Association between SARS-CoV-2 RNAemia and dysregulated immune response in acutely ill hospitalized COVID-19 patients

Sustained IFN signaling is associated with delayed development of SARS-CoV-2-specific immunity

Plasma RNAemia, delayed antibody responses and inflammation predict COVID-19 outcomes, but the mechanisms underlying these immunovirological patterns are poorly understood. We profile 782 longitudinal plasma samples from 318 hospitalized patients with COVID-19. Integrated analysis using k-means reveals four patient clusters in a discovery cohort: mechanically ventilated critically-ill cases are subdivided into good prognosis and high-fatality clusters (reproduced in a validation cohort), while non-critical survivors segregate into high and low early antibody responders. Only the high-fatality cluster is enriched for transcriptomic signatures associated with COVID-19 severity, and each cluster has distinct RBD-specific antibody elicitation kinetics. Both critical and non-critical clusters with delayed antibody responses exhibit sustained IFN signatures, which negatively correlate with contemporaneous RBD-specific IgG levels and absolute SARS-CoV-2-specific B and CD4+ T cell frequencies. These data suggest that the "Interferon paradox" previously described in murine LCMV models is operative in COVID-19, with excessive IFN signaling delaying development of adaptive virus-specific immunity.

Deciphering Fc-effector functions against SARS-CoV-2

Major efforts were deployed to study the antibody response against SARS-CoV-2. Antibodies neutralizing SARS-CoV-2 have been extensively studied in the context of infections, vaccinations, and breakthrough infections. Antibodies, however, are pleiotropic proteins that have many functions in addition to neutralization. These include Fc-effector functions such as antibody-dependent cellular cytotoxicity (ADCC) and antibody-dependent cellular phagocytosis (ADCP). Although important to combat viral infections, these Fc-effector functions were less studied in the context of SARS-CoV-2 compared with binding and neutralization. This is partly due to the difficulty in developing reliable assays to measure Fc-effector functions compared to antibody binding and neutralization. Multiple assays have now been developed and can be used to measure different Fc-effector functions. Here, we review these assays and what is known regarding anti-SARS-CoV-2 Fc-effector functions. Overall, this review summarizes and updates our current state of knowledge regarding anti-SARS-CoV-2 Fc-effector functions.

Association between SARS-CoV-2 RNAemia, skewed T cell responses, inflammation, and severity in hospitalized COVID-19 people living with HIV

Severe COVID-19 outcomes have been reported in people living with HIV (PLWH), yet the underlying pathogenetic factors are largely unknown. We therefore aimed to assess SARS-CoV-2 RNAemia and plasma cytokines in PLWH hospitalized for COVID-19 pneumonia, exploring associations with magnitude and functionality of SARS-CoV-2-specific immune responses. Eighteen unvaccinated PLWH (16/18 on cART; median CD4 T cell count 361.5/μL; HIV-RNA<50 cp/mL in 15/18) and 18 age/sex-matched people without HIV were consecutively recruited at a median time of 10 days from symptoms onset. PLWH showed greater SARS-CoV-2 RNAemia, a distinct plasma cytokine profile, and worse respiratory function (lower PaO2/FiO2nadir), all correlating with skewed T cell responses (higher perforin production by cytotoxic T cells as well as fewer and less polyfunctional SARS-CoV-2-specific T cells), despite preserved humoral immunity. In conclusion, these data suggest a link between HIV-related T cell dysfunction and poor control over SARS-CoV-2 replication/dissemination that may in turn influence COVID-19 severity in PLWH.

Effects of remdesivir on SARS-CoV-2 viral dynamics and mortality in viraemic patients hospitalized for COVID-19

BACKGROUND

Studies on the antiviral effects of remdesivir have shown conflicting results. SARS-CoV-2 viraemia could identify patients in whom antiviral treatment may be particularly beneficial.

OBJECTIVES

To investigate antiviral effects and clinical outcomes of remdesivir treatment in viraemic patients.

METHODS

Viraemic patients hospitalized for COVID-19 with ratio of arterial oxygen partial pressure to fractional inspired oxygen of ≤300, symptom duration ≤10 days, and estimated glomerular filtration rate ≥30 mL/min were included in a cohort. The rate of serum viral clearance and serum viral load decline, 60 day mortality and in-hospital outcomes were estimated. A subgroup analysis including patients with symptom duration ≤7 days was performed.

