Evaluation of VIDAS® Salmonella (SLM) Immunoassay Method with Rappaport-Vassiliadis (RV) Medium for Detection of Salmonella in Foods: Collaborative Study

A collaborative study was conducted to compare the VIDAS Salmonella (SLM) with Rappaport-Vassiliadis (RV) method for detection of Salmonella in foods to the current standard method presented in the U.S. Food and Drug Administration's Bacteriological Analytical Manual (BAM) and the culture method presented in AOAC's Official Methods of Analysis. The VIDAS SLM with RV method uses tetrathionate broth in combination with RV medium in place of selenite cystine broth for selective enrichment, thereby eliminating the hazardous waste issue for laboratories. Twenty five laboratories participated in the evaluation, each testing one or more of 8 test products: nonfat dry milk, dried egg, soy flour, lactic casein, milk chocolate, raw ground pork, raw ground turkey, and raw peeled shrimp. Results of the study showed no significant differences in the numbers of confirmed positive samples with the VIDAS SLM with RV procedure and the BAM/AOAC culture procedure. The VIDAS SLM with RV method was effective for rapid detection of Salmonella in foods. It is recommended that AOAC INTERNATIONAL modify the VIDAS Salmonella SLM procedure to include the RV method.

Recent progress of the development of a long pulse 140GHz ECRH system on EAST

A long pulse ECRH system with a goal of 140GHz 4MW 100~1000s has been developed to meet the requirement of steady-state operation on EAST. Gycom gyrotrons are employed in the No.1 and No.3 systems, CPI gyrotrons are used in the No.2 and No.4 systems. The development of the two Gycom gyrotron systems has been finished. The first short pulse EC wave injection has been demonstrated successfully during the EAST 2015 Spring campaign. In the commissioning and operation towards steady-state operation, 0.4MW 100s has been injected to plasma successfully by using the No.1 system, 4.7keV 102s L-mode and 102s H-mode plasma have been achieved on EAST with the help of ECRH. Recently, a longest pulse of 0.55MW 1000s has been obtained based on calorimetric dummy load measurements on the No.3 gyrotron. The No.2 gyrotron also has been installed and partially tested, 500kW 80s has been demonstrated in the dummy load. The remaining No.4 gyrotron will be ready to test in 2018 or 2019. The whole 4MW system will be completed within two years. The 400s fully non-inductive H-mode operation would be expected in the next four years in the condition of fully tungsten diverter on EAST.

A spectroscopic electric field vector imaging diagnostic for electron cyclotron heating systems

An experimental measurement of the wave electric field vector provides important data that can be used to directly compare against 3D full-wave simulations. This direct comparison yields the fastest approach toward identifying missing physics in computational models and providing a high fidelity validation platform. In this paper, we present a diagnostic that is capable of imaging the Electron Cyclotron (EC) wave electric field vector by acquiring filtered images of polarized D _β spectral satellites. The diagnostic is designed to have a spatial and temporal resolution on the order of 100 μm and 100 μs, respectively. The diagnostic purpose is to provide experimental data for the direct validation of full-wave codes used to predict EC beam propagation and absorption and to provide real-time monitoring of EC waves.

Evaluation of critical congenital heart defects screening using pulse oximetry in the neonatal intensive care unit

OBJECTIVE

To evaluate the implementation of early screening for critical congenital heart defects (CCHDs) in the neonatal intensive care unit (NICU) and potential exclusion of sub-populations from universal screening.

STUDY DESIGN

Prospective evaluation of CCHD screening at multiple time intervals was conducted in 21 NICUs across five states (n=4556 infants).

RESULTS

Of the 4120 infants with complete screens, 92% did not have prenatal CHD diagnosis or echocardiography before screening, 72% were not receiving oxygen at 24 to 48 h and 56% were born ⩾2500 g. Thirty-seven infants failed screening (0.9%); none with an unsuspected CCHD. False positive rates were low for infants not receiving oxygen (0.5%) and those screened after weaning (0.6%), yet higher among infants born at <28 weeks (3.8%). Unnecessary echocardiograms were minimal (0.2%).

