Blood metal analysis of plasmas from donors with and without SARS-CoV-2 using laser-induced breakdown spectroscopy and logistic regression

Research on the correlation between metal levels in blood and Covid-19 infection has been conducted primarily by assessing how each individual blood metal is linked to different aspects of the disease using samples from donors with various levels of severity to Covid-19 infection. Using logistics regression on LIBS spectra of plasma samples collected pre- and post- Covid-19 pandemic from donors known to have developed various levels of antibodies to the SARS-Cov-2 virus, we show that relying on the levels of Na, K, and Mg together is more efficient at differentiating the two types of plasma samples than any single blood alone.

Convalescent plasma with a high level of virus-specific antibody effectively neutralizes SARS-CoV-2 variants of concern

The ongoing evolution of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) variants severely limits available effective monoclonal antibody therapies. Effective drugs are also supply limited. COVID-19 convalescent plasma (CCP) qualified for high antibody levels effectively reduces immunocompetent outpatient hospitalization. The Food and Drug Administration currently allows outpatient CCP for the immunosuppressed. Viral-specific antibody levels in CCP can range 10- to 100-fold between donors, unlike the uniform viral-specific monoclonal antibody dosing. Limited data are available on the efficacy of polyclonal CCP to neutralize variants. We examined 108 pre-δ/pre-ο donor units obtained before March 2021, 20 post-δ COVID-19/postvaccination units, and 1 pre-δ/pre-ο hyperimmunoglobulin preparation for variant-specific virus (vaccine-related isolate [WA-1], δ, and ο) neutralization correlated to Euroimmun S1 immunoglobulin G antibody levels. We observed a two- to fourfold and 20- to 40-fold drop in virus neutralization from SARS-CoV-2 WA-1 to δ or ο, respectively. CCP antibody levels in the upper 10% of the 108 donations as well as 100% of the post-δ COVID-19/postvaccination units and the hyperimmunoglobulin effectively neutralized all 3 variants. High-titer CCP neutralizes SARS-CoV-2 variants despite no previous donor exposure to the variants.

High Viral Specific Antibody Convalescent Plasma Effectively Neutralizes SARS-CoV-2 Variants of Concern

The ongoing evolution of SARS-Co-V2 variants to omicron severely limits available effective monoclonal antibody therapies. Effective drugs are also supply limited. Covid-19 convalescent plasma (CCP) qualified for high antibody levels effectively reduces immunocompetent outpatient hospitalization. The FDA currently allows outpatient CCP for the immunosuppressed. Viral specific antibody levels in CCP can range ten-to hundred-fold between donors unlike the uniform viral specific monoclonal antibody dosing. Limited data are available on the efficacy of polyclonal CCP to neutralize variants. We examined 108 pre-delta/pre-omicron donor units obtained before March 2021, 20 post-delta COVID-19/post-vaccination units and one pre-delta/pre-omicron hyperimmunoglobulin preparation for variant specific virus (vaccine-related isolate (WA-1), delta and omicron) neutralization correlated to Euroimmun S1 IgG antibody levels. We observed a 2-to 4-fold and 20-to 40-fold drop in virus neutralization from SARS-CoV-2 WA-1 to delta or omicron, respectively. CCP antibody levels in the upper 10% of the 108 donations as well as 100% of the post-delta COVID-19/post-vaccination units and the hyperimmunoglobulin effectively neutralized all three variants. High-titer CCP neutralizes SARS-CoV-2 variants despite no previous donor exposure to the variants.

Key points

All of the post-delta COVID-19/post vaccination convalescent plasma effectively neutralizes the omicron and delta variants.High-titer CCP and hyperimmunoglobulin neutralizes SARS-CoV-2 variants despite no previous donor exposure to the variants.

Laser induced breakdown spectroscopy for the rapid detection of SARS-CoV-2 immune response in plasma

As the SARS-CoV-2 pandemic persists, methods that can quickly and reliably confirm infection and immune status is extremely urgently and critically needed. In this contribution we show that combining laser induced breakdown spectroscopy (LIBS) with machine learning can distinguish plasma of donors who previously tested positive for SARS-CoV-2 by RT-PCR from those who did not, with up to 95% accuracy. The samples were also analyzed by LIBS-ICP-MS in tandem mode, implicating a depletion of Zn and Ba in samples of SARS-CoV-2 positive subjects that inversely correlate with CN lines in the LIBS spectra.

