Neutralization, effector function and immune imprinting of Omicron variants.

Currently circulating SARS-CoV-2 variants have acquired convergent mutations at hot spots in the receptor-binding domain1 (RBD) of the spike protein. The effects of these mutations on viral infection and transmission and the efficacy of vaccines and therapies remains poorly understood. Here we demonstrate that recently emerged BQ.1.1 and XBB.1.5 variants bind host ACE2 with high affinity and promote membrane fusion more efficiently than earlier Omicron variants. Structures of the BQ.1.1, XBB.1 and BN.1 RBDs bound to the fragment antigen-binding region of the S309 antibody (the parent antibody for sotrovimab) and human ACE2 explain the preservation of antibody binding through conformational selection, altered ACE2 recognition and immune evasion. We show that sotrovimab binds avidly to all Omicron variants, promotes Fc-dependent effector functions and protects mice challenged with BQ.1.1 and hamsters challenged with XBB.1.5. Vaccine-elicited human plasma antibodies cross-react with and trigger effector functions against current Omicron variants, despite a reduced neutralizing activity, suggesting a mechanism of protection against disease, exemplified by S309. Cross-reactive RBD-directed human memory B cells remained dominant even after two exposures to Omicron spikes, underscoring the role of persistent immune imprinting.

Diagnostic discrimination of a novel high-sensitivity cardiac troponin I assay and derivation/validation of an assay-specific 0/1h-algorithm.

BACKGROUND: We aimed to assess the diagnostic utility of the Dimension EXL LOCI High-Sensitivity Troponin I (hs-cTnI-EXL) assay. METHODS: This multicenter study included patients with chest discomfort presenting to the emergency department. Diagnoses were centrally and independently adjudicated by two cardiologists using all available clinical information. Adjudication was performed twice including serial measurements of high-sensitivity cardiac troponin (hs-cTn) I-Architect (primary analysis) and serial measurements of hs-cTnT-Elecsys (secondary analysis) in addition to the clinically used (hs)-cTn. The primary objective was to assess and compare the discriminatory performance of hs-cTnI-EXL, hs-cTnI-Architect and hs-cTnT-Elecsys for acute myocardial infarction (MI). Furthermore, we derived and validated a hs-cTnI-EXL-specific 0/1h-algorithm. RESULTS: Adjudicated MI was the diagnosis in 204/1454 (14%) patients. The area under the receiver operating characteristics curve for hs-cTnI-EXL was 0.94 (95%CI, 0.93-0.96), and comparable to hs-cTnI-Architect (0.95; 95%CI, 0.93-0.96) and hs-cTnT-Elecsys (0.93; 95%CI, 0.91-0.95). In the derivation cohort (n = 813), optimal criteria for rule-out of MI were <9ng/L at presentation (if chest pain onset >3h) or <9ng/L and 0h-1h-change <5ng/L, and for rule-in ≥160ng/L at presentation or 0h-1h-change ≥100ng/L. In the validation cohort (n = 345), these cut-offs ruled-out 56% of patients (negative predictive value 99.5% (95%CI, 97.1-99.9), sensitivity 97.8% (95%CI, 88.7-99.6)), and ruled-in 9% (positive predictive value 83.3% (95%CI, 66.4-92.7), specificity 98.3% (95%CI, 96.1-99.3)). Secondary analyses using adjudication based on hs-cTnT measurements confirmed the findings. CONCLUSIONS: The overall performance of the hs-cTnI-EXL was comparable to best-validated hs-cTnT/I assays and an assay-specific 0/1h-algorithm safely rules out and accurately rules in acute MI. CLINICAL TRIAL REGISTRATION: ClinicalTrials.gov number, NCT00470587.

Efficiency evaluation of a SARS-CoV-2 diagnostic strategy combining high throughput quantitative antigen immunoassay and real time PCR.

