White blood cells rush to sites of injury and infection to coordinate immune responses that help the body recover from accidents and illness, which could range from bleeding to pneumonia. After assessing blood samples from patients hospitalized with the novel coronavirus (COVID-19), researchers from Yale University found neutrophil activation and production – white blood cells responding to infection – revealed biological clues about patients who later developed severe reactions to COVID-19.
The physicians started their study by assessing blood samples from 49 patients hospitalized for COVID-19 in April 2020. Forty patients were treated in an intensive care unit. Nine patients received hospital care. As a control, the researchers assessed blood samples from 13 adults with COVID-19 who did not have symptoms and who were not hospitalized. They also studied blood samples from 23 patients hospitalized for COVID-19 in May. Then, they compared results from these groups to blood samples of more than 3,000 patients hospitalized for COVID-19 at regional hospitals. After screening for 78 immune markers, they found patients who required intensive care for COVID-19, or who later died, had higher levels of five proteins associated with neutrophil activation. This immune response was seen on the first day of hospitalization and before some patients became critically ill. The researchers conclude these findings could be used in future diagnostic tests or to help inform therapeutic strategies, such as deciding about patients who may benefit most from a higher level of treatment or care.
The research published in Blood Advances and was supported by the National Heart, Lung, and Blood Institute, the National Institute of Diabetes and Digestive and Kidney Diseases, and the National Institute of General Medical Sciences.