Real-life evaluation of a human immunodeficiency virus screening algorithm using a single combined p24 antigen-antibody assay

Since May 2010, human immunodeficiency virus (HIV) screening in France has been performed using a single combined fourth-generation assay. One of our major concerns is to verify that this screening strategy is able to diagnose HIV primary infection as soon as possible. Thus, the sensitivity and specificity of this strategy were evaluated on 49,623 serum samples, including 29 primary infections, received for routine HIV testing between September 2010 and November 2011. Specimens were screened using the Enzygnost HIV Integral II enzyme-linked immunosorbent assay (ELISA) kit. All positive sera, according to the manufacturer's recommendations [signal-to-cutoff ratio (S/CO) ≥  1] were retested using the Architect HIV Ag/Ab Combo. Moreover, we defined a grey zone (0.5 < S/CO < 1) and sera within this grey zone were retested using the VIDAS HIV DUO Ultra test and HIV-1 RNA was checked by the Abbott RealTime PCR kit. Screening tests were positive for all primary infections. All samples within the grey zone proved VIDAS HIV DUO Ultra and HIV-1 RNA negative. Overall, the ELISA test sensitivity and specificity were 100 and 99.79 %, respectively. The false-positive rate was higher when S/CO was in the low range (1 to 5). Adding a second screening test for positive sera reduced the false-positive rate from 0.20 to 0.02 %. HIV screening with a single combined assay did not miss any documented primary infection during this evaluation period, even without extending the positivity zone.

Profound coordinated alterations of intratumoral NK cell phenotype and function in lung carcinoma

Both the innate and adaptive immune systems contribute to tumor immunosurveillance in mice and humans; however, there is a paucity of direct evidence of a role for natural killer (NK) cells in this important process. In this study, we investigated the intratumoral phenotypic profile and functions of NK cells in primary human tumor specimens of non-small cell lung carcinoma (NSCLC). We used in situ methods to quantify and localize NK cells using the NKp46 marker and we characterized their phenotype in blood, tumoral, and nontumoral samples of NSCLC patients. Intratumoral NK cells displayed a profound and coordinated alteration of their phenotype, with a drastic reduction of NK cell receptor expression specifically detected in the tumoral region. According to their altered phenotype, intratumoral NK cells exhibited profound defects in the ability to activate degranulation and IFN-γ production. We found that the presence of NK cells did not impact the clinical outcome of patients with NSCLC. Finally, we showed that tumor cells heterogeneously express ligands for both activating and inhibitory NK receptors. Taken together, our results suggest that the NSCLC tumor microenvironment locally impairs NK cells, rendering them less tumorcidal and thereby supportive to cancer progression.

Human breast cancer cells enhance self tolerance by promoting evasion from NK cell antitumor immunity

NK cells are a major component of the antitumor immune response and are involved in controlling tumor progression and metastases in animal models. Here, we show that dysfunction of these cells accompanies human breast tumor progression. We characterized human peripheral blood NK (p-NK) cells and malignant mammary tumor-infiltrating NK (Ti-NK) cells from patients with noninvasive and invasive breast cancers. NK cells isolated from the peripheral blood of healthy donors and normal breast tissue were used as controls. With disease progression, we found that expression of activating NK cell receptors (such as NKp30, NKG2D, DNAM-1, and CD16) decreased while expression of inhibitory receptors (such as NKG2A) increased and that this correlated with decreased NK cell function, most notably cytotoxicity. Importantly, Ti-NK cells had more pronounced impairment of their cytotoxic potential than p-NK cells. We also identified several stroma-derived factors, including TGF-β1, involved in tumor-induced reduction of normal NK cell function. Our data therefore show that breast tumor progression involves NK cell dysfunction and that breast tumors model their environment to evade NK cell antitumor immunity. This highlights the importance of developing future therapies able to restore NK cell cytotoxicity to limit/prevent tumor escape from antitumor immunity.

System-level comparison of protein-protein interactions between viruses and the human type I interferon system network

Innate immunity has evolved complex molecular pathways to protect organisms from viral infections. One pivotal line of cellular defense is the induction of the antiviral effect of interferon. To circumvent this primary response and achieve their own replication, viruses have developed complex molecular strategies. Here, we provide a systems-level study of the human type I interferon system subversion by the viral proteome, by reconstructing the underlying protein-protein interaction network. At this network level, viruses establish a massive and a gradual attack, from receptors to transcription factors, by interacting preferentially with highly connected and central proteins as well as interferon-induced proteins. We also demonstrate that viruses significantly target 22% of the proteins directly interacting with the type I interferon system network, suggesting the relevance of our network-based method to identify new candidates involved in the regulation of the antiviral response. Finally, based on the comparative analysis of interactome profiles across four viral families, we provide evidence of common and differential targeting strategies.