CONCLUSION

Given the majority of NICU infants were ⩾2500 g, not on oxygen and not preidentified for CCHD, systematic screening at 24 to 48 h may be of benefit for early detection of CCHD with minimal burden.

Improved cross-calibration of Thomson scattering and electron cyclotron emission with ECH on DIII-D

Thomson scattering produces n_e profiles from measurement of scattered laser beam intensity. Rayleigh scattering provides a first calibration of the relation n_e ∝ I_TS, which depends on many factors (e.g., laser alignment and power, optics, and measurement systems). On DIII-D, the n_e calibration is adjusted against an absolute n_e from the density-driven cutoff of the 48 channel 2nd harmonic X-mode electron cyclotron emission system. This method has been used to calibrate Thomson n_e from the edge to near the core (r/a > 0.15). Application of core electron cyclotron heating improves the quality of cutoff and depth of its penetration into the core, and also changes underlying MHD activity, minimizing crashes which confound calibration. Less fueling is needed as "ECH pump-out" generates a plasma ready to take up gas. On removal of gyrotron power, cutoff penetrates into the core as channels fall successively and smoothly into cutoff.

Avoiding Tokamak Disruptions by Applying Static Magnetic Fields That Align Locked Modes with Stabilizing Wave-Driven Currents

Nonrotating ("locked") magnetic islands often lead to complete losses of confinement in tokamak plasmas, called major disruptions. Here locked islands were suppressed for the first time, by a combination of applied three-dimensional magnetic fields and injected millimeter waves. The applied fields were used to control the phase of locking and so align the island O point with the region where the injected waves generated noninductive currents. This resulted in stabilization of the locked island, disruption avoidance, recovery of high confinement, and high pressure, in accordance with the expected dependencies upon wave power and relative phase between the O point and driven current.

Abstract 4782: Epigenetic resistance to Notch inhibition in T cell acute lymphoblastic leukemia

Resistance to therapy is one of the major challenges in cancer treatment today, equally applicable to conventional chemotherapy as well as targeted therapy. Malignant tumors have widespread epigenetic alterations including aberrant expression of chromatin modifiers in a wide variety of tumors and chromosomal translocations involving chromatin modifiers that can drive development of some cancers. In addition, cancer genome sequencing studies have identified frequent somatic alterations in many chromatin-regulating enzymes. Moreover, epigenetic changes have been implicated in the development of drug resistance.

T cell acute lymphoblastic leukemia (T-ALL) has a high rate of treatment-refractory disease and relapse that significantly lowers survival rates compared to other forms of ALL. The identification of activating somatic NOTCH1 mutations in over 50% of patients with T-ALL led to the development of γ-secretase inhibitors (GSI) that prevent cleavage and activation of NOTCH1. Although effective in vitro, the rapid development of resistance that develops with Notch inhibition in vivo has so far prevented the translation of these inhibitors into the clinical setting.

We have developed a model of therapeutic resistance to inhibition of Notch signaling in T-ALL. In this model, ‘persister’ cells readily expand in the presence of GSI and the absence of Notch signaling. Rare persister cells are pre-existing in naïve T-ALL populations. Intriguingly, in vitro resistance to NOTCH1 inhibitor therapy is reversible, suggesting that it is epigenetically mediated. When compared to GSI-sensitive cells, persisters are characterized by distinct signaling and gene expression programs, and demonstrate global chromatin compaction. Using a short-hairpin knock-down screen of ∼ 300 known chromatin regulators we identified the chromatin reader BRD4 as essential for persister T-ALL cells. BRD4 expression levels are upregulated in persister T-ALL cells. Genome-wide binding studies of BRD4 show that it is found at active regulatory elements in the genome that are associated with genes known to be important for cell proliferation, survival and signaling pathways in T-ALL, e. g. MYC and BCL2. Treatment of persisters with the BRD4 inhibitor JQ1 down-regulates expression of these target genes. Functionally, JQ1 treatment leads to growth arrest and apoptosis in persister T-ALL cells, at doses well tolerated by GSI-sensitive leukemia cells. Furthermore, combination therapy of GSI and JQ1 is significantly more effective over vehicle or single agent therapy for primary human T-ALLs in vitro and in vivo.

