In a new study, researchers found that a long-ignored white blood cell may be central to the immune system overreaction that is the most common cause of death for COVID-19 patients.
They found that rod-shaped particles can take them out of circulation.
The research was conducted by a team at the University of Michigan.
The No. 1 cause of death for COVID-19 patients echoes the way the 1918 influenza pandemic killed: their lungs fill with fluid and they essentially drown. This is called acute respiratory distress syndrome.
But a new way of drawing immune cells out of the lungs might be able to prevent this outcome.
This research is among the essential projects at U-M that have continued through the pandemic uninterrupted.
ARDS is a manifestation of a condition known as a cytokine storm, in which the immune system overreacts and begins attacking the person’s own organs.
In ARDS, out-of-control white blood cells break down lung tissue and cause fluid to build up.
Helping to lead the charge is a type of white blood cell called the neutrophil, which makes up 60% to 70% of intruder-eating “phagocyte” cells in humans.
Neutrophils aren’t specialized, which enables them to respond to many threats, she explained. But sometimes, that lack of specialization means they don’t know when to quit.
One of their actions is to emit signaling molecules called cytokines that tell cells to break down barriers and let blood and fluid into a problem site.
When that response turns bad, the neutrophils need to be stopped so that other cells can step in and repair the damage.
Previously, the team showed that plastic microparticles injected into the blood of mice could distract neutrophils, diverting them away from areas of severe inflammation in their lungs.
In the study, they found that the rod-shaped particles might distract an out-of-control COVID immune response.
hey found that when they offered rods to different phagocytes, 80% of the neutrophils ate them, whereas only 5% to 10% of other phagocytes did.
The comparisons included macrophages, another cell that eats intruders, and dendritic cells, which capture intruders and then show the other immune cells what to look for.
The team is currently exploring whether neutrophil-distracting particles can be made from medications.
They hope that it may prove useful in the fight against COVID-19.
The lead author of the study is Lola Eniola-Adefeso, University Diversity and Social Transformation Professor.
The study is published in the journal Science Advances.
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