COVID-19 Patients Develop Fatal Blood Clots Due to High Alpha Defensin Protein Levels, Find Researchers

Israeli researchers have identified the mechanism that causes a deadly COVID-19 complication that affects 30% of patients: the formation of large and small blood clots that create lethal blockages in the patient’s lungs, kidneys, heart, and brain.

Researchers from the Hadassah-University Medical Center (Jerusalem, Israel) have discovered that alpha-defensin, a peptide (an amino-acid chain) speeds up the creation of blood clots and prevents their disintegration. This finding is crucial in understanding what is happening to COVID-19 patients because existing anticoagulant drugs do not impact alpha-defensin.


A study of blood samples from patients in Hadassah’s COVID-19 Outbreak department found a high concentration of alpha-defensin. The researchers also found that the sicker the patient was, the higher the concentration of the peptide. The researchers are now working on a new way to dissolve the blood clots. They are testing colchicine, an oral medication used for gout and Familial Mediterranean fever. The drug has succeeded in reducing alpha-defensin levels and blood clots in mice, and the researchers are now awaiting approval to begin human trials. They believe that if the drug reduces blood clots in COVID-19 patients, it will vastly reduce the number of patients needing respirators.

“These patients have numerous blood clots in their lungs, preventing normative blood flow,” said Prof. Abd Al-Roof Higazi, head of the Hadassah Medical Organization’s Department of Clinical Biochemistry and Division of Laboratories. “We can give the drug to those with mild symptoms to prevent the development of blood clots.”

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Hadassah-University Medical Center