Advanced glycation end products (AGEs) activate mast cells

BACKGROUND AND PURPOSE

Advanced glycation endproducts (AGEs) represent one of the many types of chemical modifications that occur with age in long-lived proteins. AGEs also accumulate in pathologies such as diabetes, cardiovascular diseases, neurodegeneration and cancer. Mast cells are major effectors of acute inflammatory responses that also contribute to the progression of chronic diseases. Here we investigated interactions between AGEs and mast cells.

EXPERIMENTAL APPROACHES

Histamine secretion from AGEs-stimulated mast cells was measured. Involvement of a receptor for AGEs, RAGE, was assessed by PCR, immunostaining and use of inhibitors of RAGE. Production of reactive oxygen species (ROS) and cytokines was measured.

KEY RESULTS

Advanced glycation endproducts dose-dependently induced mast cell exocytosis with maximal effects being obtained within 20 s. RAGE mRNA was detected and intact cells were immunostained by a specific anti-RAGE monoclonal antibody. AGEs-induced exocytosis was inhibited by an anti-RAGE antibody and by low molecular weight heparin, a known RAGE antagonist. RAGE expression levels were unaltered after 3 h treatment with AGEs. AGE-RAGE signalling in mast cells involves Pertussis toxin-sensitive G(i)-proteins and intracellular Ca(2+) increases as pretreatment with Pertussis toxin, caffeine, 2-APB and BAPTA-AM inhibited AGE-induced exocytosis. AGEs also rapidly stimulated ROS production. After 6 h treatment with AGEs, the pattern of cytokine secretion was unaltered compared with controls.

CONCLUSIONS AND IMPLICATIONS

Advanced glycation endproducts activated mast cells and may contribute to a vicious cycle involving generation of ROS, increased formation of AGEs, activation of RAGE and to the increased low-grade inflammation typical of chronic diseases.

Expression of the HLA-C2-specific activating killer-cell Ig-like receptor KIR2DS1 on NK and T cells

Killer Ig-like receptors (KIRs) are MHC class I-specific receptors expressed by Natural Killer (NK) and T cell subsets. KIRs either inhibit (KIR-L) or activate (KIR-S) lymphocyte functions. Inhibitory KIR2DL1 and activating KIR2DS1 share ligand specificity for the HLA-C2 group, consistent with their almost identical extracytoplasmic domain. This homology hampered the distinction between KIR2DL1 and KIR2DS1. We report here the characterization of the KIR2DS1(+) subsets among primary human NK and T cells. Regardless of the host HLA-C genotype, around 10% of circulating NK cells expressed KIR2DS1 in absence of KIR2DL1. In HLA-C2 individuals, KIR2DS1 was not able to induce NK cell education (i.e., the acquisition of NK cell competence) nor to interfere with KIR2DL1-induced NK cell education. KIR2DS1 was also present on rare oligoclonal TCRalphabeta(+)CD8alpha(+) and TCRalphabeta(+)CD4(-)CD8(-) subsets. As KIR2DS1 has been associated with autoimmunity and hematopoietic stem cell transplantation, these results pave the way to dissect the function of KIR2DS1 in these clinical conditions.

Effect of early initiation of highly active antiretroviral therapy on CD4 cell count and HIV-RNA viral load trends within 24 months of the onset of acute retroviral syndrome

OBJECTIVES

The effect of starting highly active antiretroviral therapy (HAART) early after the onset of acute retroviral syndrome (ARS) on CD4 and HIV-RNA trends was studied over a 2-year follow-up period.

METHODS

Four groups of HIV-infected patients stratified according to the time interval from ARS onset to HAART initiation and a control group of untreated patients were compared.

RESULTS

The results indicated that the earlier the start of HAART, the faster was the rate of CD4 increase and HIV-RNA decrease. However, this difference did not seem to persist at 24 months.

CONCLUSIONS

The optimal treatment strategy for HIV-infected patients needs to be explored further.

Analysis of pentacyclic triterpenes by LC-MS. A comparative study between APCI and APPI

The analytical performances of three atmospheric-pressure sources, electrospray (ESI), atmospheric-pressure chemical ionization (APCI), and atmospheric-pressure photoionization (APPI), were evaluated for the analysis of pentacyclic triterpenes in liquid chromatography-mass spectrometry (LC-MS). Among these sources, APPI and APCI are particularly well adapted to sensitive analyses of pentacyclic triterpenes by LC-MS. Detection parameters were optimized for both the sources, and the effects of three dopants (toluene, acetone and anisole) on the detection (sensitivity and ion fingerprints in MS spectra) were studied in detail for APPI-MS.The limits of quantification were measured under selected ion monitoring conditions, in the range of 0.005-0.015 mg l(-1) and 0.002-0.84 mg l(-1) in APPI and APCI, respectively, depending on the studied pentacyclic triterpene. Overall, APPI was found more sensitive than APCI in positive ion mode, whereas APCI shows the greatest sensitivity for acidic triterpenes in negative ion mode.Following this study, the developed LC-MS method was used for the characterization of pentacyclic triterpenes in three plant extracts. High amounts of betulinic acid, betulinic aldehyde and betulinic aldehyde acetate were observed in plane bark. The main component of birch bark is betulin and extracts of okoume resin exhibit high amounts of alpha- and beta-amyrin.

