‘Look at that flower; look how beautiful it is,’ said an artist to his friend. ‘Art appreciates and celebrates that beauty, whereas science just takes it all apart. Science makes the flower dull.’
The friend being addressed was Nobel Prize-winning physicist Richard Feynman, and he thought that the artist’s view was ‘a bit nutty’. Feynman countered that he too could appreciate the flower’s beauty, but as a scientist he knew that the inner structure of the flower is wondrous as well – with its cells, its chemical and biological processes, all of its many intricate systems. In addition, Feynman explained, knowing that the flower attracts insects we might deduce that insects find the flower aesthetically pleasing, which in turn raises all sorts of questions about evolution, cognition and light. ‘Science,’ Feynman said, ‘only adds to the excitement and mystery and the awe of a flower. It only adds.’1
Feynman related this now-famous exchange in an interview on BBC TV in 1981, when I was aged eleven. I already knew that I wanted to be a scientist, but Feynman, with his strong New York accent and with roses swaying in the window behind him, captured the reason better than I could say myself. Now, leading a team of researchers to study human immune cells in minute detail, I’ve seen first-hand how science reveals beauty where otherwise it might have remained hidden. The inside of the human body may not have evolved to be aesthetically pleasing like a flower, but splendour ascends from its details.
In all of human biology, the process that’s been studied the most, details excavated the deepest, is the body’s response to a cut or an infection. The familiarity of the symptoms – redness, tenderness and inflammation – belies wonders taking place beneath the skin, where swarms of different cells move in to fight off germs, as well as repair the damage and deal with the debris. Far from conscious control, this reflex is essential for our survival.
A simple view of what is happening here is that the body attacks germs which invade the wound because our immune system is programmed to fight whatever is not part of us. But a moment’s reflection shows that this cannot be the whole story. Food isn’t part of your body and yet your immune system mustn’t react to everything you eat. More subtly, your immune system must be able to tell the difference between friendly bacteria that live in your gut, which should be left alone, and dangerous bacteria that might make you sick, which need to be dealt with.
This crucial realisation, that an immune response can’t be triggered by just anything alien to the human body, came only as recently as 1989, and it would take many more years before a deeper understanding emerged. In the meantime, a painstaking, game-changing scientific adventure unfolded in which the world of immunity has opened up to reveal what it really is: not a simple circuit involving a few types of immune cells but a multilayered, dynamic lattice of interlocking subsystems, one of the most complex and important frontiers of scientific enquiry we know of. As this book will show, the many discoveries that have resulted from this adventure amount to a scientific revolution in our understanding of the human body and are set to spark a revolution for medicine in the twenty-first century.
For a start, we have come to realise that our body’s ability to fight disease is continuously changing. The power of our immune system waxes and wanes, affected by stress, old age, the time of day and our state of mind. Our immune system is in constant flux; our health balanced on a tightrope. For example, the number of immune cells in our blood tends to peak in the evening and is at its lowest in the morning. There are many changes that happen to our immune system during the night, as our body enters a different state of activity and energy use, and in turn our immune system seems to be affected by how well we sleep. Reduced sleep – less than five hours per night – correlates with an increased risk of the common cold and pneumonia.2 Among other things, this book will explore the effects of night-shift work on our immune system and whether or not practices that could reduce stress, such as t’ai chi or mindfulness, are able to help us fight infections.
Mysteries remain but already these discoveries challenge the simple view we once held about how our bodies fight disease – and what it takes to be healthy. Even though it’s correct – very roughly – that the immune system targets what’s not part of you, it has become apparent that layer upon layer of biological checks and balances, run by countless cells and molecules, regulate the process. Resolving the mysteries and the complexities allows us to approach questions of major importance to our health and well-being: why do some people get cancer and can our immune system fight it? How do vaccines work and can we make them better? What exactly is an autoimmune disease and what can we do about it? The vast majority of ailments that afflict us are cured by our bodies’ natural defences. Understanding and harnessing this power might turn out to be the one of the most important gifts that science gives for the health of humankind.