These studies demonstrate epigenetic heterogeneity as a basis of drug resistance in leukemia. We suggest that combination therapies that include targeting of chromatin regulators may hold great therapeutic promise for prevention and treatment of resistant disease.

Citation Format: Birgit Knoechel, Justine Roderick, Kaylyn Williamson, Jiang Zhu, Jens Lohr, Matthew Cotton, Shawn Gillespie, Daniel Fernandez, Manching Ku, Hongfang Wang, Federica Piccioni, Serena Silver, Mohit Jain, Daniel Pearson, Michael Kluk, Christopher Ott, Dale Greiner, Michael Brehm, Leonard Shultz, Alejandro Gutierrez, Kimberly Stegmaier, Marian Harris, Lewis Silverman, Stephen Sallan, Andrew Kung, David Root, James Bradner, Jon Aster, Michelle Kelliher, Bradley Bernstein. Epigenetic resistance to Notch inhibition in T cell acute lymphoblastic leukemia. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 4782. doi:10.1158/1538-7445.AM2014-4782

Antiglioma activity of GoPI-sugar, a novel gold(I)-phosphole inhibitor: chemical synthesis, mechanistic studies, and effectiveness in vivo

Glioblastoma, an aggressive brain tumor, has a poor prognosis and a high risk of recurrence. An improved chemotherapeutic approach is required to complement radiation therapy. Gold(I) complexes bearing phosphole ligands are promising agents in the treatment of cancer and disturb the redox balance and proliferation of cancer cells by inhibiting disulfide reductases. Here, we report on the antitumor properties of the gold(I) complex 1-phenyl-bis(2-pyridyl)phosphole gold chloride thio-β-d-glucose tetraacetate (GoPI-sugar), which exhibits antiproliferative effects on human (NCH82, NCH89) and rat (C6) glioma cell lines. Compared to carmustine (BCNU), an established nitrosourea compound for the treatment of glioblastomas that inhibits the proliferation of these glioma cell lines with an IC50 of 430μM, GoPI-sugar is more effective by two orders of magnitude. Moreover, GoPI-sugar inhibits malignant glioma growth in vivo in a C6 glioma rat model and significantly reduces tumor volume while being well tolerated. Both the gold(I) chloro- and thiosugar-substituted phospholes interact with DNA albeit more weakly for the latter. Furthermore, GoPI-sugar irreversibly and potently inhibits thioredoxin reductase (IC50 4.3nM) and human glutathione reductase (IC50 88.5nM). However, treatment with GoPI-sugar did not significantly alter redox parameters in the brain tissue of treated animals. This might be due to compensatory upregulation of redox-related enzymes but might also indicate that the antiproliferative effects of GoPI-sugar in vivo are rather based on DNA interaction and inhibition of topoisomerase I than on the disturbance of redox equilibrium. Since GoPI-sugar is highly effective against glioblastomas and well tolerated, it represents a most promising lead for drug development. This article is part of a Special Issue entitled: Thiol-Based Redox Processes.

