COVID-19 may damage immune cells in bone marrow

Even bone marrow may not be a safe harbor from the ravages of COVID-19, according to a study that found previously unrecognised changes in newly produced immune cells, called monocytes, released into the blood from bone marrow.

To learn more about how the body responds to COVID-19, researchers obtained serial "snapshots" of patients' immune health by analyzing their immune cells at multiple points during their hospital stays.

In COVID-19 patients with more severe disease, the monocytes do not function properly, researchers reported last week in Science Immunology.

It was not yet clear whether the monocytes are being released from the bone marrow in an altered state or whether the alterations happen after monocytes enter the blood, coauthor Tracy Hussell of the University of Manchester in the UK told Reuters.

Either way, she said, treatments that prevent their release from the bone marrow may help reduce the exaggerated immune response that contributes to poor outcomes in patients with severe COVID-19.