Variabilität der C-terminalen gag-Region des humanen Immundefizienzvirus 1 unter antiretroviraler Therapie

Die hohe Variabilität von HIV ist bedingt durch die fehlende proof-reading Funktion der viralen reversen Transkriptase und führt zur Entstehung von Viren mit unterschiedlichsten Eigenschaften. Besonders die antiretrovirale Therapie führt neben dem Immunsystem zur Hemmung der Virusreplikation und so zur Selektion von speziell angepassten Virus-varianten. Das zunehmende Verständnis der Resistenz gegenüber den Proteaseinhibitoren führt dazu, dass mehr und mehr neben dem Enzym auch dessen Substrat, die Schnittstellen der Protease in den Vorläuferproteinen, analysiert werden. In dieser Arbeit wurde der Genbereich näher untersucht, der die spezifischen Aminosäuresequenzen für vier Schnittstellen der HIV-Protease in zwei Leserahmen kodiert, und darüber hinaus, auf RNA-Ebene verantwortlich für ein Frameshiftereignis ist, das die Entstehung der viralen Enzyme ermöglicht. Es wurden Veränderungen zwischen therapie-naiven und therapie-erfahrenen HIV-Isolaten untersucht, so dass eine Reihe von therapie-assoziierten Mutationen identifiziert werden konnte. Diese Veränderungen, die in erster Linie in den Gag-Schnitt-stellen lagen, waren eng mit resistenz-assoziierten PR-Mutationen korreliert. Auf RNA-Ebene fanden sich, neben einer Reihe von Polymorphismen, zwei therapie-assoziierte Mutationen innerhalb des frameshiftregulierenden Bereichs. Die gemessenen Frameshiftraten von HIV-Isolaten aus Patientenproben zeigten, dass die meisten Veränderungen innerhalb dieser Region zu keiner signifikanten Veränderung der Frameshifteffizienz führten, unabhängig davon, ob es sich um Insertionen, Deletionen, einzelne oder multiple Punktmutationen handelte. Wenige HIV-Isolate zeigten eine deutlich reduzierte Frameshifteffizienz, besonders bei Veränderung innerhalb der slippery site. Eine therapie-assoziierte Schnittstellenmutation führte bei gleichzeitigem Vorliegen zweier weiterer Polymorphismen zu einer leicht erhöhten Frameshifteffizienz, wobei nur 9% der HIV-Isolate mit dieser Schnittstellenveränderung diese Kombination aufwiesen. Die Schnittstellenmutation L449F führte durch das Entstehen einer zweiten slippery site zur gleichermaßen erhöhten Frameshiftrate. Insgesamt erwies sich eine Änderung der Frameshifteffizienz als kein genereller Mechanismus der Resistenz gegenüber antiretroviralen Medikamenten. Virusreplikationskinetiken von HIV-Isolaten von therapie-naiven Patienten mit dieser Schnittstellenmutation, die eventuell auf der Übertragung eines PI-resistenten Virus beruht, zeigten darüber hinaus, dass die Frameshiftrate nicht für die veränderte Substratfunktion kompensieren konnte. Vielmehr könnten Mutationen im entfernteren Gag-Bereich kompensatorische Funktionen beim Verbleib von L449F ausüben. Abschließend konnte gezeigt werden, dass diese funktionsreiche Region sich sehr gut als Ziel für Replikationsinhibition mittels siRNA eignet

FCGG renal biopsy network : first epidemiological report on pediatric renal diseases

Objective: In 2016, a regional renal biopsy network was founded as a collaboration between renal pathologists and nephrologists in order to standardize diagnosis and therapy. Uniform renal biopsy request and renal biopsy report forms were introduced, together with a new comprehensive list of renal pathology diagnoses for coding. The 2017-2018 epidemiological data of the pediatric patients (age= 0-17 years) are presented. Methods: Following informed consent and in compliance with GDPR, data registration consists of basic patient and categorical renal data, semi-structured medical information of renal histopathology and the clinical renal disease. Results: In 2017-2018, 92 renal biopsies were reported in pediatric patients or 3.6 per 100,000 pediatric inhabitants per year. Three clinical patterns were equally represented: only proteinuria >1g/day; only hematuria; and combination of proteinuria and hematuria. Acute or chronic renal failure were rare. In the youngest age group (0-5 years; N=26) minimal change disease predominated, followed by Henoch-Schönlein nephritis. The middle age group (6-11 years; N=32) mainly presented with disease characterized by hematuria: IgA nephropathy, Henoch-Schönlein nephritis and Alport’s disease. A more diverse renal disease spectrum was present in the highest age group (12-18 years; N=34): IgA nephropathy, different forms of proliferative glomerulonephritis and of nephrotic syndrome of childhood. Patients with a Caucasian descent presented with IgA nephropathy, while a nephrotic syndrome was more common in those without a Caucasian descent. Alport’s disease was particularly diagnosed in female patients, IgA nephropathy in male patients, and the gender distribution was equal in minimal change disease. Conclusion: The FCGG network provides an better cross-talk between renal pathologists and nephrologists. For the first time, reliable estimates of pediatric renal diseases based on histology are available. Genetic analyses are not yet included. Efforts to coordinate clinical care of pediatric renal diseases are ongoin

