HDV RNA assays: Performance characteristics, clinical utility, and challenges.

Coinfection with HBV and HDV results in hepatitis D, the most severe form of chronic viral hepatitis, frequently leading to liver decompensation and HCC. Pegylated interferon alpha, the only treatment option for chronic hepatitis D for many years, has limited efficacy. New treatments are in advanced clinical development, with one recent approval. Diagnosis and antiviral treatment response monitoring are based on detection and quantification of HDV RNA. However, the development of reliable HDV RNA assays is challenged by viral heterogeneity (at least 8 different genotypes and several subgenotypes), intrahost viral diversity, rapid viral evolution, and distinct secondary structure features of HDV RNA. Different RNA extraction methodologies, primer/probe design for nucleic acid tests, lack of automation, and overall dearth of standardization across testing laboratories contribute to substantial variability in performance characteristics of research-based and commercial HDV RNA assays. A World Health Organization (WHO) standard for HDV RNA, available for about 10 years, has been used by many laboratories to determine the limit of detection of their assays and facilitates comparisons of RNA levels across study centers. Here we review challenges for robust pan genotype HDV RNA quantification, discuss particular clinical needs and the importance of reliable HDV RNA quantification in the context of drug development and patient monitoring. We summarize distinct technical features and performance characteristics of available HDV RNA assays. Finally, we provide considerations for the use of HDV RNA assays in the context of drug development and patient monitoring.

Comparison of four commercial EBV DNA quantitative tests to a new test at an early stage of development.

BACKGROUND: Regular screening for Epstein-Barr virus (EBV) DNA using quantitative RT-PCR is recommended for early intervention in at-risk patients. Harmonization of quantitative RT-PCR assays is critical to avoid misinterpretation of results. Here, we compare quantitative results of the cobas® EBV assay to four commercial RT-qPCR assays. METHODS: The cobas EBV, EBV R-Gene, artus EBV RG PCR, RealStar EBV PCR kit 2.0 and Abbott EBV RealTime assays were compared for analytic performance using a 10-fold dilution series of EBV reference material, normalized to the WHO standard. For clinical performance, their quantitative results were compared using anonymized, leftover EBV-DNA-positive EDTA plasma samples. RESULTS: For analytic accuracy, the cobas EBV deviated -0.0097 log10 from target values. The other tests showed deviations between 0.0037 and -0.12 log10. For clinical performance, accuracy and linearity of cobas EBV data from both study sites were excellent. Bland-Altman bias and Deming regression analyses showed statistical correlation for cobas EBV to both EBV R-Gene and Abbott RealTime assays but an offset of cobas EBV to artus EBV RG PCR and RealStar EBV PCR kit 2.0. CONCLUSION: The cobas EBV showed the closest correlation to the reference material, followed closely by EBV R-Gene and Abbott EBV RealTime. Values obtained are stated in IU/mL, facilitating comparison across testing sites and potentially improving utilization of guidelines for diagnosis, monitoring, and treatment of patients.

SARS-CoV-2 RNA Testing Using Different Assays-Impact on Testing Strategies in a Clinical Setting.

In order to assess SARS-CoV-2 real time quantitative polymerase chain reaction (RT-qPCR) results in a real-life setting, three independent laboratories in Graz (Austria) set up a continuous cross comparison schedule. The following test systems were used: The QIAGEN NeuMoDx SARS-CoV-2 Assay, the Allplex™ 2019-nCoV Assay (Seegene) on a MicroLab Nimbus (Hamilton) platform combined with RealStar SARS-CoV-2 RT-PCR Assay (Altona Diagnostics GmbH), and the cobas SARS-CoV-2 test on a fully automated cobas 6800 system (Roche). A total of 200 samples were analysed, 184 (92%) were found to be concordant with all testing platforms, 14 (7%) discordant. Two (1%) samples tested invalid on a single platform and were excluded from further analysis. Discordant results were distributed randomly across the assays. The Ct values from all assays correlated closely with each other. All discordant samples showed Ct values ≥ 26. SARS-CoV-2 RT-qPCR assays may show considerable variability, especially in samples with low viral RNA concentrations. Decision makers should thus balance the advantages and disadvantages of RT-qPCR for mass screening and adopt suitable strategies that ensure a rational management of positive samples with high Ct values.