OBJECTIVES: Laboratory testing for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has played an important role in the effort to prevent and contain local outbreaks. The aim of this study was to assess the diagnostic accuracy of a new fully automated SARS-CoV-2 laboratory-based antigen assay (CoV2Ag) and to explore the efficiency of a diagnostic algorithm combining antigen and conventional high-throughput molecular assays to address potential future challenges of the SARS-CoV-2 pandemic. METHODS: One thousand two hundred and twenty four consecutive nasopharyngeal swabs were tested using RT-PCR and CoV2Ag assay. RESULTS: The overall sensitivity and specificity of CoV2Ag were 79.1 and 97.8%, respectively. When the analysis was restricted to cases with Ct values ≤30, the sensitivity of the assay improved to 98.1%. Acceptable sensitivity was found when the analysis was limited to patients presenting within one or two to four days of symptom onset (80.5 and 84.8%, respectively). A retrospective analysis of the use of a two-step diagnostic approach combining the CoV2Ag assay and RT-PCR during an acute pandemic phase of 97 days showed a potential reduction in the number of RT-PCR tests by 36.1%, corresponding to savings in reagent costs and technician workload of approximately €8,000 and 10.5 h per day, respectively. CONCLUSIONS: Our data show that the proposed algorithm represents a valid alternative diagnostic approach to increase testing efficiency during future pandemic phases with high positivity rates (>20%) and elevated numbers of RT-PCR test requests.

Performance of synacthen test in chronic hemodialysis patients.

BACKGROUND: Adrenal function tests (Synacthen test) in chronic hemodialysis (HD) patients are currently performed off dialysis. The study aimed to demonstrate equivalence of serum cortisol concentrations pre- and during HD, each for standard-dose (250 µg) and low-dose (1 µg) Synacthen test. METHODS: In a single-center cross-over diagnostic equivalence study, Synacthen tests were performed in four settings, in standard- and low-dose as well as pre- and during HD. Serum cortisol concentration was measured at 30 and 60 min after Synacthen administration, and additionally at 20 min in low dose test. Based on a multivariable linear mixed model the means of cortisol concentration on log-scale were estimated in each dose and test time combination. Differences in means were calculated and the TOST approach was applied to test for equivalence. Equivalence was proven if the 90% confidence interval of the difference of two cortisol means was entirely between - 0.22 and 0.22. RESULTS: In 28 chronic HD patients, serum cortisol concentrations at 30 and 60 min after Synacthen administration in both standard- and low-dose were shown to be equivalent pre- and during HD. In 10 of 56 low-dose tests, the cortisol peak was already reached after 20 min. However, cortisol concentrations at 20 and 30 min after low-dose Synacthen test pre- and during HD showed no significant difference. CONCLUSION: These results suggest that the adrenal function test may be carried out during an ongoing HD session, leading to a more patient-friendly performance of the test, less organizational effort and potentially earlier diagnosis of adrenal insufficiency.

Prevalence of markers of beta cell autoimmunity and thyroid disease in children with coeliac disease.

BACKGROUND: Over the last decades, the prevalence of coeliac disease (CD), an autoimmune disorder, rose to 1-2%. Whether patients with CD have higher risk of developing other autoimmune disorders such as type 1 diabetes, Hashimoto thyroiditis, or Graves` disease remains unclear. AIM: The aim of this study was to determine the prevalence of biomarkers of beta cell and thyroid autoimmunity in children with CD. METHODS: Retrospective cross-sectional cohort study comparing pediatric patients suffering from CD with age and sex-matched healthy controls (HC). Participant`s serum was tested by immunoassay for following autoantibodies (aAb): TSH-receptor antibodies (TRAb), anti-thyroglobulin (anti-Tg), anti-thyroid peroxidase (anti-TPO), anti-glutamic acid decarboxylase (anti-GAD), anti-zinc transporter 8 (anti-ZnT8), anti-islet antigen 2 (anti-IA2) and anti-insulin. RESULTS: A total of 95 patients with CD (mean age 8.9 years; 63% female) and 199 matched healthy controls (mean age 9.2 years; 59.8% female) were included in the study. For patients with CD, a seroprevalence of 2.1% (vs. 1.5% in HC) was calculated for anti-GAD, 1.1% for anti-IA2 (vs. 1.5% in HC), 3.2% for anti-ZnT8 (vs. 4.2% in HC), and 1.1% (vs. 1% in HC) for anti-insulin. For thyroid disease, a seroprevalence of 2.2% for TRAb (vs. 1% in HC), 0% for anti-TPO (vs. 2.5% in HC) and 4.3% for anti-Tg (vs. 3.5% in HC) was found for patients with CD. CONCLUSION: This study suggests a higher prevalence of autoimmune antibodies againstthyroid in children with CD compared to HC, whilst it is similar for pancreatic antibodies. Prospective cohort studies are needed to first evaluate the occurrence of autoimmune antibodies against beta cells and thyroid over a longer follow-up time and second to explore their clinical relevance.