RESULTS

A total of 318 viraemic patients were included. Thirty-three percent (105/318) received remdesivir. The rate of serum viral clearance [subhazard risk ratio (SHR) 1.4 (95% CI 0.9-2.0), P = 0.11] and serum viral load decline (P = 0.11) were not significantly different between remdesivir-treated patients and controls. However, the rate of serum viral clearance was non-significantly higher [SHR 1.6 (95% CI 1.0-2.7), P = 0.051] and the viral load decline was faster (P = 0.03) in remdesivir-treated patients with symptom duration ≤7 days at admission. The 60 day mortality [HR 1.0 (95% CI 0.6-1.8), P = 0.97] and adverse in-hospital outcomes [OR 1.4 (95% CI 0.8-2.4), P = 0.31] were not significantly different between remdesivir-treated patients and controls.

CONCLUSIONS

Remdesivir treatment did not significantly change the duration of SARS-CoV-2 viraemia, decline of serum viral load, 60 day mortality or in-hospital adverse outcomes in patients with ≤10 days of symptoms at admission. Remdesivir appeared to reduce the duration of viraemia in a subgroup of patients with ≤7 days of symptoms at admission.

Distinct anti-NP, anti-RBD and anti-Spike antibody profiles discriminate death from survival in COVID-19

Introduction

Infection by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) induces rapid production of IgM, IgA, and IgG antibodies directed to multiple viral antigens that may have impact diverse clinical outcomes.

Methods

We evaluated IgM, IgA, and IgG antibodies directed to the nucleocapsid (NP), IgA and IgG to the Spike protein and to the receptor-binding domain (RBD), and the presence of neutralizing antibodies (nAb), in a cohort of unvaccinated SARS-CoV-2 infected individuals, in the first 30 days of post-symptom onset (PSO) (T1).

Results

This study included 193 coronavirus disease 2019 (COVID-19) participants classified as mild, moderate, severe, critical, and fatal and 27 uninfected controls. In T1, we identified differential antibody profiles associated with distinct clinical presentation. The mild group presented lower levels of anti-NP IgG, and IgA (vs moderate and severe), anti-NP IgM (vs severe, critical and fatal), anti-Spike IgA (vs severe and fatal), and anti-RBD IgG (vs severe). The moderate group presented higher levels of anti-RBD IgA, comparing with severe group. The severe group presented higher levels of anti-NP IgA (vs mild and fatal) and anti-RBD IgG (vs mild and moderate). The fatal group presented higher levels of anti-NP IgM and anti-Spike IgA (vs mild), but lower levels of anti-NP IgA (vs severe). The levels of nAb was lower just in mild group compared to severe, critical, and fatal groups, moreover, no difference was observed among the more severe groups. In addition, we studied 82 convalescent individuals, between 31 days to 6 months (T2) or more than 6 months (T3), PSO, those: 12 mild, 26 moderate, and 46 severe plus critical. The longitudinal analyzes, for the severe plus critical group showed lower levels of anti-NP IgG, IgA and IgM, anti-Spike IgA in relation T3. The follow-up in the fatal group, reveals that the levels of anti-spike IgG increased, while anti-NP IgM levels was decreased along the time in severe/critical and fatal as well as anti-NP IgG and IgA in several/critical groups.

Discussion

In summary, the anti-NP IgA and IgG lower levels and the higher levels of anti-RBD and anti-Spike IgA in fatal compared to survival group of individuals admitted to the intensive care unit (ICU). Collectively, our data discriminate death from survival, suggesting that anti-RBD IgA and anti-Spike IgA may play some deleterious effect, in contrast with the potentially protective effect of anti-NP IgA and IgG in the survival group.

A Randomized Controlled Study Assessing Convalescent Immunoglobulins vs Convalescent Plasma for Hospitalized Patients With Coronavirus 2019

BACKGROUND

It is unknown whether convalescent immunoglobulins (cIgGs) are better than convalescent plasma (CP) for patients with coronavirus 2019 (COVID-19).

METHODS

In this randomized controlled trial, we assigned high risk COVID-19 patients with ≤10 days of symptoms, to receive cIgGs or CP. The primary endpoint was improvement on day 14 according to the World Health Organization scale. Secondary endpoints were survival on day 14, and improvement, survival, and percent of ventilated patients on day 28, and treatment response in unvaccinated and vaccinated patients.

