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Seroprevalence of anti-SARS-CoV-2 antibodies in COVID-19 patients

Seroprevalence of anti-SARS-CoV-2 antibodies in COVID-19 patients and wholesome volunteers as much as six months submit illness onset

 

  • SARS-CoV-2 has emerged as a human pathogen, inflicting scientific indicators, from fever to pneumonia – COVID-19 – however might stay delicate or asymptomatic.
  • To perceive the persevering with unfold of the virus, to detect those that are and had been contaminated, and to observe the immune response longitudinally, dependable and sturdy assays for SARS-CoV-2 detection and immunological monitoring are wanted.
  • We quantified immunoglobulin (Ig) M, IgG and IgA antibodies recognizing the SARS-CoV-2 receptor-binding area (RBD) or the Spike (S) protein over a interval of 5 months following COVID-19 onset.

 

  • We report the detailed setup to watch the humoral immune response from over 300 COVID-19 hospital patients and healthcare staff, 2500 University employees and 198 post-COVID-19 volunteers.
  • Anti-SARS-CoV-2 antibody responses observe a traditional sample with a speedy improve throughout the first three weeks after signs.
  • Although titres scale back subsequently, the power to detect anti-SARS-CoV-2 IgG antibodies remained sturdy with confirmed neutralisation exercise for as much as six months in a big proportion of beforehand virus-positive screened topics.

 

 

  • Our work offers detailed info for the assays used, facilitating additional and longitudinal evaluation of protecting immunity to SARS-CoV-2. Importantly, it highlights a continued stage of circulating neutralising antibodies in most individuals with confirmed SARS-CoV-2. This article is protected by copyright. All rights reserved.
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Renal Handling of 99m Tc-Labeled Antibody Fab Fragments with a Linkage Cleavable by Enzymes on Brush Border Membrane

 

The excessive and protracted renal radioactivity ranges after injection of radiolabeled low-molecular-weight polypeptides represent a major drawback for his or her diagnostic and therapeutic functions, particularly when they’re labeled with metallic radionuclides.

To enhance the renal radioactivity ranges of technetium-99m (99mTc)-labeled Fab fragments, a mercaptoacetyltriglycine (MAG3)-based new bifunctional chelating agent with a cleavable glycyl-phenylalanyl-lysine (GFK) linkage, MAG3-GFK-suc-TFP, was designed, synthesized, and evaluated. 99mTc-labeled Fab was obtained by reacting MAG3-GFK-Fab conjugate with 99mTc-glucarate.

The GFK linkage remained steady in plasma however was cleaved by enzymes on the renal brush border membrane. The comparative biodistribution research with indium-111 (111In)-labeled Fab utilizing SCN-CHX-A″-DTPA confirmed that whereas each radiolabeled Fabs exhibited comparable elimination charges from the blood, [99mTc]Tc-MAG3-GFK-Fab registered a lot decrease renal radioactivity ranges from 30 min post-injection onward as a result of launch and subsequent urinary excretion of [99mTc]Tc-MAG3-Gly. However, [99mTc]Tc-MAG3-GFK-Fab confirmed a rise within the intestinal radioactivity ranges with the time that was not noticed with 111In-labeled Fab.

The evaluation of the intestinal contents advised the redistribution of [99mTc]Tc-MAG3-Gly to the gut. The retrospective comparability of [99mTc]Tc-MAG3-GFK-Fab with the radiolabeled Fabs to this point ready below the similar idea advised that some portion of [99mTc]Tc-MAG3-Gly was generated after the coated vesicle formation and so they had been excreted into the blood, and subsequently redistributed within the gut by way of hepatobiliary excretion.

In conclusion, MAG3-GFK-suc-TFP supplied 99mTc-labeled Fabs that exhibit low renal radioactivity shortly after injection by the post-labeling process. The current research indicated that, opposite to our earlier proposal, the technology of the radiometabolites would proceed not solely throughout the internalization course of of the parental antibody fragments but additionally after coated vesicle formation. This research additionally confirmed that the intracellular behaviors of radiometabolites performed essential roles within the elimination charges and the routes of the radioactivity from the kidney.

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Pharmacokinetics and Pharmacodynamics of JNJ-55920839, an Antibody Targeting Interferon α/ω, in Healthy Subjects and Subjects with Mild-to-Moderate Systemic Lupus Erythematosus

 

Background: The interferon (IFN) pathway has been correlated with scientific and serological markers of illness exercise in patients with systemic lupus erythematosus (SLE).

