Expansion of highly activated invariant natural killer T cells with altered phenotype in acute dengue infection.

Invariant natural killer T (iNKT) cells are capable of rapid activation and production of cytokines upon recognition of antigenic lipids presented by CD1d molecules. They have been shown to play a significant role in many viral infections and were observed to be highly activated in patients with acute dengue infection. In order to characterize further their role in dengue infection, we investigated the proportion of iNKT cells and their phenotype in adult patients with acute dengue infection. The functionality of iNKT cells in patients was investigated by both interferon (IFN)-γ and interleukin (IL)-4 ex-vivo enzyme-linked immunospot (ELISPOT) assays following stimulation with alpha-galactosyl-ceramide (αGalCer). We found that circulating iNKT cell proportions were significantly higher (P = 0·03) in patients with acute dengue when compared to healthy individuals and were predominantly of the CD4(+) subset. iNKT cells of patients with acute dengue had reduced proportions expressing CD8α and CD161 when compared to healthy individuals. The iNKT cells of patients were highly activated and iNKT activation correlated significantly with dengue virus-specific immunoglobulin (Ig)G antibody levels. iNKT cells expressing Bcl-6 (P = 0·0003) and both Bcl-6 and inducible T cell co-stimulator (ICOS) (P = 0·006) were increased significantly in patients when compared to healthy individuals. Therefore, our data suggest that in acute dengue infection there is an expansion of highly activated CD4(+) iNKT cells, with reduced expression of CD161 markers.

Training and practice in bronchoscopy a national survey in Italy.

BACKGROUND AND AIM: Bronchoscopy is performed in a variety of different settings in Italy. The surveys conducted so far have highlighted the heterogeneity of the procedures and the frequent inability to adhere to the guidelines. The aim of this survey was to analyse procedures, training, and opinions of Italian respiratory physicians performing interventional bronchology in the clinical practice. METHODS: The study was conducted retrospectively on 300 pulmonologists. From January to June 2008, these were invited to participate in an email survey to be sent out monthly to each participant for four consecutive months. RESULTS: Two hundred and one respiratory physicians took part in the study, most of whom (83.5%) work in either Pulmonology or Interventional Pulmonology Units. The year before the survey, 21.2% of the participants had performed fewer than 100 examinations, 42.3% 100 to 300, and 36.6% more than 300 bronchoscopies; 53.9% were familiar with the international guidelines on the topic. Among the responders, 34.1% had received less than 6 months training, 55.3% considered further training in rigid bronchoscopy, laser procedures and thoracoscopy, invaluable for their professional activity. Adequate training for transbronchial needle aspirates, was reported by 49.6% of respondents. CONCLUSIONS: Our data show that interventional bronchoscopy procedures are regularly performed according to current recommendations by over half of the Italian Pulmonologists participating in our survey. The need for more comprehensive basic education and training was put forward by the majority of physicians.

Improved localization of cellular membrane receptors using combined fluorescence microscopy and simultaneous topography and recognition imaging.

The combination of fluorescence microscopy and atomic force microscopy has a great potential in single-molecule-detection applications, overcoming many of the limitations coming from each individual technique. Here we present a new platform of combined fluorescence and simultaneous topography and recognition imaging (TREC) for improved localization of cellular receptors. Green fluorescent protein (GFP) labeled human sodium-glucose cotransporter (hSGLT1) expressed Chinese Hamster Ovary (CHO) cells and endothelial cells (MyEnd) from mouse myocardium stained with phalloidin-rhodamine were used as cell systems to study AFM topography and fluorescence microscopy on the same surface area. Topographical AFM images revealed membrane features such as lamellipodia, cytoskeleton fibers, F-actin filaments and small globular structures with heights ranging from 20 to 30 nm. Combined fluorescence and TREC imaging was applied to detect density, distribution and localization of YFP-labeled CD1d molecules on alpha-galactosylceramide (alphaGalCer)-loaded THP1 cells. While the expression level, distribution and localization of CD1d molecules on THP1 cells were detected with fluorescence microscopy, the nanoscale distribution of binding sites was investigated with molecular recognition imaging by using a chemically modified AFM tip. Using TREC on the inverted light microscope, the recognition sites of cell receptors were detected in recognition images with domain sizes ranging from approximately 25 to approximately 160 nm, with the smaller domains corresponding to a single CD1d molecule.

