Epstein-Barr virus reactivation is not causative for post-COVID-19-syndrome in individuals with asymptomatic or mild SARS-CoV-2 disease course

PURPOSE

Post-COVID-19-Syndrome (PCS) frequently occurs after an infection with severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2). However, the understanding of causative mechanisms is still limited. Aim of this study was to determine the PCS rate among SARS-CoV-2 seropositive blood donors as representatives of supposedly healthy adults, who had experienced an asymptomatic or mild COVID-19 disease course, and to examine whether Epstein-Barr virus (EBV) is reactivated in individuals reporting PCS.

METHODS

The PCS rate was determined using questionnaires that included questions about infection and persistent symptoms. Pre-pandemic blood samples and samples collected at regular, pre-defined times after a SARS-CoV-2 infection were analysed for neopterin, a marker for antiviral immune responses, by an enzyme-linked immunosorbent assay (ELISA). Additionally, we determined the rate of SARS-CoV-2 anti-N total antibodies using an electrochemiluminescence immunoassay (ECLIA). Furthermore, quantitative real-time polymerase chain reaction (qPCR) to detect EBV DNA and ECLIA screening for EBV viral capsid-antigen (VCA) IgM, IgG and EBV nuclear antigen 1 (EBNA) IgG were performed.

RESULTS

Our data reveal that 18% of all infections result in PCS, with symptoms lasting for up to one year. In individuals reporting PCS, no elevated levels of neopterin were detected, indicating no persisting pro-inflammatory, antiviral immune response. SARS-CoV-2 antibody levels were declining in all participants in comparable manner over time, pointing to a successful virus clearance. In individuals with PCS, no EBV DNA could be detected. Furthermore, no differences in EBV specific antibody levels could be shown in PCS groups compared to non-PCS groups.

CONCLUSION

Our data suggest that PCS in per se healthy, immunocompetent adults cannot be ascribed to a reactivation of EBV.

When the available blood supply mismatches the needs of the patient

BACKGROUND

Substantial regional differences in the genetic patterns related to blood group have been observed across different continents. This diversity means that the blood supply, as an essential part of patient care, is increasingly impacted by global migration. Consequently, the Austrian blood donor population does not match the immigrant patient population. This mismatch is likely to result in the formation of alloantibodies to red cell antigens in the chronically transfused. Subsequently, major difficulties in providing compatible blood emerge.

MATERIAL AND METHODS

The study included patients of African origin (n=290) and Caucasians who represent the Austrian donor population (n=1,017). Genetic typing was performed for up to 69 blood group polymorphisms with a multiplex sequence specific primer-PCR including high frequency antigens and antigens for which antisera are not commercially available. By assessing differences in antigen frequencies between the two populations, and using these data for prophylactic matching, we aim to develop tools to increase the quality of patient care.

RESULTS

Results indicate various and significant differences (p<0.0001) in antigen frequencies between African patients and the European donor population, especially in the MNS, Duffy, Knops and Rhesus systems.

DISCUSSION

Our data highlight the importance of matching the donor population to the demographics of the patient population. In addition, it underlines the need to recruit donors of African origin and to focus on the upcoming challenges, such as malaria semi-immunity and a significantly higher rate of infectious disease in this population. It is also recommended to apply extended genetic typing to detect rare blood types, and (cryo)storage of rare blood in national and international rare blood banks. Co-operation with regional blood banks should also be encouraged.

Three rounds of a national external quality assessment reveal a link between disharmonic anti-SARS-CoV-2 antibody quantifications and the infection stage

OBJECTIVES

The WHO's standardized measuring unit, "binding antibody units per milliliter (BAU/mL)," should allow the harmonization of quantitative results by different commercial Anti-SARS-CoV-2 immunoassays. However, multiple studies demonstrate inter-assay discrepancies. The antigenic changes of the Omicron variant affect the performance of Spike-specific immunoassays. This study evaluated the variation of quantitative Anti-SARS-CoV-2-Spike antibody measurements among 46, 50, and 44 laboratories in three rounds of a national external quality assessment (EQA) prior to and after the emergence of the Omicron variant in a diagnostic near-to-real-life setting.

