Inflammatory Type 2 cDCs Acquire Features of cDC1s and Macrophages to Orchestrate Immunity to Respiratory Virus Infection.

The phenotypic and functional dichotomy between IRF8+ type 1 and IRF4+ type 2 conventional dendritic cells (cDC1s and cDC2s, respectively) is well accepted; it is unknown how robust this dichotomy is under inflammatory conditions, when additionally monocyte-derived cells (MCs) become competent antigen-presenting cells (APCs). Using single-cell technologies in models of respiratory viral infection, we found that lung cDC2s acquired expression of the Fc receptor CD64 shared with MCs and of IRF8 shared with cDC1s. These inflammatory cDC2s (inf-cDC2s) were superior in inducing CD4+ T helper (Th) cell polarization while simultaneously presenting antigen to CD8+ T cells. When carefully separated from inf-cDC2s, MCs lacked APC function. Inf-cDC2s matured in response to cell-intrinsic Toll-like receptor and type 1 interferon receptor signaling, upregulated an IRF8-dependent maturation module, and acquired antigens via convalescent serum and Fc receptors. Because hybrid inf-cDC2s are easily confused with monocyte-derived cells, their existence could explain why APC functions have been attributed to MCs.

Local immune response to food antigens drives meal-induced abdominal pain.

Up to 20% of people worldwide develop gastrointestinal symptoms following a meal1, leading to decreased quality of life, substantial morbidity and high medical costs. Although the interest of both the scientific and lay communities in this issue has increased markedly in recent years, with the worldwide introduction of gluten-free and other diets, the underlying mechanisms of food-induced abdominal complaints remain largely unknown. Here we show that a bacterial infection and bacterial toxins can trigger an immune response that leads to the production of dietary-antigen-specific IgE antibodies in mice, which are limited to the intestine. Following subsequent oral ingestion of the respective dietary antigen, an IgE- and mast-cell-dependent mechanism induced increased visceral pain. This aberrant pain signalling resulted from histamine receptor H1-mediated sensitization of visceral afferents. Moreover, injection of food antigens (gluten, wheat, soy and milk) into the rectosigmoid mucosa of patients with irritable bowel syndrome induced local oedema and mast cell activation. Our results identify and characterize a peripheral mechanism that underlies food-induced abdominal pain, thereby creating new possibilities for the treatment of irritable bowel syndrome and related abdominal pain disorders.

Efficacy and safety of the investigational complement C5 inhibitor zilucoplan in patients hospitalized with COVID-19: an open-label randomized controlled trial.

BACKGROUND: The efficacy and safety of complement inhibition in COVID-19 patients is unclear. METHODS: A multicenter randomized controlled, open-label trial. Hospitalized COVID-19 patients with signs of systemic inflammation and hypoxemia (PaO2/FiO2 below 350 mmHg) were randomized (2:1 ratio) to receive standard of care with or without the C5 inhibitor zilucoplan daily for 14 days, under antibiotic prophylaxis. The primary outcome was improvement in oxygenation at day 6 and 15. RESULTS: 81 patients were randomly assigned to zilucoplan (n = 55) or the control group (n = 26). 78 patients were included in the safety and primary analysis. Most were men (87%) and the median age was 63 years. The mean improvement in PaO2/FiO2 from baseline to day 6 was 56.4 mmHg in the zilucoplan group and 20.6 mmHg in the control group (mean difference + 35.8; 95% confidence interval (CI) - 9.4 to 80.9; p = 0.12), an effect also observed at day 15. Day 28 mortality was 9% in the zilucoplan and 21% in the control group (odds ratio 0.4; 95% CI 0.1 to 1.5). At long-term follow up, the distance walked in a 6-min test was 539.7 m in zilucoplan and 490.6 m in the control group (p = 0.18). Zilucoplan lowered serum C5b-9 (p < 0.001) and interleukin-8 (p = 0.03) concentration compared with control. No relevant safety differences between the zilucoplan and control group were identified. CONCLUSION: Administration of zilucoplan to COVID-19 patients in this proof-of-concept randomized trial was well tolerated under antibiotic prophylaxis. While not reaching statistical significance, indicators of respiratory function (PaO2/FiO2) and clinical outcome (mortality and 6-min walk test) suggest that C5 inhibition might be beneficial, although this requires further research in larger randomized studies.