Clinical analysis of human natural killer cells

Natural killer (NK) cells are major actors of innate immune responses against viruses, bacteria, parasites, and other mediators of pathology such as malignant transformation. These cells are also directly implicated in the link between innate and adaptive immunity, shaping T-cell responses. It is now obvious that manipulation of this lymphocyte subset could be the basis of new therapeutic approaches for cancer and/or pathogen-driven pathology. Hence, techniques enabling the phenotypic and functional analysis of patient NK cells are of major importance. In this chapter, we present an extensive immunophenotyping of patient NK cells as well as a recently described method to assess NK cell functional activity at the single-cell level.

Identification, activation, and selective in vivo ablation of mouse NK cells via NKp46

Natural killer (NK) cells contribute to a variety of innate immune responses to viruses, tumors and allogeneic cells. However, our understanding of NK cell biology is severely limited by the lack of consensus phenotypic definition of these cells across species, by the lack of specific marker to visualize them in situ, and by the lack of a genetic model where NK cells may be selectively ablated. NKp46/CD335 is an Ig-like superfamily cell surface receptor involved in human NK cell activation. In addition to human, we show here that NKp46 is expressed by NK cells in all mouse strains analyzed, as well as in three common monkey species, prompting a unifying phenotypic definition of NK cells across species based on NKp46 cell surface expression. Mouse NKp46 triggers NK cell effector function and allows the detection of NK cells in situ. NKp46 expression parallels cell engagement into NK differentiation programs because it is detected on all NK cells from the immature CD122(+)NK1.1(+)DX5(-) stage and on a minute fraction of NK-like T cells, but not on CD1d-restricted NKT cells. Moreover, human NKp46 promoter drives NK cell selective expression both in vitro and in vivo. Using NKp46 promoter, we generated transgenic mice expressing EGFP and the diphtheria toxin (DT) receptor in NK cells. DT injection in these mice leads to a complete and selective NK cell ablation. This model paves a way for the in vivo characterization and preclinical assessment of NK cell biological function.

Facial lipoatrophy: report of five cases after injection of synthetic filler into naso-labial folds

BACKGROUND

Facial lipoatrophies are rare disfiguring syndromes, most commonly characterized by loss of buccal fat pads.

AIMS

To demonstrate a relationship between facial lipoatrophy and a new synthetic filler device (Profill) used to correct naso-labial folds.

METHODS

Five cases of lipoatrophy, appeared 9 months or later after Profill injections. No systematic abnormalities were found. In one case biopsy reported a destruction of adipocytes with intense fibrosis in the hypodermis.

DISCUSSION

The culpability of this new biodegradable product is highlighted. To our knowledge, this is the first time this adverse reaction has been reported.

CONCLUSION

Serious adverse reactions may appear months after Profill injection, skin testing is not always predictive or sufficient. Clinical studies with long-term follow-up need to be carried out before new filler devices are launched on the market.

Three-year increase of gamma-glutamyltransferase level and development of type 2 diabetes in middle-aged men and women: the D.E.S.I.R. cohort

AIMS/HYPOTHESIS

Among hepatic markers, gamma-glutamyltransferase (GGT) is the main predictor for development of type 2 diabetes, but there are no data to date on changes in GGT and type 2 diabetes incidence.

METHODS

Data at baseline and at 3 years from the D.E.S.I.R. cohort were used, comprising 2,071 men and 2,130 women without baseline diabetes.

RESULTS

Changes in GGT level were correlated with changes in markers of insulin resistance (fasting insulin, homeostasis model assessment of insulin resistance), as well as with the following elements of the metabolic syndrome: central obesity, and increased fasting glucose, triglycerides and blood pressure (systolic and diastolic). The 3-year increase in GGT was associated with incident type 2 diabetes in both sexes, after adjusting for age and baseline GGT. After further adjustment for baseline confounding factors, including alanine-aminotransferase, alcohol intake, obesity and fasting insulin, the odds ratios (95% CI) for an association between incident type 2 diabetes and unchanged or increased (as opposed to decreased) GGT levels were 2.54 (1.38-4.68) in men (p=0.003) and 2.78 (1.20-6.42) in women (p=0.02). These associations were slightly attenuated after adjusting for the 3-year change in BMI, alcohol consumption and fasting insulin, the odds ratios being 2.49 (1.28-4.86) in men and 2.53 (1.01-6.40) in women. This relationship was not dependent on intra-individual variability.