Standardisation of ACPA tests: evaluation of a new candidate reference preparation.

INTRODUCTION: Commercial assays measuring antibodies to citrullinated protein/peptide (ACPA) show poor quantitative agreement. The diagnostic industry has never adopted the International Union of Immunological Societies-Centers for Disease Control and Prevention (IUIS-CDC) ACPA reference standard. Recently, the National Institute for Biological Standards and Control (NIBSC) prepared a new candidate ACPA standard (18/204). We evaluated both reference materials using different commercially available ACPA assays. MATERIALS AND METHODS: This is an international study in which the NIBSC candidate ACPA standard and the IUIS-CDC ACPA reference material were analysed together with 398 diagnostic samples from individuals with rheumatoid arthritis (RA) and in 1073 individuals who did not have RA using nine commercial ACPA assays. RESULTS: For both reference materials and samples from individuals with RA and individuals who did not have RA, there were large differences in quantitative ACPA results between assays. For most assays, values for the IUIS-CDC standard were lower than values for NIBSC 18/204 and the IUIS-CDC/NIBSC ratio was comparable for several, but not all assays. When NIBSC 18/204 was used as a calibrator, an improvement in alignment of ACPA results across several of the evaluated assays was obtained. Moreover, NIBSC 18/204 could align clinical interpretation for some but not all assays. CONCLUSION: Adoption of an international standard for ACPA determination is highly desirable. The candidate NIBSC 18/204 standard improved the standardisation and alignment of most ACPA assays and might therefore be recommended to be used as reference in commercial assays.

Identification of COVID-19 patients at risk of hospital admission and mortality: a European multicentre retrospective analysis of mid-regional pro-adrenomedullin.

BACKGROUND: Mid-Regional pro-Adrenomedullin (MR-proADM) is an inflammatory biomarker that improves the prognostic assessment of patients with sepsis, septic shock and organ failure. Previous studies of MR-proADM have primarily focussed on bacterial infections. A limited number of small and monocentric studies have examined MR-proADM as a prognostic factor in patients infected with SARS-CoV-2, however there is need for multicenter validation. An evaluation of its utility in predicting need for hospitalisation in viral infections was also performed. METHODS: An observational retrospective analysis of 1861 patients, with SARS-CoV-2 confirmed by RT-qPCR, from 10 hospitals across Europe was performed. Biomarkers, taken upon presentation to Emergency Departments (ED), clinical scores, patient demographics and outcomes were collected. Multiclass random forest classifier models were generated as well as calculation of area under the curve analysis. The primary endpoint was hospital admission with and without death. RESULTS: Patients suitable for safe discharge from Emergency Departments could be identified through an MR-proADM value of ≤ 1.02 nmol/L in combination with a CRP (C-Reactive Protein) of ≤ 20.2 mg/L and age ≤ 64, or in combination with a SOFA (Sequential Organ Failure Assessment) score < 2 if MR-proADM was ≤ 0.83 nmol/L regardless of age. Those at an increased risk of mortality could be identified upon presentation to secondary care with an MR-proADM value of > 0.85 nmol/L, in combination with a SOFA score ≥ 2 and LDH > 720 U/L, or in combination with a CRP > 29.26 mg/L and age ≤ 64, when MR-proADM was > 1.02 nmol/L. CONCLUSIONS: This international study suggests that for patients presenting to the ED with confirmed SARS-CoV-2 infection, MR-proADM in combination with age and CRP or with the patient's SOFA score could identify patients at low risk where outpatient treatment may be safe.

Respiratory morbidity in preterm infants predicted by natriuretic peptide (MR-proANP) and endothelin-1 (CT-proET-1).

