A common allele of HLA is associated with asymptomatic SARS-CoV-2 infection

Studies have demonstrated that at least 20% of individuals infected with SARS-CoV-2 remain asymptomatic1-4. Although most global efforts have focused on severe illness in COVID-19, examining asymptomatic infection provides a unique opportunity to consider early immunological features that promote rapid viral clearance. Here, postulating that variation in the human leukocyte antigen (HLA) loci may underly processes mediating asymptomatic infection, we enrolled 29,947 individuals, for whom high-resolution HLA genotyping data were available, in a smartphone-based study designed to track COVID-19 symptoms and outcomes. Our discovery cohort (n = 1,428) comprised unvaccinated individuals who reported a positive test result for SARS-CoV-2. We tested for association of five HLA loci with disease course and identified a strong association between HLA-B*15:01 and asymptomatic infection, observed in two independent cohorts. Suggesting that this genetic association is due to pre-existing T cell immunity, we show that T cells from pre-pandemic samples from individuals carrying HLA-B*15:01 were reactive to the immunodominant SARS-CoV-2 S-derived peptide NQKLIANQF. The majority of the reactive T cells displayed a memory phenotype, were highly polyfunctional and were cross-reactive to a peptide derived from seasonal coronaviruses. The crystal structure of HLA-B*15:01-peptide complexes demonstrates that the peptides NQKLIANQF and NQKLIANAF (from OC43-CoV and HKU1-CoV) share a similar ability to be stabilized and presented by HLA-B*15:01. Finally, we show that the structural similarity of the peptides underpins T cell cross-reactivity of high-affinity public T cell receptors, providing the molecular basis for HLA-B*15:01-mediated pre-existing immunity.

Factors Influencing ADME Properties of Therapeutic Antisense Oligonucleotides: Physicochemical Characteristics and Beyond

Therapeutic antisense oligonucleotides (ASOs) represent a diverse array of chemically modified singlestranded deoxyribonucleotides that work complementarily to affect their mRNA targets. They vastly differ from conventional small molecules. These newly developed therapeutic ASOs possess unique absorption, distribution, metabolism, and excretion (ADME) processes that ultimately determine their pharmacokinetic, efficacy and safety profiles. The ADME properties of ASOs and associated key factors have not been fully investigated. Therefore, thorough characterization and in-depth study of their ADME properties are critical to support drug discovery and development processes for safe and effective therapeutic ASOs. In this review, we discussed the main factors affecting the ADME characteristics of these novels and evolving therapies. The major changes to ASO backbone and sugar chemistry, conjugation approaches, sites and routes of administration, etc., are the principal determinants of ADME and PK profiles that consequentially impact their efficacy and safety profiles. In addition, species difference and DDI considerations are important in understanding ADME profile and PK translatability but are less studied for ASOs. We, therefore, have summarized these aspects based on current knowledge and provided discussions in this review. We also give an overview of the current tools, technologies, and approaches available to investigate key factors that influence the ADME of ASO drugs and provide future perspectives and knowledge gap analysis.

Detection of IgM, IgG, IgA and neutralizing antibody responses to SARS-CoV-2 infection and mRNA vaccination

Introduction. One correlate of immunity for coronavirus disease 2019 (COVID-19) is the laboratory detection of anti-severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) antibodies. These tests are widely implemented for clinical, public health, or research uses.Hypothesis/Gap Statement. Antibody responses by all classes of immunoglobulins may form from infection and vaccination, but few studies have performed direct head-to-head comparisons between these groups.Aim. The objective of this study was to evaluate the serological responses in natural SARS-CoV-2 infection and mRNA-based vaccination across multiple immunoglobulin classes and a surrogate neutralizing antibody (NAb) assay.Methodology. A suite of enzyme-linked immunosorbent assays (ELISAs) was used to qualitatively assess IgA, IgM and IgG positivity and neutralizing per cent signal inhibition of sera from RT-PCR-confirmed SARS-CoV-2-infected patients, COVID-19-immunized individuals ≥2 weeks after a second dose of mRNA vaccine and a set of pre-pandemic negative samples.Results. For confirmed SARS-CoV-2 infections, seroconversion of IgA, IgM, IgG and NAb increased by week after symptom onset, with positivity reaching 100 % after the third week for every immunoglobulin class. Vaccinated individuals demonstrated 100 % IgG positivity and high per cent signal inhibition by NAb, comparable to natural infection. High specificity, ranging from 96.7-98.9 %, was observed for each assay from a set of pre-pandemic COVID-19-negative samples.Conclusion. We make use of a comprehensive and readily adoptable suite of serological assays to provide data on the humoral immune response to SARS-CoV-2 infection and vaccination. We found that infection and vaccination both elicit robust IgG, IgM, IgA and neutralizing antibody responses.