Coronavirus disease 2019 in patients with inborn errors of immunity: An international study.

BACKGROUND: There is uncertainty about the impact of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection in individuals with rare inborn errors of immunity (IEI), a population at risk of developing severe coronavirus disease 2019. This is relevant not only for these patients but also for the general population, because studies of IEIs can unveil key requirements for host defense. OBJECTIVE: We sought to describe the presentation, manifestations, and outcome of SARS-CoV-2 infection in IEI to inform physicians and enhance understanding of host defense against SARS-CoV-2. METHODS: An invitation to participate in a retrospective study was distributed globally to scientific, medical, and patient societies involved in the care and advocacy for patients with IEI. RESULTS: We gathered information on 94 patients with IEI with SARS-CoV-2 infection. Their median age was 25 to 34 years. Fifty-three patients (56%) suffered from primary antibody deficiency, 9 (9.6%) had immune dysregulation syndrome, 6 (6.4%) a phagocyte defect, 7 (7.4%) an autoinflammatory disorder, 14 (15%) a combined immunodeficiency, 3 (3%) an innate immune defect, and 2 (2%) bone marrow failure. Ten were asymptomatic, 25 were treated as outpatients, 28 required admission without intensive care or ventilation, 13 required noninvasive ventilation or oxygen administration, 18 were admitted to intensive care units, 12 required invasive ventilation, and 3 required extracorporeal membrane oxygenation. Nine patients (7 adults and 2 children) died. CONCLUSIONS: This study demonstrates that (1) more than 30% of patients with IEI had mild coronavirus disease 2019 (COVID-19) and (2) risk factors predisposing to severe disease/mortality in the general population also seemed to affect patients with IEI, including more younger patients. Further studies will identify pathways that are associated with increased risk of severe disease and are nonredundant or redundant for protection against SARS-CoV-2.

Growing from common ground: nontuberculous mycobacteria and bronchiectasis.

Bronchiectasis and nontuberculous mycobacteria (NTM) are intricately intertwined, with NTM capable of being both a cause and consequence of bronchiectatic disease. This narrative review focuses on the common ground of bronchiectasis and NTM pulmonary disease (NTM-PD) in terms of diagnostic approach, underlying risk factors and treatment strategies. NTM-PD diagnosis relies on a combination of clinical, radiological and microbiological criteria. Although their epidemiology is complicated by detection and reporting biases, the prevalence and pathogenicity of NTM species vary geographically, with Mycobacterium avium complex and Mycobacterium abscessus subspecies most frequently isolated in bronchiectasis-associated NTM-PD. Diagnosis of nodular bronchiectatic NTM-PD should prompt investigation of host factors, including disorders of mucociliary clearance, connective tissue diseases and immunodeficiencies, either genetic or acquired. Treatment of NTM-PD in bronchiectasis involves a multidisciplinary approach and considers the (sub)species involved, disease severity and comorbidities. Current guideline-based antimicrobial treatment of NTM-PD is considered long, cumbersome and unsatisfying in terms of outcomes. Novel treatment regimens and strategies are being explored, including rifampicin-free regimens and inclusion of clofazimine and inhaled antibiotics. Host-directed therapies, such as immunomodulators and cytokine-based therapies, might enhance antimycobacterial immune responses. Optimising supportive care, as well as pathogen- and host-directed strategies, is crucial, highlighting the need for personalised approaches tailored to individual patient needs. Further research is warranted to elucidate the complex interplay between host and mycobacterial factors, informing more effective management strategies.

Inhaled GM-CSF administered during ongoing pneumovirus infection alters myeloid and CD8 T cell immunity without affecting disease outcome.