Longitudinal analysis of antibody decay in convalescent COVID-19 patients

Determining the sustainability of antibodies targeting severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is essential for predicting immune response against the Coronavirus disease 2019 (COVID-19). To quantify the antibody decay rates among the varying levels of anti-nucleocapsid (anti-N) Immunoglobulin G (IgG) in convalescent COVID-19 patients and estimate the length of time they maintained SARS-CoV-2 specific antibodies, we have collected longitudinal blood samples from 943 patients over the course of seven months after their initial detection of SARS-CoV-2 virus by RT-PCR. Anti-N IgG levels were then quantified in these blood samples. The primary study outcome was the comparison of antibody decay rates from convalescent patients with high or low initial levels of antibodies using a mixed linear model. Additional measures include the length of time that patients maintain sustainable levels of anti-N IgG. Antibody quantification of blood samples donated by the same subject multiple times shows a gradual decrease of IgG levels to the cutoff index level of 1.4 signal/cut-off (S/C) on the Abbott Architect SARS-CoV-2 IgG test. In addition, this study shows that antibody reduction rate is dependent on initial IgG levels, and patients with initial IgG levels above 3 S/C show a significant 1.68-fold faster reduction rate compared to those with initial IgG levels below 3 S/C. For a majority of the donors naturally occurring anti-N antibodies were detected above the threshold for only four months after infection with SARS-CoV-2. This study is clinically important for the prediction of immune response capacity in COVID-19 patients.

Influence of plasma cholesterol and triglyceride concentrations and eritoran (E5564) micelle size on its plasma pharmacokinetics and ex vivo activity following single intravenous bolus dose into healthy female rabbits

PURPOSE

Eritoran (E5564) is a glycophospholipid that acts as a toll-like receptor 4 (TLR4) antagonist that is being tested as a treatment for severe sepsis and septic shock. In the blood, eritoran binds to plasma lipoproteins altering its pharmacokinetic and pharmacodynamic (PD) effects in vivo. The purpose of this study was to determine the influence of changes in plasma cholesterol and triglyceride concentrations on the plasma pharmacokinetics and ex vivo activity of eritoran following single intravenous bolus dosing of eritoran to healthy female rabbits fed either a regular chow diet or a cholesterol-enriched diet. This was done with eritoran administered as stable micelle formulations of mean hydrodynamic diameters of 8 or 27 nm).

METHODS

Female New Zealand White rabbits were fed a standard diet for 7 days and then randomly assigned either a regular chow diet [regular-diet (n = 9)] or a cholesterol-enriched diet [cholesterol-diet (n = 12)] for an additional 7 days. Following feeding of these diets a single intravenous bolus dose of eritoran (0.5 mg/kg) formulated into either "small micelles" (8 nm in diameter) or "large micelles" (27 nm in diameter) was administered to regular-fed and cholesterol-fed rabbits. Serial blood samples were obtained prior to eritoran administration and at the following times post injection: 0.083 (5 min), 1, 2, 4, 8, 10, 24, 48 and 72 h. Plasma was analyzed for eritoran concentrations using LC/MS/MS. Total plasma cholesterol (TC) and triglyceride (TG) levels were quantified using enzymatic kits. Plasma eritoran pharmacokinetic (PK) parameters were estimated by non-compartmental analysis using the WinNonlin nonlinear estimation program. To analyze PD activity, whole blood obtained at 0.083 (5 min), 2, 24, 48 and 72 h following eritoran administration was assessed for ex vivo activity by measuring the ability of 1 and 10 ng/ml LPS to elicit TNF-alpha release.

RESULTS

Total plasma cholesterol and triglyceride levels were significantly higher in cholesterol-fed rabbits compared to the rabbits fed a regular chow diet. Diet had no effect on the estimated plasma PK parameters. However, PD activity of both small and large micelle eritoran as measured by an ex vivo challenge dose of 1 ng/ml LPS was reduced in blood of cholesterol-fed rabbits compared to normal-fed rabbits. Comparison of PK parameters for small and large micelles indicated that small micelles had increased AUC(0-72 h), decreased plasma clearance and increased initial concentration (measured at 5 min post administration) compared to the large micelle formulation. Consistent with this observation, eritoran formulated into small micelles had significantly greater ex vivo activity than large micelles and was independent of TC and TG concentrations.

CONCLUSIONS

These findings suggest that plasma pharmacokinetics and activity of eritoran maybe influenced by eritoran micelle size and plasma TC and TG concentrations.