DC-SIGN, a C-type lectin expressed on the surface of dendritic cells (DCs), efficiently binds and transmits HIVs and simian immunodeficiency viruses to susceptible cells in trans. A DC-SIGN ...homologue, termed DC-SIGNR, has recently been described. Herein we show that DC-SIGNR, like DC-SIGN, can bind to multiple strains of HIV-1, HIV-2, and simian immunodeficiency virus and transmit these viruses to both T cell lines and human peripheral blood mononuclear cells. Binding of virus to DC-SIGNR was dependent on carbohydrate recognition. Immunostaining with a DC-SIGNR-specific antiserum showed that DC-SIGNR was expressed on sinusoidal endothelial cells in the liver and on endothelial cells in lymph node sinuses and placental villi. The presence of this efficient virus attachment factor on multiple endothelial cell types indicates that DC-SIGNR could play a role in the vertical transmission of primate lentiviruses, in the enabling of HIV to traverse the capillary endothelium in some organs, and in the presentation of virus to CD4-positive cells in multiple locations including lymph nodes.
Since the advent of monoclonal antibodies against epidermal growth factor receptor (EGFR) in colorectal cancer therapy, the determination of RAS mutational status is needed for therapeutic ...decision-making. Most prevalent in colorectal cancer are KRAS exon 2 mutations (40% prevalence); lower prevalence is observed for KRAS exon 3 and 4 mutations (6%) and NRAS exon 2, 3, and 4 mutations (5%). The Idylla™ KRAS Mutation Test on the molecular diagnostics Idylla™ platform is a simple (<2 minutes hands-on time), highly reliable, and rapid (approximately 2 hours turnaround time) in vitro diagnostic sample-to-result solution. This test enables qualitative detection of 21 mutations in codons 12, 13, 59, 61, 117, and 146 of the KRAS oncogene being clinically relevant according to the latest clinical guidelines. Here, the performance of the Idylla™ KRAS Mutation Assay, for Research Use Only, was assessed on archived formalin-fixed paraffin-embedded (FFPE) tissue sections by comparing its results with the results previously obtained by routine reference approaches for KRAS genotyping. In case of discordance, samples were assessed further by additional methods. Among the 374 colorectal cancer FFPE samples tested, the overall concordance between the Idylla™ KRAS Mutation Assay and the confirmed reference routine test results was found to be 98.9%. The Idylla™ KRAS Mutation Assay enabled detection of 5 additional KRAS-mutated samples not detected previously with reference methods. As conclusion the Idylla™ KRAS Mutation Test can be applied as routine tool in any clinical setting, without needing molecular infrastructure or expertise, to guide the personalized treatment of colorectal cancer patients.
C-type lectins are calcium-dependent carbohydrate-binding proteins with a wide range of biological functions, many of which are related to immunity. DC-SIGN (dendritic cell-specific ICAM-grabbing ...non-integrin, where ICAM is intercellular adhesion molecule) is a recently described mannose-specific C-type lectin expressed by dendritic cells. Dendritic cells are potent antigen-presenting cells capable of activating T-lymphocytes. DC-SIGN, which is expressed by dendritic cells, binds to ICAM-3 on T-lymphocytes, therefore playing an important role in the activation of T-lymphocytes. DC-SIGN can also bind HIV, and the virus may remain bound to DC-SIGN for protracted periods. DC-SIGN may deliver bound HIV to permissive cell types, mediating infection with high efficiency. A closely related C-type lectin, DC-SIGN-related molecule (DC-SIGNR) has also been described. DC-SIGNR is expressed by restricted subsets of endothelial cells, but has similar ICAM-3 and HIV-binding properties to DC-SIGN. This review describes the mapping of DC-SIGN and DC-SIGNR to chromosome 19p13.3 adjacent to the previously described C-type lectin, CD23 the low-affinity receptor for immunoglobulin E (FcERII). The similar genomic organization of these three genes is discussed and consideration is given to the evolutionary duplications that may underlie this arrangement. Both DC-SIGN and DC-SIGNR possess a neck region, made up of multiple repeats, which supports the ligand-binding domain. Consideration is given to the biological reasons underlying the considerable polymorphism in the numbers of repeats in DC-SIGNR, but not DC-SIGN. The expression patterns of both DC-SIGN and DC-SIGNR are discussed in detail, with particular attention to the expression of both molecules in the placenta, which may have implications for the vertical transmission of HIV. Since dendritic cells may be important in determining the phenotype of many immune responses, via effects on T-lymphocytes, the differential expression of DC-SIGN by particular dendritic cell subsets may have important implications for the immunobiological functions of DC-SIGN. Similarly, the expression of DC-SIGNR by very restricted subsets of endothelial cells may give clues to the function of DC-SIGNR. Finally, the role of DC-SIGN in pathology, particularly in infective and neoplastic processes, is discussed, followed by speculation about likely future developments in this field.
