Higher neutrophil levels in blood linked to more severe COVID-19

Researchers have found that patients with coronavirus (COVID-19) infection have higher blood levels of neutrophil extracellular traps, also called NETs.

According to the study, Neutrophil extracellular traps (NETs) are extracellular webs of chromatin, microbicidal proteins, and oxidant enzymes that are released by neutrophils to contain infections and pathogens.

"However, when not properly regulated, NETs have the potential to propagate inflammation and microvascular thrombosis — including in the lungs of patients with acute respiratory distress syndrome," said first study author Yu (Ray) Zuo from the University of Michigan in the US.

"While elevated levels of blood neutrophils predict worse outcomes in COVID-19, the role of NETs has not been investigated," Zuo added.

For the findings, published in the journal JCI Insight, the researchers analysed blood samples from 50 patients with COVID-19.

The researchers found that the serum from patients with COVID-19 have elevated levels of cell-free DNA, myeloperoxidase (MPO)-DNA, and citrullinated histone H3; the latter two are highly specific markers of NETs.

According to the study, in light of the COVID-19 pandemic, there is an urgent need to better understand what causes the inflammatory storm and blood clots triggered by SARS-CoV-2 infection--a storm that leads to respiratory failure and a requirement for mechanical ventilation in many patients.

The research team believe NETs may be relevant to many aspects of COVID-19 research, given that thrombosis and inflammation are hallmarks of severe infection. IANS