Escalated complement activation during hospitalization is associated with higher risk of 60-day mortality in SARS-CoV-2-infected patients.

BACKGROUND: The complement system, an upstream recognition system of innate immunity, is activated upon SARS-CoV-2 infection. To gain a deeper understanding of the extent and duration of this activation, we investigated complement activation profiles during the acute phase of COVID-19, its persistence post-recovery and dynamic changes in relation to disease severity. METHODS: Serial blood samples were obtained from two cohorts of hospitalized COVID-19 patients (n = 457). Systemic complement activation products reflecting classical/lectin (C4d), alternative (C3bBbP), common (C3bc) and terminal pathway (TCC and C5a) were measured during hospitalization (admission, days 3-5 and days 7-10), at 3 months and after 1 year. Levels of activation and temporal profiles during hospitalization were related to disease severity defined as respiratory failure (PO2/FiO2 ratio <26.6 kPa) and/or admission to intensive care unit, 60-day total mortality and pulmonary pathology after 3 months. FINDINGS: During hospitalization, TCC, C4d, C3bc, C3bBbP and C5a were significantly elevated compared to healthy controls. Severely ill patients had significantly higher levels of TCC and C4d (p < 0.001), compared to patients with moderate COVID-19. Escalated levels of TCC and C4d during hospitalization were associated with a higher risk of 60-day mortality (p < 0.001), and C4d levels were additionally associated with chest CT changes at 3 months (p < 0.001). At 3 months and 1 year, we observed consistently elevated levels of most complement activation products compared to controls. CONCLUSION: Hospitalized COVID-19 patients display prominent and long-lasting systemic complement activation. Optimal targeting of the system may be achieved through enhanced risk stratification and closer monitoring of in-hospital changes of complement activation products.

Coagulopathy and adverse outcomes in hospitalized patients with COVID-19: results from the NOR-Solidarity trial.

Background: Several studies have examined parameters of increased thrombogenicity in COVID-19, but studies examining their association with long-term outcome and potential effects of antiviral agents in hospitalized patients with COVID-19 are scarce. Objectives: To evaluate plasma levels of hemostatic proteins during hospitalization in relation to disease severity, treatment modalities, and persistent pulmonary pathology after 3 months. Methods: In 165 patients with COVID-19 recruited into the NOR-Solidarity trial (NCT04321616) and randomized to treatment with hydroxychloroquine, remdesivir, or standard of care, we analyzed plasma levels of hemostatic proteins during the first 10 days of hospitalization (n = 160) and at 3 months of follow-up (n = 100) by enzyme immunoassay. Results: Our main findings were as follows: (i) tissue plasminogen activator (tPA) and tissue factor pathway inhibitor (TFPI) were increased in patients with severe disease (ie, the combined endpoint of respiratory failure [Po2-to-FiO2 ratio, <26.6 kPa] or need for treatment at an intensive care unit) during hospitalization. Compared to patients without severe disease, tPA levels were a median of 42% (P < .001), 29% (P = .002), and 36% (P = .015) higher at baseline, 3 to 5 days, and 7 to 10 days, respectively. For TFPI, median levels were 37% (P = .003), 25% (P < .001), and 10% (P = .13) higher in patients with severe disease at these time points, respectively. No changes in thrombin-antithrombin complex; alpha 2-antiplasmin; a disintegrin and metalloproteinase with a thrombospondin type 1 motif, member 13; or antithrombin were observed in relation to severe disease. (ii) Patients treated with remdesivir had lower levels of TFPI than those in patients treated with standard of care alone. (iii) TFPI levels during hospitalization, but not at 3 months of follow-up, were higher in those with persistent pathology on chest computed tomography imaging 3 months after hospital admission than in those without such pathology. No consistent changes in thrombin-antithrombin complex, alpha 2-antiplasmin, ADAMTS-13, tPA, or antithrombin were observed in relation to pulmonary pathology at 3 months of follow-up. Conclusion: TFPI and tPA are associated with severe disease in hospitalized patients with COVID-19. For TFPI, high levels measured during the first 10 days of hospitalization were also associated with persistent pulmonary pathology even 3 months after hospital admittance.

