Assessment of inter-operator variability in peripheral monocyte subset gating strategy using flow cytometry in patients with suspected acute stroke.

BACKGROUND: Innovative tools to reliably identify patients with acute stroke are needed. Peripheral monocyte subsets, that is, classical-Mon1, intermediate-Mon2, and non-classical-Mon3, with their activation marker expression analyzed using flow-cytometry (FCM) could be interesting cell biomarker candidates. AIM: To assess the inter-operator variability in a new peripheral monocyte subset gating strategy using FCM in patients with suspected acute stroke. METHODS: In BOOST-study ("Biomarkers-algOrithm-for-strOke-diagnoSis-and Treatment-resistance-prediction," NCT04726839), patients ≥18 years with symptoms suggesting acute stroke within the last 24 h were included. Blood was collected upon admission to emergency unit. FCM analysis was performed using the FACS-CANTO-II® flow-cytometer and Flow-Jo™-software. Analyzed markers were CD45/CD91/CD14/CD16 (monocyte backbone) and CD62L/CD11b/HLA-DR/CD86/CCR2/ICAM-1/CX3CR1/TF (activation markers). Inter-operator agreement (starting from raw-data files) was quantified by the measure distribution and, for each patient, the coefficient of variation (CV). RESULTS: Three operators analyzed 20 patient blood samples. Median inter-operator CVs were below the pre-specified tolerance limits (10% [for Mon1 counts], 20% [Mon2, Mon3 counts], 15% [activation marker median-fluorescence-intensities]). We observed a slight, but systematic, inter-operator effect. Overall, absolute inter-operator differences in fractions of monocyte subsets were <0.03. CONCLUSION: Our gating strategy allowed monocyte subset gating with an acceptable inter-operator variability. Although low, the inter-operator effect should be considered in monocyte data analysis of BOOST-patients.

Comparison of Circulating Immune Cells Profiles and Kinetics Between Coronavirus Disease 2019 and Bacterial Sepsis.

OBJECTIVES: Although clinical presentation of coronavirus disease 2019 has been extensively described, immune response to severe acute respiratory syndrome coronavirus 2 remains yet not fully understood. Similarities with bacterial sepsis were observed; however, few studies specifically addressed differences of immune response between both conditions. Here, we report a longitudinal analysis of the immune response in coronavirus disease 2019 patients, its correlation with outcome, and comparison between severe coronavirus disease 2019 patients and septic patients. DESIGN: Longitudinal, retrospective observational study. SETTING: Tertiary-care hospital during the first 2020 coronavirus disease 2019 outbreak in France. PATIENTS: All successive patients with confirmed severe acute respiratory syndrome coronavirus 2 infection admitted to the emergency department, medical ward, and ICU with at least one available immunophenotyping performed during hospital stay. MEASUREMENTS AND MAIN RESULTS: Between March and April 2020, 247 patients with coronavirus disease 2019 were included and compared with a historical cohort of 108 severe septic patients. Nonsevere coronavirus disease 2019 patients (n = 153) presented normal or slightly altered immune profiles. Severe coronavirus disease 2019 (n = 94) immune profile differed from sepsis. Coronavirus disease 2019 exhibited profound and prolonged lymphopenia (mostly on CD3, CD4, CD8, and NK cells), neutrophilia, and human leukocyte antigen D receptor expression on CD14+ monocytes down-regulation. Surprisingly, coronavirus disease 2019 patients presented a unique profile of B cells expansion, basophilia, and eosinophilia. Lymphopenia, human leukocyte antigen D receptor expression on CD14+ monocytes down-regulation, and neutrophilia were associated with a worsened outcome, whereas basophilia and eosinophilia were associated with survival. Circulating immune cell kinetics differed between severe coronavirus disease 2019 and sepsis, lack of correction of immune alterations in coronavirus disease 2019 patients during the first 2 weeks of ICU admission was associated with death and nosocomial infections. CONCLUSIONS: Circulating immune cells profile differs between mild and severe coronavirus disease 2019 patients. Severe coronavirus disease 2019 is associated with a unique immune profile as compared with sepsis. Several immune features are associated with outcome. Thus, immune monitoring of coronavirus disease 2019 might be of help for patient management.

White blood count, D-dimers, and ferritin levels as predictive factors of pulmonary embolism suspected upon admission in noncritically ill COVID-19 patients: The French multicenter CLOTVID retrospective study.