 

Objective: The pharmacokinetics and pharmacodynamics of JNJ-55920839, a completely human immunoglobulin G1κ antibody concentrating on IFNα/ω, had been investigated.

 

Methods: In a double-blind, first-in-human research, Part A enrolled 48 wholesome adults who obtained a single dose of placebo/JNJ-55920839 between 0.Three and 15 mg/kg intravenous (IV) or at 1 mg/kg subcutaneous (SC). Part B enrolled 26 adults with SLE who obtained placebo or JNJ-55920839 10 mg/kg IV 6 occasions biweekly. Pharmacokinetic parameters had been calculated by noncompartmental evaluation (NCA) and estimated by nonlinear mixed-effects modeling.

 

Results: JNJ-55920839 pharmacokinetics following a single IV infusion exhibited a biphasic disposition in wholesome topics. Maximum plasma focus (Cmax) and space below the concentration-time curve values elevated dose-proportionally. Mean clearance (CL) after a single IV infusion ranged between 2.28 and three.09 mL/kg/day. Absolute bioavailability after a single SC injection was ≥ 80.0%. Mean terminal elimination half-life (thalf) was comparable after IV (20.7 to 24.6 days) and SC administration (22.6 days).

 

Steady state of JNJ-55920839 was achieved 6 weeks after a number of 10 mg/kg IV doses in topics with SLE. Mean steady-state CL and thalf had been 4.73 mL/kg/day and 14.eight days, respectively. A linear 2-compartment inhabitants pharmacokinetic mannequin with 1st-order absorption and elimination adequately characterised the pharmacokinetics; parameters had been in line with NCA estimates. Higher CL was estimated in topics with SLE in contrast with wholesome topics, after correcting for physique weight. A pattern of elevated complete IFNα/ω ranges was noticed after remedy with JNJ-55920839.

 

Sphingosine-1-phosphate in anti-neutrophil cytoplasmic antibody-associated vasculitis: coagulation-related scientific indicators and issues

 

  • [Background] Sphingosine-1-phosphate (S1P) performs a major position in anti-neutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV). [Methods] We collected the plasma samples from 40 patients with AAV and 10 wholesome volunteers.
  • The plasma ranges of S1P had been examined by enzyme-linked immunosorbent assay (ELISA). The ranges of serum creatinine (Scr) had been examined by charge methodology, after which the glomerular filtration charge (eGFR) of the patients was calculated from the Scr, age, and gender.

 

  • Prothrombin time (PT), partial thromboplastin time (APTT), thrombin time (TT), fibrinogen (FIB), fibrinogen discount product (FDP), D-dimer and C-reactive protein (CRP) had been examined by turbidimetric inhibition immunoassays. Platelets (PLT) had been examined by fluorescently-labelled electrical impedance methodology. [Results] The plasma ranges of S1P was considerably larger in AAV patients than in wholesome volunteers.

 

 

  • Correlation evaluation confirmed that plasma ranges of S1P had been negatively correlated with glomerular filtration (p=0.022, r=-0.306), and positively correlated with circulating ranges of Birmingham vasculitis exercise rating (BVAS), PLT and D-dimer, (p=0.004, r=0.443; p<0.001, r=0.654; p=0.006, r=0.427).
  • The 40 patients with AAV had been categorized into three teams: the thromboembolism group (with issues of cerebral infarction and myocardial infarction, n=6), cerebral ischemia group (n=4), and cerebral hemorrhage group (n=2). The plasma ranges of S1P had been highest within the thromboembolism group and lowest within the cerebral hemorrhage group (p=0.003).
  • [Conclusions] Plasma ranges of S1P had been related to circulating ranges of D-dimer, PLT, and BVAS within the patients with AAV. Hence, plasma S1P stage can be utilized as a biomarker to foretell coagulation-related issues in AAV.

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Economic aspects of established antibodies and recently available therapies

Immunotherapies within the German healthcare system : Economic aspects of established antibodies and recently available therapies

 

In the German healthcare system, immunotherapies have been effectively established for years. Currently there are over 100 registrations of monoclonal antibodies (MABs). In current years, new immunotherapeutic approaches turned available, amongst them checkpoint inhibitors and CAR‑T cells in oncology. Increasing expenditures of the German statutory medical health insurance (SHI) system are regarded with issues.