Pregnant women with acute respiratory distress syndrome triggered by COVID-19. / Gravide med akutt, alvorlig respirasjonssvikt utløst av covid-19.

Background: Pregnant women with COVID-19 are probably at increased risk of serious illness. The objective of this study was to describe the course of illness in pregnant women admitted to the intensive care unit (ICU) with acute respiratory distress syndrome triggered by COVID-19. Material and method: Pregnant women with COVID-19 were registered on admission to an ICU at Rikshospitalet, Oslo University Hospital in the period March 2020 to May 2023. We reviewed the patients' medical records retrospectively and describe clinical trajectories, management parameters and laboratory data collected during the period in intensive care. Self-perceived health was surveyed 15 months after discharge from intensive care. Results: Thirteen pregnant women were admitted in the period from February to December 2021. All met criteria for acute respiratory distress syndrome (ARDS) and were treated with corticosteroids and mechanical ventilation according to current guidelines. None of the patients had been vaccinated against COVID-19. Ten patients were orally intubated after therapeutic failure with non-invasive mechanical ventilation. One patient was treated with extracorporeal membrane oxygenation (ECMO). All patients survived their stay in intensive care, but there were two cases of intrauterine fetal demise. Almost half of the patients reported moderate to significantly reduced self-perceived health and quality of life 15 months after discharge from intensive care. Interpretation: All pregnant women admitted to an ICU at Rikshospitalet, Oslo University Hospital with ARDS triggered by COVID-19 survived hospitalisation, but several had symptoms that persisted long after their stay in the ICU.

Thrombocytopenia and platelet transfusions in ICU patients: an international inception cohort study (PLOT-ICU).

PURPOSE: Thrombocytopenia (platelet count < 150 × 109/L) is common in intensive care unit (ICU) patients and is likely associated with worse outcomes. In this study we present international contemporary data on thrombocytopenia in ICU patients. METHODS: We conducted a prospective cohort study in adult ICU patients in 52 ICUs across 10 countries. We assessed frequencies of thrombocytopenia, use of platelet transfusions and clinical outcomes including mortality. We evaluated pre-selected potential risk factors for the development of thrombocytopenia during ICU stay and associations between thrombocytopenia at ICU admission and 90-day mortality using pre-specified logistic regression analyses. RESULTS: We analysed 1166 ICU patients; the median age was 63 years and 39.5% were female. Overall, 43.2% (95% confidence interval (CI) 40.4-46.1) had thrombocytopenia; 23.4% (20-26) had thrombocytopenia at ICU admission, and 19.8% (17.6-22.2) developed thrombocytopenia during their ICU stay. Absence of acquired immune deficiency syndrome (AIDS), non-cancer-related immune deficiency, liver failure, male sex, septic shock, and bleeding at ICU admission were associated with the development of thrombocytopenia during ICU stay. Among patients with thrombocytopenia, 22.6% received platelet transfusion(s), and 64.3% of in-ICU transfusions were prophylactic. Patients with thrombocytopenia had higher occurrences of bleeding and death, fewer days alive without the use of life-support, and fewer days alive and out of hospital. Thrombocytopenia at ICU admission was associated with 90-day mortality (adjusted odds ratio 1.7; 95% CI 1.19-2.42). CONCLUSION: Thrombocytopenia occurred in 43% of critically ill patients and was associated with worse outcomes including increased mortality. Platelet transfusions were given to 23% of patients with thrombocytopenia and most were prophylactic.

Circulating markers of extracellular matrix remodelling in severe COVID-19 patients.

