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Front Physiol ; 13: 932013, 2022.
Article in English | MEDLINE | ID: covidwho-2089890


Peripheral blood smear is a simple laboratory tool, which remains of invaluable help for diagnosing primary and secondary abnormalities of blood cells despite advances in automated and molecular techniques. Red blood cells (RBCs) abnormalities are known to occur in many viral infections, typically in the form of mild normo-microcytic anemia. While several hematological alterations at automated complete blood count (including neutrophilia, lymphopenia, and increased red cell distribution width-RDW) have been consistently associated with severity of COVID-19, there is scarce information on RBCs morphological abnormalities, mainly as case-reports or small series of patients, which are hardly comparable due to heterogeneity in sampling times and definition of illness severity. We report here a systematic evaluation of RBCs morphology at peripheral blood smear in COVID-19 patients within the first 72 h from hospital admission. One hundred and fifteen patients were included, with detailed collection of other clinical variables and follow-up. A certain degree of abnormalities in RBCs morphology was observed in 75 (65%) patients. Heterogenous alterations were noted, with spiculated cells being the more frequent morphology. The group with >10% RBCs abnormalities had more consistent lymphopenia and thrombocytopenia compared to those without abnormalities or <10% RBCs abnormalities (p < 0.018, and p < 0.021, respectively), thus underpinning a possible association with an overall more sustained immune-inflammatory "stress" hematopoiesis. Follow-up analysis showed a different mortality rate across groups, with the highest rate in those with more frequent RBCs morphological alterations compared to those with <10% or no abnormalities (41.9%, vs. 20.5%, vs. 12.5%, respectively, p = 0.012). Despite the inherent limitations of such simple association, our results point out towards further studies on erythropoiesis alterations in the pathophysiology of COVID-19.

Arterioscler Thromb Vasc Biol ; 40(12): 2975-2989, 2020 12.
Article in English | MEDLINE | ID: covidwho-1105571


OBJECTIVE: Pulmonary thrombosis is observed in severe acute respiratory syndrome coronavirus 2 pneumonia. Aim was to investigate whether subpopulations of platelets were programmed to procoagulant and inflammatory activities in coronavirus disease 2019 (COVID-19) patients with pneumonia, without comorbidities predisposing to thromboembolism. Approach and Results: Overall, 37 patients and 28 healthy subjects were studied. Platelet-leukocyte aggregates, platelet-derived microvesicles, the expression of P-selectin, and active fibrinogen receptor on platelets were quantified by flow cytometry. The profile of 45 cytokines, chemokines, and growth factors released by platelets was defined by immunoassay. The contribution of platelets to coagulation factor activity was selectively measured. Numerous platelet-monocyte (mean±SE, 67.9±4.9%, n=17 versus 19.4±3.0%, n=22; P<0.0001) and platelet-granulocyte conjugates (34.2±4.04% versus 8.6±0.7%; P<0.0001) were detected in patients. Resting patient platelets had similar levels of P-selectin (10.9±2.6%, n=12) to collagen-activated control platelets (8.7±1.5%), which was not further increased by collagen activation on patient platelets (12.4±2.5%, P=nonsignificant). The agonist-stimulated expression of the active fibrinogen receptor was reduced by 60% in patients (P<0.0001 versus controls). Cytokines (IL [interleukin]-1α, IL-1ß, IL-1RA, IL-4, IL-10, IL-13, IL, 17, IL-27, IFN [interferon]-α, and IFN-γ), chemokines (MCP-1/CCL2 [monocyte chemoattractant protein 1]), and growth factors (VEGF [vascular endothelial growth factor]-A/D) were released in significantly larger amounts upon stimulation of COVID-19 platelets. Platelets contributed to increased fibrinogen, VWF (von Willebrand factor), and factor XII in COVID-19 patients. Patients (28.5±0.7 s, n=32), unlike controls (31.6±0.5 s, n=28; P<0.001), showed accelerated factor XII-dependent coagulation. CONCLUSIONS: Platelets in COVID-19 pneumonia are primed to spread proinflammatory and procoagulant activities in systemic circulation.

Blood Platelets/metabolism , COVID-19/blood , Thromboembolism/etiology , Aged , Aged, 80 and over , COVID-19/complications , Cytokines/metabolism , Female , Flow Cytometry , Humans , Male , Middle Aged , Pandemics , Prognosis , Thromboembolism/blood