FCGG Renal Biopsy Network: first epidemiological report on pediatric renal disease in Flanders

FCGG Renal Biopsy Network: first epidemiological report on pediatric renal diseases Sevasti Karamaria1, Johan De Meester2, Amélie Dendooven3, Elena Levtchenko4, Noel Knops4, Koen Van Hoeck5, Dominique Trouet5, Reiner Mauel6, Ben Sprangers7, Wim Laurens8, Johan Vande Walle1, on behalf of the FCGG – NBVN working group 1 Department of Pediatrics, UZ Gent, Ghent; 2NBVN, Antwerp; 3Pathology Department, UZ Gent, Ghent; 4Department of Pediatrics, UZ Leuven, Leuven; 5Departement of Pediatrics, UZ Antwerpen, Antwerp; 6Department of Pediatrics, UZ Brussel, Brussels; 7Department of Nephrology, UZ Leuven, Leuven; 8Department of Nephrology, AZ Nikolaas, Sint-Niklaas. Objective: In 2016, a regional renal biopsy network was founded as a collaboration between renal pathologists and nephrologists in order to standardize diagnosis and therapy. Uniform renal biopsy request and renal biopsy report forms were introduced, together with a new comprehensive list of renal pathology diagnoses for coding. The 2017-2018 epidemiological data of the pediatric patients (age= 0-17 years) are presented. Methods: Following informed consent and in compliance with GDPR, data registration consists of basic patient and categorical renal data, semi-structured medical information of renal histopathology and the clinical renal disease. Results: In 2017-2018, 92 renal biopsies were reported in pediatric patients or 3.6 per 100,000 pediatric inhabitants per year. Three clinical patterns were equally represented: only proteinuria >1g/day; only hematuria; and combination of proteinuria and hematuria. Acute or chronic renal failure were rare. In the youngest age group (0-5 years; N=26) minimal change disease predominated, followed by Henoch-Schönlein nephritis. The middle age group (6-11 years; N=32) mainly presented with disease characterized by hematuria: IgA nephropathy, Henoch-Schönlein nephritis and Alport’s disease. A more diverse renal disease spectrum was present in the highest age group (12-18 years; N=34): IgA nephropathy, different forms of proliferative glomerulonephritis and of nephrotic syndrome of childhood. Patients with a Caucasian descent presented with IgA nephropathy, while a nephrotic syndrome was more common in those without a Caucasian descent. Alport’s disease was particularly diagnosed in female patients, IgA nephropathy in male patients, and the gender distribution was equal in minimal change disease. Conclusion: The FCGG network provides an better cross-talk between renal pathologists and nephrologists. For the first time, reliable estimates of pediatric renal diseases based on histology are available. Genetic analyses are not yet included. Efforts to coordinate clinical care of pediatric renal diseases are ongoing

Provirus reactivation is impaired in HIV-1 infected individuals on treatment with dasatinib and antiretroviral therapy

The latent viral reservoir formed by HIV-1, mainly in CD4 + T cells, is responsible for the failure of antiretroviral therapy (ART) to achieve a complete elimination of the virus in infected individuals. We previously determined that CD4 + T cells from individuals with chronic myeloid leukemia (CML) on treatment with dasatinib are resistant to HIV-1 infection ex vivo. The main mechanism for this antiviral effect is the preservation of SAMHD1 activity. In this study, we aimed to evaluate the impact of dasatinib on the viral reservoir of HIV-infected individuals with CML who were on simultaneous treatment with ART and dasatinib. Due to the low estimated incidence of HIV-1 infection and CML (1:65,000), three male individuals were recruited in Spain and Germany. These individuals had been on treatment with standard ART and dasatinib for median 1.3 years (IQR 1.3-5.3 years). Reservoir size and composition in PBMCs from these individuals was analyzed in comparison with HIV-infected individuals on triple ART regimen and undetectable viremia. The frequency of latently infected cells was reduced more than 5-fold in these individuals. The reactivation of proviruses from these cells was reduced more than 4-fold and, upon activation, SAMHD1 phosphorylation was reduced 40-fold. Plasma levels of the homeostatic cytokine IL-7 and CD4 effector subpopulations TEM and TEMRA in peripheral blood were also reduced. Therefore, treatment of HIV-infected individuals with dasatinib as adjuvant of ART could disturb the reservoir reactivation and reseeding, which might have a beneficial impact to reduce its size

HIV-1 suppression and durable control by combining single broadly neutralizing antibodies and antiretroviral drugs in humanized mice