BACKGROUND: Abnormal remodelling of the extracellular matrix (ECM) has generally been linked to pulmonary inflammation and fibrosis and may also play a role in the pathogenesis of severe COVID-19. To further elucidate the role of ECM remodelling and excessive fibrogenesis in severe COVID-19, we examined circulating levels of mediators involved in various aspects of these processes in COVID-19 patients. METHODS: Serial blood samples were obtained from two cohorts of hospitalised COVID-19 patients (n = 414). Circulating levels of ECM remodelling mediators were quantified by enzyme immunoassays in samples collected during hospitalisation and at 3-month follow-up. Samples were related to disease severity (respiratory failure and/or treatment at the intensive care unit), 60-day total mortality and pulmonary pathology after 3-months. We also evaluated the direct effect of inactivated SARS-CoV-2 on the release of the different ECM mediators in relevant cell lines. RESULTS: Several of the measured markers were associated with adverse outcomes, notably osteopontin (OPN), S100 calcium-binding protein A12 and YKL-40 were associated with disease severity and mortality. High levels of ECM mediators during hospitalisation were associated with computed tomography thorax pathology after 3-months. Some markers (i.e. growth differential factor 15, galectin 3 and matrix metalloproteinase 9) were released from various relevant cell lines (i.e. macrophages and lung cell lines) in vitro after exposure to inactivated SARS-CoV-2 suggesting a direct link between these mediators and the causal agent of COVID-19. CONCLUSION: Our findings highlight changes to ECM remodelling and particularly a possible role of OPN, S100A12 and YKL-40 in the pathogenesis of severe COVID-19.

Effects of remdesivir in patients hospitalised with COVID-19: a systematic review and individual patient data meta-analysis of randomised controlled trials.

BACKGROUND: Interpretation of the evidence from randomised controlled trials (RCTs) of remdesivir in patients treated in hospital for COVID-19 is conflicting. We aimed to assess the benefits and harms of remdesivir compared with placebo or usual care in these patients, and whether treatment effects differed between prespecified patient subgroups. METHODS: For this systematic review and meta-analysis, we searched PubMed, Embase, the Cochrane COVID-19 trial registry, ClinicalTrials.gov, the International Clinical Trials Registry Platform, and preprint servers from Jan 1, 2020, until April 11, 2022, for RCTs of remdesivir in adult patients hospitalised with COVID-19, and contacted the authors of eligible trials to request individual patient data. The primary outcome was all-cause mortality at day 28 after randomisation. We used multivariable hierarchical regression-adjusting for respiratory support, age, and enrollment period-to investigate effect modifiers. This study was registered with PROSPERO, CRD42021257134. FINDINGS: Our search identified 857 records, yielding nine RCTs eligible for inclusion. Of these nine eligible RCTs, individual data were provided for eight, covering 10 480 patients hospitalised with COVID-19 (99% of such patients included in such RCTs worldwide) recruited between Feb 6, 2020, and April 1, 2021. Within 28 days of randomisation, 662 (12·5%) of 5317 patients assigned to remdesivir and 706 (14·1%) of 5005 patients assigned to no remdesivir died (adjusted odds ratio [aOR] 0·88, 95% CI 0·78-1·00, p=0·045). We found evidence for a credible subgroup effect according to respiratory support at baseline (pinteraction=0·019). Of patients who were ventilated-including those who received high-flow oxygen-253 (30·0%) of 844 patients assigned to remdesivir died compared with 241 (28·5%) of 846 patients assigned to no remdesivir (aOR 1·10 [0·88-1·38]; low-certainty evidence). Of patients who received no oxygen or low-flow oxygen, 409 (9·1%) of 4473 patients assigned to remdesivir died compared with 465 (11·2%) of 4159 patients assigned to no remdesivir (0·80 [0·70-0·93]; high-certainty evidence). No credible subgroup effect was found for time to start of remdesivir after symptom onset, age, presence of comorbidities, enrolment period, or corticosteroid use. Remdesivir did not increase the frequency of severe or serious adverse events. INTERPRETATION: This individual patient data meta-analysis showed that remdesivir reduced mortality in patients hospitalised with COVID-19 who required no or conventional oxygen support, but was underpowered to evaluate patients who were ventilated when receiving remdesivir. The effect size of remdesivir in patients with more respiratory support or acquired immunity and the cost-effectiveness of remdesivir remain to be further elucidated. FUNDING: EU-RESPONSE.

[Extracorporeal membrane oxygenation for acute respiratory distress syndrome in patients with COVID-19]. / Ekstrakorporal membranoksygenering ved akutt lungesviktsyndrom hos covid-19-pasienter.