Granulocyte-macrophage colony stimulating factor (GM-CSF) is a pleiotropic cytokine, able to promote both myelopoiesis and activation of immune cells. Particularly in the lung, GM-CSF plays an important homeostatic role in the development and maintenance of alveolar macrophages, and is therefore considered to play a role in respiratory virus infections such as influenza and SARS-CoV-2, although the benefits of GM-CSF treatment in clinical studies remain inconclusive. To address this, we tested inhaled GM-CSF treatment in the Pneumonia Virus of Mice (PVM) mouse model. Our findings show that local GM-CSF therapy during PVM disease increased local neutrophilia and monocyte-derived cell influx, but diminished CD8+ T cells responses. Despite this, the observed effects on T cells and myeloid cells did not result in an altered clinical outcome during PVM infection. We conclude that inhaled GM-CSF therapy cannot be considered as a universal protective therapy in respiratory virus infections.

A complement atlas identifies interleukin-6-dependent alternative pathway dysregulation as a key druggable feature of COVID-19.

Improvements in COVID-19 treatments, especially for the critically ill, require deeper understanding of the mechanisms driving disease pathology. The complement system is not only a crucial component of innate host defense but can also contribute to tissue injury. Although all complement pathways have been implicated in COVID-19 pathogenesis, the upstream drivers and downstream effects on tissue injury remain poorly defined. We demonstrate that complement activation is primarily mediated by the alternative pathway, and we provide a comprehensive atlas of the complement alterations around the time of respiratory deterioration. Proteomic and single-cell sequencing mapping across cell types and tissues reveals a division of labor between lung epithelial, stromal, and myeloid cells in complement production, in addition to liver-derived factors. We identify IL-6 and STAT1/3 signaling as an upstream driver of complement responses, linking complement dysregulation to approved COVID-19 therapies. Furthermore, an exploratory proteomic study indicates that inhibition of complement C5 decreases epithelial damage and markers of disease severity. Collectively, these results support complement dysregulation as a key druggable feature of COVID-19.

LXR signaling controls homeostatic dendritic cell maturation.

Dendritic cells (DCs) mature in an immunogenic or tolerogenic manner depending on the context in which an antigen is perceived, preserving the balance between immunity and tolerance. Whereas the pathways driving immunogenic maturation in response to infectious insults are well-characterized, the signals that drive tolerogenic maturation during homeostasis are still poorly understood. We found that the engulfment of apoptotic cells triggered homeostatic maturation of type 1 conventional DCs (cDC1s) within the spleen. This maturation process could be mimicked by engulfment of empty, nonadjuvanted lipid nanoparticles (LNPs), was marked by intracellular accumulation of cholesterol, and was highly specific to cDC1s. Engulfment of either apoptotic cells or cholesterol-rich LNPs led to the activation of the liver X receptor (LXR) pathway, which promotes the efflux of cellular cholesterol, and repressed genes associated with immunogenic maturation. In contrast, simultaneous engagement of TLR3 to mimic viral infection via administration of poly(I:C)-adjuvanted LNPs repressed the LXR pathway, thus delaying cellular cholesterol efflux and inducing genes that promote T cell-mediated immunity. These data demonstrate that conserved cellular cholesterol efflux pathways are differentially regulated in tolerogenic versus immunogenic cDC1s and suggest that administration of nonadjuvanted cholesterol-rich LNPs may be an approach for inducing tolerogenic DC maturation.

Isolation of Conventional Murine Lung Dendritic Cell Subsets.

In the lungs, immune cells make contact with different antigens every day. This requires an adequate immune response. Dendritic cells (DCs) form a dense network in the respiratory mucosa and continuously sample inhaled allergens. They play an important role in bridging innate and adaptive immunity. DCs are classically divided into plasmacytoid DCs (pDCs) and conventional DCs (cDCs). cDCs in the steady-state are further subdivided into cDC1s and cDC2s based on their ontogeny and distinct non-redundant functions. Recently, a hyperactivated state of cDC2s has been described that arises during inflammation, coined inflammatory cDC2s (inf-cDC2s) that phenotypically mimics monocyte-derived cells and has a hybrid cDC1/macrophage functional identity. This chapter describes different enrichment methods and a fluorescence-activated cell sorting protocol that in combination allow for discrimination and isolation of pure DC subsets from the murine lung. The chapter represents an up-to-date, universal framework that can be adapted to other tissues and species which is an added value in intra- and interspecies comparative research.