Regression of diabetic complications by islet transplantation in the rat.

AIMS/HYPOTHESIS: Type 1 diabetes is a chronic disease leading to complications such as peripheral neuropathies, nephropathy and cardiovascular disease. Pancreatic islet transplantation is being extensively investigated for blood glucose control in animals and in human type 1 diabetic patients, but the question of whether it can reverse long-term diabetic complications has not been fully explored. We investigated the effects of islet transplantation on diabetic complications in a rat model of streptozotocin-induced diabetes. METHODS: Three groups of rats were used: healthy controls, diabetic and diabetic rats transplanted with microencapsulated islets at 2 months after diabetes induction, when neuropathy was detectable by a decrease in tail nerve conduction velocity (NCV) and impaired nociceptive thresholds. Blood glucose levels and body weight were measured weekly. The variables considered were: thermal (hot plate test) and mechanical sensitivity (Randal-Selitto paw withdrawal test), NCV and Na+, K+-ATPase activity in the sciatic nerve. At the end of the experiments hearts were removed for morphometric determination and myocyte number, and kidneys removed for histological examination. RESULTS: Islet transplantation in diabetic rats induced normoglycaemia in a few days, accompanied by a rapid rise in body weight and amelioration of impaired nociceptive thresholds, as well as normalisation of NCV and Na(+), K(+)-ATPase, which were both about 25% below normal in diabetic rats. Myocyte loss was reduced (-34%) by islet transplantation and the observed mild kidney damage of diabetic rats was prevented. CONCLUSIONS/INTERPRETATION: Besides controlling glycaemia, transplantation of microencapsulated pancreatic islets induced almost complete regression of neuropathy and prevented cardiovascular alterations.

Incidence of complications in bronchoscopy. Multicentre prospective study of 20,986 bronchoscopies.

AIM: To evaluate the frequency of complications in bronchoscopy from data compiled between 1/2/2002 to 1/2/2003. MATERIALS AND METHODS: Nineteen Italian centres of thoracic endoscopy participated in the study, for a total of 20,986 bronchoscopies (FBS), including 10,658 explorative bronchoscopies (EB) (50.79%), 5,520 bronchial biopsies (BB) (26.30%), 1,660 transbronchial biopsies (TBB) (7.91%), 1,127 broncho-alveolar lavages (BAL) (5.37%), 930 transbronchial needle-aspirates (TBNA) (4.43%), 1.091 therapeutic bronchoscopies (TB), comprising ND-YAG Laser, argon-plasma, electrocautery knife, stent insertion (5.20%). 82.4% of the procedures involved the use of a flexible bronchoscope, 16.3% were carried out using a rigid bronchoscope and 1.3% using the mixed technique. RESULTS: The total number of complications recorded was 227 (1.08% of the cases examined), including 20 (0.09%) during local anesthesia and pre-medication, 195 (0.92%) during the endoscopic procedures and 12 (0.05%) in the two hours following FBS. The total number of deaths was 4 (0.02%), due to cardiac arrest, pulmonary edema, delayed respiratory failure and shock in pre-medication, respectively. 68.28% of the complications were treated medically, 25.99% by means of endoscopy and 5.72% with surgery. The healing percentage was 98.2%. CONCLUSIONS: This study has shown that bronchoscopy is a safe method with low incidence of mortality and complications. The preparation, experience and continuous training of the operators of the medical and nursing team seem to play a fundamental role in reducing the incidence of complications at least in certain procedures such as BB and TBB.

Monocyte derived dendritic cells retain their functional capacity in patients following infection with hepatitis C virus.

