Long-term Follow up (> 1 year) of Plasma Donors and Patients treated with COVID-19 Convalescent Plasma within the CAPSID trial

Background: COVID-19-Convalescent Plasma (CCP) showed beneficial effects when given early in the treatment course or when it contains high-titre of neutralizing antibodies. Here we present a long-term follow up of patients of the multicentric national randomized CAPSID trial that investigated the effect of CCP in hospitalized COVID-19 patients. CCP donors were also included in the follow up and severed as a control group of patients with mild to moderate disease. Method(s): Patients and donors were invited to participate in the long-term follow up. Data on long-term overall survival (OS) were available for n=52 patients (control group: n=22, high titre CCP: n=16, low-titre CCP: n=14) and n=113 donors. Structured interview and a quality of life (QoL) assessment by questionnaires (FACIT fatigue, FACIT dyspnea and EQ-ED- 5DL) were performed. Visits took place online or on site. Laboratory tests included neutralizing antibody testing by PRNT and inflammation markers. Data are given as median with IQR. Medical events were assessed and graded according to CTCAE. For donors the median follow up time was 517 (483-553) days after the first plasmapheresis and for patients 395 (371-417) days after randomization. Result(s): Medical events during follow up were reported in 27% of donors and 16% of patients (p=0.164) with grade 3 or higher in 9% of donors and 22% of patients. More patients than donors reported a decrease in their socioeconomic status and reported more frequently about GI, pulmonal, pain symptoms or alopecia (p<0.02), but no difference in neurologic symptoms including anosmia was observed. Post COVID-Scale was worse in patients with a trend for better outcome in the CCP group (p=0.089). The trend for better OS in the CCP group became more pronounced during the long-term follow up (p=0.08) and OS remained significantly better in the high dose CCP group (p=0.01). All QoL scores showed a consistent trend towards better outcomes of the CCP group. Conclusion(s): To our knowledge, this is the first long-term follow up from a randomized trial of CCP. CCP-donors with mild to moderate COVID- 19 had a significant smaller long-term disease burden than patients with severe disease. The addition of CCP added to standard treatment in severe COVID-19 showed a trend to better OS and QoL. We had previously reported significant better outcomes in the high-titre CCP subgroup (until day 60). This was even more pronounced during the long-term follow up (> 1 year).

PAUSING METHOTREXATE IMPROVES IMMUNOGENICITY of COVID-19 VACCINATION in PATIENTS with RHEUMATIC DISEASES

Background: Several research groups have recently described a reduced vaccination response to COVID-19 vaccination under methotrexate (MTX) (1,2). The increase in humoral immune response when pausing MTX two weeks after vaccination has already been described for infuenza vaccination (3). However, data regarding MTX-hold during COVID-19 vaccination are still lacking. Objectives: To study the effect of MTX and its discontinuation on the humoral immune response after COVID-19 vaccination in patients with autoimmune rheumatic diseases (AIRD). Methods: In this retrospective study, neutralising SARS-CoV-2 antibodies were measured after second vaccination in 64 rheumatic patients on methotrexate therapy, 31 of whom temporarily paused medication without a fxed regimen. The control group consisted of 21 AIRD patients without immunosuppressive medication. Results: MTX patients showed a signifcantly lower mean antibody response compared to AIRD patients without immunosuppressive therapy (71.8 % vs 92.4 %, p<0.001). For patients taking MTX, age correlated negatively with immune response (r=-0.49;p<0.001). All nine patients with antibody levels below the cutoff were older than 60 years. Patients who held MTX during at least one vaccination showed signifcantly higher mean neutralising antibody levels after second vaccination, compared to patients who continued MTX therapy during both vaccinations (83.1 % vs 61.2 %, p=0.001). This effect was particularly pronounced in patients older than 60 years (80.8 % vs 51.9 %, p=0.001). The impact of the time period after vaccination was greater than of the time before vaccination with the critical cut-off being 10 days. Conclusion: MTX reduces the immunogenicity of SARS-CoV-2 vaccination in an age-dependent manner. Our data further suggest that holding MTX for at least 10 days after vaccination signifcantly improves the antibody response in patients over 60 years of age.