This article presents an summary of the event and standing of prescriptions and gross sales of chosen immunotherapeutics in Germany. Data from 2015-2019 had been analyzed, primarily from the GKV-Arzneimittel-Schnellinformation (GAmSi) and the consultancy IQVIA.In the group of older MABs, corresponding to immunosuppressive and antineoplastic brokers, biosimilars led to a (non permanent) enhance of functions, however reimbursement quantities are lowering.

Instruments of the SHI system like drug agreements, reference costs, and particular person low cost contracts intervene as expenditure management. Checkpoint inhibitors clearly present rising prescriptions and expenditures. Finally, the CAR‑T cells are certainly very costly therapies, however are at the moment not that necessary as a result of restricted quantity of functions. In addition, the exemption from VAT of 19% and the signed low cost agreements between suppliers and illness funds scale back the burden.

In 2015 and 2019, the web expenditures on medicine and surgical dressings accounted for 17.2% of the whole expenditures on advantages of the SHI system. Should the expenditures on medicine enhance overproportionately sooner or later, the German SHI system will be capable to counteract with already available or new devices, supported by the legislator. Manufacturers and the SHI system ought to develop joint actions to realize options for brand new remedy approaches.

 

Analysis of Tumor Depth Invasion With Anti-Smoothelin Antibody in Equivocal Transurethral Resection of Urinary Bladder Tumor Surgical Specimens

 

Objective: To look at the expression and worth of the smoothelin marker in management circumstances, to standardize the working technique, and to investigate its software in pathologic staging course of of problematic transurethral resection of bladder tumor (TURBT) circumstances.

 

Material and strategies: Immunohistochemical (IHC) staining was carried out on tumor-free bladder wall sections, tumor-free giant bowel sections, TURBTs with unequivocal tumor stage, and TURBTs with equivocal stage. The IHC staining of muscularis mucosa (MM), muscularis propria (MP), and blood vessels was evaluated semiquantitatively.

 

Results: Smoothelin IHC staining sample ranged from unfavourable (30% to 67% circumstances) to 2+ (0% to 15% circumstances) in MM and from 1+ (10% to 50% circumstances) to three+ (9% to 48% circumstances) in MP. When in contrast on the identical slide, the smoothelin expression of MP confirmed a stronger staining depth than the one of the MM in all of the analyzed circumstances. Blood vessel muscle cells stained in a relentless depth because the MM (r = 0.9808; r = 0.9604). Smoothelin decided restaging of 33% of the problematic TURBT circumstances.

 

Conclusion: Smoothelin is an IHC marker that reveals differential staining between coexistent MM and MP; nevertheless, variations in staining depth and sample might happen, aspects that may be influenced by completely different method variables. We suggest utilizing this marker as a diagnostic instrument in problematic TURBT circumstances solely when there may be adequate expertise in management circumstances with this antibody.

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Characterization of New Monoclonal PF4-Specific Antibodies as Useful Tools for Studies on Typical and Autoimmune Heparin-Induced Thrombocytopenia

 

Background: Heparin-induced thrombocytopenia (HIT) is usually brought on by platelet-activating immunoglobulin G (IgG) antibodies (Abs) towards platelet issue 4 (PF4) complexed with heparin (H). Much much less frequent “autoimmune” HIT is distinguished from typical HIT by platelet activation with out heparin and the presence of each anti-PF4/H and anti-PF4 IgG. We developed three murine monoclonal anti-PF4 Abs with a human Fc-part, 1E12, 1C12, and 2E1, resembling autoimmune HIT Abs.

 

Objectives: To characterize 1E12, 1C12, and 2E1 compared to the heparin-dependent monoclonal anti-PF4/H Abs 5B9 and KKO, and polyclonal Abs from sufferers with typical HIT (group-2) and autoimmune HIT (group-3).

 

Methods: Interactions of Abs with PF4 and PF4/H had been studied by enzyme-linked-immunosorbent assay, single-molecule drive spectroscopy, isothermal titration calorimetry, and dynamic gentle scattering. Serotonin launch assay and heparin-induced platelet activation assay had been used to evaluate platelet activation. The binding websites of monoclonal Abs on PF4 had been predicted in silico (MAbTope technique).