Background This Phase 2a dose expansion study was performed to assess the safety, tolerability and preliminary efficacy of the maximum tolerated dose of the oral histone de-acetylase (HDAC) inhibitor ...CXD101 in patients with relapsed / refractory lymphoma or advanced solid organ cancers and to assess HR23B protein expression by immunohistochemistry as a biomarker of HDAC inhibitor sensitivity. Methods Patients with advanced solid-organ cancers with high HR23B expression or lymphomas received CXD101 at the recommended phase 2 dose (RP2D). Key exclusions: corrected QT > 450 ms, neutrophils < 1.5 x 10.sup.9/L, platelets < 75 x 10.sup.9/L, ECOG > 1. Baseline HR23B expression was assessed by immunohistochemistry. Results Fifty-one patients enrolled between March 2014 and September 2019, 47 received CXD101 (19 solid-organ cancer, 28 lymphoma). Thirty-four patients received greater than or equai to80% RP2D. Baseline characteristics: median age 57.4 years, median prior lines 3, male sex 57%. The most common grade 3-4 adverse events were neutropenia (32%), thrombocytopenia (17%), anaemia (13%), and fatigue (9%) with no deaths on CXD101. No responses were seen in solid-organ cancers, with disease stabilisation in 36% or patients; the overall response rate in lymphoma was 17% with disease stabilisation in 52% of patients. Median progression-free survival was 1.2 months (95% confidence interval (CI) 1.2-5.4) in solid-organ cancers and 2.6 months (95%CI 1.2-5.6) in lymphomas. HR23B status did not predict response. Conclusions CXD101 showed acceptable tolerability with efficacy seen in Hodgkin lymphoma, T-cell lymphoma and follicular lymphoma. Further studies assessing combination approaches are warranted. Trial registration ClinicalTrials.gov identifier NCT01977638. Registered 07 November 2013. Keywords: Histone deacetylase (HDAC), HR23B, Biomarker, Lymphoma
A high prevalence of hepatic pathology (in 17 of 19 cases) was reported in post-mortem (PM) examinations of COVID-19 patients, undertaken between March 2020 and February 2021 by a single autopsy ...pathologist in two English Coronial jurisdictions. The patients in our cohort demonstrated high levels of recognised COVID-19 risk factors, including hypertension (8/16, 50%), type 2 diabetes mellitus (8/16, 50%) and evidence of arteriopathy 6/16 (38%). Hepatic abnormalities included steatosis (12/19; 63%), moderate to severe venous congestion (5/19; 26%) and cirrhosis (4/19; 21%). A subsequent literature review indicated a significantly increased prevalence of steatosis (49%), venous congestion (34%) and cirrhosis (9.3%) in COVID-19 PM cases, compared with a pre-pandemic PM cohort (33%, 16%, and 2.6%, respectively), likely reflecting an increased mortality risk in SARS-CoV-2 infection for patients with pre-existing liver disease. To corroborate this observation, we retrospectively analysed the admission liver function test (LFT) results of 276 consecutive, anonymised COVID-19 hospital patients in our centre, for whom outcome data were available. Of these patients, 236 (85.5%) had significantly reduced albumin levels at the time of admission to hospital, which was likely indicative of pre-existing chronic liver or renal disease. There was a strong correlation between patient outcome (length of hospital admission or death) and abnormal albumin at the time of hospital admission (p = 0.000012). We discuss potential mechanisms by which our observations of hepatic dysfunction are linked to a risk of COVID-19 mortality, speculating on the importance of recently identified anti-interferon antibodies.
ObjectiveCoeliac disease (CD) diagnosis generally depends on histological examination of duodenal biopsies. We present the first study analysing the concordance in examination of duodenal biopsies ...using digitised whole-slide images (WSIs). We further investigate whether the inclusion of immunoglobulin A tissue transglutaminase (IgA tTG) and haemoglobin (Hb) data improves the interobserver agreement of diagnosis.DesignWe undertook a large study of the concordance in histological examination of duodenal biopsies using digitised WSIs in an entirely virtual reporting setting. Our study was organised in two phases: in phase 1, 13 pathologists independently classified 100 duodenal biopsies (40 normal; 40 CD; 20 indeterminate enteropathy) in the absence of any clinical or laboratory data. In phase 2, the same pathologists examined the (re-anonymised) WSIs with the inclusion of IgA tTG and Hb data.ResultsWe found the mean probability of two observers agreeing in the absence of additional data to be 0.73 (±0.08) with a corresponding Cohen’s kappa of 0.59 (±0.11). We further showed that the inclusion of additional data increased the concordance to 0.80 (±0.06) with a Cohen’s kappa coefficient of 0.67 (±0.09).ConclusionWe showed that the addition of serological data significantly improves the quality of CD diagnosis. However, the limited interobserver agreement in CD diagnosis using digitised WSIs, even after the inclusion of IgA tTG and Hb data, indicates the importance of interpreting duodenal biopsy in the appropriate clinical context. It further highlights the unmet need for an objective means of reproducible duodenal biopsy diagnosis, such as the automated analysis of WSIs using artificial intelligence.
Abstract Diabetic complications include infection and cardiovascular disease. Within the immune system, host–pathogen and regulatory host–host interactions operate through binding of oligosaccharides ...by C-type lectin. A number of C-type lectins recognise oligosaccharides rich in mannose and fucose – sugars with similar structures to glucose. This raises the possibility that high glucose conditions in diabetes affect protein–oligosaccharide interactions via competitive inhibition. Mannose-binding lectin, soluble DC-SIGN and DC-SIGNR, and surfactant protein D, were tested for carbohydrate binding in the presence of glucose concentrations typical of diabetes, via surface plasmon resonance and affinity chromatography. Complement activation assays were performed in high glucose. DC-SIGN and DC-SIGNR expression in adipose tissues was examined via immunohistochemistry. High glucose inhibited C-type lectin binding to high-mannose glycoprotein and binding of DC-SIGN to fucosylated ligand (blood group B) was abrogated in high glucose. Complement activation via the lectin pathway was inhibited in high glucose and also in high trehalose – a nonreducing sugar with glucoside stereochemistry. DC-SIGN staining was seen on cells with DC morphology within omental and subcutaneous adipose tissues. We conclude that high glucose disrupts C-type lectin function, potentially illuminating new perspectives on susceptibility to infectious and inflammatory disease in diabetes. Mechanisms involve competitive inhibition of carbohydrate binding within sets of defined proteins, in contrast to broadly indiscriminate, irreversible glycation of proteins.
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