Rapid diagnostic testing for SARS-CoV-2 : Validation and comparison of three point-of-care antibody tests

With the emergence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), a need for diagnostic tests has surfaced. Point-of-care (POC) antibody tests can detect immunoglobulin (Ig) G and M against SARS-CoV-2 in serum, plasma, or whole blood and give results within 15 min. Validation of the performance of such tests is needed if they are to be used in clinical practice. In this study, we evaluated three POC antibody tests. Convalescent serum samples from 47 reverse transcription-polymerase chain reaction (RT-PCR) verified patients with coronavirus disease 2019 (COVID-19) collected at least 28 days post RT-PCR diagnosis as well as 50 negative pre-COVID-19 controls were tested. The three tests (denoted the J-, N-, and Z-tests) displayed the sensitivities of 87%, 96%, and 85%, respectively, for the detection of IgG. All tests had the same specificity for IgG (98%). The tests did not differ significantly for the detection of IgG. The sensitivities for IgM were lower (15%, 67%, and 70%) and the specificities were 90%, 98%, and 90%, respectively. The positive and negative predictive values were similar among the tests. Our results indicate that these POC antibody tests might be accurate enough to use in routine clinical practice

GATA2 mitotic bookmarking is required for definitive haematopoiesis

In mitosis, most transcription factors detach from chromatin, but some are retained and bookmark genomic sites. Mitotic bookmarking has been implicated in lineage inheritance, pluripotency and reprogramming. However, the biological significance of this mechanism in vivo remains unclear. Here, we address mitotic retention of the hemogenic factors GATA2, GFI1B and FOS during haematopoietic specification. We show that GATA2 remains bound to chromatin throughout mitosis, in contrast to GFI1B and FOS, via C-terminal zinc finger-mediated DNA binding. GATA2 bookmarks a subset of its interphase targets that are co-enriched for RUNX1 and other regulators of definitive haematopoiesis. Remarkably, homozygous mice harbouring the cyclin B1 mitosis degradation domain upstream Gata2 partially phenocopy knockout mice. Degradation of GATA2 at mitotic exit abolishes definitive haematopoiesis at aorta-gonad-mesonephros, placenta and foetal liver, but does not impair yolk sac haematopoiesis. Our findings implicate GATA2-mediated mitotic bookmarking as critical for definitive haematopoiesis and highlight a dependency on bookmarkers for lineage commitment

Heparin binding protein in severe COVID-19- A prospective observational cohort study

Background and aims Neutrophil-derived heparin binding protein (HBP; also known as azurocidin or CAP-37) is a key player in bacterial sepsis and a promising biomarker in severe infections. The aims of this study were to assess whether HBP is involved in the pathophysiology of COVID-19 and, if so, whether it can be used to predict severe disease preferably using a point-of-care test. Methods This was a prospective convenience sample study of biomarkers in patients admitted to Skåne University hospital in Sweden with a confirmed COVID-19 diagnosis. Plasma samples and clinical data were collected within 72h after admission, during hospital stay and at discharge. Plasma HBP concentrations samples were measured both with enzyme-linked immunosorbent assay (ELISA) and with a novel dry immunofluorescence analyzer (Joinstar) point-of-care test. Results Thirty-five COVID-19 patients were enrolled in the study. Twenty-nine patients had blood samples taken within 72h after admission. We compared the highest HBP value taken within 72h after admission in patients who eventually developed organ dysfunction (n = 23) compared to those who did not (n = 6), and found that HBP was significantly elevated in those who developed organ dysfunction (25.0 ng/mL (interquartile range (IQR) 16.6-48.5) vs 10.6 ng/mL (IQR 4.8-21.7 ng/mL), p = 0.03). Point-of-care test measurements correlated well with ELISA measurements (R = 0.83). HBP measured by the POC device predicted development of COVID-induced organ dysfunction with an AUC of 0.88 (95% confidence interval (CI) 0.70-1.0). Conclusions HBP is elevated prior to onset of organ dysfunction in patients with severe COVID-19 using a newly developed point-of-care test and hence HBP could be used in a clinical setting as a prognostic marker in COVID-19