Performance of Multiplex PCR and ß-1,3-D-Glucan Testing for the Diagnosis of Candidemia.

Bloodstream infections caused by Candida yeasts (candidemia) are associated with high morbidity and mortality. Diagnosis remains challenging, with the current gold standard­isolation from blood culture (BC)­being limited by low sensitivity and long turnaround time. This study evaluated the performance of two nonculture methods: PCR and ß-1,3-D-glucan (BDG) testing. The sera of 103 patients with BC-proven candidemia and of 46 controls were analyzed with the Fungiplex Candida Real-Time PCR and the Wako ß-Glucan Test. The BDG assay demonstrated higher sensitivity than the multiplex PCR (58% vs. 33%). This was particularly evident in ICU patients (60% vs. 28%) and in C. albicans candidemia (57% vs. 37%). The earlier prior to BC sampling the sera were obtained, the more the PCR sensitivity decreased (46% to 18% in the periods of 0−2 and 3−5 days before BC, respectively), while BDG testing was independent of the sampling date. No positive PCR results were obtained in sera sampled more than five days before BC. Specificities were 89% for BDG and 93% for PCR testing. In conclusion, BDG testing demonstrated several advantages over PCR testing for the diagnosis of candidemia, including higher sensitivity and earlier diagnosis. However, BC remains essential, as BDG does not allow for species differentiation.

Identification of contagious SARS-CoV-2 infected individuals by Roche's Rapid Antigen Test.

OBJECTIVES: Rapid antigen tests (RAT) can provide valuable information on the presence or absence SARS-CoV-2 within 15 min without the need of a laboratory. The analytical and diagnostic characteristics of available RATs has led to the question whether they can safely distinguish between infectious and non-infectious patients in an acute care setting. METHODS: Three nasopharyngeal swabs for the analysis by RAT, reverse transcriptase real time polymerase chain reaction (RT-qPCR), and a cell culture based infection assay were collected from 67 patients that presented to the emergency department of the University Hospital of Graz (Austria). The first swab was used for on-site RAT testing in the emergency department using the Roche SARS-CoV-2 RAT. The second swab was sent to the central laboratory of the hospital for RT-qPCR with two independent methods (Cepheid Xpert® Xpress SARS-CoV-2 assay and Roche Cobas SARS-CoV-2 Test) and repeat RAT testing using the same commercial test. With the third swab a cell culture-based infection assay was performed. RESULTS: The RATs performed from independent samples showed substantial agreement (Cohen's-kappa: 0.73, p<0.001). All patients with a positive RAT had positive RT-qPCR with cycle threshold (ct) values <25. Fifteen out of 55 RAT-negative samples were RT-qPCR positive with ct values between 25 and 40. The inoculation of cell cultures with RT-qPCR negative swabs and RT-qPCR positive swabs with ct values >25 did not induce cytopathic effects that were related to SARS-CoV-2. The infection assays from four RAT-negative patients showed cytopathic effects that were induced by other pathogens. CONCLUSIONS: The SARS-CoV-2 RAT from Roche Diagnostics is a valuable tool for managing symptomatic patients. RAT-negative patients may be regarded as non-contagious.

Improved diagnosis of antibiotic-associated haemorrhagic colitis (AAHC) in faecal specimens by a new qualitative real-time PCR assay detecting relevant toxin genes of Klebsiella oxytoca sensu lato.