METHODS

We analyzed results reported by the EQA participant laboratories from single and sequential samples from SARS-CoV-2 convalescent, acutely infected, and vaccinated individuals, including samples obtained after primary and breakthrough infections with the Omicron variant.

RESULTS

The three immunoassays most commonly used by the participants displayed a low intra-assay and inter-laboratory variation with excellent reproducibility using identical samples sent to the participants in duplicates. In contrast, the inter-assay variation was very high with all samples. Notably, the ratios of BAU/mL levels quantified by different immunoassays were not equal among all samples but differed between vaccination, past, and acute infection, including primary infection with the Omicron variant. The antibody kinetics measured in vaccinated individuals strongly depended on the applied immunoassay.

CONCLUSIONS

Measured BAU/mL levels are only inter-changeable among different laboratories when the same assay was used for their assessment. Highly variable ratios of BAU/mL quantifications among different immunoassays and infection stages argue against the usage of universal inter-assay conversion factors.

Comprehensive Comparison of Seven SARS-CoV-2-Specific Surrogate Virus Neutralization and Anti-Spike IgG Antibody Assays Using a Live-Virus Neutralization Assay as a Reference

Neutralizing antibodies (nAbs) are considered a valuable marker for measuring humoral immunity against SARS-CoV-2. However, live-virus neutralization tests (NTs) require high-biosafety-level laboratories and are time-consuming. Therefore, surrogate virus neutralization tests (sVNTs) have been widely applied, but unlike most anti-spike (S) antibody assays, NTs and sVNTs are not harmonized, requiring further evaluation and comparative analyses. This study compared seven commercial sVNTs and anti-S-antibody assays with a live-virus NT as a reference, using a panel of 720 single and longitudinal serum samples from 666 convalescent patients after SARS-CoV-2 infection. The sensitivity of these assays for detecting antibodies ranged from 48 to 94% after PCR-confirmed infection and from 56% to 100% relative to positivity in the in-house live-virus NT. Furthermore, we performed receiver operating characteristic (ROC) curve analyses to determine which immunoassays were most suitable for assessing nAb titers exceeding a specific cutoff (NT titer, ≥80) and found that the NeutraLISA and the cPass assays reached the highest area under the curve (AUC), exceeding 0.91. In addition, when the assays were compared for their correlation with nAb kinetics over time in a set of longitudinal samples, the extent of the measured decrease of nAbs after infection varied widely among the evaluated immunoassays. Finally, in vaccinated convalescent patients, high titers of nAbs exceeded the upper limit of the evaluated assays' quantification ranges. Based on data from this study, we conclude that commercial immunoassays are acceptable substitutes for live-virus NTs, particularly when additional adapted cutoffs are employed to detect nAbs beyond a specific threshold titer. IMPORTANCE While the measurement of neutralizing antibodies is considered a valuable tool in assessing protection against SARS-CoV-2, neutralization tests employ live-virus isolates and cell culture, requiring advanced laboratory biosafety levels. Including a large sample panel (over 700 samples), this study provides adapted cutoff values calculated for seven commercial immunoassays (including four surrogate neutralization assays and a protein-based microarray) that robustly correlate with specific titers of neutralizing antibodies.