Development and application of a High-Resolution mass spectrometry method for the detection of fentanyl analogs in urine and serum

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Utilization of the fentanyl analog screening kit from the Centers for Disease ControlDevelopment of a fentanyl analog high resolution mass spectrometry library.

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Fentanyl analogs are rarely identified without the co-occurrence of fentanyl.

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Fentanyl analogs fragmentation occurs at two specific bonds generating two dominate ions.

Introduction

The use of illicitly manufactured synthetic opioids, specifically fentanyl and its analogs, has escalated exponentially in the United States over the last decade. Due to the targeted nature of drug detection methods in clinical laboratories and the ever-evolving list of synthetic opioids of concern, alternative analytical approaches are needed.

Methods

Using the fentanyl analog screening (FAS) kit produced by the Centers for Disease Control and Prevention (CDC), we developed a liquid chromatography-high resolution mass spectrometry (LC-HRMS) synthetic opioid spectral library and data acquisition method using information dependent acquisition of product ion spectra. Chromatographic retention times, limits of detection and matrix effects, in urine and serum, for the synthetic opioids in the FAS kit (n = 150) were established. All urine and serum specimens sent to a clinical toxicology laboratory for comprehensive drug testing in 2019 (n = 856) and 2021 (n = 878) were analyzed with the FAS LC-HRMS library to determine the prevalence of fentanyl analogs and other synthetic opioids, retrospectively (2019) and prospectively (2021).

Results

The limit of detection (LOD) of each opioid ranged from 1 to 10 ng/mL (median, 2.5 ng/mL) in urine and 0.25–2.5 ng/mL (median, 0.5 ng/mL) in serum. Matrix effects ranged from −79 % to 86 % (median, −37 %) for urine, following dilution and direct analysis, and −80 % to 400 % (median, 0 %) for serum, following protein precipitation. The prevalence of fentanyl/fentanyl analogs in serum samples increased slightly from 2019 to 2021 while it remained the same in urine. There were only 2 samples identified that contained a fentanyl analog without the co-occurrence of fentanyl or fentanyl metabolites. Analysis of the established MS/MS spectral library revealed characteristic fragmentation patterns in most fentanyl analogs, which can be used for structure elucidation and drug identification of future analogs.

Conclusions

The LC-HRMS method was capable of detecting fentanyl analogs in routine samples sent for comprehensive drug testing. The method can be adapted to accommodate testing needs for the evolving opioid epidemic.

A common allele of HLA mediates asymptomatic SARS-CoV-2 infection

Despite some inconsistent reporting of symptoms, studies have demonstrated that at least 20% of individuals infected with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) will remain asymptomatic. Although most global efforts have focused on understanding factors underlying severe illness in COVID-19 (coronavirus disease of 2019), the examination of asymptomatic infection provides a unique opportunity to consider early disease and immunologic features promoting rapid viral clearance. Owing to its critical role in the immune response, we postulated that variation in the human leukocyte antigen (HLA) loci may underly processes mediating asymptomatic infection. We enrolled 29,947 individuals registered in the National Marrow Donor Program for whom high-resolution HLA genotyping data were available in the UCSF Citizen Science smartphone-based study designed to track COVID-19 symptoms and outcomes. Our discovery cohort (n=1428) was comprised of unvaccinated, self-identified subjects who reported a positive test result for SARS-CoV-2. We tested for association of five HLA loci (HLA-A, -B, -C, -DRB1, -DQB1) with disease course and identified a strong association of HLA-B*15:01 with asymptomatic infection, and reproduced this association in two independent cohorts. Suggesting that this genetic association is due to pre-existing T-cell immunity, we show that T cells from pre-pandemic individuals carrying HLA-B*15:01 were reactive to the immunodominant SARS-CoV-2 S-derived peptide NQKLIANQF, and 100% of the reactive cells displayed memory phenotype. Finally, we characterize the protein structure of HLA-B*15:01-peptide complexes, demonstrating that the NQKLIANQF peptide from SARS-CoV-2, and the highly homologous NQKLIANAF from seasonal coronaviruses OC43-CoV and HKU1-CoV, share similar ability to be stabilized and presented by HLA-B*15:01, providing the molecular basis for T-cell cross-reactivity and HLA-B*15:01-mediated pre-existing immunity.