 

Results: 1C12, 1E12, and 2E1 displayed larger affinity for PF4/H complexes than 5B9 and KKO, akin to human group-3 Abs. Only 1C12, 1E12, 2E1, and group-3 Abs fashioned giant complexes with native PF4, and activated platelets with out heparin. The predicted binding websites of 1C12, 1E12, and 2E1 on PF4 differed from these of KKO and 5B9, however had been shut to one another. 2E1 exhibited distinctive bivalent binding, involving its antigen recognition web site to PF4 and charge-dependent interactions with heparin.

 

Antibodies towards human neutrophil antigens in non-transfused girls with purple blood cell alloimmunisation induced by being pregnant

 

Background: Alloantibodies towards human neutrophil antigens (HNA) ensuing from allogeneic publicity could also be related to transfusion-related acute lung harm and immune neutropenia. Understanding the danger components for the formation of such antibodies may have an incredible affect on the adoption of measures to forestall probably deadly transfusion reactions. The purpose of the research was to find out the prevalence of anti-HNA alloantibodies in non-transfused pregnant girls with and with out purple blood cell (RBC) alloantibodies.

 

Materials and strategies: HNA alloantibodies had been investigated in blood samples from 147 pregnant girls with RBC alloimmunisation induced by being pregnant as the one allogeneic stimulus (group 1). The management group (group 2) consisted of 563 girls with not less than one being pregnant with out RBC alloimmunisation. Both teams had been investigated for the presence and id of HNA alloantibodies utilizing granulocyte agglutination checks, white blood cell immunofluorescence testing, and the bead-based LABScreen Multi Kit. Genotyping was carried out to verify the specificity of the HNA alloantibodies.

 

Results: Group 1 girls had a statistically larger quantity of HNA alloantibodies in comparison with group 2 girls (9/147 [6.1%] vs 9/563 [1.6%]; p=0.005, OR=4.01; 95% CI 1.5-10.3). Considering solely multiparous girls, there was the next statistical significance for the distinction within the presence of HNA alloantibodies between the 2 teams (7/82 [8.5%] vs 9/493 [1.8%]; p=0.002, OR=5.02; 95% CI 1.8-13.9).

 

Characterization of G-quadruplex antibody reveals differential specificity for G4 DNA varieties

 

  • Accumulating proof means that human genome can fold into non-B DNA buildings, when applicable sequence and beneficial situations are current. Among these, G-quadruplexes (G4-DNA) are related to gene regulation, chromosome fragility and telomere upkeep. Although a number of strategies are utilized in detecting such buildings in vitro, understanding their intracellular existence has been difficult.
  • Recently, an antibody, BG4, was described to check G4-structures inside cells. Here, we characterize BG4 for its affinity in direction of G4-DNA, utilizing a number of biochemical and biophysical instruments. BG4 certain to G-rich DNA derived from a number of genes that type G-quadruplexes, not like complementary C-rich or random sequences. BLI research revealed sturdy binding affinity (Kd = 17.Four nM).
  • Gel shift assays present BG4 binds to inter and intramolecular G4-DNA, when it’s in parallel orientation. Mere presence of G4-motif in duplex DNA is inadequate for antibody recognition. Importantly, BG4 can bind to G4-DNA inside telomere sequence in a supercoiled plasmid. Finally, we present that BG4 binds to type environment friendly foci in 4 cell traces, irrespective of their lineage, demonstrating presence of G4-DNA in genome.
  • Importantly, quantity of BG4 foci inside the cells could be modulated, upon knockdown of G4-resolvase, WRN. Thus, we set up specificity of BG4 in direction of G4-DNA and talk about its potential functions.

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Systemic phenotype associated to major Sjögren’s syndrome in 279 sufferers

Systemic phenotype associated to major Sjögren’s syndrome in 279 sufferers carrying remoted anti-La/SSB antibodies

 

Objectives: To consider the systemic phenotype related to the presence of remoted anti-La/SSB antibodies in a big worldwide registry of sufferers with major Sjögren’s syndrome (pSS) fulfilling the 2002 classification standards.

 

Methods: The Big Data Sjögren Project Consortium is a world, multicentre registry created in 2014. Baseline scientific info from main centres on scientific analysis in SS of the 5 continents was collected. Combination patterns of anti-Ro/SSA-La/SSB antibodies on the time of analysis outlined the next 4 immunological phenotypes: double optimistic (mixed Ro/SSA and La/SSB,) remoted anti-Ro/SSA, remoted anti-La/SSB, and immunonegative.

