth— with about 1,400 square yards of surface area. So, better catch enemies at the borders that are significantly smaller and therefore easier to defend.

But easier does not mean easy. Let's do a fun experiment and imagine that we wanted to build a human body to scale but from actual people—like living, breathing humans—just to see what sort of crazy dimensions we encounter here.

So first, we need a lot of people for that. The average human body is made from around 40 trillion cells. Trillion— 40 trillion is 40,000,000,000,000. A truly impressive number! If we want your cells to be represented by individual people, then we need more than 100 times as many people as have lived in the 250,000-year-long history of humanity.

Let's try to visualize this a bit. Right now, around 7.8 billion people are alive. If we put them shoulder-to-shoulder, they surprisingly would only cover an area of around 700 square miles— about 1,800 kilometers— which is a little bit more than the surface area of London.

To get 40 trillion people, we need to multiply this by 120. And this is only half of the story because your body hosts bacteria that you need to survive. How many? One bacterium for each of the 40 trillion cells in your body, which happens to be a pretty good ballpark in terms of size!

If you were the size of an average body cell, a bacterium would be roughly the size of a bunny. Let us imagine them as baby bunnies to make the thought less horrifying. Most of these cute bunnies live in your gut, in this ginormous cave— 36 trillion bunnies live their lives constantly dying and reproducing, breaking down chunks of food the size of skyscrapers so it can be distributed to all the people making up the continent to flesh.

The other 4 trillion bunnies are crawling on your skin, are inside your lungs, hopping over your teeth, your tongue. They swim in the fluid of your eyes, crawl in and out of your ears. We'll talk more about them later, but for now, just imagine yourselves being covered by cute bunnies who are your friends and have only your best interests in mind.

Okay, so we now have 40 trillion people standing shoulder to shoulder. This ocean of people would cover the whole of the United Kingdom—every last corner, lake, and mountain. To make a body to scale made of people representing cells, we need to stack them until trillions of people are standing on top of each other, holding hands and linking arms, forming living structures.

A giant made out of flesh rises 60 to 100 kilometers into the sky, reaching the edge of space. The giant is made up of caverns as wide as small countries, bones as dense and wide as mountains, filled with intricate caves and tunnels. Its arteries are filled with oceans of fluid and people carrying food and oxygen tanks to every last corner.

If you were a red blood cell—or in this case, a red blood person—you would travel the distance from Paris to Rome and back once a minute in a stream pumped by a heart as large as a city. Things could be great; everybody would work together to keep the mountain of flesh—and in consequence, themselves—alive.

But the enormous richness of resources and food and the abundance of warm space is just too attractive. The giant is not only the size of a continent for its inhabitants, but also for unwelcome visitors—literally billions of parasites are trying to get inside the flesh giant. Some are as large as elephants or blue whales, and they want to lay giant eggs so their young can feast on the poor people that make up the tissues.

Others are the size of raccoons or rats who want to steal the food and make the giant their permanent home—home to raise generations of their offspring. They may not intend to harm the people making up the body, but they will do so by defecating everywhere, making life miserable.

The most disgusting vermin our flesh giant has to deal with daily are billions of spiders who want to enter the cell people's mouths or ears to breed in the stomachs of their victims. For a giant made up of trillions of people, losing a few here and there is not really dangerous, but if the vermin were allowed to create freely, it could be its end.

Isn't the idea horrifying? This is what your cells deal with every single day and night from your birth until the day you die. Staying alive is not a thing you should take for granted.

But don't let this idea of being attacked distress you too much. You are not just a mountain of flesh waiting to be conquered. Thankfully, you have a great ally in this fight for survival that, as we now know, we simply don't cherish and celebrate as much as it deserves: your immune system.

It makes you a fortress, and even more, a fortress filled with billions of the most effective and fierce soldiers in the universe. They have countless weapons at their disposal, and they use them without mercy. Your immune system army has already killed billions of enemies and parasites in your life, and it is ready to kill billions or trillions more.

Okay, that's it for now! If you want to learn more about the epic tale of your immune system, you can pre-order the book via the links below. It's available as an audiobook and as a real book with 45 illustrations in German and English. Thank you for listening! [Music]