Prospective longitudinal evaluation of hospitalised COVID-19 survivors 3 and 12 months after discharge.

Background: Long-term outcome data of coronavirus disease 2019 (COVID-19) survivors are needed to understand their recovery trajectory and additional care needs. Methods: A prospective observational multicentre cohort study was carried out of adults hospitalised with COVID-19 from March through May 2020. Workup at 3 and 12 months following admission consisted of clinical review, pulmonary function testing, 6-min walk distance (6MWD), muscle strength, chest computed tomography (CT) and quality of life questionnaires. We evaluated factors correlating with recovery by linear mixed effects modelling. Results: Of 695 patients admitted, 299 and 226 returned at 3 and 12 months, respectively (median age 59 years, 69% male, 31% severe disease). About half and a third of the patients reported fatigue, dyspnoea and/or cognitive impairment at 3 and 12 months, respectively. Reduced 6MWD and quadriceps strength were present in 20% and 60% at 3 months versus 7% and 30% at 12 months. A high anxiety score and body mass index correlated with poor functional recovery. At 3 months, diffusing capacity for carbon monoxide (D LCO) and total lung capacity were below the lower limit of normal in 35% and 18%, decreasing to 21% and 16% at 12 months; predictors of poor D LCO recovery were female sex, pre-existing lung disease, smoking and disease severity. Chest CT improved over time; 10% presented non-progressive fibrotic changes at 1 year. Conclusion: Many COVID-19 survivors, especially those with severe disease, experienced limitations at 3 months. At 1 year, the majority showed improvement to almost complete recovery. To identify additional care or rehabilitation needs, we recommend a timely multidisciplinary follow-up visit following COVID-19 admission.

Loss of GM-CSF-dependent instruction of alveolar macrophages in COVID-19 provides a rationale for inhaled GM-CSF treatment.

GM-CSF promotes myelopoiesis and inflammation, and GM-CSF blockade is being evaluated as a treatment for COVID-19-associated hyperinflammation. Alveolar GM-CSF is, however, required for monocytes to differentiate into alveolar macrophages (AMs) that control alveolar homeostasis. By mapping cross-species AM development to clinical lung samples, we discovered that COVID-19 is marked by defective GM-CSF-dependent AM instruction and accumulation of pro-inflammatory macrophages. In a multi-center, open-label RCT in 81 non-ventilated COVID-19 patients with respiratory failure, we found that inhalation of rhu-GM-CSF did not improve mean oxygenation parameters compared with standard treatment. However, more patients on GM-CSF had a clinical response, and GM-CSF inhalation induced higher numbers of virus-specific CD8 effector lymphocytes and class-switched B cells, without exacerbating systemic hyperinflammation. This translational proof-of-concept study provides a rationale for further testing of inhaled GM-CSF as a non-invasive treatment to improve alveolar gas exchange and simultaneously boost antiviral immunity in COVID-19. This study is registered at ClinicalTrials.gov (NCT04326920) and EudraCT (2020-001254-22).

TIM3+ TRBV11-2 T cells and IFNγ signature in patrolling monocytes and CD16+ NK cells delineate MIS-C.

In rare instances, pediatric SARS-CoV-2 infection results in a novel immunodysregulation syndrome termed multisystem inflammatory syndrome in children (MIS-C). We compared MIS-C immunopathology with severe COVID-19 in adults. MIS-C does not result in pneumocyte damage but is associated with vascular endotheliitis and gastrointestinal epithelial injury. In MIS-C, the cytokine release syndrome is characterized by IFNγ and not type I interferon. Persistence of patrolling monocytes differentiates MIS-C from severe COVID-19, which is dominated by HLA-DRlo classical monocytes. IFNγ levels correlate with granzyme B production in CD16+ NK cells and TIM3 expression on CD38+/HLA-DR+ T cells. Single-cell TCR profiling reveals a skewed TCRß repertoire enriched for TRBV11-2 and a superantigenic signature in TIM3+/CD38+/HLA-DR+ T cells. Using NicheNet, we confirm IFNγ as a central cytokine in the communication between TIM3+/CD38+/HLA-DR+ T cells, CD16+ NK cells, and patrolling monocytes. Normalization of IFNγ, loss of TIM3, quiescence of CD16+ NK cells, and contraction of patrolling monocytes upon clinical resolution highlight their potential role in MIS-C immunopathogenesis.

