Functional Activity of the Complement System in Hospitalized COVID-19 Patients: A Prospective Cohort Study.

AIMS: Although the exact factors promoting disease progression in COVID-19 are not fully elucidated, unregulated activation of the complement system (CS) seems to play a crucial role in the pathogenesis of acute lung injury (ALI) induced by SARS-CoV-2. In particular, the lectin pathway (LP) has been implicated in previous autopsy studies. The primary purpose of our study is to investigate the role of the CS in hospitalized COVID-19 patients with varying degrees of disease severity. METHODS: In a single-center prospective observational study, 154 hospitalized patients with PCR-confirmed SARS-CoV-2 infection were included. Serum samples on admission to the COVID-19 ward were collected for analysis of CS pathway activities and concentrations of LP proteins [mannose-binding lectin (MBL) and ficolin-3 (FCN-3)] & C1 esterase inhibitor (C1IHN). The primary outcome was mechanical ventilation or in-hospital death. RESULTS: The patients were predominately male and had multiple comorbidities. ICU admission was required in 16% of the patients and death (3%) or mechanical ventilation occurred in 23 patients (15%). There was no significant difference in LP activity, MBL and FCN-3 concentrations according to different peak disease severities. The median alternative pathway (AP) activity was significantly lower (65%, IQR 50-94) in patients with death/invasive ventilation compared to patients without (87%, IQR 68-102, p=0.026). An optimal threshold of <65.5% for AP activity was derived from a ROC curve resulting in increased odds for death or mechanical ventilation (OR 4,93; 95% CI 1.70-14.33, p=0.003) even after adjustment for confounding factors. Classical pathway (CP) activity was slightly lower in patients with more severe disease (median 101% for death/mechanical ventilation vs 109%, p=0.014). C1INH concentration correlated positively with length of stay, inflammatory markers and disease severity on admission but not during follow-up. CONCLUSION: Our results point to an overactivated AP in critically ill COVID-19 patients in vivo leading to complement consumption and consequently to a significantly reduced AP activity in vitro. The LP does not seem to play a role in the progression to severe COVID-19. Apart from its acute phase reaction the significance of C1INH in COVID-19 requires further studies.

The impact of the COVID-19 pandemic on autoimmune diagnostics in Europe: A lesson to be learned.

INTRODUCTION: The first wave of COVID-19 pandemic has disrupted almost all areas of the health care services to some extent throughout the world. Although the negative impact of COVID-19 on patients with autoimmune diseases has also been recognized, available data in this regard are limited. In the current study of the European Autoimmunity Standardisation Initiative (EASI) we aimed to provide reliable data on the extent of the impact of COVID-19 pandemic on test requests for different autoantibodies in European countries. METHODS: Data on test numbers and on the number of positive results were collected in 97 clinical laboratories from 15 European countries on a monthly basis for the year before (2019) and the year during (2020) the COVID-19 pandemic. RESULTS: A reduction in the number of autoantibody tests was observed in all European countries in the year 2020 compared to 2019. The reduction affected all autoantibody tests with an overall decrease of 13%, ranging from 1.4% (Switzerland) to 25.5% (Greece). In all countries, the decrease was most pronounced during the first wave of the pandemic (March-May 2020) with an overall decrease in those three months of 45.2%. The most affected autoantibodies were those commonly requested by general practitioners (anti-tTG IgA (-71%), RF IgM (-66%) and ACPA (-61%)). In the second wave of the pandemic (October-December 2020) the decrease was less pronounced (6.8%). With respect to the rate of positive results, subtle differences were observed for distinct autoantibodies during the pandemic, but the total rate of positive results was similar in both years. CONCLUSIONS: Our study demonstrated a strong decrease in autoantibody requests during the first wave of the COVID-19 pandemic in 15 European countries. The second wave was characterized by a less pronounced impact, with some participating countries hardly affected, while some other countries experienced a second decline. The decrease was clearly associated with the level of lock-down and with the required adjustments in the health care systems in different countries, supporting the importance of an effective strategy for the coordination of autoimmune testing in challenging situations as the COVID-19 pandemic.

Recombinant human C1 esterase inhibitor (conestat alfa) in the prevention of severe SARS-CoV-2 infection in hospitalized patients with COVID-19: A structured summary of a study protocol for a randomized, parallel-group, open-label, multi-center pilot trial (PROTECT-COVID-19).