Studies assessing the function of monocyte derived dendritic cells (MD-DC) in individuals with hepatitis C virus (HCV) infection have shown conflicting results. Impaired MD-DC function in chronic HCV infection would have important implications both for understanding the pathogenesis of HCV infection and in the use of autologous MD-DC in vaccination strategies. We determined the allostimulatory capacity of MD-DC in the same patient before and after HCV infection. Next, the phenotype, cytokine production and allostimulatory function of immature and mature MD-DC in individuals with persistent HCV infection were compared directly with MD-DC from healthy individuals. Finally, we assessed the ability of MD-DC to prime autologous naïve peptide specific CD8+ T cells using HLA-A2 class-I tetramers. DCs retained the same allostimulatory capacity before and following the establishment of persistent HCV infection. The surface phenotype and the amount of interleukin (IL)-10 and IL-12(p70) produced during DC maturation did not differ between HCV-infected individuals and healthy controls. Mature DCs from HCV-infected individuals performed comparably in an allogeneic MLR compared with healthy individuals. Mature MD-DC from HCV-infected individuals stimulated the expansion of peptide specific naïve CD8+ T cells. MD-DC from HCV-infected and healthy individuals are phenotypically indistinguishable and perform comparably in functional assays.

Harnessing NKT cells for therapeutic applications.

Activation of NKT cells leads to the maturation of dendritic cells and efficiently assists priming of antigen-specific immune responses. The lack of polymorphism of CDld molecules and the evolutionary conservation of NKT cell responses highlight the important role of these cells in bridging innate and adaptive immune responses and advocate the value of harnessing this system in clinical settings. Compounds capable of fine tuning NKT cell activation should be actively exploited as potent adjuvants in vaccination strategies or as immunomodulators of autoimmune diseases.

T cells in peripheral blood after gluten challenge in coeliac disease.

BACKGROUND: Current understanding of T cell epitopes in coeliac disease (CD) largely derives from intestinal T cell clones in vitro. T cell clones allow identification of gluten peptides that stimulate T cells but do not quantify their contribution to the overall gluten specific T cell response in individuals with CD when exposed to gluten in vivo. AIMS: To determine the contribution of a putative dominant T cell epitope to the overall gliadin T cell response in HLA-DQ2 CD in vivo. PATIENTS: HLA-DQ2+ individuals with CD and healthy controls. METHODS: Subjects consumed 20 g of gluten daily for three days. Interferon gamma (IFN-gamma) ELISPOT was performed using peripheral blood mononuclear cells (PBMC) to enumerate and characterise peptide and gliadin specific T cells before and after gluten challenge. RESULTS: In 50/59 CD subjects, irrespective of homo- or heterozygosity for HLA-DQ2, IFN-gamma ELISPOT responses for an optimal concentration of A-gliadin 57-73 Q-E65 were between 10 and 1500 per million PBMC, equivalent to a median 51% of the response for a "near optimal" concentration of deamidated gliadin. Whole deamidated gliadin and gliadin epitope specific T cells induced in peripheral blood expressed an intestinal homing integrin (alpha4beta7) and were HLA-DQ2 restricted. Peripheral blood T cells specific for A-gliadin 57-73 Q-E65 are rare in untreated CD but can be predictably induced two weeks after gluten exclusion. CONCLUSION: In vivo gluten challenge is a simple safe method that allows relevant T cells to be analysed and quantified in peripheral blood by ELISPOT, and should permit comprehensive high throughput mapping of gluten T cell epitopes in large numbers of individuals with CD.

Mature dendritic cells differentiated in the presence of interferon-beta and interleukin-3 prime functional antigen-specific CD8 T cells.

Dendritic cell (DC)-based immunization represents a promising approach for the immunotherapy of cancer. The optimal conditions required to prepare DCs remain to be defined. Monocytes incubated in the presence of interferon (IFN)-beta and interleukin (IL)-3 give rise to a distinct type of DCs (IFN-beta/IL-3 DCs) that are particularly efficient at eliciting IFN-gamma and IL-5 production by allogeneic helper T cells. We assessed the capacity of this new type of DCs to prime antigen-specific naive CD8(+) T cells and compared them to the conventional DCs differentiated in the presence of granulocyte-macrophage colony stimulating factor (GM-CSF) and IL-4 (GM-CSF/IL-4 DCs). We demonstrate that IFN-beta/IL-3 DCs matured by TLR3 or CD40 ligation efficiently prime Melan-A(26-35)-specific CD8(+) T cells in vitro, at a similar level as GM-CSF/IL-4 DCs. Activated antigen-specific CD8(+) T cells produced IFN-gamma and displayed potent cytotoxic activity against peptide-pulsed target cells. Expansion of CD8(+) T cell numbers was generally higher following priming with CD40-L than with polyinosinic-polycytidylic acid (poly I:C) matured DCs. Cytolytic activity was induced by both maturing agents. These data indicate that IFN-beta/IL-3 DCs represent a promising cell population for the immunotherapy of cancer.