BACKGROUND: Bronchopulmonary dysplasia (BPD) is a major complication in preterm infants <32 weeks. We aimed to assess whether plasma levels of mid-regional pro-atrial natriuretic peptide (MR-proANP) and C-terminal pro-endothelin-1 (CT-proET-1) predict respiratory morbidity. METHODS: This was a prospective, two-center, observational cohort study. MR-proANP and CT-proET-1 were measured at day 7 (±2) of life. Associations with duration of supplemental oxygen and the composite outcome of moderate or severe BPD or death (BPD/death) were investigated. RESULTS: Two hundred and twenty-nine infants <32 weeks were included (median gestational age [GA] 29.6 weeks [interquartile range 29.0-30.7], median birth weight 1150 g [IQR 840-1410]). MR-proANP and CT-proET-1 were associated with the duration of supplemental oxygen in univariable analysis (both p < 0.001) but not after adjusting for co-factors. Infants with BPD/death showed higher plasma levels of MR-proANP (623.50 pmol/L [IQR 458.50-881.38] vs. 308.35 pmol/L [IQR 216.72-538.10]; p < 0.001) and CT-proET-1 (255.40 pmol/L [IQR 202.60-311.15] vs. 198.30 pmol/L [IQR 154.70-297.95]; p = 0.015) compared to infants without BPD/death. Levels of both biomarkers were significantly associated with BPD/death in univariable models but not after adjusting for co-factors. CONCLUSIONS: MR-proANP and CT-proET-1 are associated with the duration of supplemental oxygen and the composite outcome BPD/death, but their prognostic value does not complement that of clinical risk factors. IMPACT: Plasma levels of MR-proANP and CT-proET-1, measured on day 7 of life (±2 days) are associated in univariable analyses with duration of supplemental oxygen and the combined outcome of BPD or death in VLGA infants. Associations between both biomarkers and respiratory morbidity do not persist in multivariable models, in particular when gestational age is included. MR-proANP and CT-proET-1 have limited additional value to predict respiratory morbidity in VLGA infants compared to clinical parameters.

Call, chosen, HA2T2, ANDC: validation of four severity scores in COVID-19 patients.

PURPOSE: To externally validate four previously developed severity scores (i.e., CALL, CHOSEN, HA2T2 and ANDC) in patients with COVID-19 hospitalised in a tertiary care centre in Switzerland. METHODS: This observational analysis included adult patients with a real-time reverse-transcription polymerase chain reaction or rapid-antigen test confirmed severe acute respiratory syndrome coronavirus type 2 (SARS-CoV-2) infection hospitalised consecutively at the Cantonal Hospital Aarau from February to December 2020. The primary endpoint was all-cause in-hospital mortality. The secondary endpoint was disease progression, defined as needing invasive ventilation, ICU admission or death. RESULTS: From 399 patients (mean age 66.6 years ± 13.4 SD, 68% males), we had complete data for calculating the CALL, CHOSEN, HA2T2 and ANDC scores in 297, 380, 151 and 124 cases, respectively. Odds ratios for all four scores showed significant associations with mortality. The discriminative power of the HA2T2 score was higher compared to CALL, CHOSEN and ANDC scores [area under the curve (AUC) 0.78 vs. 0.65, 0.69 and 0.66, respectively]. Negative predictive values (NPV) for mortality were high, particularly for the CALL score (≥ 6 points: 100%, ≥ 9 points: 95%). For disease progression, discriminative power was lower, with the CHOSEN score showing the best performance (AUC 0.66). CONCLUSION: In this external validation study, the four analysed scores had a lower performance compared to the original cohorts regarding prediction of mortality and disease progression. However, all scores were significantly associated with mortality and the NPV of the CALL and CHOSEN scores in particular allowed reliable identification of patients at low risk, making them suitable for outpatient management.

IgA rheumatoid factor in rheumatoid arthritis.

OBJECTIVES: Rheumatoid factor (RF) is a well-established marker for the diagnosis and classification of rheumatoid arthritis (RA). Most studies evaluated IgM RF or isotype-nonspecific total RF assays. We evaluated the added value of IgA RF in this context. METHODS: An international sample cohort consisting of samples from 398 RA patients and 1073 controls was tested for IgA RF with 3 commercial assays. For all RA patients and 100 controls essential clinical and serological data for ACR/EULAR classification were available. RESULTS: The sensitivity of IgA RF for diagnosing RA was lower than the sensitivity of IgM RF. Differences in numerical values between IgA RF assays were observed. With all assays, the highest IgA RF values were found in patients with primary Sjögren's syndrome. Double positivity for IgM RF and IgA RF had a higher specificity for RA than either IgM RF or IgA RF. The sensitivity of double positivity was lower than the sensitivity of either IgA RF or IgM RF. Single positivity for IgA RF was at least as prevalent in controls than in RA patients. Adding IgA RF to IgM RF and anti-citrullinated protein antibodies (ACPA) did not affect RA classification. However, combined positivity for IgA RF, IgM RF and IgG ACPA had a higher specificity and lower sensitivity for RA classification than positivity for either of the antibodies. CONCLUSIONS: IgA RF showed a lower sensitivity than IgM RF. Combining IgA RF with IgM RF and ACPA did not improve sensitivity of RA classification. Combined positivity (IgA-RF/IgM-RF/ACPA) increased specificity.

