Genomic DNA functions as a universal external standard in quantitative real-time PCR

Real-time quantitative PCR (qPCR) is a powerful tool for quantifying specific DNA target sequences. Although determination of relative quantity is widely accepted as a reliable means of measuring differences between samples, there are advantages to being able to determine the absolute copy numbers of a given target. One approach to absolute quantification relies on construction of an accurate standard curve using appropriate external standards of known concentration. We have validated the use of tissue genomic DNA as a universal external standard to facilitate quantification of any target sequence contained in the genome of a given species, addressing several key technical issues regarding its use. This approach was applied to validate mRNA expression of gene candidates identified from microarray data and to determine gene copies in transgenic mice. A simple method that can assist achieving absolute quantification of gene expression would broadly enhance the uses of real-time qPCR and in particular, augment the evaluation of global gene expression studies

A Multicenter Study Validates the WHO 2022 Classification for Conjunctival Melanocytic Intraepithelial Lesions With Clinical and Prognostic Relevance

Several nomenclature and grading systems have been proposed for conjunctival melanocytic intraepithelial lesions (C-MIL). The fourth "WHO Classification of Eye Tumors" (WHO-EYE04) proposed a C-MIL classification, capturing the progression of noninvasive neoplastic melanocytes from low- to high-grade lesions, onto melanoma in situ (MIS), and then to invasive melanoma. This proposal was revised to the WHO-EYE05 C-MIL system, which simplified the high-grade C-MIL, whereby MIS was subsumed into high-grade C-MIL. Our aim was to validate the WHO-EYE05 C-MIL system using digitized images of C-MIL, stained with hematoxylin and eosin and immunohistochemistry. However, C-MIL cases were retrieved from 3 supraregional ocular pathology centers. Adequate conjunctival biopsies were stained with hematoxylin and eosin, Melan-A, SOX10, and PReferentially expressed Antigen in Melanoma. Digitized slides were uploaded on the SmartZoom platform and independently scored by 4 ocular pathologists to obtain a consensus score, before circulating to 14 expert eye pathologists for independent scoring. In total, 105 cases from 97 patients were evaluated. The initial consensus diagnoses using the WHO-EYE04 C-MIL system were as follows: 28 benign conjunctival melanoses, 13 low-grade C-MIL, 37 high-grade C-MIL, and 27 conjunctival MIS. Using this system resulted in 93% of the pathologists showing only fair-to-moderate agreement (kappa statistic) with the consensus score. The WHO-EYE05 C-MIL system (with high-grade C-MIL and MIS combined) improved consistency between pathologists, with the greatest level of agreement being seen with benign melanosis (74.5%) and high-grade C-MIL (85.4%). Lowest agreements remained between pathologists for low-grade C-MIL (38.7%). Regarding WHO-EYE05 C-MIL scoring and clinical outcomes, local recurrences of noninvasive lesions developed in 8% and 34% of the low- and high-grade cases. Invasive melanoma only occurred in 47% of the cases that were assessed as high-grade C-MIL. This extensive international collaborative study is the first to undertake a comprehensive review of the WHO-EYE05 C-MIL scoring system, which showed good interobserver agreement and reproducibility.</p

Tim-3 expression defines a novel population of dysfunctional T cells with highly elevated frequencies in progressive HIV-1 infection

Progressive loss of T cell functionality is a hallmark of chronic infection with human immunodeficiency virus 1 (HIV-1). We have identified a novel population of dysfunctional T cells marked by surface expression of the glycoprotein Tim-3. The frequency of this population was increased in HIV-1–infected individuals to a mean of 49.4 ± SD 12.9% of CD8+ T cells expressing Tim-3 in HIV-1–infected chronic progressors versus 28.5 ± 6.8% in HIV-1–uninfected individuals. Levels of Tim-3 expression on T cells from HIV-1–infected inviduals correlated positively with HIV-1 viral load and CD38 expression and inversely with CD4+ T cell count. In progressive HIV-1 infection, Tim-3 expression was up-regulated on HIV-1–specific CD8+ T cells. Tim-3–expressing T cells failed to produce cytokine or proliferate in response to antigen and exhibited impaired Stat5, Erk1/2, and p38 signaling. Blocking the Tim-3 signaling pathway restored proliferation and enhanced cytokine production in HIV-1–specific T cells. Thus, Tim-3 represents a novel target for the therapeutic reversal of HIV-1–associated T cell dysfunction