Effect of anti-interleukin drugs in patients with COVID-19 and signs of cytokine release syndrome (COV-AID): a factorial, randomised, controlled trial.

BACKGROUND: Infections with SARS-CoV-2 continue to cause significant morbidity and mortality. Interleukin (IL)-1 and IL-6 blockade have been proposed as therapeutic strategies in COVID-19, but study outcomes have been conflicting. We sought to study whether blockade of the IL-6 or IL-1 pathway shortened the time to clinical improvement in patients with COVID-19, hypoxic respiratory failure, and signs of systemic cytokine release syndrome. METHODS: We did a prospective, multicentre, open-label, randomised, controlled trial, in hospitalised patients with COVID-19, hypoxia, and signs of a cytokine release syndrome across 16 hospitals in Belgium. Eligible patients had a proven diagnosis of COVID-19 with symptoms between 6 and 16 days, a ratio of the partial pressure of oxygen to the fraction of inspired oxygen (PaO2:FiO2) of less than 350 mm Hg on room air or less than 280 mm Hg on supplemental oxygen, and signs of a cytokine release syndrome in their serum (either a single ferritin measurement of more than 2000 µg/L and immediately requiring high flow oxygen or mechanical ventilation, or a ferritin concentration of more than 1000 µg/L, which had been increasing over the previous 24 h, or lymphopenia below 800/mL with two of the following criteria: an increasing ferritin concentration of more than 700 µg/L, an increasing lactate dehydrogenase concentration of more than 300 international units per L, an increasing C-reactive protein concentration of more than 70 mg/L, or an increasing D-dimers concentration of more than 1000 ng/mL). The COV-AID trial has a 2 × 2 factorial design to evaluate IL-1 blockade versus no IL-1 blockade and IL-6 blockade versus no IL-6 blockade. Patients were randomly assigned by means of permuted block randomisation with varying block size and stratification by centre. In a first randomisation, patients were assigned to receive subcutaneous anakinra once daily (100 mg) for 28 days or until discharge, or to receive no IL-1 blockade (1:2). In a second randomisation step, patients were allocated to receive a single dose of siltuximab (11 mg/kg) intravenously, or a single dose of tocilizumab (8 mg/kg) intravenously, or to receive no IL-6 blockade (1:1:1). The primary outcome was the time to clinical improvement, defined as time from randomisation to an increase of at least two points on a 6-category ordinal scale or to discharge from hospital alive. The primary and supportive efficacy endpoints were assessed in the intention-to-treat population. Safety was assessed in the safety population. This study is registered online with ClinicalTrials.gov (NCT04330638) and EudraCT (2020-001500-41) and is complete. FINDINGS: Between April 4, and Dec 6, 2020, 342 patients were randomly assigned to IL-1 blockade (n=112) or no IL-1 blockade (n=230) and simultaneously randomly assigned to IL-6 blockade (n=227; 114 for tocilizumab and 113 for siltuximab) or no IL-6 blockade (n=115). Most patients were male (265 [77%] of 342), median age was 65 years (IQR 54-73), and median Systematic Organ Failure Assessment (SOFA) score at randomisation was 3 (2-4). All 342 patients were included in the primary intention-to-treat analysis. The estimated median time to clinical improvement was 12 days (95% CI 10-16) in the IL-1 blockade group versus 12 days (10-15) in the no IL-1 blockade group (hazard ratio [HR] 0·94 [95% CI 0·73-1·21]). For the IL-6 blockade group, the estimated median time to clinical improvement was 11 days (95% CI 10-16) versus 12 days (11-16) in the no IL-6 blockade group (HR 1·00 [0·78-1·29]). 55 patients died during the study, but no evidence for differences in mortality between treatment groups was found. The incidence of serious adverse events and serious infections was similar across study groups. INTERPRETATION: Drugs targeting IL-1 or IL-6 did not shorten the time to clinical improvement in this sample of patients with COVID-19, hypoxic respiratory failure, low SOFA score, and low baseline mortality risk. FUNDING: Belgian Health Care Knowledge Center and VIB Grand Challenges program.