OBJECTIVE: Toxin-producing Klebsiella oxytoca causes antibiotic-associated haemorrhagic colitis (AAHC). The disease-relevant cytotoxins tilivalline and tilimycine produced by certain K. oxytoca isolates are encoded by the non-ribosomal peptide synthetase genes A (npsA) and B (npsB). In this study, the new LightMix® Modular kit for the detection of relevant K. oxytoca sensu lato (s.l.) toxin genes was evaluated. METHODS: DNA was extracted on the automated EMAG® platform. Amplification was done on the Light Cycler® 480 II instrument. In total, 130 residual faecal specimens collected from patients with antibiotic-associated diarrhoea were studied to determine the clinical sensitivity and specificity. Toxigenic culture served as reference method. RESULTS: With the new kit, the limit of detection was 15 CFU/mL for all targets. For the pehX target specific to K. oxytoca s.l., 65 of 130 clinical specimens were positive, while toxin-specific targets (npsA/npsB) were positive in 47 of 130. The npsA/npsB PCR targets showed a clinical sensitivity of 100% (95%CI 80.5-100%) and a specificity of 73.5% (95%CI 64.3-81.3%) with a positive predictive value of 16.5% (95%CI 12.7-21.2%) and a negative predictive value of 100%. CONCLUSION: Compared with culture, additional clinical specimens positive for K. oxytoca s.l. were detected with real-time PCR. The specificity of the toxin targets appears moderate due to the inferior sensitivity of the culture-based reference method. Since the developed assay is highly sensitive, it may be used as first-line method to improve the diagnosis of AAHC.

Hepatitis D virus (HDV) prevalence in Austria is low but causes considerable morbidity due to fast progression to cirrhosis.

BACKGROUND: Hepatitis D virus (HDV) coinfection aggravates the course of hepatitis B virus (HBV). The prevalence of HDV in Austria is unknown. OBJECTIVE: This national study aimed at (i) recording the prevalence of HDV-infection in Austria and (ii) characterizing the "active" HDV cohort in Austria. METHODS: A total of 10 hepatitis treatment centers in Austria participated in this multicenter study and retrospectively collected their HDV patients between Q1/2010 and Q4/2020. Positive anti-HDV and/or HDV-RNA-polymerase chain reaction (PCR) results were retrieved from local database queries. Disease severity was assessed by individual chart review. Viremic HDV patients with clinical visits in/after Q1/2019 were considered as the "active" HDV cohort. RESULTS: A total of 347 anti-HDV positive patients were identified. In 202 (58.2%) patients, HDV-RNA-PCR test was performed, and 126/202 (62.4%) had confirmed viremia. Hepatocellular carcinoma was diagnosed in 7 (5.6%) patients, 7 (5.6%) patients underwent liver transplantation, and 11 (8.7%) patients died during follow-up. The "active" Austrian HDV cohort included 74 (58.7%) patients: Evidence for advanced chronic liver disease (ACLD, i.e., histological F3/F4 fibrosis, liver stiffness ≥10 kPa, varices, or hepatic venous pressure gradient ≥6 mmHg) was detected in 38 (51.4%) patients, including 2 (5.3%) with decompensation (ascites/hepatic encephalopathy). About 37 (50.0%) patients of the "active" HDV cohort had previously received interferon treatment. Treatment with the sodium-taurocholate cotransporting polypeptide inhibitor bulevirtide was initiated in 20 (27.0%) patients. CONCLUSION: The number of confirmed HDV viremic cases in Austria is low (<1% of HBV patients) but potentially underestimated. Testing all HBV patients will increase the diagnostic yield. More than half of viremic HDV patients had ACLD. Improved HDV testing and workup strategies will facilitate access to novel antiviral therapies.

Evaluation of Endothelial Dysfunction and Inflammatory Vasculopathy After SARS-CoV-2 Infection-A Cross-Sectional Study.

