Comparison of Anti-SARS-CoV-2 S1 Receptor-Binding Domain Antibody Immunoassays in Health Care Workers Before and After the BNT162b2 mRNA Vaccine

OBJECTIVES

The Pfizer-BioNTech BNT162b2 vaccine against SARS-CoV-2 infection is now available. This vaccine induces antibody production against the receptor-binding domain (RBD) of the spike glycoprotein S1 (S1-RBD). This study evaluated the performance of new immunoassays to measure this type of antibody.

METHODS

Blood samples were collected at t0 (prime dose), after 21 days (t1, booster dose), and then after another 15 days (t2) from 70 health care professionals who had tested negative for previous SARS-CoV-2 infection and underwent vaccination with BNT162b2.

RESULTS

Antibodies against S1-RBD were measured using 4 commercial assays. At t0, t1, and t2, the median antibody concentrations (interquartile range) were, respectively, 0.2 (0.1-0.4), 49.5 (19.1-95.7), and 888.0 (603.6-1,345.8) U/mL by Maglumi SARS-CoV-2 S-RBD immunoglobulin G (IgG) (Shenzen New Industries Biomedical Engineering, Snibe Diagnostics); 0.0 (0.0-0.0), 7.9 (4.2-15.6), and 112.3 (76.4-205.6) U/mL by Atellica IM SARS-CoV-2 IgG assay (Siemens Healthineers); 0.0 (0.0-0.0), 59.9 (18.3-122.0), and 2,646.0 (1,351.2-4,124.0) U/mL by Elecsys Anti-SARS-CoV-2 S assay (Roche Diagnostics); and 1.8 (1.8-1.8), 184 (94-294), and 1,841.0 (1,080.0-2,900.0) AU/mL by LIAISON SARS-CoV-2 TrimericS IgG assay (DiaSorin). The differences between medians at t0, t1, and t2 were all statistically significant (P < .001).

CONCLUSIONS

Antibodies against nucleocapsid proteins (N) were also measured using Maglumi 2019-nCoV IgG assay, which showed all negative results. All the considered anti-RBD methods detected response to the vaccine, while the method directed against anti-N failed to show response.

Anti SARS-CoV-2 antibodies monitoring in a group of residents in a long term care facility during COVID-19 pandemic peak

Objectives Clinical laboratories plays a key role in screening, diagnosis and containment of the Coronavirus 2019 infection epidemic. The etiological diagnosis presupposes the isolation of virus genetic material in the patient's biological sample but laboratory diagnostics also make use of searching possibility for immunoglobulin (Ig)G, IgM classes antibodies. The characteristics of the antibody response are not yet completely clear. Methods This study describes a serological monitoring of subjects, elderly nursing care residence guests, interested by a very large infection outbreak. After first nasopharyngeal swab, all the positive subjects (43) were monitored for the persistence of the virus infection through nasopharyngeal swab after 20 days (16-24), 32 days (28-36) and after 49 days (47-50). At the same time, during the second (day 32) and third (day 49) follow up, all the guests were investigated for IgM and IgG anti SARS-CoV-2 antibodies, by using a quantitative chemiluminescence method. Results Thirty two days after performing the first diagnostic swab, 39 of 43 patients (90%) had IgG higher than the cut off value. After 49 days the four patients with negative IgG were still negative. The comparison of the levels of IgG-Ab between the controls shows a significant decrease in concentrations (-10%). Conclusions Our study confirms that in most patients affected by COVID-19 there is a typical antibody response with IgG-Ab present in 90% of nursing care COVID-19 positive residence guests. For IgM-Ab only 23% of tested subjects were positive on the 32nd and 49th day of illness, always in parallel with the IgG-Ab positivity.

P0727P-CRESYL SULFATE AND INDOXYL SULFATE: A POSSIBLE ROLE AS BIOMARKERS IN THE PREDICTION OF RENAL FUNCTION AND CKD PROGRESSION

Background and Aims

Uremic toxins are markedly accumulated in chronic kidney disease (CKD) patients. Among these two protein-bound compounds, indoxyl sulfate (IXS) and p-cresyl sulfate (PCS) derived from gut bacterial transformation, play an important role. Recent evidences demonstrate their toxic effects in vitro and may contribute in vivo to CKD progression and mortality in uremic patients. For this reason, bacterial metabolism and its metabolites are therapeutic targets in CKD. While, several studies have evaluated possible associations between these two compounds and renal function decline in CKD, while no study has evaluated them according to the stage of progression (CKD stage). In this study, PCS and IXS are considered to highlight the possible role as biomarkers in the prediction of renal function and CKD progression (GFR stage 1-5).

