Rethinking the Origins of Inflammatory Diseases
Research on how the immune system can go wrong is changing the way medicine thinks about everything from Covid-19 to heart disease
When the Covid pandemic took hold in late 2019, an urgent question soon emerged: Why did some individuals experience worse outcomes than others? A few patterns made intuitive sense. The elderly tended to fare worse. So did those with certain health conditions, including obesity, heart disease, hypertension, diabetes and lung or kidney disease. But severe infections were not exclusive to the elderly, those with pre-existing health conditions or healthcare and other essential workers. As scientists scrambled to better understand why this was so, inflammation and the immune system appeared to play a fundamental role.
With Covid-19 and many other infections, the germ itself or a measured immune reaction to it triggers most symptoms—like a fever, which alerts the body to the attack, or the coughs and loose stools that expel microscopic infectious particles. But if the immune system doesn’t succeed in managing the germ, it can later resort to a flood of inflammation, where immune cells churn out reams of cytokines—small proteins that act as messengers in an attempt to fight the germ.