Background: Rising data suggest that COVID-19 affects vascular endothelium while the underlying mechanisms promoting COVID-19-associated endothelial dysfunction and inflammatory vasculopathy are largely unknown. The aim was to evaluate the contribution of COVID-19 to persisting vascular injury and to identify parameters linked to COVID-19-associated endothelial dysfunction and inflammatory vasculopathy. Methods: In a cross-sectional design, flow-mediated dilation (FMD), nitroglycerine-related dilation (NMD), pulse-wave velocity (PWV), augmentation index, intima-media thickness (IMT), compounds of the arginine and kynurenine metabolism, homocysteine, von Willebrand factor (vWF), endothelial microparticles (EMP), antiendothelial cell antibodies, inflammatory, and immunological parameters, as well as nailfold capillary morphology were measured in post-COVID-19 patients, patients with atherosclerotic cardiovascular diseases (ASCVD) and healthy controls without prior or recent SARS-CoV-2 infection. Results: Post-COVID-19 patients had higher values of PWV, augmentation index, IMT, asymmetric and symmetric dimethylarginine, vWF, homocysteine, CD31+/CD42b- EMP, C-reactive protein, erythrocyte sedimentation rate, interleukin-6, and ß-2-glycoprotein antibodies as well as lower levels of homoarginine and tryptophan compared to healthy controls (all with p < 0.05). A higher total number of pathologically altered inflammatory conditions and higher rates of capillary ramifications, loss, caliber variability, elongations and bushy capillaries with an overall higher microangiopathy evolution score were also observed in post-COVID-19 patients (all with p < 0.05). Most parameters of endothelial dysfunction and inflammation were comparably altered in post-COVID-19 patients and patients with ASCVD, including FMD and NMD. Conclusion: COVID-19 may affect arterial stiffness, capillary morphology, EMP and selected parameters of arginine, kynurenine and homocysteine metabolism as well as of inflammation contributing to COVID-19-associated endothelial dysfunction and inflammatory vasculopathy.

Reliable quantification of plasma HDV RNA is of paramount importance for treatment monitoring: A European multicenter study.

OBJECTIVES: Quantification of plasma hepatitis D virus (HDV) RNA is the essential tool for patient management under antiviral therapy. The aim of this European multicenter study was to improve the comparability of quantitative results reported by different laboratories using the CE/IVD-labeled RoboGene HDV RNA Quantification Kit 2.0 (Roboscreen GmbH) with different manual or automated nucleic acid extraction protocols/platforms and amplification/detection devices. METHODS: For harmonization of HDV RNA concentrations obtained by different protocols, correction factors (CF) were determined using the 1st WHO International Standard for HDV RNA. The limit of detection (LOD) and accuracy were determined for each protocol by using reference material. Furthermore, clinical samples were analyzed and results compared. RESULTS: The CF ranged from 20 to 1,870 depending on the protocol used. The LOD was found between 4 and 450 IU/ml. When accuracy was tested, external quality control (EQC) samples containing low HDV RNA concentrations were not detected by those protocols with higher LODs. For EQC samples, the maximum standard deviation of HDV RNA concentrations was found to be 0.53 log10 IU/ml, for clinical samples 0.87 log10 IU/mL. CONCLUSION: To ensure reliability in quantification of HDV RNA, any modification of the extraction and amplification/detection protocol validated by the manufacturer requires revalidation. With the 1st WHO International Standard for HDV RNA, the CF could easily be calculated leading to harmonization of quantitative results. This warrants both accurate monitoring of response to existing anti-HDV treatment and comparability of study results investigating novel anti-HDV drugs.

Alternative detection of SARS-CoV-2 RNA by a new assay based on mass spectrometry.

