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CHICAGO, November 14 (Xinhua) – A study from Washington University School of Medicine in St. Louis and St. Jude Children’s Research Hospital in Memphis, Tennessee suggests that only 4% of COVID-19 patients had very high levels of the molecules which means a so-called “cytokine storm”.
The researchers analyzed immune cells and molecules in blood samples from 168 COVID-19 patients, 26 flu patients and 16 healthy people. Samples were taken from flu patients in 2019 or 2020 and from COVID-19 patients and healthy controls this year. They also gathered information on how each patient performed – whether a patient needed intensive care or mechanical ventilation – and whether he survived.
The number of inflammatory cells in the blood of COVID-19 and flu patients was roughly the same. Seven to 4 percent of COVID-19 patients showed signs of a cytokine storm, with extremely high levels of cytokines even compared to other critically ill patients. Most COVID-19 patients with acute respiratory failure not only did not have a cytokine storm, but had less inflammation than flu patients who were equally ill.
Clinical studies have shown that some severely ill COVID-19 patients improve on steroid drugs such as dexamethasone that suppress inflammation. The key will be to find a way to identify people at high risk of a cytokine storm when they first arrive at the hospital.
“Subjects in the cohort with the ‘true’ cytokine storm phenotype are such outliers compared to the others, it seems likely that there are significant differences in the multiple immune pathways that drive this phenotype,” said co-senior author Paul Thomas . “If we can identify the features of those pathways that can be rapidly assessed in a clinical setting, it could be useful for patient stratification.”
With the cytokine storm largely ruled out, the cause of most cases of respiratory failure in COVID-19 patients remains unknown.
“In the population we studied, 24 percent died but only 4 percent had a cytokine storm,” said senior co-author Philip Mudd, an assistant professor of emergency medicine who sees patients at the Barnes-Jewish Hospital. “Most of the people who have died from COVID-19 have died without a cytokine storm. Severe influenza is more inflammatory than severe COVID-19. So what’s causing their lungs to fail? We don’t know yet. We are. trying to find out. “
The results were published Friday in Science Advances. Enditem
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