A Multicenter Study Validates the WHO 2022 Classification for Conjunctival Melanocytic Intraepithelial Lesions With Clinical and Prognostic Relevance

Several nomenclature and grading systems have been proposed for conjunctival melanocytic intraepithelial lesions (C-MIL). The fourth WHO Classification of Eye Tumors (WHO-EYE04) proposed a C-MIL classification, capturing the progression of noninvasive neoplastic melanocytes from low- to high-grade lesions, onto melanoma in situ (MIS), and then to invasive melanoma. This proposal was revised to the WHO-EYE05 C-MIL system, which simplified the high-grade C-MIL, whereby MIS was subsumed into high-grade C-MIL. Our aim was to validate the WHO-EYE05 C-MIL system using digitized images of C-MIL, stained with hematoxylin and eosin and immunohistochemistry. However, C-MIL cases were retrieved from 3 supraregional ocular pathology centers. Adequate conjunctival biopsies were stained with hematoxylin and eosin, Melan-A, SOX10, and PReferentially expressed Antigen in Melanoma. Digitized slides were uploaded on the SmartZoom platform and independently scored by 4 ocular pathologists to obtain a consensus score, before circulating to 14 expert eye pathologists for independent scoring. In total, 105 cases from 97 patients were evaluated. The initial consensus diagnoses using the WHO-EYE04 C-MIL system were as follows: 28 benign conjunctival melanoses, 13 low-grade C-MIL, 37 high-grade C-MIL, and 27 conjunctival MIS. Using this system resulted in 93% of the pathologists showing only fair-to-moderate agreement (kappa statistic) with the consensus score. The WHO-EYE05 C-MIL system (with high-grade C-MIL and MIS combined) improved consistency between pathologists, with the greatest level of agreement being seen with benign melanosis (74.5%) and high-grade C-MIL (85.4%). Lowest agreements remained between pathologists for low-grade C-MIL (38.7%). Regarding WHO-EYE05 C-MIL scoring and clinical outcomes, local recurrences of noninvasive lesions developed in 8% and 34% of the low- and high-grade cases. Invasive melanoma only occurred in 47% of the cases that were assessed as high-grade C-MIL. This extensive international collaborative study is the first to undertake a comprehensive review of the WHO-EYE05 C-MIL scoring system, which showed good interobserver agreement and reproducibility

HIV Delays IFN-α Production from Human Plasmacytoid Dendritic Cells and Is Associated with SYK Phosphorylation

Plasmacytoid dendritic cells (pDC) are the major producers of type I interferons (IFNs) in humans and rapidly produce IFN-α in response to virus exposure. Although HIV infection is associated with pDC activation, it is unclear why the innate immune response is unable to effectively control viral replication. We systematically compared the effect of HIV, Influenza, Sendai, and HSV-2 at similar target cell multiplicity of infection (M.O.I.) on human pDC function. We found that Influenza, Sendai, HSV-2 and imiquimod are able to rapidly induce IFN-α production within 4 hours to maximal levels, whereas HIV had a delayed induction that was maximal only after 24 hours. In addition, maximal IFN-α induction by HIV was at least 10 fold less than that of the other viruses in the panel. HIV also induced less TNF-α and MIP-1β but similar levels of IP-10 compared to other viruses, which was also mirrored by delayed upregulation of pDC activation markers CD83 and CD86. BDCA-2 has been identified as an inhibitory receptor on pDC, signaling through a pathway that involves SYK phosphorylation. We find that compared to Influenza, HIV induces the activation of the SYK pathway. Thus, HIV delays pDC IFN-α production and pDC activation via SYK phosphorylation, allowing establishment of viral populations

Host Genetics and HIV-1: The Final Phase?