BACKGROUND: A high prevalence of pulmonary embolism (PE) has been described during COVID-19. Our aim was to identify predictive factors of PE in non-ICU hospitalized COVID-19 patients. METHODS: Data and outcomes were collected upon admission during a French multicenter retrospective study, including patients hospitalized for COVID-19, with a CT pulmonary angiography (CTPA) performed in the emergency department for suspected PE. Predictive factors significantly associated with PE were identified through a multivariate regression model. RESULTS: A total of 88 patients (median [IQR] age of 68 years [60-78]) were analyzed. Based on CTPA, 47 (53.4%) patients were diagnosed with PE, and 41 were not. D-dimer ≥3000 ng/mL (OR 8.2 [95% CI] 1.3-74.2, sensitivity (Se) 0.84, specificity (Sp) 0.78, P = .03), white blood count (WBC) ≥12.0 G/L (29.5 [2.3-1221.2], Se 0.47, Sp 0.92, P = .02), and ferritin ≥480 µg/L (17.0 [1.7-553.3], Se 0.96, Sp 0.44, P = .03) were independently associated with the PE diagnosis. The presence of the double criterion D-dimer ≥3000 ng/mL and WBC ≥12.0 G/L was greatly associated with PE (OR 21.4 [4.0-397.9], P = .004). CONCLUSION: The white blood count, the D-dimer and ferritin levels could be used as an indication for CTPA to confirm PE on admission in non-ICU COVID-19 patients.

Factors Influencing Anti-Xa Assays: A Multicenter Prospective Study in Critically Ill and Noncritically Ill Patients Receiving Unfractionated Heparin.

BACKGROUND: The presence of dextran sulfate (DS) in reagents and the type of blood collection tube (citrate/citrated-theophylline-adenosine-dipyridamole [CTAD]) can lead to discrepancies between unfractionated heparin (UFH) anti-Xa levels. OBJECTIVES: To evaluate the extent of the effect (1) of different reagents containing or not containing DS and (2) of the blood collection tubes, on UFH anti-Xa levels, in various clinical situations (NCT04700670). METHODS: We prospectively included patients from eight centers: group (G)1, cardiopulmonary bypass (CPB) after heparin neutralization (n = 39); G2, cardiothoracic intensive care unit (ICU) after CPB (n = 35); G3, medical ICU (n = 53); G4, other medical inpatients (n = 38). Blood was collected into citrated and CTAD tubes. Chromogenic anti-Xa assays were centrally performed, using seven reagent/analyzer combinations including two without DS. The association between anti-Xa levels and covariates was tested using a linear mixed-effects model. RESULTS: We analyzed 4,546 anti-Xa values from 165 patients. Median anti-Xa levels were systematically higher with reagents containing DS, whatever the patient group, with the greatest effect observed in G1 (0.32 vs. 0.05 IU/mL). Anti-Xa levels were slightly higher in CTAD than in citrate samples, irrespective of the assay. The model showed: (1) a significant dextran-patient group interaction (p < 0.0001), the effect of DS on anti-Xa levels varying from 30.9% in G4 to 296% in G1, and (2) a significant effect of CTAD, varying between patient groups (p = 0.0302). CONCLUSION: The variability of anti-Xa levels with a great overestimation of the values, using a reagent containing DS, can lead to different treatment decisions, especially after heparin neutralization by protamine. Clinical consequences of these differences remain to be demonstrated.

[Lupus anticoagulant and ischemic strokes: about two case reports]. / Anticoagulant lupique et accidents vasculaires cérébraux ischémiques : à propos de deux observations.

Antiphospholipid syndrome (APS) is an autoimmune disease characterized by thrombotic clinical manifestations, including ischemic stroke. Testing for lupus anticoagulant (LA) among antiphospholipid antibodies is key to the diagnosis of antiphospholipid syndrome (APS). Given the impact on patient management, close clinician-pathologist collaboration is crucial for the presence of LA in a thrombotic setting. Testing for LA must be carried out using specific and appropriate clotting assays and the pathologist should be aware of interferences. We report here two cases of stroke associated with the presence of LA, and recall the strategy for screening for LA.

D-Dimer Level and Neutrophils Count as Predictive and Prognostic Factors of Pulmonary Embolism in Severe Non-ICU COVID-19 Patients.

The incidence of pulmonary embolism (PE) is high during severe Coronavirus Disease 2019 (COVID-19). We aimed to identify predictive and prognostic factors of PE in non-ICU hospitalized COVID-19 patients. In the retrospective multicenter observational CLOTVID cohort, we enrolled patients with confirmed RT-PCR COVID-19 who were hospitalized in a medicine ward and also underwent a CT pulmonary angiography for a PE suspicion. Baseline data, laboratory biomarkers, treatments, and outcomes were collected. Predictive and prognostics factors of PE were identified by using logistic multivariate and by Cox regression models, respectively. A total of 174 patients were enrolled, among whom 86 (median [IQR] age of 66 years [55-77]) had post-admission PE suspicion, with 30/86 (34.9%) PE being confirmed. PE occurrence was independently associated with the lack of long-term anticoagulation or thromboprophylaxis (OR [95%CI], 72.3 [3.6-4384.8]) D-dimers ≥ 2000 ng/mL (26.3 [4.1-537.8]) and neutrophils ≥ 7.0 G/L (5.8 [1.4-29.5]). The presence of these two biomarkers was associated with a higher risk of PE (p = 0.0002) and death or ICU transfer (HR [95%CI], 12.9 [2.5-67.8], p < 0.01). In hospitalized non-ICU severe COVID-19 patients with clinical PE suspicion, the lack of anticoagulation, D-dimers ≥ 2000 ng/mL, neutrophils ≥ 7.0 G/L, and these two biomarkers combined might be useful predictive markers of PE and prognosis, respectively.