Complement activation induces excessive T cell cytotoxicity in severe COVID-19

Severe COVID-19 is linked to both dysfunctional immune response and unrestrained immunopathology, and it remains unclear whether T cells contribute to disease pathology. Here, we combined single-cell transcriptomics and single-cell proteomics with mechanistic studies to assess pathogenic T cell functions and inducing signals. We identified highly activated CD16(+) T cells with increased cytotoxic functions in severe COVID-19. CD16 expression enabled immune-complex-mediated, T cell receptor-independent degranulation and cytotoxicity not found in other diseases. CD16(+) T cells from COVID-19 patients promoted microvascular endothelial cell injury and release of neutrophil and monocyte chemoattractants. CD16(+) T cell clones persisted beyond acute disease maintaining their cytotoxic phenotype. Increased generation of C3a in severe COVID-19 induced activated CD16(+) cytotoxic T cells. Proportions of activated CD16(+) T cells and plasma levels of complement proteins upstream of C3a were associated with fatal outcome of COVID-19, supporting a pathological role of exacerbated cytotoxicity and complement activation in COVID-19.

Late versus early administration of convalescent plasma in hospitalized patients with covid-19: Results from the randomized open label clinical trial capsid

Background: Several observational studies suggested efficacy of COVID-19 convalescent plasma (CCP) but the results of several randomized clinical trials of CCP are not consistent. The trials differ in treatment schedules in terms of timing, volume and antibody content of CCP as well as enrolled patient populations and endpoints. The CAPSID was designed at the beginning of the pandemic and assessed the efficacy of neutralizing antibody containing high-dose COVID-19 convalescent plasma (CCP) in hospitalized patients with severe COVID-19. Methods: Patients (n=105) in 13 hospitals in Germany were randomized to either receive standard treatment and three units of CCP on days 1, 3 and 5 (total dose 846 ml) (n=53) or standard treatment alone (n=52). Patients in the control group with progress on day 14 could receive CCP (crossover group;n=7) on days 15, 17 and 19. The primary outcome was a dichotomous composite outcome of survival and no longer fulfilling criteria of severe COVID-19 on day 21. For Cross over patients a propensity matching with patients of the plasma group was performed. Results: Neutralizing antibodies were present at baseline in 18.2% of CCP and 19.2% of control group patients. In the ITT analysis the primary outcome occurred in 43.4% of patients in the CCP and 32.7% in the control group (p=0.32). The CCP group showed a trend for shorter times to clinical improvement (40 days, p=0.27) and discharge from hospital (20 days, p=0.24). Among those in the CCP group who received a higher or lower cumulative amount of neutralizing antibodies the primary outcome occurred in 56.0% and 32.1% of patients The high titer group showed significantly shorter intervals to clinical improvement or hospital discharge and a better overall survival (p=0.02). None of the patients in the crossover group (CG) achieved clinical improvement and survived. Comparing the CG to 14 CCP patients matched by baseline characteristics resulted in worse OS in the CG group (p=0.02) while comparison with 6 day 14 matched patients showed equal OS. Interpretation: CCP added to standard treatment did not result in a significant difference in the primary and secondary outcomes. A pre-defined subgroup analysis showed a signal of benefit for CCP among those who received a larger amount of neutralizing antibodies. A progress on day 14 is an indicator for poor outcome in COVID-19. Late administration of CCP is not supported by our results.

