Electromagnetic reflection from an extended turbulent medium: Cumulative forward-scatter single-backscatter approximation

Background/Aims: Arteritis is an inflammatory disease of the vascular wall leading to ischemia and vascular occlusion. Complications of arteritis include anemia, which could, at least in theory, result from suicidal erythrocyte death or eryptosis, which is characterized by erythrocyte shrinkage and phosphatidylserine (PS) exposure at the erythrocyte surface. Cellular mechanisms involved in the stimulation of eryptosis include increased cytosolic Ca2+-concentration ([Ca2+]i), oxidative stress and ceramide formation. The present study explored whether and how arteritis influences eryptosis. Methods: Blood was drawn from patients suffering from arteritis (n=17) and from healthy volunteers (n=21). PS exposure was estimated from annexin V-binding, erythrocyte volume from forward scatter, [Ca2+]i from Fluo3-fluorescence, reactive oxygen species (ROS) from DCFDA fluorescence and ceramide abundance from FITC-conjugated antibody binding in flow cytometry. The patients suffered from anemia despite 2.8±0.4% reticulocytes. Results: The percentage of PS-exposing erythrocytes was significantly higher in patients (1.1±0.1%) than in healthy volunteers (0.3±0.1%). The increase in PS exposure was paralleled by increase in oxidative stress and [Ca2+]i but not by significant changes of ceramide abundance. Erythrocyte PS exposure and ROS production were significantly enhanced in erythrocytes exposed to patient plasma as compared to exposure to plasma from healthy volunteers. Conclusion: Arteritis is associated with enhanced eryptosis due to increased [Ca2+]i and oxidative stress. The eryptosis contributes to or even accounts for the anemia in those patients. As eryptotic erythrocytes adhere to endothelial cells of the vascular wall, they could impede microcirculation and thus contribute to vascular occlusion.

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Hemocytometric characteristics of COVID-19 patients with and without cytokine Storm syndrome on the Sysmex XN-10 hematology analyzer

Clinical Chemistry and Laboratory Medicine (CCLM) ◽

10.1515/cclm-2020-1529 ◽

2020 ◽

Vol 0 (0) ◽

Author(s):

Remy J. H. Martens ◽

Arjan J. van Adrichem ◽

Nadine J. A. Mattheij ◽

Calvin G. Brouwer ◽

Daan J. L. van Twist ◽

...

Keyword(s):

Peripheral Blood ◽

Cytokine Storm ◽

Forward Scatter ◽

Global Pandemic ◽

Hematology Analyzer ◽

Blood Neutrophils ◽

Fatal Form ◽

High Fluorescence ◽

The Moment ◽

Respiratory Complaints

AbstractObjectivesCOVID-19 is an ongoing global pandemic. There is an urgent need for identification and understanding of clinical and laboratory parameters related to progression towards a severe and fatal form of this illness, often preceded by a so-called cytokine-storm syndrome (CSS). Therefore, we explored the hemocytometric characteristics of COVID-19 patients in relation to the deteriorating clinical condition CSS, using the Sysmex XN-10 hematology analyzer.MethodsFrom March 1st till May 16th, 2020, all patients admitted to our hospital with respiratory complaints and suspected for COVID-19 were included (n=1,140 of whom n=533 COVID-19 positive). The hemocytometric parameters of immunocompetent cells in peripheral blood (neutrophils [NE], lymphocytes [LY] and monocytes [MO]) obtained upon admission to the emergency department (ED) of COVID-19 positive patients were compared with those of the COVID-19 negative ones. Moreover, patients with CSS (n=169) were compared with COVID-19 positive patients without CSS, as well as with COVID-19 negative ones.ResultsIn addition to a significant reduction in leukocytes, thrombocytes and absolute neutrophils, it appeared that lymphocytes-forward scatter (LY-FSC), and reactive lymphocytes (RE-LYMPHO)/leukocytes were higher in COVID-19-positive than negative patients. At the moment of presentation, COVID-19 positive patients with CSS had different neutrophils-side fluorescence (NE-SFL), neutrophils-forward scatter (NE-FSC), LY-FSC, RE-LYMPHO/lymphocytes, antibody-synthesizing (AS)-LYMPHOs, high fluorescence lymphocytes (HFLC), MO-SSC, MO-SFL, and Reactive (RE)-MONOs. Finally, absolute eosinophils, basophils, lymphocytes, monocytes and MO-FSC were lower in patients with CSS.ConclusionsHemocytometric parameters indicative of changes in immunocompetent peripheral blood cells and measured at admission to the ED were associated with COVID-19 with and without CSS.

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