OBJECTIVES: Conestat alfa, a recombinant human C1 esterase inhibitor, is a multi-target inhibitor of inflammatory cascades including the complement, the kinin-kallikrein and the contact activation system. The study objective is to investigate the efficacy and safety of conestat alfa in improving disease severity and short-term outcome in COVID-19 patients with pulmonary disease. TRIAL DESIGN: This study is an investigator-initiated, randomized (2:1 ratio), open-label, parallel-group, controlled, multi-center, phase 2a clinical trial. PARTICIPANTS: This trial is conducted in 3 hospitals in Switzerland, 1 hospital in Brazil and 1 hospital in Mexico (academic and non-academic). All patients with confirmed SARS-CoV-2 infection requiring hospitalization for at least 3 calendar days for severe COVID-19 will be screened for study eligibility. INCLUSION CRITERIA: - Signed informed consent - Age 18-85 years - Evidence of pulmonary involvement on CT scan or X-ray of the chest - Duration of symptoms associated with COVID-19 ≤ 10 days - At least one of the following risk factors for progression to mechanical ventilation on the day of enrolment: 1) Arterial hypertension 2) ≥ 50 years 3) Obesity (BMI ≥ 30 kg/m2) 4) History of cardiovascular disease 5) Chronic pulmonary disease 6) Chronic renal disease 7) C-reactive protein > 35mg/L 8) Oxygen saturation at rest of ≤ 94% when breathing ambient air Exclusion criteria: - Incapacity or inability to provide informed consent - Contraindications to the class of drugs under investigation (C1 esterase inhibitor) - Treatment with tocilizumab or another IL-6R or IL-6 inhibitor before enrolment - History or suspicion of allergy to rabbits - Pregnancy or breast feeding - Active or anticipated treatment with any other complement inhibitor - Liver cirrhosis (any Child-Pugh score) - Admission to an ICU on the day or anticipated within the next 24 hours of enrolment - Invasive or non-invasive ventilation - Participation in another study with any investigational drug within the 30 days prior to enrolment - Enrolment of the study investigators, their family members, employees and other closely related or dependent persons INTERVENTION AND COMPARATOR: Patients randomized to the experimental arm will receive conestat alfa in addition to standard of care (SOC). Conestat alfa (8400 U followed by 4200 U every 8 hours) will be administered as a slow intravenous injection (5-10 minutes) over a 72-hour period (i.e. 9 administrations in total). The first conestat alfa treatment will be administered on the day of enrolment. The control group will receive SOC only. SOC treatment will be administered according to local institutional guidelines, including supplemental oxygen, antibiotics, corticosteroids, remdesivir, and anticoagulation. MAIN OUTCOMES: The primary endpoint of this trial is disease severity on day 7 after enrolment assessed by an adapted WHO Ordinal Scale for Clinical Improvement (score 0 will be omitted and score 6 and 7 will be combined) from 1 (no limitation of activities) to 7 (death). Secondary outcomes include (i) the time to clinical improvement (time from randomization to an improvement of two points on the WHO ordinal scale or discharge from hospital) within 14 days after enrolment, (ii) the proportion of participants alive and not having required invasive or non-invasive ventilation at 14 days after enrolment and (iii) the proportion of subjects without an acute lung injury (defined by PaO2/FiO2 ratio of ≤300mmHg) within 14 days after enrolment. Exploratory outcomes include virological clearance, C1 esterase inhibitor pharmacokinetics and changes in routine laboratory parameters and inflammatory proteins. RANDOMISATION: Subjects will be randomised in a 2:1 ratio to treatment with conestat alfa in addition to SOC or SOC only. Randomization is performed via an interactive web response system (SecuTrial®). BLINDING (MASKING): In this open-label trial, participants, caregivers and outcome assessors are not blinded to group assignment. NUMBERS TO BE RANDOMISED (SAMPLE SIZE): We will randomise approximately 120 individuals (80 in the active treatment arm, 40 in the SOC group). Two interim analyses after 40 and 80 patients are planned according to the Pocock adjusted levels αp = 0.0221. The results of the interim analysis will allow adjustment of the sample size (Lehmacher, Wassmer, 1999). TRIAL STATUS: PROTECT-COVID-19 protocol version 3.0 (July 07 2020). Participant recruitment started on July 30 2020 in one center (Basel, Switzerland, first participant included on August 06 2020). In four of five study centers patients are actively recruited. Participation of the fifth study center (Mexico) is anticipated by mid December 2020. Completion of trial recruitment depends on the development of the SARS-CoV-2 pandemic. TRIAL REGISTRATION: Clinicaltrials.gov, number: NCT04414631 , registered on 4 June 2020 FULL PROTOCOL: The full protocol is attached as an additional file, accessible from the Trials website (Additional file 1). In the interest of expediting dissemination of this material, the familiar formatting has been eliminated; this Letter serves as a summary of the key elements of the full protocol.

Treatment of COVID-19 With Conestat Alfa, a Regulator of the Complement, Contact Activation and Kallikrein-Kinin System.

A dysregulated immune response with hyperinflammation is observed in patients with severe coronavirus disease 2019 (COVID-19). The aim of the present study was to assess the safety and potential benefits of human recombinant C1 esterase inhibitor (conestat alfa), a complement, contact activation and kallikrein-kinin system regulator, in severe COVID-19. Patients with evidence of progressive disease after 24 h including an oxygen saturation <93% at rest in ambient air were included at the University Hospital Basel, Switzerland in April 2020. Conestat alfa was administered by intravenous injections of 8400 IU followed by 3 additional doses of 4200 IU in 12-h intervals. Five patients (age range, 53-85 years; one woman) with severe COVID-19 pneumonia (11-39% lung involvement on computed tomography scan of the chest) were treated a median of 1 day (range 1-7 days) after admission. Treatment was well-tolerated. Immediate defervescence occurred, and inflammatory markers and oxygen supplementation decreased or stabilized in 4 patients (e.g., median C-reactive protein 203 (range 31-235) mg/L before vs. 32 (12-72) mg/L on day 5). Only one patient required mechanical ventilation. All patients recovered. C1INH concentrations were elevated before conestat alfa treatment. Levels of complement activation products declined after treatment. Viral loads in nasopharyngeal swabs declined in 4 patients. In this uncontrolled case series, targeting multiple inflammatory cascades by conestat alfa was safe and associated with clinical improvements in the majority of severe COVID-19 patients. Controlled clinical trials are needed to assess its safety and efficacy in preventing disease progression.