SARS-CoV-2 seroprevalence in high-risk health care workers in a Belgian general hospital: evolution from the first wave to the second.

Health care workers (HCWs) are at the frontline for combatting the ongoing severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic. To describe recent or past infections, the novel development of serological assays enabled the assessment of the immune response developed in coronavirus disease (COVID-19). Here, we investigate SARS-CoV-2 seroprevalence in high-risk HCWs in a Belgian general hospital after both the first and the second waves. Three different immunoassays were used to determine immune response to SARS-CoV-2 in volunteer HCWs who worked in at least one COVID-19-dedicated ward [emergency department, intensive care unit (ICU) and internal medicine department] in our institution from 8 May 2020 to 19 May 2020 (n = 267) and from 18 January 2021 to 8 February 2021 (n = 189). Risk factors for seropositivity were also assessed using a questionnaire filled out by all participants. We report a steep increase in seroprevalence after the second wave and report a higher seropositivity in HCWs than in the general population. Furthermore, we show that ICU personnel and especially nurses exhibit a proportionally lower SARS-CoV-2 seroprevalence. This study documents the rapid increase in SARS-CoV-2 seroprevalence in highly exposed HCWs in a context of high viral circulation prior to vaccination campaigns. Most importantly, it suggests a lower occupational risk in ICU and illustrates the role of diagnostic labeling and use of personal protective equipment during the COVID-19 pandemic.

Impact of solid cancer on in-hospital mortality overall and among different subgroups of patients with COVID-19: a nationwide, population-based analysis.

BACKGROUND: Cancer seems to have an independent adverse prognostic effect on COVID-19-related mortality, but uncertainty exists regarding its effect across different patient subgroups. We report a population-based analysis of patients hospitalised with COVID-19 with prior or current solid cancer versus those without cancer. METHODS: We analysed data of adult patients registered until 24 May 2020 in the Belgian nationwide database of Sciensano. The primary objective was in-hospital mortality within 30 days of COVID-19 diagnosis among patients with solid cancer versus patients without cancer. Severe event occurrence, a composite of intensive care unit admission, invasive ventilation and/or death, was a secondary objective. These endpoints were analysed across different patient subgroups. Multivariable logistic regression models were used to analyse the association between cancer and clinical characteristics (baseline analysis) and the effect of cancer on in-hospital mortality and on severe event occurrence, adjusting for clinical characteristics (in-hospital analysis). RESULTS: A total of 13 594 patients (of whom 1187 with solid cancer (8.7%)) were evaluable for the baseline analysis and 10 486 (892 with solid cancer (8.5%)) for the in-hospital analysis. Patients with cancer were older and presented with less symptoms/signs and lung imaging alterations. The 30-day in-hospital mortality was higher in patients with solid cancer compared with patients without cancer (31.7% vs 20.0%, respectively; adjusted OR (aOR) 1.34; 95% CI 1.13 to 1.58). The aOR was 3.84 (95% CI 1.94 to 7.59) among younger patients (<60 years) and 2.27 (95% CI 1.41 to 3.64) among patients without other comorbidities. Severe event occurrence was similar in both groups (36.7% vs 28.8%; aOR 1.10; 95% CI 0.95 to 1.29). CONCLUSIONS: This population-based analysis demonstrates that solid cancer is an independent adverse prognostic factor for in-hospital mortality among patients with COVID-19. This adverse effect was more pronounced among younger patients and those without other comorbidities. Patients with solid cancer should be prioritised in vaccination campaigns and in tailored containment measurements.

[Large granular lymphocytic leukemia CD3-CD56-: a challenge for the biologist and the physician]. / Leucémie à grands lymphocytes granuleux CD3-CD56- : un défi pour le biologiste et le clinicien.

Large granular lymphocyte leukemia (LGL) are chronic lymphoproliferative disorders classified into three main groups: T-cell LGL leukemia (T-LGL), aggressive NK-cell leukemia and chronic lymphoproliferative disorder of NK cells (NK-LGL). Patients with LGL leukemia exhibit chronic (>3 months) and moderate (<1G/L) to substantial monoclonal expansion of large granular lymphocytes in the peripheral blood. Cytologically, large granular lymphocytes are medium to large cells which are further characterized by an eccentric nucleus and a slightly basophilic cytoplasm containing azurophilic granules. Typically, T-LGL (CD3-and mostly CD8+) can be differentiated from NK-LGL disorders (CD3-) based on flow cytometry analysis. However, distinction between LGL leukemias can be tricky. We report here the case of a 47-year-old woman patient diagnosed with large granular lymphocytes leukemia associated with atypical CD3-CD56- immunophenotyping and clinical manifestations of pseudo-Felty's syndrome.