While some drugs, such as penicillin, kill germs directly, many human maladies, from cancer to diabetes, may be fought best with new kinds of medicine that enhance (or in some cases suppress) the activity of our immune system. Unlike penicillin, and medicines like it that are made naturally – by a fungus in the case of penicillin – and merely isolated by scientists, these new medicines that work with our immune system are designed by scientists. Scientists studying the immune system can have ideas which become therapies and multibillion-dollar drugs. But these medicines must be tuned to work with utmost precision. If we over-activate the immune system, healthy cells and tissues will be destroyed, and if we switch it off entirely we will become susceptible to all kinds of germs that are normally easily dealt with. The potential benefits are transformative but the consequences when things go wrong can be terrible.
The vast endeavour to understand immunity has also thrown up new insights into many other areas of human biology too, such as the ageing process. 80–90% of people who die because of the flu virus are over sixty-five.3 Why is it that as we age, our defence against infections grow weaker? Why do we heal less easily and are more likely to succumb to autoimmune diseases? We have learnt that part of the problem is that the elderly have fewer of some types of immune cells circulating in their blood. Another is that immune cells in the elderly are worse at detecting disease. Compounding the challenges of ageing itself is the fact that the elderly often struggle with sleep-deprivation and stress, which also affect our immune system. Working out how much each of these various factors affects our health can be extremely difficult because it is almost impossible to isolate any one of them. While stress affects our immune system, it also correlates with sleep loss, making it hard to know the effect of either on its own.
In fact, pretty much everything in the body is connected with everything else – even more so than you might imagine. It has recently emerged that the immune system is intimately connected with a huge range of diseases that appear to be unrelated to its role in fighting germs: heart problems, neurological disorders, even obesity. My first book, The Compatibility Gene, discussed one element of the immune system, a handful of genes that influence our individual responses to infections. The Beautiful Cure is about the bigger picture: how and why the activity of our immune system varies, how it is regulated and directed, all of its component parts – the whole shebang.
This is also a book about how scientific ideas develop. The quest to understand immunity is one of humankind’s greatest scientific adventures, and the impersonal knowledge we have now has been won through a saga of personal hardships, triumphs and sacrifices. Many men and women have devoted their careers, and much of their lives, to understanding a mere fragment of the whole. This quest has created many deep friendships; passion for science can be a powerful bond. On the other hand, there are a few scientists involved who now can’t stand to be in same room together. Countless researchers have contributed, each making wondrous discoveries about particular cells or molecules in our immune system, but in the end, any one person’s contribution is small – even the geniuses’ – and the sacrifices some scientists have made might seem out of all proportion, beyond what most people would be willing to accept.
My own research involves using specialist microscopes to watch what happens at the point of contact between immune cells when they interact with one another, and to watch the contacts immune cells make with other cells to decide whether they are healthy or diseased. My discoveries have helped show how immune cells communicate with each other and how they detect signs of disease in other cells, which in turn helps us understand precisely how the immune system is regulated. We each add a little, focusing on one part of the system at a time.
When we divide an integrated system into separate elements in this way, it doesn’t make it dull – as Richard Feynman’s artist friend thought – but it’s not entirely fulfilling either. Things work together and each component only makes sense when it’s seen as part of a whole. Textbooks about the immune system tend to discuss the role of each molecule or cell in turn, but that’s like explaining a bicycle by describing what a wheel is, and then what a handlebar is, and then what a brake is. None of these single elements are properly understood without the others; their meaning lies in the relationships between them. Just as much as the parts build up a system, the system defines the parts. We marvel at the details but we must also pan out to the big picture, because it’s only when we do this that we can begin to exploit our knowledge of immunity for a revolution in health.
We will explore that revolution in the second half of the book. First, The Beautiful Cure charts the global scientific adventure that has led to it, revealing a world of unsung heroes and rebels who have discovered how and why the immune system works the way it does. If solace or joy can ever be gleaned from the beauty of nature, then what they have uncovered – the complexity, delicacy and elegance of our immune system – is as inspirational as any other frontier of science, from the substructure of atoms to the birth of stars.