Too hard to control: compromised pain anticipation and modulation in mild traumatic brain injury

Mild traumatic brain injury (MTBI) is a vulnerability factor for the development of pain-related conditions above and beyond those related to comorbid traumatic and emotional symptoms. We acquired functional magnetic resonance imaging (fMRI) on a validated pain anticipation task and tested the hypotheses that individuals with a reported history of MTBI, compared with healthy comparison subjects, would show increased brain response to pain anticipation and ineffective pain modulation after controlling for psychiatric symptoms. Eighteen male subjects with a reported history of blast-related MTBI related to combat, and eighteen healthy male subjects with no reported history of MTBI (healthy controls) underwent fMRI during an event-related experimental pain paradigm with cued high or low intensity painful heat stimuli. No subjects in either group met diagnostic criteria for current mood or anxiety disorder. We found that relative to healthy comparison subjects, after controlling for traumatic and depressive symptoms, participants with a reported history of MTBI showed significantly stronger activations within midbrain periaqueductual grey (PAG), right dorsolateral prefrontal cortex and cuneus during pain anticipation. Furthermore, we found that brain injury was a significant moderator of the relationship between anticipatory PAG activation and reported subjective pain. Our results suggest that a potentially disrupted neurocognitive anticipatory network may result from damage to the endogenous pain modulatory system and underlie difficulties with regulatory pain processing following MTBI. In other words, our findings are consistent with a notion that brain injury makes it more difficult to control acute pain. Understanding these mechanisms of dysfunctional acute pain processing following MTBI may help shed light on the underlying causes of increased vulnerability for the development of pain-related conditions in this population.

Mutational heterogeneity in cancer and the search for new cancer-associated genes

Major international projects are underway that are aimed at creating a comprehensive catalogue of all the genes responsible for the initiation and progression of cancer. These studies involve the sequencing of matched tumour-normal samples followed by mathematical analysis to identify those genes in which mutations occur more frequently than expected by random chance. Here we describe a fundamental problem with cancer genome studies: as the sample size increases, the list of putatively significant genes produced by current analytical methods burgeons into the hundreds. The list includes many implausible genes (such as those encoding olfactory receptors and the muscle protein titin), suggesting extensive false-positive findings that overshadow true driver events. We show that this problem stems largely from mutational heterogeneity and provide a novel analytical methodology, MutSigCV, for resolving the problem. We apply MutSigCV to exome sequences from 3,083 tumour-normal pairs and discover extraordinary variation in mutation frequency and spectrum within cancer types, which sheds light on mutational processes and disease aetiology, and in mutation frequency across the genome, which is strongly correlated with DNA replication timing and also with transcriptional activity. By incorporating mutational heterogeneity into the analyses, MutSigCV is able to eliminate most of the apparent artefactual findings and enable the identification of genes truly associated with cancer.

Performance of endovenous foam sclerotherapy in the USA for the treatment of venous disorders: ACP/SVM/AVF/SIR quality improvement guidelines

Objective

This report summarizes the findings of the consensus panel based on the results of the comprehensive questionnaire of US American College of Phlebology annual congress attendees and results of the systematic meta-analysis of the literature and provides quality improvement guidelines for the use of endovenous foam sclerotherapy (EFS) for the treatment of venous disorders, as well as identifies areas of needed research.

Methods

Based on the above data, quality improvement guidelines were developed and reviewed by the ten US consensus panel members and approved by their respective societies.

Results

EFS is effective for the treatment of truncal and tributary varicose veins, both as primary treatment and for treatment of recurrence. It may improve the signs and symptoms associated with varicose veins including pain and swelling. EFS is contraindicated in patients who have experienced an allergic reaction to previous treatment with foam or liquid sclerosant, and in patients with acute venous thrombosis events secondary to EFS.

Conclusion

These guidelines for the use of EFS in the treatment of venous disorders provide an initial framework for the safe and efficacious use of this therapy, and the impetus to promote the evaluation of the questions remaining regarding the use of EFS through well-designed randomized and cohort studies.