Evaluation of the Roche® Elecsys and the Diasorin® Liaison S100 kits in the management of mild head injury in the emergency room.

INTRODUCTION: The aim of this single-center prospective study is to compare two commercially available S100ß kits (the Roche® Elecsys and the Diasorin® Liaison S100 kits) in terms of analytical and clinical performances in a population admitted in the emergency room for mild traumatic brain injury (mTBI). MATERIAL AND METHOD: 110 patients were enrolled from September 2014 to May 2015. Blood sample draws were performed within 3h after head trauma and the study population was split into pediatric and adult subpopulations (>18years of age). RESULTS: Although both kits correlated well, we observed a significant difference in terms of S100ß levels (P value<0.05) in both subpopulations. In the pediatric subpopulation, both kits showed elevated S100ß levels for the only patient (3.5%) who displayed abnormal findings on a CT-scan. However, we observed a poor agreement between both kits (Cohen's kappa=0.345, P value=0.077). In the adult subpopulation, a total of 10 patients (12.2%) had abnormal head computed tomography scans. Using the Roche® (cut off=0.1µg/L) and the Diasorin® (cut off=0.15µg/L) S100ß kits, brain injuries were detected with a sensitivity of 100% (95% CI: 65-100%) and 100% (95% CI: 63-100%) and a specificity of 15.28% (95% CI: 7.9-25.7%) and 24.64% (95% CI: 15-36.5) respectively. Finally, a moderate agreement was concluded between both kits (Cohen's kappa=0.569, P value=0.001). CONCLUSION: Although a good correlation could be found between both kits, emergency physicians should be aware of discrepancies observed between both methods, making those immunoassays not interchangeable. Furthermore, more studies are still needed to validate cut off used according to technique and to age, especially in the population below the age of 2years.

Comparison of the Liaison® Calprotectin kit with a well established point of care test (Quantum Blue - Bühlmann-Alere®) in terms of analytical performances and ability to detect relapses amongst a Crohn population in follow-up.

BACKGROUND: Although colonoscopy associated with histopathological sampling remains the gold standard in the diagnostic and follow-up of inflammatory bowel disease (IBD), calprotectin is becoming an essential biomarker in gastroenterology. The aim of this work is to compare a newly developed kit (Liaison® Calprotectin - Diasorin®) and its two distinct extraction protocols (weighing and extraction device protocol) with a well established point of care test (Quantum Blue® - Bühlmann-Alere®) in terms of analytical performances and ability to detect relapses amongst a Crohn's population in follow-up. METHODS: Stool specimens were collected over a six month period and were composed of control and Crohn's patients. Amongst the Crohn's population disease activity (active vs quiescent) was evaluated by gastroenterologists. RESULTS: A significant difference was found between all three procedures in terms of calprotectin measurements (weighing protocol=30.3µg/g (median); stool extraction device protocol=36.9µg/g (median); Quantum Blue® (median)=63; Friedman test, P value=0.05). However, a good correlation was found between both extraction methods coupled with the Liaison® analyzer and between the Quantum Blue® (weighing protocol/extraction device protocol Rs=0.844, P=0.01; Quantum Blue®/extraction device protocol Rs=0.708, P=0.01; Quantum Blue®/weighing protocol, Rs=0.808, P=0.01). Finally, optimal cut-offs (and associated negative predictive values - NPV) for detecting relapses were in accordance with above results (Quantum Blue® 183.5µg/g and NPV of 100%>extraction device protocol+Liaison® analyzer 124.5µg/g and NPV of 93.5%>weighing protocol+Liaison® analyzer 106.5µg/g and NPV of 95%). CONCLUSIONS: Although all three methods correlated well and had relatively good NPV in terms of detecting relapses amongst a Crohn's population in follow-up, the lack of any international standard is the origin of different optimal cut-offs between the three procedures.