OBJECTIVES: Accurate detection of SARS-CoV-2 RNA is essential to stopping the spread of SARS-CoV-2. The aim of this study was to evaluate the performance of the recently introduced MassARRAY® SARS-CoV-2 Panel and to compare it to the cobas® SARS-CoV-2 Test. METHODS: The MassARRAY® SARS-CoV-2 Panel consists of five assays targeting different sequences of the SARS-CoV-2 genome. Accuracy was determined using national and international proficiency panels including 27 samples. For clinical evaluation, 101 residual clinical samples were analyzed and results compared. Samples had been tested for SARS-CoV-2 RNA with the cobas® SARS-CoV-2 Test. RESULTS: When accuracy was tested with the MassARRAY® SARS-CoV-2 Panel, 25 of 27 (92.6%) samples revealed correct results. When clinical samples were analyzed with the MassARRAY® SARS-CoV-2 Panel and compared to the cobas® SARS-CoV-2 Test, 100 samples showed concordant results. One sample was found to be inconclusive with the MassARRAY® SARS-CoV-2 Panel. When time-to-results were compared, the new assay showed longer total and hands-on times. CONCLUSIONS: The MassARRAY® SARS-CoV-2 Panel showed a good performance and proved to be suitable for use in the routine diagnostic laboratory. Especially during phases of shortage of reagents and/or disposables, the new test system appears as beneficial alternative to standard assays used for detection of SARS-CoV-2 RNA.

COVID-19 and its effects on endothelium in HIV-positive patients in sub-Saharan Africa: Cardiometabolic risk, thrombosis and vascular function (ENDOCOVID STUDY).

BACKGROUND: COVID-19 has affected almost every country in the world, especially in terms of health system capacity and economic burden. People from sub-Saharan Africa (SSA) often face interaction between human immunodeficiency virus (HIV) infection and non-communicable diseases such as cardiovascular disease. Role of HIV infection and anti-retroviral treatment (ART) in altered cardiovascular risk is questionable and there is still need to further carry out research in this field. However, thus far it is unclear, what impact the COVID-19 co-infection in people living with HIV (PLHIV), with or without therapy will have. The ENDOCOVID project aims to investigate whether and how HIV-infection in COVID-19 patients modulates the time course of the disease, alters cardiovascular risk, and changes vascular endothelial function and coagulation parameters/ thrombosis risk. METHODS: A total of 1026 patients will be included into this study. Cardiovascular research PLHIV with (n = 114 in each of the three recruiting centers) - or without - ART (n = 114 in each of the three recruiting centers) with COVID-19 and HIV-negative with COVID-19 (n = 114 in each of the three recruiting centers) will be carried out via clinical and biochemical measurements for cardiovascular risk factors and biomarkers of cardiovascular disease (CVD). Vascular and endothelial function will be measured by brachial artery flow-mediated dilatation (FMD), carotid intima-media thickness (IMT) assessments, and retinal blood vessel analyses, along with vascular endothelial biomarkers and cogualation markers. The correlation between HIV-infection in COVID-19 PLHIV with or without ART and its role in enhancement of cardiovascular risk and endothelial dysfunction will be assessed at admission, weekly, at discharge and, 4 weeks post-discharge (if possible). IMPACT OF PROJECT: The ENDOCOVID project aims to evaluate in the long-term the cardiovascular risk and vascular endothelial function in PLHIV thus revealing an important transitional cardiovascular phenotype in COVID-19. The study was registered under clinicaltrials.gov (NCT04709302).

Case Report: Changes of Vascular Reactivity and Arterial Stiffness in a Patient With Covid-19 Infection.

Covid-19 infection may be associated with a higher incidence developing cardiovascular complications, however, the underlying mechanisms contributing to cardiovascular complications are largely unknown, while endothelial cell damage may be present. We want to report a 24-year-old woman with Covid-19 infection who had undergone measurements of vascular reactivity and arterial stiffness, including flow-mediated dilation (FMD), nitroglycerin-mediated dilation (NMD), aortic pulse wave velocity (PWV), augmentation index and carotid intima-media-thickness (cIMT) at the time when Covid-19 was diagnosed. Reduced FMD of 0.0% and NMD of 15.5% were observed, while PWV (5.9 m/s), Aix (27%) and cIMT with 0.4 mm of both common carotid arteries were unremarkable. Repeated measurements of FMD, NMD, PWV, Aix, and cIMT 6 weeks after Covid-19 infection revealed persistently reduced FMD (0.0%), while NMD (17.24%), PWV (5.6 m/s) and augmentation index (13%) ameliorated. This case suggests potential impact of Covid-19 infection on endothelial function, also in young Covid-19 patients without any co-morbidity.