This is a crucial transition time for human genetics in general, and for HIV host genetics in particular. After years of equivocal results from candidate gene analyses, several genome-wide association studies have been published that looked at plasma viral load or disease progression. Results from other studies that used various large-scale approaches (siRNA screens, transcriptome or proteome analysis, comparative genomics) have also shed new light on retroviral pathogenesis. However, most of the inter-individual variability in response to HIV-1 infection remains to be explained: genome resequencing and systems biology approaches are now required to progress toward a better understanding of the complex interactions between HIV-1 and its human host

Diagnostic Value of MAML2 Rearrangements in Mucoepidermoid Carcinoma

Mucoepidermoid carcinoma (MEC) is often seen in salivary glands and can harbor MAML2 translocations (MAML2+). The translocation status has diagnostic utility as an objective confirmation of the MEC diagnosis, for example, when distinction from the more aggressive adenosquamous carcinoma (ASC) is not straightforward. To assess the diagnostic relevance of MAML2, we examined our 5-year experience in prospective testing of 8106 solid tumors using RNA-seq panel testing in combinations with a two-round Delphi-based scenario survey. The prevalence of MAML2+ across all tumors was 0.28% (n = 23/8106) and the majority of MAML2+ cases were found in head and neck tumors (78.3%), where the overall prevalence was 5.9% (n = 18/307). The sensitivity of MAML2 for MEC was 60% and most cases (80%) were submitted for diagnostic confirmation; in 24% of cases, the MAML2 results changed the working diagnosis. An independent survey of 15 experts showed relative importance indexes of 0.8 and 0.65 for “confirmatory MAML2 testing” in suspected MEC and ASC, respectively. Real-world evidence confirmed that the added value of MAML2 is a composite of an imperfect confirmation test for MEC and a highly specific exclusion tool for the diagnosis of ASC. Real-world evidence can help move a rare molecular-genetic biomarker from an emerging tool to the clinic

Gene Expression Changes in Immune Cells During Human Immunodeficiency Virus 1 (HIV-1) Infection

Human immunodeficiency virus infection is a chronic condition causing significant changes in the immune system, which are reflected in the altered gene expression patterns of the immune cells. By studying these patterns through gene expression profiling it is possible to describe not only the current states the cells are in, but also to extrapolate the proximal signals that resulted in the observed patterns. In the studies described herein, we have applied this approach to better understand the alterations in the immune function that occur in HIV infection. First, we have obtained transcriptional profiles of CD4+ and CD8+ T cells from patients in early infection, in chronic infection, and in non-progressive infection, and we compared these profiles to each other and to the profiles from uninfected donors. The analyses of the profiles revealed no discernable changes in the T cells of the non-progressive patients when compared to the uninfected individuals. On the other hand, T cells from patients with progressive infection, both early and late, showed patterns characteristic of type I interferon (IFN) exposure. We next examined experimentally the possible proximal causes of the observed transcriptional profiles. We analyzed the gene expression patterns induced by TGFβ, 13 type I interferons, as well as recombinant HIV Tat protein, in T cells and peripheral blood mononuclear cells. The TGFβ responses were inconsistent with the transcriptional profiles seen in HIV-infected patients, whereas both type I IFNs and HIV Tat induced genes in patterns consistent with those seen in patients. In fact, the thirteen IFN-induced patterns were indistinguishable from each other. Tat treatments induced interferon-stimulated genes (ISGs) as well as other genes and the response was not dependent on the presence of plasmacytoid dendritic cells (pDCs), suggesting monocytes as the possible source of the interferon response. In the last study, we examined the responses of plasmacytoid dendritic cells (pDCs) to HIV and other stimuli in healthy and HIV-infected subjects. We observed induction of IFN genes in pDCs of all subjects in response to influenza virus and TLR7 agonist imiquimod, but not to HIV virus. In summary, HIV infection results in chronic induction of type I IFN response in cells of the immune system. The source of this response is likely to be type I IFNs produced by monocytes/macrophages rather than plasmacytoid cells. The monocytic production of type I IFN may be a Tat-dependent response.Ph

Heat shock-induced global transcriptional changes in T-lymphocytes analyzed using DNA array technology

grantor: University of TorontoCells respond to stress by activation of the heat shock (hs) response, regulated by the hs transcription factor, HSF. In human T-lymphocyte-derived PEER cells, a 90 min hs at 42°C results in increased transcription of a set of genes termed hs genes. Parallel analysis of transcriptional changes using both nylon DNA arrays and glass-based microarrays revealed transcriptional activation of genes previously not known to be hs-inducible. These proposed novel hs genes show smaller changes in transcript levels during hs than the well-characterized hs genes. Expression of a constitutively active form of HSF at non-hs temperature (37°C) results in a different expression profile: the up-regulation of the known hs transcripts is reduced and that of the novel hs transcripts is not observed, indicating that the heat itself likely pays a role in activating full transcriptional activity of HSF.M.Sc