Effective control of HIV-1 infection in humans is achieved using combinations of antiretroviral therapy (ART) drugs. In humanized mice (hu-mice), control of viremia can be achieved using either ART or by immunotherapy using combinations of broadly neutralizing antibodies (bNAbs). Here we show that treatment of HIV-1–infected hu-mice with a combination of three highly potent bNAbs not only resulted in complete viremic control but also led to a reduction in cell-associated HIV-1 DNA. Moreover, lowering the initial viral load by coadministration of ART and immunotherapy enabled prolonged viremic control by a single bNAb after ART was withdrawn. Similarly, a single injection of adeno-associated virus directing expression of one bNAb produced durable viremic control after ART was terminated. We conclude that immunotherapy reduces plasma viral load and cell-associated HIV-1 DNA and that decreasing the initial viral load enables single bNAbs to control viremia in hu-mice

TRY plant trait database – enhanced coverage and open access

Plant traits - the morphological, anatomical, physiological, biochemical and phenological characteristics of plants - determine how plants respond to environmental factors, affect other trophic levels, and influence ecosystem properties and their benefits and detriments to people. Plant trait data thus represent the basis for a vast area of research spanning from evolutionary biology, community and functional ecology, to biodiversity conservation, ecosystem and landscape management, restoration, biogeography and earth system modelling. Since its foundation in 2007, the TRY database of plant traits has grown continuously. It now provides unprecedented data coverage under an open access data policy and is the main plant trait database used by the research community worldwide. Increasingly, the TRY database also supports new frontiers of trait‐based plant research, including the identification of data gaps and the subsequent mobilization or measurement of new data. To support this development, in this article we evaluate the extent of the trait data compiled in TRY and analyse emerging patterns of data coverage and representativeness. Best species coverage is achieved for categorical traits - almost complete coverage for ‘plant growth form’. However, most traits relevant for ecology and vegetation modelling are characterized by continuous intraspecific variation and trait–environmental relationships. These traits have to be measured on individual plants in their respective environment. Despite unprecedented data coverage, we observe a humbling lack of completeness and representativeness of these continuous traits in many aspects. We, therefore, conclude that reducing data gaps and biases in the TRY database remains a key challenge and requires a coordinated approach to data mobilization and trait measurements. This can only be achieved in collaboration with other initiatives

Epistatic Interactions in NS5A of Hepatitis C Virus Suggest Drug Resistance Mechanisms

Hepatitis C virus (HCV) causes a major health burden and can be effectively treated by direct-acting antivirals (DAAs). The non-structural protein 5A (NS5A), which plays a role in the viral genome replication, is one of the DAAs’ targets. Resistance-associated viruses (RAVs) harbouring NS5A resistance-associated mutations (RAMs) have been described at baseline and after therapy failure. A mutation from glutamine to arginine at position 30 (Q30R) is a characteristic RAM for the HCV sub/genotype (GT) 1a, but arginine corresponds to the wild type in the GT-1b; still, GT-1b strains are susceptible to NS5A-inhibitors. In this study, we show that GT-1b strains with R30Q often display other specific NS5A substitutions, particularly in positions 24 and 34. We demonstrate that in GT-1b secondary substitutions usually happen after initial R30Q development in the phylogeny, and that the chemical properties of the corresponding amino acids serve to restore the positive charge in this region, acting as compensatory mutations. These findings may have implications for RAVs treatment

Rituximab in children with steroid-dependent nephrotic syndrome: experience of a tertiary center and review of the literature

Rituximab (RTX) is a new treatment option in children with difficult-to-treat steroid-dependent nephrotic syndrome (SDNS). We evaluated the experience of our tertiary center and reviewed the current literature.peerreview_statement: The publishing and review policy for this title is described in its Aims & Scope. aims_and_scope_url: http://www.tandfonline.com/action/journalInformation?show=aimsScope&journalCode=yacb20status: publishe

Epistatic Interactions in NS5A of Hepatitis C Virus Suggest Drug Resistance Mechanisms

Hepatitis C virus (HCV) causes a major health burden and can be effectively treated by direct-acting antivirals (DAAs). The non-structural protein 5A (NS5A), which plays a role in the viral genome replication, is one of the DAAs' targets. Resistance-associated viruses (RAVs) harbouring NS5A resistance-associated mutations (RAMs) have been described at baseline and after therapy failure. A mutation from glutamine to arginine at position 30 (Q30R) is a characteristic RAM for the HCV sub/genotype (GT) 1a, but arginine corresponds to the wild type in the GT-1b; still, GT-1b strains are susceptible to NS5A-inhibitors. In this study, we show that GT-1b strains with R30Q often display other specific NS5A substitutions, particularly in positions 24 and 34. We demonstrate that in GT-1b secondary substitutions usually happen after initial R30Q development in the phylogeny, and that the chemical properties of the corresponding amino acids serve to restore the positive charge in this region, acting as compensatory mutations. These findings may have implications for RAVs treatment

Rethinking peritubular capillary basement membrane multilayering in renal transplant pathology: a case report

Severe multilayering (ML) of the peritubular capillary basement membranes in kidney allografts is considered to be an ultrastructural hallmark of chronic antibody-mediated rejection (CAMR). We describe here the unexpected findings in a young male adolescent with underlying focal segmental glomerulosclerosis who underwent a living-related donor transplant procedure, a case which brought into question the specificity of ML.status: publishe