Donated blood from COVID-19 survivors could be an effective treatment in helping others fight the illness – and should be tested more broadly to see if it can “change the course of this pandemic,” two Emory pathologists say.
The idea of using a component of survivors’ donated blood, or “convalescent plasma,” is that antibodies from patients who have recovered can be used in other people to help them defend against coronavirus.
Emory pathologists John Roback, MD, PhD and Jeannette Guarner, MD, wrote about the prospects of using the donated blood in a commentary published in JAMA. Their article accompanied a small study in China of five patients on ventilators whose condition improved after they were treated with convalescent plasma.
“Deploying passive antibody therapies against the rapidly increasing number of COIVD-19 cases provides an unprecedented opportunity to perform clinical studies of the efficacy of this treatment against a viral agent,” the two wrote. “If the results of rigorously conducted investigations, such as a large-scale randomized clinical trial, demonstrate efficacy, use of this therapy also could help change the course of this pandemic.”
The patients in Shenzhen were also treated with other antiviral and antiinflammatory agents, and the study was too small to come to definite conclusions. Still, the Emory authors say, the Shenzhen study provides an example of an approach that should be tested on a larger scale. Read more
More than 9 million people donate blood in the United States every year, according to the American Red Cross. Current guidelinesÂ say that blood can be stored for up to six weeks before use.
What happens to red blood cells while they are in storage, which transfusion experts call the â€œstorage lesionâ€? Multiple studies have shown that older blood may have sub-optimal benefits for patients receiving a transfusion. The reasons include: depletion of the messenger molecule nitric oxide, lysis of red blood cells and alterations in the remaining cellsâ€™ stiffness.
To that list, we could add the accumulation of microparticles, tiny membrane-clothed bags that contain proteins and RNA, which have effects on blood vessels and the immune system upon transfusion. Note: microparticles are similar to exosomes but larger â€“ the dividing line for size is about 100 nanometers. Both are much smaller than red blood cells.
EUH blood bank director John Roback recently gave a talk on the blood storage issue, and afterwards, cardiologist Charles Searles and research fellow Adam Mitchell were discussing their work on microparticles that come from red blood cells (RBCs). They have been examining the effects RBC-derived microparticles have on endothelial cells, which line blood vessels, and on immune cellsâ€™ stickiness.
Mitchell mentioned that he had some striking electron microscope images of microparticles and some of the particles looked like worms. With the aim of maintaining Lab Landâ€™s â€œCool Imageâ€ feature, I resolved to obtain a few of his photos, and Mitchell generously provided several.
â€œThose worms definitely had me mesmerized for a while,â€ he says.
In his talk, Roback described some of the metabolomics research he has been pursuing with Dean Jones. Instead of focusing only on how long blood should be stored, Robackâ€™s team is examining how much differences between donors may affect donated bloodâ€™s capacity to retain its freshness. Read more
Nature Medicine has a nice feature from Jeanne Erdmann highlighting the debate over how long donated blood can be stored. It sets the stage for two prospective clinical trials (RECESS and ABLE), which recently concluded but are still being analyzed. The trials were looking at how the age of stored blood affects patients undergoing cardiac surgery or in intensive care, respectively. Erdmann alsoÂ mentions that the NIHâ€™s Clinical Center already has tightened its standards for blood storage time.
Emory Blood Bank director John Roback and cardiologist Arshed Quyyumi have been participants in this debate, both theoretically and experimentally. In 2011, they proposed that depletion of the messenger molecule nitric oxide limits the benefits donated blood can provide to patients. In addition to nitric oxide depletion, the â€œstorage lesionâ€ is likely to include several changes, such as lysis of red blood cells, mechanical alterations in the remaining cells, and other chemical changes.
Since then, Emory research has shown that transfusion of donated blood more than three weeks old results in impaired blood vessel function in hospitalized patients, but in contrast, not in healthy volunteers. This informationÂ could allow doctors to prioritize fresher blood for patients with cardiovascular diseases.