Natural killers are coming for Covid-19 and the therapy, experts say, could make things worse

Jimin Gao

When Jimin Gao learned of the lockdown in Wuhan, he went to his lab at Wenzhou Medical University in Southeast China and ordered several bags of blood. The blood, from the umbilical cord of volunteering women, contained a part of the immune system known as natural killer cells.

Gao extracted the NK cells and over the next few weeks designed receptors to attach to them, receptors he theorized would help them find and destroy human cells infected with the novel coronavirus. He then rigged the cells with a protein called IL-15 that would keep them alive inside a patient.

A month and a half later, he had his therapy: CAR-NK cells. And after an extensive search for a hospital to take them, he found a medical center in Chongqing, just outside of the Hubei Province. Five Covid-19 patients with fever ? two of t