[Biomarkers for the diagnosis of cognitive impairment - Recommendations from the Swiss Memory Clinics]. / Biomarqueurs des pathologies neurodégénératives dans le diagnostic des troubles cognitifs - Revue et recommandations de Swiss Memory Clinics.

Established cerebrospinal fluid (CSF) biomarkers allow for earlier and more accurate etiological diagnosis of cognitive impairment. Information and counselling are needed both before and after biomarker-supported diagnosis. The procedures for diagnostic lumbar punctures and pre-analytical sample handling should follow published consensus recommendations. The results must be interpreted in the context of the other available history information and assessments. Blood-based biomarkers and other non-invasive markers are expected to become available for clinical practice soon. Consequently, a broader usage of biomarkers is expected and may accelerate the development of individually tailored prevention and treatment approaches. This article provides the recommendations of the Swiss Memory Clinics for the use of biomarkers in clinical practice.

Les marqueurs du liquide céphalorachidien établis permettent un diagnostic des troubles cognitifs plus précoce et précis. Il est nécessaire de conseiller les patients avant et après un examen des biomarqueurs. Les procédures de la ponction lombaire et de traitement préanalytique des échantillons doivent suivre des recommandations publiées. L'interprétation des résultats prendra en compte les antécédents médicaux et les autres résultats d'examen disponibles. Des marqueurs sanguins pourraient être disponibles dans un avenir proche. Cela pourrait conduire à une utilisation plus large des biomarqueurs et accélérer le développement d'approches personnalisées de prévention et de traitement. Cet article présente les recommandations de Swiss Memory Clinics concernant l'utilisation des biomarqueurs en pratique clinique.

Association of endothelial activation assessed through endothelin-I precursor peptide measurement with mortality in COVID-19 patients: an observational analysis.

BACKGROUND: Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) disease (COVID-19) has been linked to thrombotic complications and endothelial dysfunction. We assessed the prognostic implications of endothelial activation through measurement of endothelin-I precursor peptide (proET-1), the stable precursor protein of Endothelin-1, in a well-defined cohort of patients hospitalized with COVID-19. METHODS: We measured proET-1 in 74 consecutively admitted adult patients with confirmed COVID-19 and compared its prognostic accuracy to that of patients with community-acquired pneumonia (n = 876) and viral bronchitis (n = 371) from a previous study by means of logistic regression analysis. The primary endpoint was all-cause 30-day mortality. RESULTS: Overall, median admission proET-1 levels were lower in COVID-19 patients compared to those with pneumonia and exacerbated bronchitis, respectively (57.0 pmol/l vs. 113.0 pmol/l vs. 96.0 pmol/l, p < 0.01). Although COVID-19 non-survivors had 1.5-fold higher admission proET-1 levels compared to survivors (81.8 pmol/l [IQR: 76 to 118] vs. 53.6 [IQR: 37 to 69]), no significant association of proET-1 levels and mortality was found in a regression model adjusted for age, gender, creatinine level, diastolic blood pressure as well as cancer and coronary artery disease (adjusted OR 0.1, 95% CI 0.0009 to 14.7). In patients with pneumonia (adjusted OR 25.4, 95% CI 5.1 to 127.4) and exacerbated bronchitis (adjusted OR 120.1, 95% CI 1.9 to 7499) we found significant associations of proET-1 and mortality. CONCLUSIONS: Compared to other types of pulmonary infection, COVID-19 shows only a mild activation of the endothelium as assessed through measurement of proET-1. Therefore, the high mortality associated with COVID-19 may not be attributed to endothelial dysfunction by the surrogate marker proET-1.

The vasoactive peptide MR-pro-adrenomedullin in COVID-19 patients: an observational study.