Sample Buffer Containing Guanidine-Hydrochloride Combines Biological Safety and RNA Preservation for SARS-CoV-2 Molecular Diagnostics

The COVID-19 pandemic has elicited the need to analyse and store large amounts of infectious samples for laboratory diagnostics. Therefore, there has been a demand for sample storage buffers that effectively inactivate infectious viral particles while simultaneously preserving the viral RNA. Here, we present a storage buffer containing guanidine-hydrochloride that fulfils both requirements. Its ability to preserve RNA stability was confirmed by RT-qPCR, and virus-inactivating properties were tested by tissue culture infectious dose assay. Our data revealed that RNA from samples diluted in this storage buffer was efficiently preserved. Spiking samples with RNase A resulted in RNAse concentrations up to 100 ng/mL being efficiently inhibited, whereas spiking samples with infectious SARS-CoV-2 particles demonstrated rapid virus inactivation. In addition, our buffer demonstrated good compatibility with several commercially available RNA extraction platforms. The presented guanidine-hydrochloride-based storage buffer efficiently inactivates infectious SARS-CoV-2 particles and supports viral RNA stability, leading to a reduced infection risk during sample analysis and an increased period for follow-up analysis, such as sequencing for virus variants. Because the presented buffer is uncomplicated to manufacture and compatible with a variety of commercially available test systems, its application can support and improve SARS-CoV-2 laboratory diagnostics worldwide.

Persistence of Naturally Acquired and Functional SARS-CoV-2 Antibodies in Blood Donors One Year after Infection

The developmental course of antibodies produced after a SARS-CoV-2 infection has been insufficiently investigated so far. Therefore, the aim of this study was to investigate the dynamics of SARS-CoV-2 antibody levels against the viral nucleocapsid- and spike-protein among Austrian blood donors as a representative group of a supposedly healthy population within the first year after a SARS-CoV-2 infection. The impact of age, sex, vaccination status, AB0-blood group and awareness about the infection was evaluated. Our study shows that the level of anti-N antibodies is declining, while anti-S antibody levels remain stable. Antibodies detected were functional in vitro. Age, sex and blood group do not influence antibody dynamics. However, blood group AB shows significantly lower antibody levels and in vitro functionality compared to other blood groups. Our data reveal that one out of five individuals was not aware of a previous SARS-CoV-2 infection and that the disease course neither affects the level of antibody production nor the in vitro functionality. We also found that 14% of participants show persisting COVID-19-related symptoms for up to nine months. Our results provide valuable insights into the dynamics of the immune response after a SARS-CoV-2 infection in a representative cohort of adult blood donors in Central Europe.

Adjunctive treatment with high-titre convalescent plasma in severely and critically ill COVID-19 patients - a safe but futile intervention. A comparative cohort study

Background

Convalescent plasma (CP) containing antibodies derived from coronavirus disease 2019 (COVID-19) survivors has been proposed as a promising therapeutic option for severe COVID-19.

Methods

In our intensive care unit (ICU), 55 patients (46 male, median age 61 years) with PCR-confirmed COVID-19 (35 = 63.6% on mechanical ventilation, 7 = 14.5% on high-flow nasal oxygen, 12 = 20% on non-invasive ventilation, 1 = 1.8% without respiratory support) were treated with high-titre CP (200 mL per dose, range 1–6 doses, median 3 doses per patient, minimum titre > 1:100, Wantai test). 139 COVID-19 patients treated in the same ICU who did not receive CP served as control group. In 27 patients, the effect of CP on the individual levels of SARS-CoV-2 IgG antibodies was assessed by ELISA in serum sample pairs collected before and after CP transfusion.

Results

The first CP dose was administered at a median of 8 days after symptom onset. 13 patients in the plasma cohort died (28-day mortality 24.1%), compared to 42 (30.2%) in the cohort who did not receive CP (p = 0.5, Pearson Chi-squared test). Out of the 27 individuals investigated for the presence of IgG antibodies, 8 did not have detectable IgG levels before the first CP transfusion. In this subpopulation, 3 patients (37.5%) died. Not a single confirmed adverse reaction to CP was noted.

Conclusions

While adjunctive treatment with CP for severe and life-threatening COVID-19 was a very safe intervention, we did not observe any effect on mortality.