Impact of cardiopulmonary bypass and surgical complexity on plasma soluble urokinase-type plasminogen activator receptor levels after cardiac surgery

Background: Circulating soluble urokinase plasminogen activator receptor (suPAR) is a marker of inflammation with prognostic value for elevated risk of morbidity and mortality. It has not yet been shown how the inflammatory process induced by cardiac surgery affects suPAR concentrations postoperatively Methods: In a prospective observational study, plasma suPAR levels were measured in 30 patients undergoing cardiac surgery with cardiopulmonary bypass (CPB), pre-, peri, post-operatively, and 3–5 days after surgery. Fifteen patients underwent coronary artery bypass grafting (CABG) and 15 underwent complex procedures with longer CPB duration. Concentrations of suPAR at each time point were compared to the preoperative levels and compared between the two groups. Results: In both groups, plasma suPAR concentrations were significantly higher on the first postoperative day (3.27 (interquartile range (IQR) 2.75–3.86) µg/L compared to baseline (2.62 (1.98–3.86)) µg/L, p <.001. There were no significant differences in suPAR concentrations between the groups at any time point. Preoperatively, the median suPAR concentration was 2.57 (2.01–3.60) µg/L in the CABG group versus 2.67 (1.89–3.97) µg/L in the complex group (p =.567). At ICU arrival 2.48 (2.34–3.23) µg/L versus 2.73 (2.28–3.44) µg/L in CABG and complex patients, respectively (p =.914). There was no difference in suPAR concentrations between the groups on postoperative day 1 (3.34 (2.89–3.89) versus 3.19 (2.57–3.62) p =.967) or 3–5 days after surgery (2.72 (1.98–3.16) versus 2.96 (2.39–4.28) p =.085. Conclusions: After a transient rise on the first postoperative day, the suPAR levels returned to the preoperative levels by the third postoperative day. There was no significant difference in suPAR levels between the routine CABG and complex group with longer CPB time

Heparin-binding protein in lower airway samples as a biomarker for pneumonia

Abstract Objectives Ventilator-associated pneumonia (VAP) is difficult to diagnose using clinical criteria and no biomarkers have yet been proved to be sufficiently accurate. The use of the neutrophil-derived Heparin-binding protein (HBP) as a biomarker for pneumonia was investigated in this exploratory case–control study in two intensive care units at a tertiary referral hospital. Methods Patients with clinical signs of pneumonia were recruited and bronchoalveolar lavage fluid (BALF) or bronchial wash (BW) samples were collected. Mechanically ventilated and lung healthy subjects were recruited as controls. HBP was measured with enzyme-linked immunosorbent assay. Results BALF was collected from 14 patients with pneumonia and 14 healthy controls. Median HBP in BALF pneumonia samples was 14,690 ng/ml and controls 16.2 ng/ml (p < 0.0001). BW was collected from 10 pneumonia patients and 10 mechanically ventilated controls. Median HBP in BW pneumonia was 9002 ng/ml and controls 7.6 ng/ml (p < 0.0001). Conclusions These data indicate that HBP concentrations is significantly higher in lower airway samples from patients with pneumonia than control subjects and is a potentially useful biomarker for diagnosis of VAP