 

Results: The cohort included 12,084 sufferers (11,293 females, imply 52.Four years) with recorded ESSDAI scores out there. Among them, 279 (2.3%) had remoted anti-La/SSB antibodies. The imply whole ESSDAI rating at analysis of sufferers with pSS carrying remoted anti-La/SSB was 6.0, and 80.4% of sufferers had systemic exercise (international ESSDAI rating ≥1) at analysis. The domains with the very best frequency of lively sufferers had been the organic (42.8%), glandular (36.8%) and articular (31.2%) domains.

 

Patients with remoted anti-La/SSB confirmed the next frequency of lively sufferers in all ESSDAI domains however two (articular and peripheral nerve) as compared with immune-negative sufferers, and even the next absolute frequency in six scientific ESSDAI domains as compared with sufferers with remoted anti-Ro/SSA.

In addition, sufferers with remoted anti-La/SSB confirmed the next frequency of lively sufferers in two ESSDAI domains (pulmonary and glandular) with respect to essentially the most lively immunological subset (double-positive antibodies). Meanwhile, systemic exercise detected in sufferers with remoted anti-La/SSB was overwhelmingly low. Even in ESSDAI domains the place sufferers with remoted anti-La/SSB had the very best frequencies of systemic exercise (lymphadenopathy and muscular), the share of sufferers with average or excessive exercise was decrease as compared with the mixed Ro/SSA and La/SSB group.

 

Conclusions: Patients carrying remoted La/SSB antibodies symbolize a really small subset of sufferers with a systemic SS phenotype characterised by a big frequency of lively sufferers in most scientific ESSDAI domains however with a relative low frequency of the very best extreme organ-specific involvements. Primary SS nonetheless stays the most effective scientific analysis for this subset of sufferers.

 

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Seroprevalence of Specific Antibodies in opposition to SARS-CoV-2 from Hotspot Communities within the Dominican Republic

 

  • Seroprevalence surveys are of utmost significance to evaluate the proportion of a inhabitants that has developed antibodies in opposition to a newly launched virus and will subsequently probably exhibit immunologic safety in opposition to subsequent an infection. This research goals to know the distribution of IgM and IgG antibodies within the Dominican Republic.
  • We surveyed a complete of 12,897 contributors between April and June 2020 in 10 provinces of the Dominican Republic. Survey efforts in rising hotspots yielded a positivity for all contributors of anti-SARS-CoV-2 IgM of three.8% and IgG of 5.4%, indicating that the pathogen was in circulation earlier than the identification of these specific communities as hotspots.
  • We discovered vital age variations between contributors who participated within the serological research the place the next imply age is related IgM positivity and a decrease age with IgG positivity. Our outcomes spotlight the necessity for methods that contain community-based seroprevalence monitoring. These ought to preclude syndromic case identification.
  • Also, the upper imply age of IgM-positive contributors means that methods primarily based on syndromic surveillance may establish hotspots at later phases, primarily based on the variety of instances detected on the healthcare heart, as such community-based seroprevalence monitoring could also be an efficient intervention for future outbreaks.

SARS-CoV-2 antibody prevalence, titres and neutralising exercise in an antenatal cohort, United Kingdom, 14 April to 15 June 2020

 

SARS-CoV-2 IgG screening of 1,000 antenatal serum samples within the Oxford space, United Kingdom, between 14 April and 15 June 2020, yielded a 5.3% seroprevalence, mirroring contemporaneous regional knowledge. Among the 53 optimistic samples, 39 confirmed in vitro neutralisation exercise, correlating with IgG titre (Pearson’s correlation p<0.0001). While SARS-CoV-2 seroprevalence in being pregnant cohorts may probably inform inhabitants surveillance, scientific correlates of an infection and immunity in being pregnant, and antenatal epidemiology evolution over time want additional research.

Coronavirus Disease 2019 in a Premature Infant: Vertical Transmission and Antibody Response or Lack Thereof

With the worldwide unfold of extreme acute respiratory syndrome coronavirus 2 (SARS-CoV-2) an infection, a number of studies spotlight its results on pregnant ladies. Based on scant out there knowledge, vertical transmission is taken into account unlikely. We current right here a preterm neonate born to a critically sick mom with SARV-CoV-2 with early proof of an infection with a optimistic reverse transcription polymerase chain response on day 1.

