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The SARS-CoV-2 detection campaign is a key element in the viral pandemic response. Here we present a monocentric study to evaluate a simplified molecular amplification technology alternative to classical RT-qPCR platforms. The test, C4Covid-19 HumanTM makes use of saliva as a starting sample allowing for self, painless collection, avoiding risk of viral transmission for the operator who performs the nasopharyngeal (NP) procedure. Total time to result is 30 minutes. The principle relies on an extraction-free detection of two targets within the viral genomic RNA, RdRp and N genes, by real-time reverse transcription loop mediated isothermal amplification (RT-LAMP). Saliva and NP swabs were collected simultaneously from 1491 symptomatic or contact cases and analyzed in parallel by RT-LAMP and RT-qPCR respectively. The 249 positives RT-qPCR samples had a Ct

International audience; Legionella pneumophila is a pathogenic bacterium involved in regular outbreaks characterized by a relatively high fatality rate and an important societal impact. Frequent monitoring of the presence of this bacterium in environmental water samples is necessary to prevent these epidemic events, but the traditional culture-based detection and identification method requires up to 10 days. Reported herein is a method allowing identification of Legionella pneumophila by metabolic lipopolysaccharide labeling which targets, for the first time, a precursor to monosaccharides that are specifically present within the O-antigen of the bacterium. This new approach allows easy detection of living Legionella pneumophila, while other Legionella species are not labeled.

Background. The polymorphisms of IFNL4 are strongly associated with both spontaneous hepatitis C virus (HCV) clearance and response to peg-IFN-α/ribavirin treatment. To further establish the biological effects of the IFNL4 and rs1297860 variations, we studied the activity of liver immune cells. Methods. Fresh liver samples were collected from HCV-infected patients before any treatment and from NASH patients as controls. Degranulation activity of each lymphocyte type was assessed by the surface expression of CD107a. IFNL4 polymorphisms and HCV genotypes were determined. Results. In the liver, frequency of CD107a + immune cells was significantly higher in HCV patients compared to NASH patients. Higher degranulation activity was observed in lymphocytes of HCV patients with favorable IFNL4 genotypes compared to patients with unfavorable genotypes. Multivariate regression analyses indicated that serum ALT levels were dependent on both Metavir activity score and frequency of CD107a positive NKT cells. The high level of degranulation activity observed before treatment was associated with a high HCV RNA decline at the early stage of peg-IFN-α/ribavirin treatment in patients with favorable genotypes. Conclusions. These data underline that intrahepatic lymphocyte degranulation activity in HCV-infected patients is associated with IFNL4 polymorphisms and contributes to the clearance of HCV in patients with favorable genotypes under antiviral therapy.

Brucellaspecies are responsible for the global zoonotic disease brucellosis. These intracellular pathogens express a set of factors – including lipopolysaccharides, virulence regulator proteins and phosphatidylcholine – to ensure their full virulence. Some virulence factors are essential for invasion of the host cell, whereas others are crucial to avoid elimination by the host. They allowBrucellaspp. to survive and proliferate within its replicative vacuole and enable the bacteria to escape detection by the host immune system. Several strategies have been used to develop animal vaccines against brucellosis, but no adequate vaccine yet exists to cure the disease in humans. This is probably due to the complicated pathophysiology of humanBrucellaspp. infection, which is different than in animal models. Here we reviewBrucellaspp. virulence factors and how they control bacterial trafficking within the host cell.

During chronic hepatitis C virus (HCV) infection, the role of intra-hepatic (IH) natural killer (NK) cells is still controversial. To clarify their functions, we investigated anti-viral and cytotoxic activity of NK cells in human fresh liver biopsies. We compared the functions of IH-NK cells in HCV-infected and NASH patients in physiological conditions as well as after stimulation using flow cytometric and immunohistochemical analyses. Interestingly, few IH-NK cells produced anti-viral cytokine IFN-γ in HCV-infected patients similarly as in non-infected individuals. Spontaneous degranulation activity was extremely low in peripheral NK cells compared to IH-NK cells, and was significantly higher in IH-NK cells from HCV-infected patients compared to non-infected individuals. Immunohistochemical analysis revealed that perforin granules were polarized at the apical pole of IH-NK cells. The presence of CD107a and perforin in IH-NK cells demonstrated that NK cells exerted a cytolytic activity at the site of infection. Importantly, IH-NK cell functions from HCV-infected patients were inducible by specific exogenous stimulations. Upon ex vivo K562 target cell stimulations, the number of degranulating NK cells was significantly increased in the pool of IH-NK cells compared to circulating NK cells. Interestingly, after stimulation, the frequency of IFN-γ-producing IH-NK cells in HCV-infected patients was significantly higher at early stage of inflammation whereas the spontaneous IH-NK cell degranulation activity was significantly impaired in patients with highest inflammation and fibrosis Metavir scores. Our study highlights that some IH-NK cells in HCV-infected patients are able to produce INF-γ and degranulate and that those two activities depend on liver environment including the severity of liver injury. Thus, we conclude that critical roles of IH-NK cells have to be taken into account in the course of the liver pathogenesis associated to chronic HCV infection.