OBJECTIVES: Midregional pro-adrenomedullin (MR-proADM) is a vasoactive peptide with key roles in reducing vascular hyperpermeability and thereby improving endothelial stability during infection. While MR-proADM is useful for risk stratification in patients with sepsis, clinical data about prediction accuracy in patients with severe acute respiratory syndrome coronavirus 2 disease (COVID-19) is currently missing. METHODS: We included consecutively adult patients hospitalized for confirmed COVID-19 at a tertiary care center in Switzerland between February and April 2020. We investigated the association of MR-proADM levels with in-hospital mortality in logistic regression and discrimination analyses. RESULTS: Of 89 included COVID-19 patients, 19% (n=17) died while in the hospital. Median admission MR-proADM levels (nmol/L) were increased almost 1.5-fold increased in non-survivors compared to survivors (1.3 [interquartile range IQR 1.1-2.3]) vs. 0.8 [IQR 0.7-1.1]) and showed good discrimination (area under the curve 0.78). An increase of 1 nmol/L of admission MR-proADM was independently associated with a more than fivefold increase in in-hospital mortality (adjusted odds ratio of 5.5, 95% confidence interval 1.4-21.4, p=0.015). An admission MR-proADM threshold of 0.93 nmol/L showed the best prognostic accuracy for in-hospital mortality with a sensitivity of 93%, a specificity of 60% and a negative predictive value of 97%. Kinetics of follow-up MR-proADM provided further prognostic information for in-hospital treatment. CONCLUSIONS: Increased levels of MR-proADM on admission and during hospital stay were independently associated with in-hospital mortality and may allow a better risk stratification, and particularly rule-out of fatal outcome, in COVID-19 patients.

Trimethylamine-N-oxide (TMAO) predicts short- and long-term mortality and poor neurological outcome in out-of-hospital cardiac arrest patients.

Objectives: Prior research found the gut microbiota-dependent and pro-atherogenic molecule trimethylamine-N-oxide (TMAO) to be associated with cardiovascular events as well as all-cause mortality in different patient populations with cardiovascular disease. Our aim was to investigate the prognostic value of TMAO regarding clinical outcomes in patients after out-of-hospital cardiac arrest (OHCA). Methods: We included consecutive OHCA patients upon intensive care unit admission into this prospective observational study between October 2012 and May 2016. We studied associations of admission serum TMAO with in-hospital mortality (primary endpoint), 90-day mortality and neurological outcome defined by the Cerebral Performance Category (CPC) scale. Results: We included 258 OHCA patients of which 44.6% died during hospitalization. Hospital non-survivors showed significantly higher admission TMAO levels (µmol L-1) compared to hospital survivors (median interquartile range (IQR) 13.2 (6.6-34.9) vs. 6.4 (2.9-15.9), p<0.001). After multivariate adjustment for other prognostic factors, TMAO levels were significantly associated with in-hospital mortality (adjusted odds ratios (OR) 2.1, 95%CI 1.1-4.2, p=0.026). Results for secondary outcomes were similar with significant associations with 90-day mortality and neurological outcome in univariate analyses. Conclusions: In patients after OHCA, TMAO levels were independently associated with in-hospital mortality and other adverse clinical outcomes and may help to improve prognostication for these patients in the future. Whether TMAO levels can be influenced by nutritional interventions should be addressed in future studies.

Derivatization-free determination of short-chain volatile amines in human plasma and urine by headspace gas chromatography-mass spectrometry.

BACKGROUND: Short-chain volatile amines (SCVA) are an interesting compound class playing crucial roles in physiological and toxicological human settings. Dimethylamine (DMA), trimethylamine (TMA), diethylamine (DEA), and triethylamine (TEA) were investigated in detail. METHODS: Headspace gas chromatography coupled to mass spectrometry (HS-GC-MS) was used for the simultaneous qualitative and quantitative determination of four SCVA in different human body fluids. Four hundred microliters of Li-heparin plasma and urine were analyzed after liberation of volatile amines under heated conditions in an aqueous alkaline and saline environment. Target analytes were separated on a volatile amine column and detected on a Thermo DSQ II mass spectrometer scheduled in single ion monitoring mode. RESULTS: Chromatographic separation of selected SCVA was done within 7.5 minutes. The method was developed and validated with respect to accuracy, precision, recovery and stability. Accuracy and precision criteria were below 12% for all target analytes at low and high levels. The selected extraction procedure provided recoveries of more than 92% from both matrices for TMA, DEA and TEA. The recovery of DMA from Li-heparin plasma was lower but still in the acceptable range (>75%). The newly validated method was successfully applied to plasma and urine samples from healthy volunteers. Detected concentrations of endogenous metabolites DMA and TMA are comparable to already known reference ranges. CONCLUSION: Herein, we describe the successful development and validation of a reliable and broadly applicable HS-GC-MS procedure for the simultaneous and quantitative determination of SCVA in human plasma and urine without relying on derivatization chemistry.