Lack of parental contact previous to testing and strict adherence to really helpful airborne precautions perinatally recommend vertical transmission of an infection. Critical maternal sickness and medicines might have contributed to the necessity for intensive resuscitation at beginning and spotlight the significance of shut fetal monitoring. Infant lacked immunoglobulin G antibody response by Three weeks, presumably secondary to delicate scientific course and prematurity. Effects of SARS-CoV-2 in preterm infants, their antibody response and potential for asymptomatic carriage stay unsure.

 

Towards middle-up evaluation of polyclonal antibodies: subclass-specific N-glycosylation profiling of murine immunoglobulin G (IgG) by the use of HPLC-MS

 

  • In current years, superior HPLC-MS methods primarily based on intact protein (“top-down”) or protein subunit (“middle-up/middle-down”) evaluation have been carried out for the characterization of therapeutic monoclonal antibodies. Here, we assess feasibility of middle-up/middle-down evaluation for polyclonal IgGs exhibiting intensive sequence variability. Specifically, we addressed IgGs from mouse, representing an vital mannequin system in immunological investigations.
  • To receive Fc/2 parts as conserved subunits of IgGs, we made use of the bacterial protease SpeB. For this goal, we initially decided SpeB cleavage websites in murine IgGs. The ensuing Fc/2 parts attribute of various subclasses had been subsequently analysed by ion-pair reversed-phase HPLC hyphenated to high-resolution mass spectrometry.
  • This enabled simultaneous relative quantification of IgG subclasses and their N-glycosylation variants, each of which affect IgG effector capabilities. To assess methodology capabilities in an immunological context, we utilized the analytical workflow to polyclonal antibodies obtained from BALB/c mice immunized with the grass pollen allergen Phl p 6.
  • The research revealed a shift in IgG subclasses and Fc-glycosylation patterns in whole and antigen-specific IgGs from totally different mouse cohorts, respectively. Eventually, Fc/2 characterization might reveal different protein modifications together with oxidation, amino acid exchanges, and C-terminal lysine, and should thus be carried out for high quality management of useful antibodies.

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Moxifloxacin-Induced Thrombocytopenia Mediated by Moxifloxacin

Moxifloxacin-Induced Thrombocytopenia Mediated by Moxifloxacin-Dependent IgM and IgG Antiplatelet Antibodies: A Case Report

 

  • Moxifloxacin is a rare but important cause of drug-induced immune thrombocytopenia (DIT). We describe a patient who presented with an acute onset of severe thrombocytopenia complicated by petechial rash, epistaxis, and melena. Recent new drug exposures included moxifloxacin and two proton pump inhibitors.

 

  • On presentation to the hospital, all recently initiated medications were discontinued and the patient’s thrombocytopenia was treated with platelet transfusions, intravenous immunoglobulin, and high-dose corticosteroids. Her thrombocytopenia improved over the next seven days and she was discharged on hospital day 8.

 

  • Serologic testing revealed strongly positive moxifloxacin-dependent IgM and IgG antiplatelet antibodies, confirming a diagnosis of moxifloxacin-induced immune thrombocytopenia. DIT has been reported with other fluoroquinolone antibiotics, especially ciprofloxacin. This case documents a rare but potentially fatal complication of exposure to moxifloxacin and is the first to demonstrate objective evidence of acute sensitization with IgM antibody positivity.

 

  • It highlights the need to consider this potential reaction when choosing antibiotic therapy, particularly in patients who are at high risk for bleeding, have hematologic disorders, or are receiving myelosuppressive therapies, and perhaps in those with a history of multiple drug allergies.

 

Inhibitory anti ADAMTS13 antibodies with a new rapid fully automated CLiA assay

 

Background: Thrombotic thrombocytopenic purpura (TTP) is a life-threatening disorder characterized by severe ADAMTS13 deficiency. The acquired form is associated with autoantibodies directed against ADAMTS13. Both noninhibitory and inhibitory autoantibodies can be detected by ELISA assay, while only inhibitory autoantibodies are detected by Bethesda assay. Due to its short TAT and good performance, chemiluminescence (CliA) ADAMTS13 activity (HemosIL Acustar) has proven to be a good choice in the diagnosis of TTP in emergency settings. Aim of this study was to analyse the performance of the CliA ADAMTS13 activity assay in detecting inhibitory ADAMTS13 antibodies using the Bethesda assay.