CHF-1024, a DA2/alpha2 agonist, blunts norepinephrine excretion and cardiac fibrosis in pressure overload.

We compared the effects of an ACE inhibitor, captopril, with those of a DA2-dopaminergic/alpha2-adrenergic receptor agonist (CHF-1024) on neuroendocrine activation and cardiac fibrosis in a model of pressure-overload hypertrophy. Interrenal aortic stenosis was performed in 89 rats, treated with CHF-1024 (0.33, 2 or 6 mg kg(-1) day(-1)), or captopril (1 g/L). Hemodynamic variables were recorded. Cardiac and renal weights, plasma aldosterone, renin activity and urinary catecholamine excretion were measured, as well as cardiac collagen. Blood pressure was lower in stenotic animals treated with CHF-1024 compared to vehicle (161 +/- 10 vs 219 +/- 10 mmHg, p < 0.01), but LV weight was similar. CHF-1024 elicited a marked dose-dependent attenuation of urinary norepinephrine excretion (1.80 +/- 0.18 in controls compared to 0.40 +/- 0.14 microg/24 h at the highest dose, p < 0.01) and of LV perivascular fibrosis. Captopril provoked a marked hypotension, reduced cardiac and body weights, plasma aldosterone concentration, dopamine excretion and perivascular collagen. The DA2/alpha2 agonist CHF-1024 effectively blunts adrenergic drive and cardiac fibrosis in a rat model of pressure overload.

Mature dendritic cells prime functionally superior melan-A-specific CD8+ lymphocytes as compared with nonprofessional APC.

Priming of melan-A(26/27-35)-specific CTL occurs only in a fraction of late stage melanoma patients, whereas during the early stages of the disease and in healthy volunteers, melan-A CTL have functional and phenotypic markers consistent with a naive phenotype. To study the requirements for expansion of naive melan-A CTL from healthy donors, we set up an in vitro priming protocol and, using tetramer assays, we demonstrate that the activity and phenotype of the expanded melan-A CTL are profoundly influenced by the type of APC used. Priming by nonprofessional APC leads to expansion of melan-A CTL with reduced cytolytic activity and low level of IFN-gamma secretion. In contrast, mature dendritic cells (DC) expand cytolytic and IFN-gamma-producing melan-A CTL. Priming by mature DC is also efficient at low peptide concentration and requires only one round of stimulation. Finally, we observed that a significant fraction of CD45RO(+) melan-A CTL primed by mature DC expresses high levels of the homing receptor CD62L, whereas CTL primed by nonprofessional APC express CD62L in lower percentages and at lower levels. These results suggest that suboptimal priming by nonprofessional APC could account for the presence in vivo of dysfunctional cells and strongly support the immunotherapeutic use of mature DC for expansion of effector and memory Ag-specific CTL.

A shift in the phenotype of melan-A-specific CTL identifies melanoma patients with an active tumor-specific immune response.

In a significant proportion of melanoma patients, CTL specific for the melan-A(26/7-35) epitope can be detected in peripheral blood using HLA-A2/peptide tetramers. However, the functional capacity of these CTL has been controversial, since although they prove to be effective killers after in vitro expansion, in some patients they have blunted activation responses ex vivo. We used phenotypic markers to characterize melan-A tetramer(+) cells in both normal individuals and melanoma patients, and correlated these markers with ex vivo assays of CTL function. Melanoma patients with detectable melan-A tetramer(+) cells in peripheral blood fell into two groups. Seven of thirteen patients had a CCR7(+) CD45R0(-) CD45RA(+) phenotype, the same as that found in some healthy controls, and this phenotype was associated with a lack of response to melan-A peptide ex vivo. In the remaining six patients, melan-A tetramer(+) cells were shifted toward a CCR7(-) CD45R0(+) CD45RA(-) phenotype, and responses to melan-A peptide could be readily demonstrated ex vivo. When lymph nodes infiltrated by melan-A-expressing melanoma cells were examined, a similar dichotomy emerged. These findings demonstrate that activation of melan-A-specific CTL occurs in only some patients with malignant melanoma, and that only patients with such active immune responses are capable of responding to Ag in ex vivo assays.