Transcriptional regulation of DC fate specification.

Dendritic cells function in the immune system to instruct adaptive immune cells to respond accordingly to different threats. While conventional dendritic cells can be subdivided into two main subtypes, termed cDC1s and cDC2s, it is clear that further heterogeneity exists within these subtypes, particularly for cDC2s. Understanding the signals involved in specifying each of these lineages and subtypes thereof is crucial to (i) enable us to determine their specific functions and (ii) put us in a position to be able to target these cells to promote or prevent a specific function in any given disease setting. Although we still have much to learn regarding the specification of these cells, here we review the most recent advances in our understanding of this and highlight some of the next questions for the future.

CCR2- and Flt3-Dependent Inflammatory Conventional Type 2 Dendritic Cells Are Necessary for the Induction of Adaptive Immunity by the Human Vaccine Adjuvant System AS01.

The Adjuvant System AS01 contains monophosphoryl lipid A (MPL) and the saponin QS-21 in a liposomal formulation. AS01 is included in recently developed vaccines against malaria and varicella zoster virus. Like for many other adjuvants, induction of adaptive immunity by AS01 is highly dependent on the ability to recruit and activate dendritic cells (DCs) that migrate to the draining lymph node for T and B cell stimulation. The objective of this study was to more precisely address the contribution of the different conventional (cDC) and monocyte-derived DC (MC) subsets in the orchestration of the adaptive immune response after immunization with AS01 adjuvanted vaccine. The combination of MPL and QS-21 in AS01 induced strong recruitment of CD26+XCR1+ cDC1s, CD26+CD172+ cDC2s and a recently defined CCR2-dependent CD64-expressing inflammatory cDC2 (inf-cDC2) subset to the draining lymph node compared to antigen alone, while CD26-CD64+CD88+ MCs were barely detectable. At 24 h post-vaccination, cDC2s and inf-cDC2s were superior amongst the different subsets in priming antigen-specific CD4+ T cells, while simultaneously presenting antigen to CD8+ T cells. Diphtheria toxin (DT) mediated depletion of all DCs prior to vaccination completely abolished adaptive immune responses, while depletion 24 h after vaccination mainly affected CD8+ T cell responses. Vaccinated mice lacking Flt3 or the chemokine receptor CCR2 showed a marked deficit in inf-cDC2 recruitment and failed to raise proper antibody and T cell responses. Thus, the adjuvant activity of AS01 is associated with the potent activation of subsets of cDC2s, including the newly described inf-cDC2s.

Correction to: Treatment of severely ill COVID-19 patients with anti-interleukin drugs (COV-AID): A structured summary of a study protocol for a randomised controlled trial.

An amendment to this paper has been published and can be accessed via the original article.

Correction to: Sargramostim to treat patients with acute hypoxic respiratory failure due to COVID-19 (SARPAC): A structured summary of a study protocol for a randomised controlled trial.

An amendment to this paper has been published and can be accessed via the original article.

Sargramostim to treat patients with acute hypoxic respiratory failure due to COVID-19 (SARPAC): A structured summary of a study protocol for a randomised controlled trial.

