COVID-19 May Cause Long-Term Changes to Blood Cells

Researchers have shown for the first time that COVID-19 causes significant changes to the size and stiffness of red and white blood cells that can persist for months after infection. The findings have been accepted for publication in Biophysical Journal.

Recovered patients often experience long-term health effects from SARS-CoV-2, including chronic headaches, concentration disorders, and shortness of breath. These effects may arise from COVID-related impairment of circulation and oxygen delivery.

To better understand if changes to blood cells could contribute to long-term problems with circulation and oxygen delivery, the researchers analyzed more than four million blood cells—erythrocytes, lymphocytes, monocytes, neutrophils, and eosinophils—from 17 COVID-19 positive patients, 14 recovered patients, and 24 age-matched volunteers that were free from infection. For the analysis, they used a microfluidic technique called real-time deformability cytometry (RT-DC) that can mechanically examine up to 1,000 cells per second with label-free imaging.

COVID-19 infection resulted in significant changes in lymphocyte stiffness, monocyte size, and neutrophil and erythrocyte size and deformability, according to the paper. Some of those changes recovered to normal values after the patients were discharged from the hospital, while others persisted for up to 14 months after the infection had subsided. 

The researchers hypothesize that the persistent phenotypic changes to blood cells following infection may contribute to the long-term circulation and oxygen delivery problems that have been linked to COVID-19.