Evaluation of autologous retransfusion from a closed suction drainage system for patient blood management in elective total hip and knee replacement: A two cohort study.

BACKGROUND: Postoperative autologous retransfusion of drainage blood might reduce the transfusion of red blood cell concentrates after major orthopaedic surgery. OBJECTIVES: Our primary objective was to evaluate the effectiveness of a blood collection and retransfusion system. Secondary objectives included safety issues and the quality of the drainage blood collected. DESIGN: Combined retrospective and prospective cohort study. SETTING: Swiss regional hospital, from 1 January to 31 December 2015 (retrospective cohort) and 1 January to 31 August 2018 (prospective cohort). PATIENTS: The retrospective and prospective cohort included 216 and 46 patients, respectively, who underwent elective hip or knee replacement. INTERVENTIONS: Use of a postoperative blood collection and retransfusion system. MAIN OUTCOME MEASURES: The primary outcome was the postoperative haemoglobin in patients with and without autotransfusion. Secondary outcomes were percentage of patients with transfusion of allogeneic blood products and with adverse events with and without autotransfusion. Tertiary outcomes were laboratory levels of specific inflammation and coagulation parameters in collected drain blood directly after surgery and 6 h postoperatively. RESULTS: Autologous retransfusion was performed in 50 patients (23%) in the retrospective analysis. Postoperative haemoglobin level was increased by 5 g dl (P = 0.017) in retransfused patients compared with those without retransfusion. However, there was no difference in the number of transfused allogeneic red blood cell concentrates. Mild adverse transfusion reactions were reported in 13 retransfused patients (26%). Laboratory analyses for the second prospective part detected massively elevated concentrations of myeloperoxidase and IL-6 in the drainage blood, but C-reactive protein and procalcitonin concentrations were within normal ranges at both time points. D-dimers levels were above the upper normal level in 37 and 24% at the two time points, respectively, and tended to decrease over time (P = 0.060). CONCLUSION: Our study questions the effectiveness of postoperative autotransfusion as part of a patient blood management programme. In addition, the obvious signs of inflammatory reactions and coagulation activation raise safety concerns. TRIAL REGISTRATION: The cohort study was not registered in a trial registry.

Metabolomics and Their Ability to Distinguish Thyroid Disorders: A Retrospective Pilot Study.

Early diagnosis of thyroid disorders is key to further treatment. We assessed the ability of a high-throughput proton NMR metabolomic profile to distinguish disease type amongst of Graves' disease (n=87), Hashimoto's thyroiditis (n=17), toxic goiter (n=11), and autoimmune thyroiditis [i. e., subacute thyroiditis (n=4), postpartum thyroiditis (n=1)]. This observational study was conducted investigating patients presenting with a thyroid disorder at a Swiss hospital endocrine referral center and an associated endocrine outpatient clinic. The main outcome was diagnosis of thyroid disorder based on classical parameters. Blood draws took place as close as possible to treatment initiation. We performed one-way ANOVA and partial least squares discriminant analysis (PLS-DA) as multivariate classification and feature ranking method. One-way ANOVA analysis yielded following significantly different metabolites, triglycerides in small VLDL, triglycerides in very small VLDL, and triglycerides in large LDL (FDR=0.04). There was no distinct separation of any of the 4 diagnoses by PLS-DA. We did not find a metabolomic biomarker combination capable of predicting diagnosis. Preanalytical issues might have influenced our results. We strongly suggest replicating our work in another cohort.

Association of serum sphingomyelin profile with clinical outcomes in patients with lower respiratory tract infections: results of an observational, prospective 6-year follow-up study.