The Pharmacokinetics of Ketamine in the Breast Milk of Lactating Women: Quantification of Ketamine and Metabolites

Ketamine is a general anesthetic with over 50 years of safe administration that is in increasing use for psychiatric indications. This is evidenced by the recent FDA approval of intranasal esketamine (the S-enantiomer) for the treatment of depression. With respect to ketamine and lactation, incredibly there are no available data on the secretion of ketamine or its metabolites in human breast milk. This information is essential to guide the use of ketamine in breastfeeding women who suffer with postpartum emotional disorders, ongoing depression, PTSD, and more. To address this unmet need, we conducted a pharmacokinetic analysis of the presence of ketamine and several of its major metabolites (norketamine, dehydronorketamine, and hydroxynorketamine isomers) in four women receiving two different intramuscular doses of ketamine - 0.5 mg/kg and 1.0 mg/kg. Our results demonstrate low and rapidly declining levels of ketamine and metabolites in breast milk during the 12-hour post-dosing period. The mean relative infant dose (RID) obtained from AUC estimates for the 0.5 and 1.0 mg/kg doses were 0.650% and 0.766%, respectively. This provides the foundation for studying the use of ketamine during the post-partum period.

Development of a high-throughput differential mobility separation-tandem mass spectrometry (DMS-MS/MS) method for clinical urine drug testing

INTRODUCTION

Differential mobility separation (DMS) is an analytical technique used for rapid separation of ions and isomers based on gas phase mobility prior to entering a mass spectrometer for analysis. The entire DMS process is accomplished in fewer than 20 ms and can be used as a rapid alternative to chromatographic separation.

OBJECTIVE

The primary objective was to evaluate the utility of DMS-tandem mass spectrometry (DMS-MS/MS) as a replacement for immunoassay-based clinical toxicology testing.

METHODS

A sensitive DMS-MS/MS method was developed and validated for simultaneous identification of 33 drugs and metabolites in human urine samples. After DMS optimization, the method was validated and used to screen 56 clinical urine samples. These results were compared to results obtained by immunoassay.

RESULTS

The DMS-MS/MS method achieved limits of detection ranging from 5 to 100 ng/mL. Moreover, the total analysis time was 2 min per sample. For the method performance evaluation, DMS-MS/MS results were compared with previously obtained urine toxicology immunoassay results. DMS-MS/MS showed higher sensitivity and identified 20% more drugs in urine, which were confirmed by LC-MS/MS.

CONCLUSION

The DMS-MS/MS as applied in our lab demonstrated the capability for rapid drug screening and provided better analytical performance than immunoassay.

Diagnostic Value of Nucleocapsid Protein in Blood for SARS-CoV-2 Infection

BACKGROUND

Biomarkers have been widely explored for coronavirus disease 2019 diagnosis. Both viral RNA or antigens (Ag) in the respiratory system and antibodies (Ab) in blood are used to identify active infection, transmission risk, and immune response but have limitations. This study investigated the diagnostic utility of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) nucleocapsid protein (N-Ag) in serum.

METHODS

We retrospectively studied 208 randomly selected cases with SARS-CoV-2 infection confirmed by viral RNA test in swabs. N-Ag concentrations were measured in remnant serum samples, compared to viral RNA or Ab results, and correlated to electronic health records for clinical value evaluation.

RESULTS

Serum N-Ag was detected during active infection as early as day 2 from symptom onset with a diagnostic sensitivity of 81.5%. Within 1 week of symptom onset, the diagnostic sensitivity and specificity reached 90.9% (95% CI, 85.1%-94.6%) and 98.3% (95% CI, 91.1%-99.9%), respectively. Moreover, serum N-Ag concentration closely correlated to disease severity, reflected by highest level of care, medical interventions, chest imaging, and the length of hospital stays. Longitudinal analysis revealed the simultaneous increase of Abs and decline of N-Ag.

CONCLUSIONS

Serum N-Ag is a biomarker for SARS-CoV-2 acute infection with high diagnostic sensitivity and specificity compared to viral RNA in the respiratory system. There is a correlation between serum N-Ag concentrations and disease severity and an inverse relationship of N-Ag and Abs. The diagnostic value of serum N-Ag, as well as technical and practical advantages it could offer, may meet unsatisfied diagnostic and prognostic needs during the pandemic.