OBJECTIVES: The hypothesis of the proposed intervention is that Granulocyte-macrophage colony-stimulating factor (GM-CSF) has profound effects on antiviral immunity, and can provide the stimulus to restore immune homeostasis in the lung with acute lung injury post COVID-19, and can promote lung repair mechanisms, that lead to a 25% improvement in lung oxygenation parameters. Sargramostim is a man-made form of the naturally-occurring protein GM-CSF. TRIAL DESIGN: A phase 4 academic, prospective, 2 arm (1:1 ratio), randomized, open-label, controlled trial. PARTICIPANTS: Patients aged 18-80 years admitted to specialized COVID-19 wards in 5 Belgian hospitals with recent (< 2 weeks prior to randomization) confirmed COVID-19 infection and acute respiratory failure defined as a PaO2/FiO2 below 350 mmHg or SpO2 below 93% on minimal 2 L/min supplemental oxygen. Patients were excluded from the trial in case of (1) known serious allergic reactions to yeast-derived products, (2) lithium carbonate therapy, (3) mechanical ventilation prior to randomization, (4) peripheral white blood cell count above 25.000/µL and/or active myeloid malignancy, (5) high dose systemic steroid therapy (> 20 mg methylprednisolone or equivalent), (6) enrolment in another investigational study, (7) pregnant or breastfeeding or (8) ferritin levels > 2000 µg/mL. INTERVENTION AND COMPARATOR: Inhaled sargramostim 125 µg twice daily for 5 days in addition to standard care. Upon progression of disease requiring mechanical ventilation or to acute respiratory distress syndrome (ARDS) and initiation of mechanical ventilator support within the 5 day period, inhaled sargramostim will be replaced by intravenous sargramostim 125 µg/m2 body surface area once daily until the 5 day period is reached. From day 6 onwards, progressive patients in the active group will have the option to receive an additional 5 days of IV sargramostim, based on the treating physician's assessment. Intervention will be compared to standard of care. Subjects progressing to ARDS and requiring invasive mechanical ventilatory support, from day 6 onwards in the standard of care group will have the option (clinician's decision) to initiate IV sargramostim 125m µg/m2 body surface area once daily for 5 days. MAIN OUTCOMES: The primary endpoint of this intervention is measuring oxygenation after 5 days of inhaled (and intravenous) treatment through assessment of a change in pretreatment and post-treatment ratio of PaO2/FiO2 and through measurement of the P(A-a)O2 gradient (PAO2= Partial alveolar pressure of oxygen, PaO2=Partial arterial pressure of oxygen; FiO2= Fraction of inspired oxygen). RANDOMISATION: Patients will be randomized in a 1:1 ratio. Randomization will be done using REDCap (electronic IWRS system). BLINDING (MASKING): In this open-label trial neither participants, caregivers, nor those assessing the outcomes will be blinded to group assignment. NUMBERS TO BE RANDOMISED (SAMPLE SIZE): A total of 80 patients with confirmed COVID-19 and acute hypoxic respiratory failure will be enrolled, 40 in the active and 40 in the control group. TRIAL STATUS: SARPAC protocol Version 2.0 (April 15 2020). Participant recruitment is ongoing in 5 Belgian Hospitals (i.e. University Hospital Ghent, AZ Sint-Jan Bruges, AZ Delta Roeselare, University Hospital Brussels and ZNA Middelheim Antwerp). Participant recruitment started on March 26th 2020. Given the current decline of the COVID-19 pandemic in Belgium, it is difficult to anticipate the rate of participant recruitment. TRIAL REGISTRATION: The trial was registered on Clinical Trials.gov on March 30th, 2020 (ClinicalTrials.gov Identifier: NCT04326920) - retrospectively registered; https://clinicaltrials.gov/ct2/show/NCT04326920?term=sarpac&recrs=ab&draw=2&rank=1 and on EudraCT on March 24th, 2020 (Identifier: 2020-001254-22). FULL PROTOCOL: The full protocol is attached as an additional file, accessible from the Trials website (Additional file 1). In the interest in 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 severely ill COVID-19 patients with anti-interleukin drugs (COV-AID): A structured summary of a study protocol for a randomised controlled trial.