Jknull alleles in two patients with anti-Jk3

BACKGROUND

As of publication, a total of 41 null alleles have been acknowledged by the International Society of Blood Transfusion (ISBT) to cause the rare Jknull phenotype, but none have been discovered in Austria thus far.

MATERIALS AND METHODS

Two patients with anti-Jk3 were serologically identified by a positive antibody screening and typed as Jk(a-b-). The initial genotyping using an SSP-PCR method for the common 838A/G polymorphism indicated a JK*02/02, or JK*01/02 genotype, respectively. To find the disruptive mutations, Sanger sequencing was performed and results were compared to the reference sequence. The patient's antibodies were characterized with a monocyte monolayer assay (MMA) for their potential clinical significance.

RESULTS

Three novel null-mutations of the SLC14A1 gene were found in two patients. Patient 1 was homozygous for a 10bp deletion in exon 4 (c.157_166del on JK*02). Testing of her family members revealed Mendelian inheritance of the deletional allele. The other patient was compound heterozygous for two mutations: one allele carrying a single base deletion in exon 4 (c.267delC on JK*01) and the other a splice site mutation in intron 3 (c.152-1g>a on JK*02). The MMA results suggest high clinical significance of the anti-Jk3 in both patients.

DISCUSSION

The detected mutations led to Jknull phenotypes and are the first description of JKnull alleles in the Austrian population.

Characterization of 100 sequential SARS-CoV-2 convalescent plasma donations

Background

Transfusion of severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2) convalescent plasma is a promising treatment for severe coronavirus disease 2019 (COVID‐19) cases, with success of the intervention based on neutralizing antibody content. Measurement by serologic correlates without biocontainment needs as well as an understanding of donor characteristics that may allow for targeting of more potent donors would greatly facilitate effective collection.

Study Design and Methods

One hundred convalescent plasma units were characterized for functionally active SARS‐CoV‐2 neutralizing antibodies, as well as for SARS‐CoV‐2 binding antibodies, with the intention to establish a correlation between the functionally more relevant neutralization assay and the more accessible enzyme‐linked immunosorbent assay (ELISA). Donor demographics such as COVID‐19 severity, age, and sex were correlated with antibody titers.

Results

A mean neutralization titer 50% of 230 (range, <8‐1765) was seen for the 100 convalescent plasma units, with highly significant (P < .0001) yet quantitatively limited (R² = 0.2830) correlation with results of the ELISA. Exclusion of units with particularly high titers (>500) from analysis improved correlation (R² = 0.5386). A tendency of higher‐titer plasma units from donors with increased disease severity, of advanced age, and of male sex was seen, yet the functional relevance of this difference is questionable.

Conclusion

The ELISA‐based correlation to neutralization titer enabled a threshold proposal that could be used to eliminate lower‐titer units from the clinical supply for COVID‐19 treatment. Disease severity may be associated with the development of higher titers of neutralizing antibodies, although larger case numbers will be needed for additional confirmation.

Leukocyte-Reactive Antibodies in Female Blood Donors: The Austrian Experience

Introduction

Antibody-mediated transfusion-related acute lung injury (TRALI) is caused by antibodies against human leukocyte antigens (HLAs) or human neutrophil antigens (HNAs), and is one of the most serious complications associated with transfusion medicine. Prevention strategies like testing allo-exposed female blood donors have not yet been introduced nationwide in Austria. To assess the need and feasibility of routine leukocyte antibody testing, the prevalence of leukocyte-reactive antibodies in an Austrian female donor population was been determined using classical cell-based methods which were compared with a high-throughput bead-based method.

Methods

Sera from 1,022 female blood donors were screened using a granulocyte aggregation test (GAT) and a white blood cell immunofluorescence test (WIFT) after retesting and specification of positive samples by granulocyte immunofluorescence test (GIFT) and monoclonal antibody-specific immobilization of granulocyte antigens (MAIGA). Potential HLA reactivities were confirmed using the microbeads assay LabScreen^TM Mixed. The results in 142 donor sera and 38 well-defined reference sera were investigated by the microbeads assay LabScreen^TM Multi and compared with classical cell-based methods.

