For most people, red blood cells travel smoothly through the body. Round and flexible, they flow through arteries and veins, carrying with them cargoes of life-sustaining oxygen.
But in a slice of the population, these cells are misshapen, contorted by a genetic mutation into sharp-edged scythes that snag in blood vessels. The blockages can cause acute agony — crises of pain that recur again and again in people with severe sickle cell disease.
These pain episodes have been a lifelong peril for Elinam Joe Tsogbe, putting him in the hospital more than a dozen times some years. The regular assault on his body has accumulated into deeper scars: a gallbladder removed at 14, a hip replaced at 19 and a dangerous trip to the intensive care unit in his early 30s.
Over the past three years, though, Tsogbe hasn’t had any pain crises.
In early 2021, Tsogbe received an experimental transplant of his own stem cells, which had been collected and edited in a laboratory using CRISPR gene editing, biomedicine’s most cutting-edge tool. Called exa-cel, the treatment is a kind...