OBJECTIVES: The purpose of this study is to test the safety and effectiveness of individually or simultaneously blocking IL-6, IL-6 receptor and IL-1 versus standard of care on blood oxygenation and systemic cytokine release syndrome in patients with COVID-19 coronavirus infection and acute hypoxic respiratory failure and systemic cytokine release syndrome. TRIAL DESIGN: A phase 3 prospective, multi-center, interventional, open label, 6-arm 2x2 factorial design study. PARTICIPANTS: Subjects will be recruited at the specialized COVID-19 wards and/or ICUs at 16 Belgian participating hospitals. Only adult (≥18y old) patients will be recruited with recent (≤16 days) COVID-19 infection and acute hypoxia (defined as PaO2/FiO2 below 350mmHg or PaO2/FiO2 below 280 on supplemental oxygen and immediately requiring high flow oxygen device or mechanical ventilation) and signs of systemic cytokine release syndrome characterized by high serum ferritin, or high D-dimers, or high LDH or deep lymphopenia or a combination of those, who have not been on mechanical ventilation for more than 24 hours before randomisation. Patients should have had a chest X-ray and/or CT scan showing bilateral infiltrates within the last 2 days before randomisation. Patients with active bacterial or fungal infection will be excluded. INTERVENTION AND COMPARATOR: Patients will be randomized to 1 of 5 experimental arms versus usual care. The experimental arms consist of Anakinra alone (anti-IL-1 binding the IL-1 receptor), Siltuximab alone (anti-IL-6 chimeric antibody), a combination of Siltuximab and Anakinra, Tocilizumab alone (humanised anti-IL-6 receptor antibody) or a combination of Anakinra with Tocilizumab in addition to standard care. Patients treated with Anakinra will receive a daily subcutaneous injection of 100mg for a maximum of 28 days or until hospital discharge, whichever comes first. Siltuximab (11mg/kg) or Tocilizumab (8mg/kg, with a maximum dose of 800mg) are administered as a single intravenous injection immediately after randomization. MAIN OUTCOMES: The primary end point is the time to clinical improvement defined as the time from randomization to either an improvement of two points on a six-category ordinal scale measured daily till day 28 or discharge from the hospital or death. This ordinal scale is composed of (1) Death; (2) Hospitalized, on invasive mechanical ventilation or ECMO; (3) Hospitalized, on non-invasive ventilation or high flow oxygen devices; (4) Hospitalized, requiring supplemental oxygen; (5) Hospitalized, not requiring supplemental oxygen; (6) Not hospitalized. RANDOMISATION: Patients will be randomized using an Interactive Web Response System (REDCap). A 2x2 factorial design was selected with a 2:1 randomization regarding the IL-1 blockade (Anakinra) and a 1:2 randomization regarding the IL-6 blockade (Siltuximab and Tocilizumab). BLINDING (MASKING): In this open-label trial neither participants, caregivers, nor those assessing the outcomes are blinded to group assignment. NUMBERS TO BE RANDOMISED (SAMPLE SIZE): A total of 342 participants will be enrolled: 76 patients will receive usual care, 76 patients will receive Siltuximab alone, 76 patients will receive Tocilizumab alone, 38 will receive Anakinra alone, 38 patients will receive Anakinra and Siltuximab and 38 patients will receive Anakinra and Tocilizumab. TRIAL STATUS: COV-AID protocol version 3.0 (15 Apr 2020). Participant recruitment is ongoing and started on April 4th 2020. Given the current decline of the COVID-19 pandemic in Belgium, it is difficult to anticipate the rate of participant recruitment. TRIAL REGISTRATION: The trial was registered on Clinical Trials.gov on April 1st, 2020 (ClinicalTrials.gov Identifier: NCT04330638) and on EudraCT on April 3rd 2020 (Identifier: 2020-001500-41). FULL PROTOCOL: The full protocol is attached as an additional file, accessible from the Trials website (Additional file 1). In the interest in 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.

Case Report: Convalescent Plasma, a Targeted Therapy for Patients with CVID and Severe COVID-19.

The disease course of COVID-19 in patients with immunodeficiencies is unclear, as well as the optimal therapeutic strategy. We report a case of a 37-year old male with common variable immunodeficiency disorder and a severe SARS-CoV-2 infection. After administration of convalescent plasma, the patient's condition improved rapidly. Despite clinical recovery, viral RNA remained detectable up to 60 days after onset of symptoms. We propose that convalescent plasma might be considered as a treatment option in patients with CVID and severe COVID-19. In addition, in patients with immunodeficiencies, a different clinical course is possible, with prolonged viral shedding.