RESULTS

A total of 319 patients were included: 166 received cIgGs and 153 CP. Median age was 64 to 66 years. A total of 112 patients (67.5%) in the cIgG group and 103 patients (67.3%) in the CP group reached the primary endpoint. Difference between groups was 0.1 (95% confidence interval, -10.1 to 10.4; P = .026), failing to reach noninferiority. More patients receiving cIgG improved by day 28 (136 patients [81.9%] and 108 patients [70.6%], respectively; 95% confidence interval, 1.9-20.7; P < .001; for superiority P = .018). Seventeen patients in the cIgG group (10.2%) and 25 patients (16.3%) in the CP group required mechanical ventilation (P = .136). Sixteen (9.6%) and 23 (15%) patients, respectively, died (P = .172). More unvaccinated patients improved by day 28 in the cIgG group (84.1% vs 66.1%; P = .024), and survival was better in the cIgG group (89.9% vs 77.4%; P = .066).

CONCLUSIONS

cIgGs failed to reach the primary noninferiority endpoint on day 14 but was superior to CP on day 28. Survival and improvement by day 28 in unvaccinated patients treated with cIgGs were better. In the face of new variants, cIgGs are a viable option for treating COVID-19.

TRIAL REGISTRATION NUMBER

My Trials MOH_2021-01-14_009667.

Six-month immune responses to mRNA-1273 vaccine in combination antiretroviral therapy treated late presenter people with HIV according to previous SARS-CoV-2 infection

OBJECTIVE

Immune responses to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) mRNA vaccines in people with HIV (PWH) with a history of late presentation (LP) and their durability have not been fully characterized.

DESIGN

In this prospective, longitudinal study, we sought to assess T-cell and humoral responses to SARS-CoV-2 mRNA vaccination up to 6 months in LP-PWH on effective combination antiretroviral therapy (cART) as compared to HIV-negative healthcare workers (HCWs), and to evaluate whether previous SARS-CoV-2 infection modulates immune responses to vaccine.

METHODS

SARS-CoV-2 spike (S)-specific T-cell responses were determined by two complementary flow cytometry methodologies, namely activation-induced marker (AIM) assay and intracellular cytokine staining (ICS), whereas humoral responses were measured by ELISA [anti-receptor binding domain (RBD) antibodies) and receptor-binding inhibition assay (spike-ACE2 binding inhibition activity), before vaccination (T0), 1 month (T1) and 5 months (T2) after the second dose.

RESULTS

LP-PWH showed at T1 and T2 significant increase of: S-specific memory and circulating T follicular helper (cTfh) CD4 + T cells; polyfunctional Th1-cytokine (IFN-γ, TNF-α, IL-2)- and Th2-cytokine (IL-4)-producing S-specific CD4 + T cells; anti-RBD antibodies and spike-ACE2 binding inhibition activity. Immune responses to vaccine in LP-PWH were not inferior to HCWs overall, yet S-specific CD8 + T cells and spike-ACE2 binding inhibition activity correlated negatively with markers of immune recovery on cART. Interestingly, natural SARS-CoV-2 infection, while able to sustain S-specific antibody response, seems less efficacious in inducing a T-cell memory and in boosting immune responses to vaccine, possibly reflecting an enduring partial immunodeficiency.

CONCLUSIONS

Altogether, these findings support the need for additional vaccine doses in PWH with a history of advanced immune depression and poor immune recovery on effective cART.

The kinetics of SARS-CoV-2 viremia in COVID-19 patients receiving remdesivir

Detection of SARS-CoV-2 RNA in serum, viremia, has been linked to disease severity and outcome. The kinetics of viremia in patients receiving remdesivir has not been thoroughly studied and could help predict treatment response and outcome. We investigated the kinetics of SARS-CoV-2 viremia and factors associated with baseline viremia, viral clearance and 30-day mortality in patients receiving remdesivir. An observational study including 378 hospitalised patients (median age 67 years, 67% male) sampled with serum SARS-CoV-2 RT-PCR within ± 24 h of initiation of remdesivir treatment. Baseline viremia was present in 206 (54%) patients with a median Ct value of 35.3 (IQR = 33.3-37.1). In patients with baseline viremia, the estimated probability of viral clearance was 72% by day 5. Ct values decreased significantly during remdesivir treatment for viremic patients, indicating an increase in viral load. In total, 44 patients (12%) died within 30 days, and mortality was significantly associated with viremia at baseline (OR = 2.45, p = 0.01) and lack of viral clearance by day 5 (OR = 4.8, p =  < 0.01). Viral clearance was not associated with any individual risk factor. Viremia appears to be a prognostic marker before and during remedesivir treatment. The resolution of viremia was similar to patients not receiving remdesivir in other studies, and the decrease in Ct values during treatment questions the antiviral capacity of remdesivir in vivo. Prospective studies are warranted to confirm our findings.