Method

In our observational, prospective study we evaluated total (t) and free (f) PCS and IXS plasmatic fractions using Ultra High Performance Liquid Chromatography Infinity 1260 (Agilent technologies) coupled to an API 3200™ triple quadrupole mass spectrometry (ABSciex). Data were shown as mean ± SD or median (25th-75th). Statistical analysis was done by SPSS version 24.0

Results

We evaluated 80 CKD patients: 54.68 ± 12.88 yrs, 39 F and 41 M. The median creatinine was 1.58 (0.90-3.32) mg/dL, median urea 58.50 (42.0-121.25) mg/dL and eGFR (CKD-EPI) 42 (17.25-85.75) mL/min/1.73 m2. On the table 1, it was summarized the levels of PCS and IXS in all patients and classified by GFR (G) stages. We found the statistically significant increase of total and free fractions of PCS (p&lt;0.001) and IXS (p&lt;0.001) with the progression of CKD by G stage and inverse strong correlation between eGFR (CKD-EPI) and PCSt (Spearman's Rho (r)=-0.70, p&lt;0.001), PCSf (r=-0.75, p&lt;0.001), IXSt (r=-0.76, p&lt;0.001), IXSf (r=-0.82, p&lt;0.001).

Moreover, the increase of PCS and IXS predicts the eGFR decline significantly, according to the linear regression model using eGFR as dependent variable: PCSt (R-squared (R2)= 0.34, p&lt;0.001). PCSf (R2=0.21, p&lt;0.001). IXSt (R2=0.27, p&lt;0.001). IXSf (R2=0.19, p&lt;0.001). By multivariate analysis, the total compounds of both toxins remain predictive of eGFR: PCSt (β=-0.72, p=0.003; 95%CI:-2.43;-0.54) and IXSt (β=-0.70, p=0.011; 95%CI:-5.15;-0.70).

Conclusion

In conclusion, in our study we show the strong correlations between and PCS and IXS and eGFR and we found the significantly increase of PCS and IXS (total and free) with the progression of CKD in all G stage (1-5). We highlight the use of mass spectrometry in the evaluation of renal function especially in the earliest stages of CKD with the possibility of measuring minimum concentrations of PCSf and IXSf.

Assuming the predictive value of PCS and IXS towards the reduction of eGFR, we could hypothesize the identification of cut-offs based on confidence intervals, for the prediction and progression of renal function impairment.

The use of "2-octyl cyanoacrylate" as skin adhesive in pediatric and congenital cardiac surgery

AIM

The aim of this paper was to evaluate the safety and cost-effectiveness of "2-octyl-cyanoacrylate" as skin adhesive in congenital heart surgery.

METHODS

From April 2010 to December 2011, we collected data from 300 patients who underwent cardiac surgery for congenital heart disease. We divided our population into 3 groups: group-1 (N.=100):"2-octyl-cyanoacrylate" has been used to replace the intra-dermal suture line; group-2 (N.=100):"2-octyl-cyanoacrylate" has been utilized as a barrier ("add-on measure") in addition to the intra-dermal suture line, group-3 (N.=100) with a standard intra-dermal suture line.

RESULTS

Median age of patients was 1.36 years. One-hundred and thirty-nine patients were younger than 12 months and 56 older than 16 years. There were 11 wound dehiscence (3.6%) (2 in group-1 and 9 in group-3, P=0.001) and 1 superficial wound infection (group-1). Six patients (2%) required surgical wound revision (2 in group-1 and 4 in group-3, P=NS). Wound complication was significantly associated to delayed sternal closure (3/12 patients, 25% versus 13/288 patients, 4.5%) (P=0.04). Median cost (intra-/postoperative) for wound treatment was lower in group-1 and 2 (19±5.5 and 23.9±7.4 € respectively) when compared to Group-3 (26.7±3.2) (P<0.0001).

