Elizabeth Middleton - February 17, 2021

Elizabeth Middleton, MD, Associate Director, MICU, Pulmonary and Critical Care Medicine, University of Utah, COVID19 and Clots: The Contribution of Platelets and Immunothrombosis

Dr. Middleton hypothesized, “Alteration in platelet physiology may contribute to the pathogenesis of Covid-19.” The first part of the study is the functional of platelet in Covid-19 patients.  Platelet counts showed neither thrombocytopenia nor leukocytosis in Covid-19 patients in their study.  The platelet numbers are not significantly different between non-ICU and ICU Covid-19 patients, 234 and 242, respectively. Platelet RNA Seq. showed ~3,000 genes are altered in Covid-19 patients (~1,700 genes upregulated and ~1,300 downregulated) sampled from 6-Non-ICU and 4 ICU patients.

Platelets do not express the SARS-CoV-2 binding receptor ACE2 in both HD (healthy donor) and Covid-19 patients but detected the SARS-CoV-2 N1 gene in 2 out of 25 patients. However, they are not sure yet if they need further investigation or not. They investigated D-dimer, and soluble platelet activation markers (VWF antigen, Platelet factor4, and RANTES) and they are all elevated in plasma in Covid-19 patients indicating the patient’s platelets are more reactive. Light transmission aggregation (LAT) assay was employed to investigate classical function of platelets, and the result shown higher aggregation in the Covid-10 patients.  They also studied the immune role of platelets in Covid-19. Monocyte, CD4 T-cell, CD8 T-cell and Neutrophil were appeared to be a higher degree of aggregation with platelets indicating a heterotypic aggregate feature of platelets in Covid-19 patients.