CONCLUSIONS/INTERPRETATION

An unchanged or increased GGT level over time, even when GGT is in the normal range, is correlated with increasing insulin resistance and is associated with a risk of incident type 2 diabetes in both sexes, independently of baseline GGT, which is itself a diabetes risk factor.

Human NK Cell Education by Inhibitory Receptors for MHC Class I

Natural killer (NK) cells recognize the absence of self MHC class I as a way to discriminate normal cells from cells in distress. In humans, this "missing self" recognition is ensured by inhibitory receptors such as KIR, which dampen NK cell activation upon interaction with their MHC class I ligands. We show here that NK cells lacking inhibitory KIR for self MHC class I molecules are present in human peripheral blood. These cells harbor a mature NK cell phenotype but are hyporesponsive to various stimuli, including MHC class I-deficient target cells. This response is in contrast to NK cells that express a single inhibitory KIR specific for self MHC class I, which are functionally competent when exposed to the same stimuli. These results show the involvement of KIR-MHC class I interactions in the calibration of NK cell effector capacities, suggesting its role in the subsequent "missing self" recognition.

Cyclin dependent kinase inhibitors prevent apoptosis of postmitotic mouse motoneurons

Recent evidence suggests that apoptosis in post-mitotic neurons involves an aborted attempt of cells to re-enter the cell cycle which is characterized by increased expression of cyclins, such as cyclin D1, prior to death. However, such cyclins activation prior to apoptotic cell death remains controversial. Many neurological disorders are characterized by neuronal loss, particularly amyotrophic lateral sclerosis (ALS). ALS is a motoneuronal degenerative condition in which motoneuron loss could be due to an inappropriate return of these cells in the cell cycle. In the present study, we observed that deprivation of neurotrophic factor in purified motoneuron cultures induces an apoptotic pathway. After neurotrophic factor withdrawal, DAPI (4,6-diamidin-2-phenylindol dichlorohydrate) staining revealed the presence of nuclear condensation, DNA fragmentation, and perinuclear apoptotic body. Similarly, release of apoptotic microparticles and activation of caspases-3 and -9 were observed within the first hours following neurotrophic factor withdrawal. Next, we tested whether inhibition of cell cycle-related cyclin-dependent kinases (cdks) can prevent motoneuronal cell death. We showed that three cdk inhibitors, olomoucine, roscovitine and flavopiridol, suppress the death of motoneurons. Finally, we observed early increases in cyclin D1 and cyclin E expression after withdrawal of neurotrophic factors. These findings support the hypothesis that after removal of trophic support, post-mitotic neuronal cells die due to an attempt to re-enter the cell cycle in an uncoordinated and inappropriate manner.

Hepatic markers and development of type 2 diabetes in middle aged men and women: a three-year follow-up study. The D.E.S.I.R. Study (Data from an Epidemiological Study on the Insulin Resistance syndrome)

AIM

It has been shown, mainly in men, that gamma-glutamyltransferase (gammaGT) and alanine-aminotransferase (ALT) predict the development of type 2 diabetes. This study investigates the association between hepatic markers and the 3-year risk of diabetes.

METHODS

Incident diabetes was studied in 2071 men and 2130 women without diabetes at baseline from the D.E.S.I.R. cohort.

RESULTS

Adjusting on age, only gammaGT was predictive of diabetes in both sexes, whereas ALT and aspartate-aminotransferase (AST) were only predictive in men, and bilirubin was not predictive. After adjustment on classical confounding factors and on ALT activity, the odds ratios (OR) for incident diabetes increased across baseline gammaGT quartiles: 1, 3.1, 2.6, 5.0 in men (P<0.0003) and 1, 0.9, 3.2, 3.5 in women (P<0.01). The relations with ALT and AST were not significant after adjusting on gammaGT. Additional adjustment on markers of insulin resistance, BMI or fasting plasma glucose attenuated the risk associated with gammaGT in both sexes, and it remained significantly predictive only in the men. Pooling men and women, those with gammaGT above the median had adjusted ORs of developing diabetes of 13.7 (1.8-99.8) if WHR > =0.85 and 1.7 (0.6-4.8) if WHR<0.85 (interaction P<0.007).

CONCLUSION

gammaGT was the main hepatic risk marker for type-2 diabetes in both sexes, especially in subjects with central adiposity.