CONCLUSION

The use of "2-octyl-cyanoacrylate" proved to be safe and effective; the "add-on measure" strategy provided the best cost-effective solution.

The use fibrinogen/thrombin-coated equine collagen patch in children requiring reoperations for congenital heart disease. A single center clinical experience

AIM

The aim of this study was to evaluate the efficacy and cost-effectiveness of fibrinogen/thrombin-coated collagen patch (FTCCP)(TachoSil®) during intraoperative hemostasis in patients with congenital heart disease, who required a reoperation during childhood.

METHODS

We reviewed data on the intraoperative blood product requirements and hospital costs of children (age <16 years) who underwent a reoperation for treating their congenital heart disease between January 2009 and December 2011.

RESULTS

One-hundred and seventeen patients were included. Median age at surgery was 2.1 years (range 3 days-14.1 years). Main causes of intraoperative bleeding were: 1) reinforcement of suture lines (106 patients, 90.6%); 2) lung lesions (5 patients, 4.2%); 3) epicardial lesions (3 patients, 2.6%); and 4) chest wall lesions (3 patients, 2.6%). At logistic regression the amount of packed red blood cells (PRBC) requirement was significantly higher in patients with preoperative cyanosis (P=0.008, OR=3.85) and in patients who required the use of cardiopulmonary bypass (P=0.005, OR=21.19). The use of FTCCP (N.=90 patients) as first line treatment was significantly associated with a lower PRBC requirement (P=0.0003, OR=0.1) which in addition to the avoidance of other hemostatic/sealant agents, leads to lower hospital cost.

CONCLUSION

FTCCP is an effective hemostatic agent which can be safely used during the hemostasis of children requiring reoperations for their congenital heart malformations. When used as first line treatment, with specific indications, FTCCP limited the intraoperative PRBC requirement and the use of other hemostatic/sealant agents thus reducing hospital costs.

Comparison of methods to identify individuals at increased risk of cardiovascular disease in Italian cohorts

BACKGROUND AND AIMS

Guidelines for the primary prevention of cardiovascular disease recommend the use of risk-assessment methods to identify high risk patients who can benefit from lifestyle changes and/or drug treatment. Although all these risk-prediction methods are based on the same principle, they produce different risk estimates. The aim of this study was to compare the most recent and widely used cardiovascular risk-prediction methods and the respective guidelines when applied to Italian cohorts.

METHODS AND RESULTS

Seven different risk-assessment methods were applied to two groups of subjects, 536 healthy individuals and 426 diabetic patients. Sensitivity and specificity of Framingham-based risk-assessment methods were calculated using the Framingham full equation as the reference standard. The extent of concordance among the different risk-assessment methods was determined by kappa test. By using NCEP-ATPIII risk calculator, modified Sheffield tables, Joint European Societies charts, Joint British Societies charts, Italian CUORE Project charts, European SCORE charts and New Zealand National Heart Foundation charts in the group of 536 healthy subjects, lipid-lowering treatment would be recommended in 17.5%, 12.7%, 12.1%, 8.6%, 5.0%, 4.7%, and 1.1% subjects, respectively. By using the same risk-assessment methods in the group of 426 diabetic patients, treatment would be recommended for 100%, 82.9%, 66.9%, 77.7%, 43.0%, 74.9%, and 47.4% patients, respectively. The Joint British charts and the modified Sheffield tables showed the closest agreement with the reference standard.

CONCLUSIONS

Our study confirms that the use of different risk-assessment methods in clinical practice can substantially change risk estimation and consequently statin prescription rate. The Framingham-based risk-assessment methods and particularly the NCEP-ATPIII guidelines select for lipid-lowering treatment a higher number of subjects than those identified according to European and Italian recommendations.

Mitochondrial permeability transition and release of cytochrome c induced by retinoic acids

Retinoic acids, structurally related to vitamin A, inhibit the in vitro proliferation of different types of normal and neoplastic cells. The effects of all-trans, 9-cis, and 13-cis retinoic acids were tested on mitochondria isolated from rat liver. All the compounds were able to induce the membrane permeability transition observed as swelling and decrease in membrane potential, but 13-cis retinoic acid appeared to be the most effective. The latter was also shown to stimulate the release of cytochrome c from mitochondria, suggesting a potential target of retinoids in the induction of cell apoptosis. Interestingly, EGTA and cyclosporin A, which strongly inhibit the permeability transition induced by 13-cis retinoic acid, were without effect on the release of cytochrome c from the mitochondrial intermembrane space.