BACKGROUND: COVID-19 can lead to acute respiratory distress syndrome (ARDS). In some patients for whom conventional mechanical ventilation is insufficient, venovenous (VV) extracorporeal membrane oxygenation (ECMO) can be life-saving. MATERIAL AND METHOD: Retrospective analysis of data from patients with ARDS triggered by COVID-19 who received ECMO therapy between March 2020 and February 2022. Premorbid health condition, course of respiratory distress and respiratory support before, during and after ECMO therapy were registered. RESULTS: Thirty patients received ECMO therapy. Median age was 57 years, median body mass index 28 kg/m2, and 23 patients were men. Median duration of lung protective mechanical ventilation with tidal volume 5.8 mL/kg predicted body weight before initiation of ECMO therapy was 8 days. Treatment indication was primarily severe hypoxaemia, frequently combined with hypercapnia. Twenty-three patients developed at least one severe complication while receiving ECMO therapy. Sixteen patients died, 13 during ongoing ECMO therapy. Fourteen were discharged from hospital. Median duration of ECMO and mechanical ventilation was 27 and 37 days, respectively. INTERPRETATION: ECMO therapy for patients with ARDS triggered by COVID-19 can be life-saving, but the treatment is accompanied by severe complications and a high mortality rate.

SEVERE CORONAVIRUS DISEASE 2019: FROM PATHOGENESIS TO THERAPY.

ABSTRACT: The COVID-19 pandemic has been a challenge to propose efficient therapies. Because severe SARS-CoV2 infection is a viral sepsis eventually followed by an immunological autoinflammatory phenomenon, many approaches have been inspired by the previous attempts made in bacterial sepsis, while specific antiviral strategies (use of interferon or specific drugs) have been additionally investigated. We summarize our current thinking on the use of SARS-CoV-2 antivirals, corticosteroids, anti-IL-1, anti-IL-6, anti-C5a, as well as stem cell therapy in severe COVID-19. Patient stratification and appropriate time window will be important to be defined to guide successful treatment.

Titers of antibodies against ancestral SARS-CoV-2 correlate with levels of neutralizing antibodies to multiple variants.

Diagnostic assays currently used to monitor the efficacy of COVID-19 vaccines measure levels of antibodies to the receptor-binding domain of ancestral SARS-CoV-2 (RBDwt). However, the predictive value for protection against new variants of concern (VOCs) has not been firmly established. Here, we used bead-based arrays and flow cytometry to measure binding of antibodies to spike proteins and receptor-binding domains (RBDs) from VOCs in 12,000 serum samples. Effects of sera on RBD-ACE2 interactions were measured as a proxy for neutralizing antibodies. The samples were obtained from healthy individuals or patients on immunosuppressive therapy who had received two to four doses of COVID-19 vaccines and from COVID-19 convalescents. The results show that anti-RBDwt titers correlate with the levels of binding- and neutralizing antibodies against the Alpha, Beta, Gamma, Delta, Epsilon and Omicron variants. The benefit of multiplexed analysis lies in the ability to measure a wide range of anti-RBD titers using a single dilution of serum for each assay. The reactivity patterns also yield an internal reference for neutralizing activity and binding antibody units per milliliter (BAU/ml). Results obtained with sera from vaccinated healthy individuals and patients confirmed and extended results from previous studies on time-dependent waning of antibody levels and effects of immunosuppressive agents. We conclude that anti-RBDwt titers correlate with levels of neutralizing antibodies against VOCs and propose that our method may be implemented to enhance the precision and throughput of immunomonitoring.

End of life decisions in immunocompromised patients with acute respiratory failure.

