AN ELEGANT DEFENSE

An expert examination of the immune system and recent impressive advances in treating immune diseases.

Scientists describe the brain as the most complex organ, but novelist and Pulitzer Prize–winning New York Times journalist Richtel (A Deadly Wandering: A Tale of Tragedy and Redemption in the Age of Attention, 2014, etc.) maintains that our immune system gives it a run for its money. Around 3.5 billion years ago, the earliest cells developed means to identify alien threats and (usually) fight them off. As organisms evolved greater complexity, their immune systems kept pace with mammals, humans included, which possess a dazzling collection of organs, tissues, wandering cells, DNA, messengers, and chemicals keeping watch on our “festival of life.” “The thymus makes T cells,” writes the author. “The bone marrow is the origin of B cells….The T cells, when alerted by dendritic cells, behave as soldiers, spitting out cytokines; the B cells use antibodies to connect to antigens as if they are keys in search of a lock. Macrophages, neutrophils, and natural killer cells roam the body, tasting, exploring, and killing.” In the first of many jolts, Richtel downplays the claims of enthusiasts who urge us to attain the strongest possible immune system. Immunity resembles less a comic-book superhero than a trigger-happy police force, equally capable of smiting villains and wreaking havoc on innocent bystanders. To illustrate, the author devotes equal space to its role in fending off threats (infections, cancer) and attacking healthy tissues during allergies and autoimmune diseases such as asthma, diabetes, colitis, rheumatoid arthritis, and lupus. Scientific breakthroughs in producing specific antibodies have led to spectacularly effective—if toxic and wildly expensive—treatments for many. A newsman’s truism insists that readers love articles that include real people, so the author introduces us to four. All illustrate the good and bad features of modern immunotherapy, but the courses of their diseases are too bizarre to be typical.

Richtel illuminates a complex subject so well that even physicians will learn.