Differences in Post-mRNA Vaccination Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) Immunoglobulin G (IgG) Concentrations and Surrogate Virus Neutralization Test Response by Human Immunodeficiency Virus (HIV) Status and Type of Vaccine: A Matched Case-Control Observational Study

Following severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) mRNA vaccination, people living with human immunodeficiency virus (HIV, PLWH) had lower surrogate virus neutralization test response (P = .03) and a trend toward lower immunoglobulin G (IgG) response (P = .08), particularly among those with lower CD4+ T-cell counts and who received the BNT162b2 vaccine. Study of the impact of supplemental vaccine doses among PLWH is needed.

LB8. Lower SARS-CoV-2 IgG and Pseudovirus Neutralization Titers Post-mRNA Vaccination among People Living with HIV

Background

Limited data are available on whether there are differences in the immune response to SARS-CoV-2 vaccination by HIV status or by mRNA vaccine type.

Methods

We saved residual outpatient laboratory samples of all previously mRNA-vaccinated individuals in the adult medicine clinics of a public hospital with a large outpatient HIV clinic during May 2021, and then excluded individuals with prior SARS-CoV-2 infection. We next 1:1 matched 100 PLWH to 100 outpatient HIV-negative adult medicine patients receiving care for chronic medical conditions on days since completion of second vaccination (minimum 10), sex, age +/-5 years, and the type of mRNA vaccine received. We defined a non-response as reciprocal pseudovirus neutralizing titer< 10 and anti-RBD IgG< 10 relative fluorescent units, and compared non-response by HIV status using mixed models.

Results

In each matched group there were 13 women; 25 received the mRNA-1273 vaccine and 75 received the BNT162b2 vaccine; the median age was 59. The median time from second vaccination was 35 days (IQR: 20–63). Among PLWH, the median CD4+ T-cell count was 511 (IQR: 351–796) and 5 individuals had HIV RNA > 200.

We found 2.4-fold greater odds of pseudovirus neutralizing antibody non-response among PLWH compared to people without HIV (95% CI=1.1–5.4). Although few individuals in each group did not mount an IgG response (12 among PLWH vs. 5; p=0.08), continuous anti-RBD IgG concentrations were 43% lower among PLWH (95% CI=0.36–0.88).

Among PLWH, when adjusting for age, sex, and days post-vaccination, each 100-cell increase in CD4+T-cell count was associated with 22% higher neutralizing antibody titers (GMR 1.22; 95% CI=1.09–1.37). Unsuppressed HIV RNA >200 was associated with 89% lower neutralizing antibody titers (GMR 0.11; 95% CI=0.01–0.84). Receipt of the BNT162b2 vs. mRNA-1273 vaccine was associated with 77% lower neutralizing titers (GMR 0.23; 95% CI=0.08–0.65) among PLWH.

Post-mRNA Vaccination SARS-CoV-2 IgG Concentrations and Pseudovirus Neutralizing Titers by HIV Status and Vaccine

Conclusion

PLWH had lower than expected response to mRNA SARS-CoV-2 vaccines, with the highest non-response among those with low CD4+ counts, unsuppressed HIV RNA, and those who received the BNT162b2 vaccine. Immunization strategies to improve immune responses among PLWH should be studied, and may include booster vaccination or preference of the mRNA-1273 vaccine in this group.

Disclosures

Matthew A. Spinelli, MD, MAS, Nothing to disclose Monica Gandhi, MD, MPH, Nothing to disclose

Longitudinal Study of SARS-CoV-2 Antibody Characteristics Using Label-Free Immunoassays

Introduction/Objective

Since the start of the COVID-19 pandemic, much research has focused on the kinetics and magnitude of humoral immune response. With the advantages of monitoring real-time immunoreactions, label-free immunoassay (LFIA) is becoming a powerful tool in serology studies. We have developed LFIAs to measure SARS- CoV-2 antibody avidity and neutralization activity in a cohort of COVID-19 patients and determine if they correlate with antibody concentration. Serial serum samples collected from mild to severe COVID-19 patients were measured out to 8 months post-symptom onset to determine the durability of the neutralizing antibody response.

Methods/Case Report

Based on thin-film interferometry technology, we established a label-free IgG avidity assay and a label-free surrogate virus neutralization test (LF-sVNT). For measurement, sensing probes pre-coated with receptor-binding domain (RBD) of SARS-CoV-2 spike protein are applied to serum samples containing SARS-CoV-2 antibodies. The label-free IgG avidity assay measures the binding strength between RBD and IgG under urea dissociation. The LF-sVNT analyzes the binding ability of RBD to ACE2 after neutralizing RBD with antibodies.