PURPOSE: To identify patient, disease and organizational factors associated with decisions to forgo life-sustaining therapies (DFLSTs) in critically ill immunocompromised patients admitted to the intensive care unit (ICU) for acute respiratory failure. MATERIAL AND METHODS: We performed a secondary analysis of the international EFRAIM prospective study, which enrolled 1611 immunocompromised patients with acute respiratory failure admitted to 68 ICUs in 16 countries between October 2015 and June 2016. Multivariate logistic analysis was performed to identify independent predictors of DFLSTs. RESULTS: The main causes of immunosuppression were hematological malignancies (50%) and solid tumor (38%). Patients had a median age of 63 yo (54-71). A pulmonologist was involved in the patient management in 38% of cases. DFLSTs had been implemented in 28% of the patients. The following variables were independently associated with DFLSTs: 1) patient-related: older age (OR 1.02 per one year increase, 95% confidence interval(CI) 1.01-1.03,P < 0.001), poor performance status (OR 2.79, 95% CI 1.98-3.93, P < 0.001); 2) disease-related: shock (OR 2.00, 95% CI 1.45-2.75, P < 0.001), liver failure (OR 1.59, 95% CI 1.14-2.21, P = 0.006), invasive mechanical ventilation (OR 1.79, 95% CI 1.31-2.46, P < 0.001); 3) organizational: having a pulmonologist involved in patient management (OR 1.85, 95% CI 1.36-2.52, P < 0.001), and the presence of a critical care outreach services (OR 1.63, 95% CI 1.11-2.38, P = 0.012). CONCLUSIONS: A DFLST is made in one in four immunocompromised patient admitted to the ICU for acute respiratory failure. Involving a pulmonologist in patient's management is associated with less non beneficial care.

Platelet transfusions and thrombocytopenia in intensive care units: Protocol for an international inception cohort study (PLOT-ICU).

INTRODUCTION: Thrombocytopenia is frequent in intensive care unit (ICU) patients and has been associated with worse outcome. Platelet transfusions are often used in the management of ICU patients with severe thrombocytopenia. However, the reported frequencies of thrombocytopenia and platelet transfusion practices in the ICU vary considerably. Therefore, we aim to provide contemporary epidemiological data on thrombocytopenia and platelet transfusion practices in the ICU. METHODS: We will conduct an international inception cohort, including at least 1000 acutely admitted adult ICU patients. Routinely available data will be collected at baseline (ICU admission), and daily during ICU stay up to a maximum of 90 days. The primary outcome will be the number of patients with thrombocytopenia (a recorded platelet count < 150 × 109 /L) at baseline and/or during ICU stay. Secondary outcomes include mortality, days alive and out of hospital, days alive without life-support, the number of patients with at least one bleeding episode, at least one thromboembolic event and at least one platelet transfusion in the ICU, the number of platelet transfusions and the indications for transfusion. The primary and secondary outcomes will be presented descriptively. In addition, we will assess risk factors for developing thrombocytopenia during ICU stay and the association between thrombocytopenia at baseline and 90-day mortality using logistic regression analyses. CONCLUSION: The outlined international PLOT-ICU cohort study will provide contemporary epidemiological data on the burden and clinical significance of thrombocytopenia in adult ICU patients and describe the current platelet transfusion practice.

Persistent T-cell exhaustion in relation to prolonged pulmonary pathology and death after severe COVID-19: Results from two Norwegian cohort studies.

BACKGROUND: T-cell activation is associated with an adverse outcome in COVID-19, but whether T-cell activation and exhaustion relate to persistent respiratory dysfunction and death is unknown. OBJECTIVES: To investigate whether T-cell activation and exhaustion persist and are associated with prolonged respiratory dysfunction and death after hospitalization for COVID-19. METHODS: Plasma and serum from two Norwegian cohorts of hospitalized patients with COVID-19 (n = 414) were analyzed for soluble (s) markers of T-cell activation (sCD25) and exhaustion (sTim-3) during hospitalization and follow-up. RESULTS: Both markers were strongly associated with acute respiratory failure, but only sTim-3 was independently associated with 60-day mortality. Levels of sTim-3 remained elevated 3 and 12 months after hospitalization and were associated with pulmonary radiological pathology after 3 months. CONCLUSION: Our findings suggest prolonged T-cell exhaustion is an important immunological sequela, potentially related to long-term outcomes after severe COVID-19.

High Circulating Levels of the Homeostatic Chemokines CCL19 and CCL21 Predict Mortality and Disease Severity in COVID-19.