Clinical correlates of elevated plasma natriuretic peptides and Big endothelin-1 in a population of ambulatory patients with heart failure. A substudy of the Italian Network on Congestive Heart Failure (IN-CHF) registry. IN-CHF Investigators.

BACKGROUND: Activation of neuroendocrine factors plays a major role in the pathophysiology and progression of heart failure. The aim of the present study was 1) to assess the clinical correlates of elevated plasma natriuretic peptides [atrial natriuretic peptide (ANP) and brain natriuretic peptide (BNP)] and Big endothelin-1 in a population of 180 ambulatory patients from the Italian registry of heart failure (Italian Network on Congestive Heart Failure, IN-CHF) in 22 clinical centers, 2) to assess the within-patient variability of plasma BNP concentration, and 3) to evaluate the analytical agreement for BNP determination between a core laboratory and local sites. METHODS: ANP and BNP were measured with specific immunoradiometric methods, Big endothelin-1 with an enzyme immunoassay. RESULTS: Elevated BNP was associated with severe mitral valve regurgitation (odds ratio 8.546, 95% confidence interval 1.879-38.510, p = 0.0052); high circulating concentrations of ANP and BNP were found in older patients, and in patients with higher NYHA functional class or reduced left ventricular ejection fraction. Elevated plasma concentration of Big endothelin-1 was a strong and independent predictor of atrial fibrillation (odds ratio 4.001, 95% confidence interval 1.531-10.454, p = 0.0047). Plasma concentration of BNP was reasonably stable at 3-month interval in patients with mild-to-moderate heart failure (mean between-visit difference -1.5+/-45 pg/ml, n = 96). There was a satisfactory analytical agreement between the central laboratory and sites, over a broad range of concentrations (2-1133 pg/ml, n = 283) with a slope for the best line fitted by linear regression of 1.09 (r2 = 0.96). CONCLUSIONS: BNP assay may become an appropriate tool for routine clinical practice in patients with congestive heart failure.

Dendritic cell maturation is induced by mycoplasma infection but not by necrotic cells.

To identify environmental stimuli that induce dendritic cell (DC) maturation, we exposed human monocyte-derived immature DC to apoptotic or necrotic cells and measured the levels of expression of costimulatory molecules and cytokine production. While most necrotic or apoptotic cells did not have any effect, some induced DC maturation as detected by up-regulation of CD83 and B7.2 and production of IL-12 and IL-6. The capacity of these cell lines to induce DC maturation was due to their contamination by mycoplasma, since the maturation-inducing effect disappeared when the cells were treated with cyproxin. Furthermore, cell lines deliberately infected with mycoplasma containing supernatant acquired the capacity to induce DC maturation. Our results reveal that DC are able to sense mycoplasma infection and mature as they do in response to most viruses and bacteria. In contrast, apoptotic or necrotic cells fail to induce DC maturation.

Aspirin does not interact with ACE inhibitors when both are given early after acute myocardial infarction: results of the GISSI-3 Trial.