Results (if a Case Study enter NA)

IgG avidity indices and neutralizing antibody titers (IC50) were determined from serum samples (n=246) from COVID-19 patients (n=113). IgG concentrations were measured using a fluorescent immunoassay. The neutralizing antibody titers showed a weak correlation with IgG concentrations and no correlation with IgG avidity indices. Over the time course up to 8 months post-symptom onset, IgG concentrations and neutralizing antibody titers presented similar trends: an initial rise, plateau and then in some cases a gradual decline after 40 days. The IgG avidity indices, in the same cases, plateaued after the initial rise.

Conclusion

The results demonstrated that LFIA could be used an excellent solution in the determination of SARS- CoV-2 antibody characteristics. The study found that IgG concentration and neutralizing antibody titer declined over time, while IgG avidity index remained constant after reaching a plateau. The decline of antibody neutralization activity can be attributed to the reduction in antibody quantity rather than the deterioration of antibody quality, as measured by antibody avidity.

Type I interferon autoantibodies are associated with systemic immune alterations in patients with COVID-19

Neutralizing autoantibodies against type I interferons (IFNs) have been found in some patients with critical coronavirus disease 2019 (COVID-19), the disease caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). However, the prevalence of these antibodies, their longitudinal dynamics across the disease severity scale, and their functional effects on circulating leukocytes remain unknown. Here, in 284 patients with COVID-19, we found type I IFN–specific autoantibodies in peripheral blood samples from 19% of patients with critical disease and 6% of patients with severe disease. We found no type I IFN autoantibodies in individuals with moderate disease. Longitudinal profiling of over 600,000 peripheral blood mononuclear cells using multiplexed single-cell epitope and transcriptome sequencing from 54 patients with COVID-19 and 26 non–COVID-19 controls revealed a lack of type I IFN–stimulated gene (ISG-I) responses in myeloid cells from patients with critical disease. This was especially evident in dendritic cell populations isolated from patients with critical disease producing type I IFN–specific autoantibodies. Moreover, we found elevated expression of the inhibitory receptor leukocyte-associated immunoglobulin-like receptor 1 (LAIR1) on the surface of monocytes isolated from patients with critical disease early in the disease course. LAIR1 expression is inversely correlated with ISG-I expression response in patients with COVID-19 but is not expressed in healthy controls. The deficient ISG-I response observed in patients with critical COVID-19 with and without type I IFN–specific autoantibodies supports a unifying model for disease pathogenesis involving ISG-I suppression through convergent mechanisms.

Micromagnetic simulation of microstructure effect for binary-main-phase Nd-Ce-Fe-B magnets

We investigate the magnetic properties of a chemically heterogeneous binary-main-phase (BMP) Nd-Ce-Fe-B magnet with a core-shell structure via micromagnetic simulation. It is found that the coercivity strongly depends on the shell thickness. The BMP magnet's coercivity initially increases and then decreases with increasing Nd-rich shell thickness, and so there is the optimal shell thickness which shows the maximum coercivity for any given Ce concentration. The simulation shows the significant difference in coercivity and maximum energy product between the BMP and single-main-phase magnets. Notably, the magnetization reversal mechanism of the BMP magnet is revealed in the simulation. Local reversals in the BMP magnet first occur in the Ce-rich shells, followed by the Nd-rich cores. Then, the magnetization in Ce-rich core/Nd-rich shell typed grains is switched after reversed magnetization of all the Nd-rich core/Ce-rich shell typed grains. The BMP magnet represents a further increased coercivity for a larger GB thickness, which can be well explained by a maximum stray field.

Discordant Virus-Specific Antibody Levels, Antibody Neutralization Capacity, and T-cell Responses Following 3 Doses of SARS-CoV-2 Vaccination in a Patient With Connective Tissue Disease

We report a patient with connective tissue disease who developed modest severe acute respiratory syndrome coronavirus 2 receptor binding domain–specific antibody levels and a lack of neutralization capacity, despite having received 3 mRNA coronavirus disease 2019 vaccines and holding anti-B-cell therapy for >7 months before vaccination. The patient developed virus-specific T-cell responses.