Results

Reactivity with either granulocytes and/or lymphocytes was detected in 79 sera (7.7%), with the majority being HLA-specific. Antibodies against HNA were obtained in 7 samples (0.7%). The aggregating potential of the detected antibodies was observed in 9 cases (0.9%). Most of the leukocyte-reactive antibodies occurred at a donor age of between 35 and 59 years (n = 61). LabScreen Multi showed good agreement (κ = 0.767) for HNA antibody detection by cell-based assays, but double/multiple specificities (100% of 7 anti-HNA-1b sera) as well as false-negative results (40% of 15 HNA-3-specific sera) occurred.

Discussion

Leukocyte-reactive antibody screening is advised in Austrian female donors for safe blood transfusion, including single-donor convalescent plasma treatment of COVID-19 that may be implemented soon. For the introduction of LabScreen Multi, the combination with GAT should be considered to ensure correct anti-HNA-3a detection.

Increase in human West Nile and Usutu virus infections, Austria, 2018

Between 28 June and 17 September 2018, 27 cases of human West Nile virus infections were recorded in Austria; four cases of West Nile neuroinvasive disease, 11 cases of West Nile fever, six infections detected by blood donation screening and six imported cases. In addition, 18 cases of human Usutu virus infections (all blood donors) were recorded. This is the highest number of annual infections recorded in Austria since the introduction of both viruses.

When Yawning Occurs in Elephants

Yawning is a widely recognized behavior in mammalian species. One would expect that elephants yawn, although to our knowledge, no one has reported observations of yawning in any species of elephant. After confirming a behavioral pattern matching the criteria of yawning in two Asian elephants (Elephas maximus) in a zoological setting, this study was pursued with nine captive African elephants (Loxodonta africana) at a private reserve in the Western Cape, South Africa, the Knysna Elephant Park. Observations were made in June–September and in December. In the daytime, handlers managed seven of the elephants for guided interactions with visitors. At night, all elephants were maintained in a large enclosure with six having limited outdoor access. With infrared illumination, the elephants were continuously recorded by video cameras. During the nights, the elephants typically had 1–3 recumbent sleeping/resting bouts, each lasting 1–2 h. Yawning was a regular occurrence upon arousal from a recumbency, especially in the final recumbency of the night. Yawning was significantly more frequent in some elephants. Yawning was rare during the daytime and during periods of standing around in the enclosure at night. In six occurrences of likely contagious yawning, one elephant yawned upon seeing another elephant yawning upon arousal from a final recumbency; we recorded the sex and age category of the participants. The generality of yawning in both African and Asian elephants in other environments was documented in video recordings from 39 zoological facilities. In summary, the study provides evidence that yawning does occur in both African and Asian elephants, and in African elephants, yawning was particularly associated with arousal from nighttime recumbencies.

Phase II trial of fludarabine phosphate for adenocarcinoma of the pancreas. An Illinois Cancer Center study

We have conducted a phase II trial of fludarabine phosphate for advanced measurable adenocarcinoma of the pancreas. The drug was administered every 4 weeks by a daily-times-5 bolus schedule beginning at 20 mg/m2/day. No responses were observed in 20 evaluable patients, 18 of whom were previously untreated. Dose-limiting toxicity was leukopenia, and gastroenterologic side effects were frequent. Life-threatening or fatal renal dysfunction occurred in 3 patients. In this schedule fludarabine phosphate is ineffective against adenocarcinoma of the pancreas and appears to have unpredictable severe renal toxicity.