Background Sphingolipids - the structural cell membrane components - and their metabolites are involved in signal transduction and participate in the regulation of immunity. We investigated the prognostic implications of sphingolipid metabolic profiling on mortality in a large cohort of patients with lower respiratory tract infections (LRTIs). Methods We measured 15 different sphingomyelin (SM) types in patients with LRTIs from a previous Swiss multicenter trial that examined the impact of procalcitonin-guided antibiotic therapy on total antibiotic use and rates and duration of hospitalization. Primary and secondary end points were adverse outcomes - defined as death or intensive care unit admission within 30 days - and 6-year mortality. Results Of 360 patients, 8.9% experienced an adverse outcome within 30 days and 46% died within 6 years. Levels of all SM types were significantly lower in pneumonia patients vs. those with chronic obstructive pulmonary disease (COPD) exacerbation (p<0.0001 for all comparisons). Sphingomyelin subspecies SM (OH) C22:1 and SM (OH) C22:2 were associated with lower risk for short-term adverse outcomes (sex-, gender- and comorbidity-adjusted odds ratios [OR]: 0.036; 95% confidence interval [CI], 0.002-0.600; p=0.021 and 0.037; 95% CI, 0.001-0.848; p=0.039, respectively). We found no significant associations with 6-year mortality for any SM. Conclusions Circulating sphingolipid levels are lower in inflammatory conditions such as pneumonia and correlate with adverse short-term outcomes. Further characterization of the physiological, pathophysiological and metabolic roles of sphingolipids under inflammatory conditions may facilitate understanding of their roles in infectious disease.

Variable and inaccurate serum IgG4 levels resulting from lack of standardization in IgG subclass assay calibration.

Background The quantification of serum IgG4 is commonly performed during the diagnostic workup of IgG4-related diseases (IgG4-RD). According to recent literature, IgG4 values above 1.35 g/L are characteristic of IgG4-RD and support its diagnosis at initial presentation. The purpose of this study was to evaluate comparability and accuracy of the two main commercially available IgG4 assays (Siemens Healthineers and The Binding Site). Methods Method comparison was performed for IgG and IgG subclasses using a collective of selected samples with elevated serum IgG4. In addition, we assessed the accuracy of both assays using purified polyclonal and monoclonal IgG4 preparations. Results Our data show significant discrepancies between the two IgG subclass assays for the measurement of IgG4 and, to a lesser extent, IgG3. Conclusions The lack of standardization between the two main providers of commercially available IgG4 assays leads to significant inter-assay result discrepancies, which might potentially cause unnecessary clinical workup. We conclude that serum IgG4 assay-specific decision limits, and not an assay-independent single cut-off level for IgG4 (e.g. 1.35 g/L), should be used when assessing patients for IgG4-RD. An internationally recognized, certified reference material for IgG subclasses is urgently needed, and assay manufactures are encouraged to undertake steps toward standardization of measurements of IgG4 and other IgG subclasses.

Comparison of Five TSH-Receptor Antibody Assays in Graves' disease: results from an observational pilot study.

BACKGROUND: Early diagnosis and relapse prediction in Graves' disease influences treatment. We assessed the abilities of four TSH-receptor antibody tests [TRAb] and one cyclic adenosine monophosphate bioassay to predict relapse of Graves' disease. METHODS: Observational study investigating patients presenting with Graves' disease at a Swiss hospital endocrine referral center or an endocrine outpatient clinic. Main outcomes were diagnosis and relapse of Graves' disease after stop of anti-thyroid drugs. We used Cox regression to study associations of TRAb levels with relapse risk and calculated c-statistics [AUC] to assess discrimination. Blood draws took place as close as possible to treatment initiation. RESULTS: AUCs ranged from 0.90 (TSAb Biossay by RSR) to 0.97 (IMMULITE TSI by Siemens). Highest sensitivity (94.0%) was observed for IMMULITE TSI and RSR TRAb Fast, while the greatest specificity (97.9%) was found with the EliA anti-TSH-R (by Thermo Fisher). In Cox regression analysis comparing the highest versus the lower quartiles, the highest hazard ratio [HR] for relapse was found for BRAHMS TRAK (by Thermo Fisher) (2.98, 95% CI 1.13-7.84), IMMULITE TSI (2.40, 95% CI 0.91-6.35), EliA anti-TSH-R (2.05, 95% CI 0.82-5.10), RSR Fast TRAb (1.80, 95% CI 0.73-4.43), followed by RSR STIMULATION (1.18, 95% CI 0.46-2.99). Discrimination analyses showed respective AUCs of 0.68, 0.65, 0.64, 0.64, and 0.59. CONCLUSION: The assays tested had good diagnostic power and relapse risk prediction with few differences among the new assays. Due to the small sample size and retrospective design with possible selection bias, our data need prospective validation.