Unraveling single-cell responses in human AKI

Background: Acute kidney injury (AKI) is frequently observed in critically ill patients and is associated with a poor prognosis. AKI has recently moved into the focus of interest during the SARS-CoV-2 pandemic as high rates of AKI have been reported in severe COVID-19. We aimed to delineate cell type-specific molecular phenotypes associated with human AKI, including COVID-associated AKI. Methods: We analyzed human kidney tissues using histology and single-nuclei RNA sequencing. Samples included kidney biopsies obtained within 2 hours post mortem from patients who succumbed to critical illness with and without evidence of AKI. Samples also included tumor-adjacent normal kidney tissues obtained during surgeries. AKI cases included patients with severe courses of COVID-19 (COVID AKI) and patients with other types of critical illness associated with systemic inflammation (Non-COVID AKI). Postmortem kidney tissues obtained 30 min, 1 hour and 2 hours after death from a brain-dead patient without AKI were analyzed to assess the impact of post-mortem effects. Results: Single-nuclei sequencing from kidney tissues yielded data of high transcriptional depth, which allowed transcriptome-based identification and de-novo spatial reconstruction of kidney cells. Principal component and differential gene expression analyses indicated that the presence of clinically confirmed AKI was the primary driver of global kidney transcriptomes and that different molecular subtypes of AKI existed. In contrast, the sampling time post-mortem and the presence of COVID-19 had minor effects. Subclustering analyses of different kidney cell types identified subclasses of cells representing injured kidney tubular cells, which were marked by distinct biomarker expression and expression signatures signifying intrinsic responses to inflammation, an induction of epithelial-to-mesenchymal transition, and an upregulation of hitheto unrecognized novel receptor-ligand pairs. Conclusions: We provide the first cell type-specific molecular atlas of human AKI, revealing unanticipated disease subtypes and cell type-specific injury patterns.

Pre-activated antiviral innate immunity in the upper airways controls early SARS-CoV-2 infection in children.

Children have reduced severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection rates and a substantially lower risk for developing severe coronavirus disease 2019 compared with adults. However, the molecular mechanisms underlying protection in younger age groups remain unknown. Here we characterize the single-cell transcriptional landscape in the upper airways of SARS-CoV-2-negative (n = 18) and age-matched SARS-CoV-2-positive (n = 24) children and corresponding samples from adults (n = 44), covering an age range of 4 weeks to 77 years. Children displayed higher basal expression of relevant pattern recognition receptors such as MDA5 (IFIH1) and RIG-I (DDX58) in upper airway epithelial cells, macrophages and dendritic cells, resulting in stronger innate antiviral responses upon SARS-CoV-2 infection than in adults. We further detected distinct immune cell subpopulations including KLRC1 (NKG2A)+ cytotoxic T cells and a CD8+ T cell population with a memory phenotype occurring predominantly in children. Our study provides evidence that the airway immune cells of children are primed for virus sensing, resulting in a stronger early innate antiviral response to SARS-CoV-2 infection than in adults.

Olfactory transmucosal SARSCoV-2 invasion as port of central nervous system entry in COVID-19

Introduction: Coronavirus disease 2019 (COVID-19) is a pandemic respiratory disease which is accompanied by a broad spectrum of neurological manifestations in more than one-third of COVID-19 cases. For the latter, olfactory and gustatory disturbances such as anosmia and ageusia, are often leading symptoms of SARS-CoV-2 infection. Given the close proximity of neuronal and supporting cells the olfactory mucosa as a neural-mucosal interface may represent a potential port of CNS entry for SARS-CoV-2. Objectives: Identifying potential sites of SARS-COV-2 CNS entry and morphological changes associated with SARS-CoV-2 infection. Methods: We systematically investigated postmortem tissue of the CNS and nasopharynx from 75 individuals with COVID-19. Based on the correlation of clinical data and (neuro-) pathological examinations, SARSCoV- 2-specific morphological changes were determined. Using quantitative real-time PCR, RNAscope in situ hybridization, immunohistochemistry and electron microscopy, we characterized the CNS tropism of SARSCoV- 2 and the consequences thereof. Results: Acute thromboembolic ischemic infarcts (n = 10/64) and a strong innate immune response, mediated by HLA-DR+ microglia with a linked increase in proinflammatory mediators in the cerebrospinal fluid, are leading alterations in the CNS. Besides, a distinct immunoreactivity for SARSCoV Spike protein was found in the olfactory epithelium - here co-localizing with neural/neuronal cells - and cerebral endothelial cells. We were also able to illustrate intact coronavirus particles in the olfactory mucosa ultrastructurally. Conclusion: SARSCoV- 2 can enter the nervous system by crossing the neural-mucosal interface in the olfactory mucosa. SARSCoV- 2 infection results in an innate immune response with activation of HLA-DR+ microglia and increased levels of inflammatory mediators in the CNS.