Evaluation of homoharringtonine efficacy in the treatment of squamous cell carcinoma of the head and neck: a phase II Illinois Cancer Council Study

Eighteen patients entered this study of the efficacy of homoharringtonine (HHT) treatment in advanced squamous cell carcinoma of the head and neck (SCCHN). Seventeen eligible patients received at least one day of the first 5-day cycle of HHT (4.0 mg/m2/day) by continuous IV infusion. Cycles were scheduled to repeat every 28 days. The major severe toxicities encountered were hypotension and myelosuppression. There was one drug-related death. Fourteen patients were evaluable for response, and no patient exhibited an objective response to treatment with HHT.

Serum concentrations of ampicillin and probenecid and ampicillin excretion after repeated oral administration of a pivampicillin-probenecid salt (MK-356)

Twenty male volunteers received oral doses (2100, 1050, and 525 mg) of a pivampicillin-probenecid salt in a 1 to 1 molar ratio (MK-356) at 12 hour intervals. After each dose peak serum concentrations of probenecid were observed 2 hours later than peak concentrations of ampicillin. Following the first dose of MK-356 the apparent elimination rate of ampicillin was dose-dependent and did not follow first order kinetics, as it showed a longer apparent half life after a higher dose. An equal dose of MK-356 administered 12 hours later caused an increase in the peak serum ampicillin level greater than expected from the concentration of ampicillin after the preceding dose. In twelve male volunteers who received at random 525 mg of MK-356 or 350 mg of pivampicillin, each three times daily for 4 days, the areas under the ampicillin concentration curve were the same after the first or last dose of either drug. When 2100 or 1050 mg of MK-356 was taken as an initial dose, 30 to 40 per cent of the ampicillin was recovered from urine in the ensuing 12 hours. The results indicate that when at least 400 mg probenecid was coadministered twice daily with 700 mg pivampicillin (MK-356), the peak serum concentrations of ampicillin were increased and its elimination rate slowed following successive doses.

Effect of treadmill exercise testing on serum enzymes and the resting electrocardiogram

Fifty-three adult male patients with chest pain underwent treadmill exercise stress testing according to the Bruce protocol. The resting 12-lead electrocardiogram (ECG) and serum concentrations of glutamic oxaloacetic transaminase, lactic dehydrogenase creatine phosphokinase and alpha-hydroxybutyrate dehydrogenase were evaluated before, and at 1 and 20 hours after exercise. Twenty-eight subjects (53 percent) had a normal test result, 10 (19 percent) had ischemic ST -segment changes and anginal pain, and 15 (28 percent) were considered to have equivocal results because of an abnormal baseline ECG or the concurrent administration of cardioactive medication. In contrast to earlier reports, no significant changes in the serum enzyme values were seen in any of the three groups orin any individual subject, nor were ECG changes detected after recovery from exercise. The diagnostic evaluation of the exercise ECG must depend upon the demonstration of ischemic ST -segment changes and not upon changes in concentrations of serum enzymes.

Electron-capture GLC determination of a new antiarrhythmic agent, alpha,alpha-dimethyl-4-(alpha,alpha,beta,beta-tetrafluorophenethyl) benzylamine, in biological fluids

A highly specific and sensitive GLC method was developed for the analysis of alpha,alpha-dimethyl-4-(alpha,alpha,beta,beta-tetrafluorophenethyl) benzylamine, a new orally active antiarrhythmic drug, in biological fluids. The procedure involves the addition of an internal standard, 4-(alpha,alpha,beta,beta-tetrafluorophenethyl)benzylamine, to the plasma or urine samples followed by extraction of the drugs into benzene at pH 8. The extracted amines are converted to the trifluoroacetyl derivatives (characterized by GLG-mass spectrometry), chromatographed, and detected with a 63Ni electron-capture detector. The sensitivity of the method is such that 10 ng of alpha,alpha-dimethyl-4-(alpha,alpha,beta,beta-tetrafluorophenethyl)benzylamine/ml of plasma can be analyzed. These levels are suitable for the analysis of samples obtained following a therapeutic dose.