 

Methods: A method comparison study was performed on 69 stored samples: 11 acute TTPs, 38 TTP follow-ups, 5 TTP relapses, 1 congenital TTP, 10 HUS, 4 suspected TTPs. We retrieved the results of tests previously run in ELISA for both activity and autoantibodies. At the same time, we reran new tests including ELISA and CliA activity, ELISA autoantibodies, and ELISA and CliA Bethesda assays on thawed frozen samples.

 

Results: Very good correlation was observed between ELISA and CliA activity assay results (r = 0.96) and between archived ELISA and CliA activity results (r = 0.93). Agreement between the anti-ADAMTS13 assays ranged from good (k = 0.63) to very good (k = 0.92).

 

Conclusions: CliA and ELISA Bethesda assays showed very good agreement with samples run at the same time using ELISA ADAMTS13-autoantibody assay. Albeit more expensive, the CliA Bethesda assay identified inhibitory anti-ADAMTS13 within almost the same TAT as ELISA, but with better automation and limited operator involvement.

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Development of a multiplex microsphere immunoassay for the detection of antibodies against highly pathogenic viruses in human and animal serum samples

 

Surveillance of highly pathogenic viruses circulating in both human and animal populations is crucial to unveil endemic infections and potential zoonotic reservoirs. Monitoring the burden of disease by serological assay could be used as an early warning system for imminent outbreaks as an increased seroprevalance often precedes larger outbreaks.

However, the multitude of highly pathogenic viruses necessitates the need to identify specific antibodies against several targets from both humans as well as from potential reservoir animals such as bats. In order to address this, we have developed a broadly reactive multiplex microsphere immunoassay (MMIA) for the detection of antibodies against several highly pathogenic viruses from both humans and animals.

To this aim, nucleoproteins (NP) of Ebola virus (EBOV), Marburg virus (MARV) and nucleocapsid proteins (NP) of Crimean-Congo haemorrhagic fever virus, Rift Valley fever virus and Dobrava-Belgrade hantavirus were employed in a 5-plex assay for IgG detection. After optimisation, specific binding to each respective NP was shown by testing sera from humans and non-human primates with known infection status.

The usefulness of our assay for serosurveillance was shown by determining the immune response against the NP antigens in a panel of 129 human serum samples collected in Guinea between 2011 and 2012 in comparison to a panel of 88 sera from the German blood bank. We found good agreement between our MMIA and commercial or in-house reference methods by ELISA or IIFT with statistically significant higher binding to both EBOV NP and MARV NP coupled microspheres in the Guinea panel.

Finally, the MMIA was successfully adapted to detect antibodies from bats that had been inoculated with EBOV- and MARV- virus-like particles, highlighting the versatility of this technique and potentially enabling the monitoring of wildlife as well as human populations with this assay. We were thus able to develop and validate a sensitive and broadly reactive high-throughput serological assay which could be used as a screening tool to detect antibodies against several highly pathogenic viruses.

Maternal Epstein-Barr virus-specific antibodies and risk of infection in Ugandan infants

 

Background: Epstein-Barr virus (EBV) infection is a major cause of malignancy worldwide. Maternal antibody is thought to prevent EBV infection because it is uncommon in early infancy. Maternal HIV infection is associated with an increased incidence of EBV infection in exposed infants, which we hypothesized results from impaired transfer of EBV-neutralizing maternal antibodies.

 

Methods: Among Ugandan infants followed for EBV acquisition from birth, we measured antibody binding to EBV glycoproteins (e.g., gp350, gH/gL) involved in B cell and epithelial cell entry, as well as viral neutralization and antibody-dependent cellular cytotoxicity (ADCC) activity in plasma samples prior to infection. These serologic data were analyzed for differences between HIV-exposed uninfected (HEU) and unexposed (HUU) infants, and for associations with incident infant EBV infection.

 

Results: HEU infants had significantly higher titers than HUU infants for all EBV-binding and neutralizing antibodies measured (p<0.01), but not ADCC activity, which was similar between groups. No antibody measure was associated with a decreased risk of EBV acquisition in the cohort.

 

Conclusions: Our findings indicate that in this cohort maternal antibody did not protect infants against EBV infection through viral neutralization. The identification of protective non-neutralizing antibody functions would be invaluable for the development of an EBV vaccine