European multicenter evaluation of Xpert® Xpress SARS-CoV-2/Flu/RSV test.

Rapid diagnostics for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) are paramount for reducing the spread of the current pandemic. During additional seasonal epidemics with influenza A/B and respiratory syncytial virus (RSV), the clinical signs and symptoms cannot be distinguished easily from SARS-CoV-2. Therefore, a new assay combining four targets in the form of the new Xpert Xpress SARS-CoV-2/Flu/RSV assay was evaluated. The assay was compared to the Xpert Xpress SARS-CoV-2, Xpert Xpress Flu/RSV, Seegene Flu/RSV, influenza A/B r-gene® and RSV/hMPV r-gene®. A total of 295 nasopharyngeal and throat swabs were tested at four institutes throughout Europe including 72 samples positive for SARS-CoV-2, 65 for influenza A, 47 for influenza B, and 77 for RSV. The sensitivity of the new assay was above 95% for all targets, with the highest for SARS-CoV-2 (97.2%). The overall correlation of SARS-CoV-2 Ct values between Xpert Xpress SARS-CoV-2 assay and Xpert Xpress SARS-CoV-2/Flu/RSV assay was high. The agreement between Ct values above 30 showed the multiplex giving higher Ct values for SARS-CoV-2 on average than the singleplex assay. In conclusion, the new assay is a rapid and reliable alternative with less hands-on time for the detection of not one, but four upper respiratory tract pathogens that may circulate at the same time.

Low Rate of SARS-CoV-2 Infections in Symptomatic Patients Attending a Pediatric Emergency Department.

Children and adolescents seem to be at lower risk of developing clinical symptoms of COVID-19. We analyzed the rate of SARS-CoV-2 infections among 3,605 symptomatic children and adolescents at 4,402 outpatient visits presenting to a pediatric emergency department. In a total of 1,105 (32.6%) episodes, the patients fulfilled clinical case definitions for SARS-CoV-2 infection and were tested by nucleic acid testing. A SARS-CoV-2 infection was diagnosed in 10/1,100 episodes (0.3% of analyzed episodes, 0.91% of validly tested patients). Symptoms at presentation did not differ between patients with and without SARS-CoV-2 infection, apart from the frequency of measured temperature ≥37.5°C at presentation. Three percent of analyzed children reported disturbances of olfactory or gustatory senses, but none of them was infected with SARS-CoV-2. The rate of SARS-CoV-2 infections among symptomatic children and adolescents was low and SARS-CoV-2 infections could not reliably be differentiated from other infections without nucleic acid testing.

[Systemic consequences and clinical aspects of SARS-CoV-2 infection]. / Systemische Auswirkungen und klinische Aspekte der SARS-CoV-2-Infektion.

BACKGROUND: COVID-19 is considered a systemic disease. A severe course with fatal outcome is possible and unpredictable. OBJECTIVES: Which organ systems are predominantly involved? Which diseases are predisposed for a fatal course? Which organ changes are found with lethal outcome? MATERIALS AND METHODS: Data from published autopsy studies (28 cases by our group) with respect to organ changes and possible cause of death. RESULTS: The most severe alterations are found in the lungs by diffuse alveolar damage as a symptom of an acute respiratory distress syndrome (ARDS), in part with fibrosis. Thrombosis of small- to mid-sized pulmonary arteries is associated with hemorrhagic lung infarction. Frequent complications are bacterial pneumonias and less frequently fungal pneumonias by aspergillus. Pulmonary thromboembolism is found in 20-30% of lethal courses, also in the absence of deep venous thrombosis. Intestinal involvement of COVID-19 can be associated with intestinal ischemia, caused by shock or local thrombosis. In most cases, the kidneys display acute tubular injury reflecting acute renal failure, depletion of lymphocytes in the lymph nodes and spleen, and hyperplastic adrenal glands. The liver frequently reveals steatosis, liver cell necrosis, portal inflammation, and proliferation of Kupffer cells. Important preexisting diseases in autopsy studies are arterial hypertension with hypertensive and ischemic cardiomyopathy and diabetes mellitus but large population-based studies reveal increased risk of mortality only for diabetes mellitus not for arterial hypertension. CONCLUSIONS: Alterations of the pulmonary circulation with pulmonary arterial thrombosis, infarction, and bacterial pneumonia are important and often lethal complications of COVID-19-associated ARDS. Findings from autopsy studies have influenced therapy and prophylaxis.