BACKGROUND: Immune dysregulation is a major factor in the development of severe coronavirus disease 2019 (COVID-19). The homeostatic chemokines CCL19 and CCL21 have been implicated as mediators of tissue inflammation, but data on their regulation in severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection is limited. We thus investigated the levels of these chemokines in COVID-19 patients. METHODS: Serial blood samples were obtained from patients hospitalized with COVID-19 (n = 414). Circulating CCL19 and CCL21 levels during hospitalization and 3-month follow-up were analyzed. In vitro assays and analysis of RNAseq data from public repositories were performed to further explore possible regulatory mechanisms. RESULTS: A consistent increase in circulating levels of CCL19 and CCL21 was observed, with high levels correlating with disease severity measures, including respiratory failure, need for intensive care, and 60-day all-cause mortality. High levels of CCL21 at admission were associated with persisting impairment of pulmonary function at the 3-month follow-up. CONCLUSIONS: Our findings highlight CCL19 and CCL21 as markers of immune dysregulation in COVID-19. This may reflect aberrant regulation triggered by tissue inflammation, as observed in other chronic inflammatory and autoimmune conditions. Determination of the source and regulation of these chemokines and their effects on lung tissue is warranted to further clarify their role in COVID-19. CLINICAL TRIALS REGISTRATION: NCT04321616 and NCT04381819.

Anti-PF4/polyanion antibodies in COVID-19 patients are associated with disease severity and pulmonary pathology.

Thromboembolic events are frequent and associated with poor outcome in severe COVID-19 disease. Anti-PF4/polyanion antibodies are related to heparin-induced thrombocytopenia (HIT) and thrombus formation, but data on these antibodies in unselected COVID-19 populations are scarce. We assessed the presence of anti-PF4/polyanion antibodies in prospectively collected serum from an unselected cohort of hospitalized COVID-19 patients and evaluated if elevated levels could give prognostic information on ICU admission and respiratory failure (RF), were associated with markers of inflammation, endothelial activation, platelet activation, coagulation and fibrosis and were associated with long-term pulmonary CT changes. Five out of 65 patients had anti-PF4/polyanion reactivity with OD ≥0.200. These patients had more severe disease as reflected by ICU admission without any evidence of HIT. They also had signs of enhanced inflammation and fibrinogenesis as reflected by elevated ferritin and osteopontin, respectively, during the first 10 days of hospitalization. Increased ferritin and osteopontin persisted in these patients at 3 months follow-up, concomitant with pulmonary CT pathology. Our finding shows that the presence of anti-PF4/polyanion antibodies in unselected hospitalized COVID-19 patients was not related to HIT, but was associated with disease severity, inflammation, and pulmonary pathology after 3 months.

Respiratory dysfunction three months after severe COVID-19 is associated with gut microbiota alterations.

BACKGROUND: Although coronavirus disease 2019 (COVID-19) is primarily a respiratory infection, mounting evidence suggests that the gastrointestinal tract is involved in the disease, with gut barrier dysfunction and gut microbiota alterations being related to disease severity. Whether these alterations persist and are related to long-term respiratory dysfunction remains unknown. METHODS: Plasma was collected during hospital admission and after 3 months from the NOR-Solidarity trial (n = 181) and analyzed for markers of gut barrier dysfunction and inflammation. At the 3-month follow-up, pulmonary function was assessed by measuring the diffusing capacity of the lungs for carbon monoxide (DLCO ). Rectal swabs for gut microbiota analyses were collected (n = 97) and analyzed by sequencing the 16S rRNA gene. RESULTS: Gut microbiota diversity was reduced in COVID-19 patients with respiratory dysfunction, defined as DLCO below the lower limit of normal 3 months after hospitalization. These patients also had an altered global gut microbiota composition, with reduced relative abundance of 20 bacterial taxa and increased abundance of five taxa, including Veillonella, potentially linked to fibrosis. During hospitalization, increased plasma levels of lipopolysaccharide-binding protein (LBP) were strongly associated with respiratory failure, defined as pO2 /fiO2 (P/F ratio) <26.6 kPa. LBP levels remained elevated during and after hospitalization and were associated with low-grade inflammation and respiratory dysfunction after 3 months. CONCLUSION: Respiratory dysfunction after COVID-19 is associated with altered gut microbiota and persistently elevated LBP levels. Our results should be regarded as hypothesis generating, pointing to a potential gut-lung axis that should be further investigated in relation to long-term pulmonary dysfunction and long COVID.