Purification of mitochondrial thioredoxin reductase and its involvement in the redox regulation of membrane permeability

The isolation to purity of a rat liver mitochondrial thioredoxin reductase is reported. The mitochondrial enzyme shows a chromatographic behavior different from that of the cytosolic enzyme. The purified enzyme, after sodium dodecylsulfate-polyacrylamide gel electrophoresis, yields a single band with a molecular weight of approximately 54 kDa. The apparent Km for E. coli thioredoxin is about 13 microM, while the apparent Km for 5,5'-dithiobis (2-nitrobenzoic acid) is 530 microM, values comparable to those reported for the cytosolic enzyme. Mitochondrial thioredoxin reductase, in addition to its natural substrate thioredoxin, is also able to reduce chemically unrelated compounds such as 5,5 '-dithiobis (2-nitrobenzoic acid), selenite, and alloxan; the enzyme is inhibited by classical inhibitors of the cytosolic enzyme such as 1-chloro-2,4-dinitrobenzene and 13-cis-retinoic acid. A strong inhibitory action is also elicited by Mn2+ and Zn2+ ions. Thiol status appears critically involved in the control of membrane permeability and, therefore, a thiol/disulfide transition involving reduced pyridine nucleotides, matrix soluble thiols, and inner membrane thiols appears to play a fundamental role. The potential role of thioredoxin/thioredoxin reductase system in the control and redox regulation of the mitochondrial membrane permeability, is discussed.

Influence of the redox state of pyridine nucleotides on mitochondrial sulfhydryl groups and permeability transition

This work addresses a correlation between the redox state of pyridine nucleotides and that of sulfhydryl groups of the mitochondrial membranes. Several major observations emerge: (1) Conditions leading to an oxidation of the pyridine nucleotides such as incubation with tert-butyl hydroperoxide or acetoacetate determine a decrease of total mitochondrial sulfhydryl groups. Glutathione does not follow the same pattern since it decreases in the presence of tert-butyl hydroperoxide but not in the presence of acetoacetate. In addition, only in the presence of tert-butyl hydroperoxide is the decrease of sulfhydryl groups concomitant with a membrane protein polymerization, observed by polyacrylamide gel electrophoresis. (2) Under all conditions tested, the oxidation of sulfhydryl groups is further stimulated by the presence of calcium and phosphate ions. (3) Respiratory substrates, which prevent the swelling of mitochondria, also partially prevent the decrease of sulfhydryl groups.

Effect of polycation peptides on mitochondrial permeability transition

Synthetic polycation peptides obtained with the basic aminoacids lysine, arginine and ornithine are able to inhibit the permeability transition induced in mitochondria by calcium ions and inorganic phosphate. At least three basic aminoacid residues must be present in the peptide in order to elicit the inhibitory effect. In the presence of synthetic polycations and similarly to spermine, a lack of correlation between inhibition of swelling and glutathione release is apparent, since glutathione release occurs before the onset of a large amplitude swelling. The same lack of correlation is observed in the presence of cyclosporin. From the results obtained with the above reported polycations, different in both aminoacid composition and length, it appears that the effect is not to be referred to the individual properties of the molecules examined but rather to their cationic character; in addition, a critical number of positive charges is necessary to elicit the effect.

Inhibitory effect of pyruvate on release of glutathione and swelling of rat heart mitochondria

Pyruvate prevents the permeability transition of rat heart mitochondria induced by the system calcium ions + phosphate or by the dithiol reagent phenylarsenoxide and measured as swelling. Since swelling induced by the latter is relieved by the dithiol 2,3-dimercaptopropanol (BAL), it is inferred that the effect of pyruvate might be mediated by the reduction of lipoic acid. In isolated mitochondria, pyruvate also exerts a protective effect when calcium + phosphate-induced swelling is exacerbated by hypoxic conditions. These results agree with our previous observations that pyruvate markedly prevents the loss of cytosolic and mitochondrial glutathione after ischemia or ischemia followed by reperfusion.