Abstract 4600: Analysis of clonal evolution in cancer using whole exome sequence data reveals that subclonal driver mutations predict poor prognosis in chronic lymphocytic leukemia

Clonal evolution is a key feature of cancer progression and relapse. We present a computational technique for analyzing whole exome sequence data to measure the fraction of cancer cells harboring each somatic mutation and resolve subclonal cell populations. We applied our methods to 149 chronic lymphocytic leukemia (CLL) samples to classify driver mutations as predominantly clonal or subclonal, corresponding to initiating and progression events in CLL evolution. We identified driver mutations as predominantly clonal (e.g., MYD88, trisomy 12 and del(13q)) or subclonal (e.g., SF3B1, TP53), corresponding to earlier and later events in CLL evolution. We sampled leukemia cells from 18 patients at two timepoints and found that 10 of 12 CLL cases treated with chemotherapy (but only 1 of 6 without treatment) underwent clonal evolution, predominantly involving subclones with driver mutations (e.g., SF3B1, TP53) that expanded over time. Furthermore, presence of a subclonal driver mutation was an independent risk factor for rapid disease progression. Our methods uncover patterns of clonal evolution in cancer, providing insights into its stepwise transformation and linking the presence of subclones with adverse clinical outcome. Because our methods require only whole exome sequence data, they are readily applicable to a large corpus of approximately 6,000 sequenced cancer exomes, and are ideally suited for application in future exome-based clinical cancer sequencing pipelines. We present additional application of our methods to analysis of prostate cancer, multiple myeloma, and glioblastoma multiforme datasets.

Citation Format: Scott L. Carter, Dan-Avi Landau, Petar Stojanov, Aaron McKenna, Kristian Cibulskis, Michael S. Lawrence, Jens Lohr, Kristen Stevenson, Donna Neuberg, Matthew Meyerson, Catherine J. Wu, Gad Getz. Analysis of clonal evolution in cancer using whole exome sequence data reveals that subclonal driver mutations predict poor prognosis in chronic lymphocytic leukemia. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 4600. doi:10.1158/1538-7445.AM2013-4600

Performance of endovenous foam sclerotherapy in the USA

Purpose

To assess practice patterns of endovenous foam sclerotherapy (EFS) use in the USA.

Methods

A multidisciplinary panel of US experts was convened and developed a questionnaire to assess use of EFS. US attendees at the American College of Phlebology 2009 Annual Congress were asked to complete the questionnaire.

Results

Of 776 questionnaires distributed, 239 were completed (31%). The majority of respondents (87%) reported using EFS for the treatment of venous disorders. Foam sclerotherapy was used by a wide variety of specialists in every region of the USA. The most common indication was sclerosis of recurrent truncal or tributary veins of the leg. There was variation among practitioners in the indications for use, pre- and postprocedural evaluation and procedure methodology.

Conclusions

The results of this questionnaire show widespread usage of EFS and are important in the development of national quality improvement guidelines for the performance of EFS.

Identification of blood biomarkers for psychosis using convergent functional genomics

There are to date no objective clinical laboratory blood tests for psychotic disease states. We provide proof of principle for a convergent functional genomics (CFG) approach to help identify and prioritize blood biomarkers for two key psychotic symptoms, one sensory (hallucinations) and one cognitive (delusions). We used gene expression profiling in whole blood samples from patients with schizophrenia and related disorders, with phenotypic information collected at the time of blood draw, then cross-matched the data with other human and animal model lines of evidence. Topping our list of candidate blood biomarkers for hallucinations, we have four genes decreased in expression in high hallucinations states (Fn1, Rhobtb3, Aldh1l1, Mpp3), and three genes increased in high hallucinations states (Arhgef9, Phlda1, S100a6). All of these genes have prior evidence of differential expression in schizophrenia patients. At the top of our list of candidate blood biomarkers for delusions, we have 15 genes decreased in expression in high delusions states (such as Drd2, Apoe, Scamp1, Fn1, Idh1, Aldh1l1), and 16 genes increased in high delusions states (such as Nrg1, Egr1, Pvalb, Dctn1, Nmt1, Tob2). Twenty-five of these genes have prior evidence of differential expression in schizophrenia patients. Predictive scores, based on panels of top candidate biomarkers, show good sensitivity and negative predictive value for detecting high psychosis states in the original cohort as well as in three additional cohorts. These results have implications for the development of objective laboratory tests to measure illness severity and response to treatment in devastating disorders such as schizophrenia.