Distinctive features of SARS-CoV-2-specific T cells predict recovery from severe COVID-19

Although T cells are likely players in severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) immunity, little is known about the phenotypic features of SARS-CoV-2-specific T cells associated with recovery from severe coronavirus disease 2019 (COVID-19). We analyze T cells from 34 individuals with COVID-19 with severity ranging from mild (outpatient) to critical, culminating in death. Relative to individuals who succumbed, individuals who recovered from severe COVID-19 harbor elevated and increasing numbers of SARS-CoV-2-specific T cells capable of homeostatic proliferation. In contrast, fatal COVID-19 cases display elevated numbers of SARS-CoV-2-specific regulatory T cells and a time-dependent escalation in activated bystander CXCR4+ T cells, as assessed by longitudinal sampling. Together with the demonstration of increased proportions of inflammatory CXCR4+ T cells in the lungs of individuals with severe COVID-19, these results support a model where lung-homing T cells activated through bystander effects contribute to immunopathology, whereas a robust, non-suppressive SARS-CoV-2-specific T cell response limits pathogenesis and promotes recovery from severe COVID-19.

A SARS-CoV-2 Label-Free Surrogate Virus Neutralization Test and a Longitudinal Study of Antibody Characteristics in COVID-19 Patients

Methods designed to measure severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) humoral response include virus neutralization tests to determine antibody neutralization activity. For ease of use and universal applicability, surrogate virus neutralization tests (sVNTs) based on antibody-mediated blockage of molecular interactions have been proposed. A surrogate virus neutralization test was established on a label-free immunoassay platform (LF-sVNT). The LF-sVNT analyzes the binding ability of SARS-CoV-2 spike protein receptor-binding domain (RBD) to angiotensin-converting enzyme 2 (ACE2) after neutralizing RBD with antibodies in serum. The LF-sVNT neutralizing antibody titers (50% inhibitory concentration [IC50]) were determined from serum samples (n = 246) from coronavirus disease 2019 (COVID-19) patients (n = 113), as well as the IgG concentrations and the IgG avidity indices. Although there was variability in the kinetics of the IgG concentrations and neutralizing antibody titers between individuals, there was an initial rise, plateau, and then in some cases a gradual decline at later time points after 40 days after symptom onset. The IgG avidity indices, in the same cases, plateaued after an initial rise and did not show a decline. The LF-sVNT can be a valuable tool in research and clinical laboratories for the assessment of the presence of neutralizing antibodies to COVID-19. This study is the first to provide longitudinal neutralizing antibody titers beyond 200 days post-symptom onset. Despite the decline of IgG concentration and neutralizing antibody titer, IgG avidity index increases, reaches a plateau, and then remains constant up to 8 months postinfection. The decline of antibody neutralization activity can be attributed to the reduction in antibody quantity rather than the deterioration of antibody quality, as measured by antibody avidity.

Evaluation of Biomarkers in Sepsis: High Dimethylarginine (ADMA and SDMA) Concentrations Are Associated with Mortality

BACKGROUND

As modulators of nitric oxide generation, asymmetric dimethylarginine (ADMA) and symmetric dimethylarginine (SDMA) may play important roles in sepsis. Current data on dimethylarginines are conflicting, and direct comparison data with other biomarkers are limited.

METHODS

Fifty-five patients were included in the final analysis and were divided into 4 groups: infection without sepsis, sepsis, severe sepsis, and septic shock. The first available samples on hospital admission were analyzed for ADMA, SDMA, procalcitonin (PCT), C-reactive protein, heparin binding protein (HBP), zonulin, soluble CD25 (sCD25), and soluble CD163 (sCD163). White blood cell (WBC) counts and lactate results were obtained from the medical record.

RESULTS

There were no statistically significant differences in ADMA and SDMA concentrations among the 4 groups; however, PCT, WBC, HBP, and sCD25 showed statistically significant differences. Lactate only trended toward statistical significance, likely because of limited availability in the medical record. Differences between survivors of sepsis and nonsurvivors at 30 days were highly statistically significant for ADMA and SDMA. Areas under the curve (AUCs) for ROC analysis were 0.88 and 0.95, respectively. There was also a statistically significant difference between survivors of sepsis and nonsurvivors for HBP, lactate, sCD25, and sCD163; however, AUCs for ROC curves were not statistically significantly different from 0.5.

CONCLUSIONS

Analysis of biomarkers other than dimethylarginines were in general agreement with expectations from the literature. ADMA and SDMA may not be specific markers for diagnosis of sepsis; however, they may be useful in short-term mortality risk assessment.