Aspirin (ASA) and angiotensin-converting enzyme inhibitor (ACEi) therapy reduce mortality when administered early after the onset of myocardial infarction. ASA can antagonize some effects of ACEi therapy by inhibiting the synthesis of vasodilating prostaglandins; however, the evidence for this effect from large controlled trials is contradictory. The authors analyzed a database of 18,895 patients of the Gruppo Italiano per lo Studio della Sopravvivenza nell'Infarto Miocardio-3 (GISSI-3) Trial in which patients were allocated either to receive lisinopril or not to receive lisinopril within 24 hours of the onset of symptoms of myocardial infarction. The aim of the study was to verify the possible negative interaction between ASA and the ACEi lisinopril in the postacute phase of acute myocardial infarction. Of 18,895 analyzable patients, 15,841 received ASA at entry. Overall lisinopril reduced 42-day mortality from 7.1% to 6.3%. In patients receiving ASA, mortality was reduced by lisinopril from 6.0% to 5.4%, and from 13.0% to 10.8% in patients not receiving ASA. The difference in proportional reductions of mortality corresponds to the fact that a more marked lisinopril effect is seen in patients at higher baseline risk across all study subgroups, one of which coincides with the no-ASA group. The analysis of the inhospital incidence of major clinical events did not reveal a potentially negative interaction between ASA and lisinopril. The same findings were obtained from the analysis of reinfarction at 42 days. The interaction between ASA and lisinopril was also tested by multivariate analysis adjusted for confounding variables at entry, and the interaction tests were not statistically significant. Serum creatinine levels at 42 days were significantly higher in lisinopril group than in the control group. Systolic and diastolic blood pressures in lisinopril group were significantly lower than controls at 42 days. The effect of lisinopril on creatinine and blood pressure did not differ between the ASA and no-ASA groups. ASA does not decrease the mortality benefit of early lisinopril after myocardial infarction, nor does it increase the risk of major adverse events. Lisinopril is safe and effective when given early after the onset of myocardial infarction, regardless of a concomitant administration of ASA started early and continued over a 6-week period.

Inhibition of dendritic cell maturation by herpes simplex virus.

Maturation of dendritic cells (DC), leading to migration and increased T cell stimulatory capacity, is essential for the initiation of immune responses. This process is triggered by a variety of stimuli, such as inflammatory cytokines, bacterial and viral products. Using a recombinant disabled infectious single cycle herpes simplex virus 1 (HSV-1) encoding green fluorescent protein, we show that the infected DC are defective in up-regulating co-stimulatory molecules, do not produce cytokines, and do not acquire responsiveness to chemokines required for migration to secondary lymphoid organs. These results reveal yet another strategy used by HSV-1 to evade the immune response, namely the inhibition of signaling pathways involved in DC maturation.

Maturation, activation, and protection of dendritic cells induced by double-stranded RNA.

The initiation of an immune response is critically dependent on the activation of dendritic cells (DCs). This process is triggered by surface receptors specific for inflammatory cytokines or for conserved patterns characteristic of infectious agents. Here we show that human DCs are activated by influenza virus infection and by double-stranded (ds)RNA. This activation results not only in increased antigen presentation and T cell stimulatory capacity, but also in resistance to the cytopathic effect of the virus, mediated by the production of type I interferon, and upregulation of MxA. Because dsRNA stimulates both maturation and resistance, DCs can serve as altruistic antigen-presenting cells capable of sustaining viral antigen production while acquiring the capacity to trigger naive T cells and drive polarized T helper cell type 1 responses.

Essential and partially overlapping role of CD3gamma and CD3delta for development of alphabeta and gammadelta T lymphocytes.

CD3gamma and CD3delta are two highly related components of the T cell receptor (TCR)-CD3 complex which is essential for the assembly and signal transduction of the T cell receptor on mature T cells. In gene knockout mice deficient in either CD3delta or CD3gamma, early thymic development mediated by pre-TCR was either undisturbed or severely blocked, respectively, and small numbers of TCR-alphabeta+ T cells were detected in the periphery of both mice. gammadelta T cell development was either normal in CD3delta-/- mice or partially blocked in CD3gamma-/- mice. To examine the collective role of CD3gamma and CD3delta in the assembly and function of pre-TCR and in the development of gammadelta T cells, we generated a mouse strain with a disruption in both CD3gamma and CD3delta genes (CD3gammadelta-/-). In contrast to mice deficient in either CD3gamma or CD3delta chains, early thymic development mediated by pre-TCR is completely blocked, and TCR-alphabeta+ or TCR-gammadelta+ T cells were absent in the CD3gammadelta-/- mice. Taken together, these studies demonstrated that CD3gamma and CD3delta play an essential, yet partially overlapping, role in the development of both alphabeta and gammadelta T cell lineages.