GATA2 at the mitosis-to-G1 transition is critical for definitive hematopoiesis

In mitosis, transcription factors (TFs) and RNA polymerase disperse across the cytoplasm leading to transcriptional silencing, but some TFs are retained on condensed chromatin and mark genomic sites, a mechanism termed mitotic bookmarking. In pluripotent and differentiated cells this mechanism is important for pluripotency maintenance, cell reprogramming and lineage inheritance. However, the role of bookmarking in adult stem cells or in an in vivo system is yet to be addressed. Hematopoietic stem cells undergo drastic changes in cell cycle during development while balancing self-renewal and differentiation, suggesting a possible role for bookmarking.Here, we first addressed the mitotic retention capacity of the hemogenic TFs GATA2, GFI1B and FOS. We show that GATA2 remains bound to chromatin at all phases of cell cycle, as opposed to GFI1B and FOS. The C-terminal zinc finger (C-ZF) and the nuclear localization signal domains are required for GATA2 mitotic binding. Point mutations in the C-ZF associated with leukemia also impact GATA2 retention. To address the role of GATA2-mediated mitotic bookmarking, we have fused GATA2 to a mitosis degradation (MD) domain, which promotes protein destruction at the mitosis-to-G1 transition (M-G1). Degradation of GATA2 at M-G1 impacts the reprogramming of human fibroblasts to hemogenic cells. To address the role of GATA2 at M-G1 in vivo, we have generated a mouse model with the MD domain inserted upstream the Gata2 gene. Remarkably, homozygous mice are lethal, phenocopying Gata2 null mice which die at the onset of definitive hematopoiesis, showing a deficit in hematopoietic stem and progenitor cells.These findings implicate GATA2 as a mitotic bookmarking factor and its critical role at M-G1 for definitive hematopoiesis. Overall, our study highlights a dependency on mitotic bookmarkers for in vivo lineage commitment

The Dynamics of Heparin-Binding Protein in Cardiothoracic Surgery—A Pilot Study

Objectives: To explore the preoperative, intraoperative, and postoperative dynamics of heparin-binding protein (HBP) in cardiothoracic surgery. Design: This was a prospective, observational study. Setting: The study was conducted at a single university hospital. Participants: Thirty patients undergoing cardiac surgery with cardiopulmonary bypass (CPB) were included, 15 of whom underwent coronary artery bypass grafting surgery and 15 of whom underwent complex procedures. Ten patients undergoing lung surgery also were included as a conventional surgery reference group. Interventions: No interventions were performed. Measurements and Main Results: HBP was measured at nine different perioperative times. HBP levels increased immediately after heparin administration, further increased during CPB, but decreased rapidly after protamine administration. At arrival to the intensive care unit, median HBP levels were 24.8 (15.6-38.1) ng/mL for coronary artery bypass grafting patients and 51.2 (34.0-117.7) ng/mL for complex surgery patients (p = 0.011). One day after surgery, HBP levels in all three groups were below the proposed cutoff of 30 ng/mL, which previously was found to predict development of organ dysfunction in patients with infection. Conclusions: HBP levels are elevated by the administration of heparin and the use of CPB but reduced by protamine administration. At postoperative day one, HBP levels were less than the threshold for organ dysfunction in patients with infection. The usefulness of HBP for predicting postoperative infections in cardiothoracic surgery should be investigated in future studies

GATA2 mitotic bookmarking is required for definitive haematopoiesis

Abstract In mitosis, most transcription factors detach from chromatin, but some are retained and bookmark genomic sites. Mitotic bookmarking has been implicated in lineage inheritance, pluripotency and reprogramming. However, the biological significance of this mechanism in vivo remains unclear. Here, we address mitotic retention of the hemogenic factors GATA2, GFI1B and FOS during haematopoietic specification. We show that GATA2 remains bound to chromatin throughout mitosis, in contrast to GFI1B and FOS, via C-terminal zinc finger-mediated DNA binding. GATA2 bookmarks a subset of its interphase targets that are co-enriched for RUNX1 and other regulators of definitive haematopoiesis. Remarkably, homozygous mice harbouring the cyclin B1 mitosis degradation domain upstream Gata2 partially phenocopy knockout mice. Degradation of GATA2 at mitotic exit abolishes definitive haematopoiesis at aorta-gonad-mesonephros, placenta and foetal liver, but does not impair yolk sac haematopoiesis. Our findings implicate GATA2-mediated mitotic bookmarking as critical for definitive haematopoiesis and highlight a dependency on bookmarkers for lineage commitment