Relationship between Endothelial Function, Antiretroviral Treatment and Cardiovascular Risk Factors in HIV Patients of African Descent in South Africa: A Cross-Sectional Study.

Limited information on the effect of antiretroviral treatment (ART) on vascular function in South Africans of African descent living with human immunodeficiency virus (HIV) is available. The relationship between ART, vascular function and cardiovascular risk factors in South Africans of African ancestry with HIV was therefore studied. This cross-sectional study recruited 146 HIV-positive individuals on ART (HIV+ART+), 163 HIV-positive individuals not on ART (HIV+ART-) and 171 individuals without HIV (HIV-) in Mthatha, Eastern Cape Province of South Africa. Flow-mediated dilation (FMD) test was performed to assess endothelial function. Anthropometry and blood pressure parameters were measured. Lipid profile, glycaemic indices, serum creatinine as well as CD4 count and viral load were assayed in blood. Urinary albumin to creatinine ratio (ACR) was determined as a marker of cardiovascular risk. Obesity and albuminuria were positively associated with HIV, and HIV+ART+ participants had significantly higher HDL cholesterol. Dyslipidaemia markers were significantly higher in hypertensive HIV+ART+ participants compared with the controls (HIV+ART- and HIV- participants). FMD was not different between HIV+ART+ participants and the controls. Moreover, HIV+ART+ participants with higher FMD showed lower total cholesterol and LDL cholesterol comparable to that of HIV- and HIV+ART- participants. A positive relationship between FMD and CD4 count was observed in HIV+ART+ participants. In conclusion, antiretroviral treatment was associated with cardiovascular risk factors, particularly dyslipidaemia, in hypertensive South Africans of African ancestry with HIV. Although, ART was not associated with endothelial dysfunction, flow-mediated dilatation was positively associated with CD4 count in HIV-positive participants on ART.

Post-mortem viral dynamics and tropism in COVID-19 patients in correlation with organ damage.

The persistence of SARS-CoV-2 after death of infected individuals is unclear. The aim of this study was to investigate the presence of SARS-CoV-2 RNA in different organs in correlation with tissue damage and post-mortem viral dynamics in COVID-19 deceased. Twenty-eight patients (17 males, 11 females; age 66-96 years; mean 82.9, median 82.5 years) diagnosed with COVID-19 were studied. Swabs were taken post-mortem during autopsy (N = 19) from the throat, both lungs, intestine, gallbladder, and brain or without autopsy (N = 9) only from the throat. Selective amplification of target nucleic acid from the samples was achieved by using primers for ORF1a/b non-structural region and the structural protein envelope E-gene of the virus. The results of 125 post-mortem and 47 ante-mortem swabs were presented as cycle threshold (Ct) values and categorized as strong, moderate, and weak. Viral RNA was detected more frequently in the lungs and throat than in the intestine. Blood, bile, and the brain were negative. Consecutive throat swabs were positive up to 128 h after death without significant increase of Ct values. All lungs showed diffuse alveolar damage, thrombosis, and infarction and less frequently bronchopneumonia irrespective of Ct values. In 30% the intestine revealed focal ischemic changes. Nucleocapsid protein of SARS-CoV-2 was detected by immunohistochemistry in bronchial and intestinal epithelium, bronchial glands, and pneumocytes. In conclusion, viral RNA is still present several days after death, most frequently in the respiratory tract and associated with severe and fatal organ damage. Potential infectivity cannot be ruled out post-mortem.