Introduction The single nucleotide polymorphisms (rs12979860), near the IL28B gene, is correlated with a sustained virological response (SVR) in Hepatitis C Virus (HCV) infected patients treated with Pegylated Interferon-α combined with Ribavirin (1,2). However, the association of rs12979860 polymorphism with immune function of the liver, the site of HCV production, and the mechanism of SVR remain still undefined. Methods Patients chronically HCV-infected patients were genotyped for rs12979860 defining C/T polymorphism. C allele is associated to SVR. Liver samples were collected from the needle biopsy achieved for the diagnosis prior any treatment. Single cell suspensions were prepared by mechanical disruption. Liver lymphocytes (T, Treg, NK and NKT) were identified by flow cytometry for the expression of CD45, CD3, CD4, CD8, CD56 and FoxP3 as markers and CD107a for degranulation activity. Expression of CD8β, FoxP3, IL10 and HPRT genes was measured by PCR. Immunohistochemistry were performed on in paraffin sections for the detection of CD8 and FoxP3. Statistical analysis wwas done with Mann–Whitney U test and Wilcoxon matched-t test. Results Lymphocytes from 52 fresh liver biopsies displayed similar distributions of T (CD3), NKT (CD3, CD56) and NK (CD56) among CD45 cells by flow cytometry multi parametric analysis, whatever the IL28B genotype of the patients. Strikingly, higher degranulation activity, revealed by CD107a surface expression, was observed in T (p = 0.000), NKT (p = 0.002) and NK cells (p = 0.015) of patients with CC genotype (n = 17) compared to patients with CT or TT genotypes (n = 35); patients with CC genotype displayed two fold higher degranulation activity than patients with CT genotype in T (p = 0.001), NKT (p = 0.002) and NK cells (p = 0.011); no significant difference was observed between patients with CT and TT genotypes. Sections of liver from 19 patients showed the frequency of CD4-FoxP3 lymphocytes two fold higher (p = 0.004) in patients with CC genotype (n = 11) as compared to patients with CT genotype (n = 8) supporting the presence of Treg. Previous study demonstrated that the ratio between the number of CD8 cells and FoxP3 cells in parenchymatous necro-inflammatory areas is maintained in the early stage of the chronic hepatitis (3). This is found only in patients with CC genotype, whereas this ratio is reduced in patients with CT genotype due to lower number of FoxP3 cells. Transcriptional analyses confirmed these data and further showed two strong correlations between: one between FoxP3 and CD8β, another between FoxP3 and IL-10 expressions in patients with CC genotype. Conclusion Collectively these data provide new insights into the role of IL28B polymorphism related to SVR in treatment of HCV infected patients. CC genotype, which is linked to good response, is associated to higher efficiency of effector lymphocytes (T, NK and NKT) of the liver. The liver immune response appears tightly regulated as suggested by the links between CD8 cells and CD4-FoxP3 cells, and between IL10 and FoxP3 gene expression.

OHdG – HPLC-EC)], telomere length [T/S – RT-PCR], apoptosis [M30 – ELISA test] and liver fibrosis [Pro-Collagen III (PIIINP – ELISA)]. At t0 the patients were categorized into two groups, in relation to their routine coffee intake (0–2 and 3–5 cups/day). Results: At t0, AST, GGT and ALP levels were significantly lower while HCV-RNA levels significantly higher in patients with higher coffee consumption (p =0.05). During the month of coffee intake, 8-OHdG and PIIINP levels significantly dropped, to regrow during the abstinence period (p =0.05/p = 0.04, respectively), while T/S became significantly shorter (p = 0.006). A significant negative correlation was found between T/S and 8-OHdG levels (p = 0.03). HCV-RNA and M30 (apoptosis) levels were significantly higher during coffee intake (p =0.002 and p=0.04). Conclusions: During coffee intake, despite an increase in viral load, that however is not considered a strong prognostic factor for HCC development, we observed: – a lower level of collagen deposition in the liver, that probably mediates the protection exerted by coffee with respect to progression to cirrhosis; – a reduction in oxidative DNA damage, correlated with increased telomere length (with consequent increased genomic stability) and an increased apoptosis, that both potentially mediate the reduced risk of HCC development. Supported by ISIC Scientific Committee.

Brucella is an intracellular pathogen able to persist for long periods of time within the host and establish a chronic disease. We show that soon after Brucella inoculation in intestinal loops, dendritic cells from ileal Peyer's patches become infected and constitute a cell target for this pathogen. In vitro, we found that Brucella replicates within dendritic cells and hinders their functional activation. In addition, we identified a new Brucella protein Btp1, which down-modulates maturation of infected dendritic cells by interfering with the TLR2 signaling pathway. These results show that intracellular Brucella is able to control dendritic cell function, which may have important consequences in the development of chronic brucellosis., Author Summary A key determinant for intracellular pathogenic bacteria to induce infectious diseases is their ability to avoid recognition by the host immune system. Although most microorganisms internalized by host cells are efficiently cleared, Brucella behave as a Trojan horse causing a zoonosis called brucellosis that affects both humans and animals. Here we show that pathogenic Brucella are able to target host cell defense mechanisms by controlling the function of the sentinels of the immune system, the dendritic cells. In particular, the Brucella TIR-containing protein (Btp1) targets the Toll-like receptor 2 activation pathway, which is a major host response system involved in bacterial recognition. Btp1 is involved in the inhibition of dendritic cell maturation. The direct consequence is a control of inflammatory cytokine secretion and antigen presentation to T lymphocytes. These bacterial proteins are not specific for Brucella and have been identified in other pathogens and may be part of a general virulence mechanism used by several intracellular pathogens to induce disease.