SARS-CoV-2 seroprevalence, and IgG concentration and pseudovirus neutralising antibody titres after infection, compared by HIV status: a matched case-control observational study

Background

Most cohorts show similar or lower COVID-19 incidence among people living with HIV compared with the general population. However, incidence might be affected by lower testing rates among vulnerable populations. We aimed to compare SARS-CoV-2 IgG seroprevalence, disease severity, and neutralising antibody activity after infection among people with and without HIV receiving care in a county hospital system over a 3-month period.

Methods

In this matched case-control observational study, remnant serum samples were collected between Aug 1 and Oct 31, 2020, from all people living with HIV who underwent routine outpatient laboratory testing in a municipal health-care system (San Francisco General Hospital, CA, USA). Samples from people living with HIV were date of collection-matched (same day) and age-matched (±5 years) to samples from randomly selected adults (aged 18 years or older) without HIV receiving care for chronic conditions at the same hospital. We compared seroprevalence by HIV status via mixed-effects logistic regression models, accounting for the matched structure of the data (random effects for the matched group), adjusting for age, sex, race or ethnicity, and clinical factors (ie, history of cardiovascular or pulmonary disease, and type 2 diabetes). Severe COVID-19 was assessed in participants with past SARS-CoV-2 (IgG or PCR) infection by chart review and compared with multivariable mixed-effects logistic regression, adjusting for age and sex. SARS-CoV-2 IgG, neutralising antibody titres, and antibody avidity were measured in serum of participants with previous positive PCR tests and compared with multivariable mixed-effects models, adjusting for age, sex, and time since PCR-confirmed SARS-CoV-2 infection.

Findings

1138 samples from 955 people living with HIV and 1118 samples from 1062 people without HIV were tested. SARS-CoV-2 IgG seroprevalence was 3·7% (95% CI 2·4 to 5·0) among people with HIV compared with 7·4% (5·7 to 9·2) among people without HIV (adjusted odds ratio 0·50, 95% CI 0·30 to 0·83). Among 31 people with HIV and 70 people without HIV who had evidence of past infection, the odds of severe COVID-19 were 5·52 (95% CI 1·01 to 64·48) times higher among people living with HIV. Adjusting for time since PCR-confirmed infection, SARS-CoV-2 IgG concentrations were lower (percentage change −53%, 95% CI −4 to −76), pseudovirus neutralising antibody titres were lower (−67%, −25 to −86), and avidity was similar (7%, −73 to 87) among people living with HIV compared with those without HIV.

Interpretation

Although fewer infections were detected by SARS-CoV-2 IgG testing among people living with HIV than among those without HIV, people with HIV had more cases of severe COVID-19. Among people living with HIV with past SARS-CoV-2 infection, lower IgG concentrations and pseudovirus neutralising antibody titres might reflect a diminished serological response to infection, and the similar avidity could be driven by similar time since infection.

Funding

US National Institute of Allergy and Infectious Diseases, US National Institutes of Health.

Longitudinal single-cell epitope and RNA-sequencing reveals the immunological impact of type 1 interferon autoantibodies in critical COVID-19: Anti-IFN antibodies in critical COVID-19 correlate with poor ISG response and upregulation of LAIR1 surface protein in PBMCs

Type I interferon (IFN-I) neutralizing autoantibodies have been found in some critical COVID-19 patients; however, their prevalence and longitudinal dynamics across the disease severity scale, and functional effects on circulating leukocytes remain unknown. Here, in 284 COVID-19 patients, we found IFN-I autoantibodies in 19% of critical, 6% of severe and none of the moderate cases. Longitudinal profiling of over 600,000 peripheral blood mononuclear cells using multiplexed single-cell epitope and transcriptome sequencing from 54 COVID-19 patients, 15 non-COVID-19 patients and 11 non-hospitalized healthy controls, revealed a lack of IFN-I stimulated gene (ISG-I) response in myeloid cells from critical cases, including those producing anti-IFN-I autoantibodies. Moreover, surface protein analysis showed an inverse correlation of the inhibitory receptor LAIR-1 with ISG-I expression response early in the disease course. This aberrant ISG-I response in critical patients with and without IFN-I autoantibodies, supports a unifying model for disease pathogenesis involving ISG-I suppression via convergent mechanisms.

A15 EFFICACY AND SAFETY OF FILGOTINIB AS INDUCTION THERAPY FOR PATIENTS WITH MODERATELY TO SEVERELY ACTIVE ULCERATIVE COLITIS: RESULTS FROM THE PHASE 2B/3 SELECTION STUDY

Aims

The SELECTION (NCT02914522) Induction Studies evaluated the efficacy/safety of filgotinib (FIL), a preferential JAK1 inhibitor, as induction therapy for patients (pts) with moderately to severely active ulcerative colitis (UC) who were biologic-naïve but failed conventional therapy (Induction Study A) or failed prior biologics (Induction Study B).

Methods

Pts were randomized 2:2:1 to once–daily FIL 200mg, FIL 100mg or placebo (PBO). The primary (clinical remission), key secondary (Mayo Clinic Score [MCS] remission, endoscopic remission, and histologic remission), and exploratory endpoints (MCS response and endoscopic improvement) were assessed at Week 10.

Results

In both studies, baseline demographics and disease characteristics were similar across treatment groups. In Study A, 659 pts were randomized and treated. Baseline mean MCS was 8.6 and 56% had a Mayo endoscopic subscore (ES)=3. A significantly higher proportion of biologic-naïve pts on FIL 200mg achieved clinical remission vs PBO and all key secondary endpoints (Table). In Study B, 689 pts were randomized and treated. Baseline mean MCS was 9.3 and 78% had ES=3. Prior treatment failures were: anti-TNF (86%), vedolizumab (52%) and both (dual-refractory; 43%). A significantly higher proportion of biologic-experienced pts on FIL 200mg achieved clinical remission vs PBO. In Studies A and B, a greater proportion of pts on FIL 200 mg achieved an MCS response and endoscopic improvement vs PBO.

The rates of AEs, serious AEs and discontinuations due to AEs were similar across FIL and PBO groups during induction. In the PBO, FIL 100mg and FIL 200mg groups, serious infections occurred in 0.7%, 0.7% and 0.4% pts in Study A and 1.4%, 1.4% and 0.8% pts in Study B; H Zoster occurred in &lt;1% in both groups for both cohorts.

Conclusions

SELECTION included a high proportion of dual-refractory pts, and pts with severe endoscopic disease. Both doses of FIL were well tolerated. Filgotinib 200mg was effective induction therapy for both biologic-naïve/-experienced pts with moderately to severely active UC.

Funding Agencies

None

Distinctive features of SARS-CoV-2-specific T cells predict recovery from severe COVID-19

Although T cells are likely players in SARS-CoV-2 immunity, little is known about the phenotypic features of SARS-CoV-2-specific T cells associated with recovery from severe COVID-19. We analyzed T cells from longitudinal specimens of 34 COVID-19 patients with severities ranging from mild (outpatient) to critical culminating in death. Relative to patients that succumbed, individuals that recovered from severe COVID-19 harbored elevated and increasing numbers of SARS-CoV-2-specific T cells capable of homeostatic proliferation. In contrast, fatal COVID-19 displayed elevated numbers of SARS-CoV-2-specific regulatory T cells and a time-dependent escalation in activated bystander CXCR4+ T cells. Together with the demonstration of increased proportions of inflammatory CXCR4+ T cells in the lungs of severe COVID-19 patients, these results support a model whereby lung-homing T cells activated through bystander effects contribute to immunopathology, while a robust, non-suppressive SARS-CoV-2-specific T cell response limits pathogenesis and promotes recovery from severe COVID-19.

Citywide serosurveillance of the initial SARS-CoV-2 outbreak in San Francisco

Serosurveillance provides a unique opportunity to quantify the proportion of the population that has been exposed to pathogens. Here, we developed and piloted Serosurveillance for Continuous, ActionabLe Epidemiologic Intelligence of Transmission (SCALE-IT), a platform through which we systematically tested remnant samples from routine blood draws in two major hospital networks in San Francisco for SARS-CoV-2 antibodies during the early months of the pandemic. Importantly, SCALE-IT allows for algorithmic sample selection and rich data on covariates by leveraging electronic medical record data. We estimated overall seroprevalence at 4.2%, corresponding to a case ascertainment rate of only 4.9%, and identified important heterogeneities by neighborhood, homelessness status, and race/ethnicity. Neighborhood seroprevalence estimates from SCALE-IT were comparable to local community-based surveys, while providing results encompassing the entire city that have been previously unavailable. Leveraging this hybrid serosurveillance approach has strong potential for application beyond this local context and for diseases other than SARS-CoV-2.