High volumes of intravenous fluid during cardiac surgery are associated with increased mortality

INTRODUCTION

Positive fluid balance during abdominal surgery has been associated with increased morbidity. We hypothesized that administration of large volumes of intravenous fluids in cardiac surgery is associated with increased mortality.

METHODS

Retrospective analysis of data on 1358 patients who underwent cardiac surgery from 2001 to 2005 at two major hospitals in Western New York. Patients were divided in to those who received intravenous fluids above the median volume (3.9 L) and those who received less than the median volume of intra-operative fluid. Acute Kidney Injury Network criteria based on serum creatinine were used to define Acute Kidney injury.

RESULTS

Logistic regression and Cox-proportional models showed increased 90 day mortality (HR -2.8, 95% CI -1.16-7.01) in those patients who received greater than the median volume of intravenous during cardiac surgery. This was confirmed with propensity score analysis. Furthermore, the marginal effects analysis revealed that after about 4.0 liters of intravenous fluid, the survival probability falls significantly in cardiac surgery patients.

CONCLUSIONS

Administration of large volumes of intra-operative intravenous fluid is independently associated with an increase in 90 day mortality in cardiac surgery.

[New international classification of chronic pancreatitis (2007) M-ANNHEIM]

Beginning in 1963, proposed various classifications of chronic pancreatitis. These classifications were based on the latest at the time the results of studies of the pancreas and to reflect the latest achievements pancreatology at the time, but not one of these classifications was not a simple unified classification system for chronic pancreatitis simultaneously etiology, clinical stage, severity of disease. The authors have developed a new classification that included all of the above listed characteristics. As a result, developed a multifactor classification of M-ANNHEIM, taking into account the many risk factors for CP. This classification allows to divide the patients with chronic pancreatitis into categories according to etiology, clinical stage and severity of CP. The severity of the disease is classified by the system of assessment, which takes into account the clinical symptoms and treatment options for CP. This new classification is optimal for the evaluation of various risk factors and their interactions.

Balance of Th1 and Th17 effector and peripheral regulatory T cells

Transfer of antigen-specific T cells into antigen-expressing lymphopenic recipients leads to the sequential generation of Th1 and Th17 effector and protective CD25(+)FoxP3(+) regulatory cells in the periphery with surprisingly different kinetics. Such an experimental model is potentially valuable for defining the stimuli that regulate lineage decision and plasticity of various T cell effectors and peripheral regulatory T cells. Our studies have shown that IL-17 production occurs rapidly and declines within the first week with the appearance of IFN-gamma producing T cells. Regulatory T cells appear during the recovery phase of the disease. The factors that mediate this complex differentiation originating from a starting naïve T cell population remain to be defined.

Cutting edge: contributions of apoptosis and anergy to systemic T cell tolerance

Multiple pathways can induce and maintain peripheral T cell tolerance. The goal of this study was to define the contributions of apoptosis and anergy to the maintenance of self-tolerance to a systemic Ag. Upon transfer into mice expressing OVA systemically, OVA-specific DO11 CD4+ T cells are activated transiently, cease responding, and die. Bim is the essential apoptosis-inducing trigger and apoptosis proceeds despite increased expression of Bcl-2 and Bcl-x. However, preventing apoptosis by eliminating Bim does not restore proliferation or cytokine production by DO11 cells. While Foxp3 is transiently induced, anergy is not associated with the stable development of regulatory T cells. Thus, apoptosis is dispensable for tolerance to a systemic self-Ag and cell-intrinsic anergy is sufficient to tolerize T cells.

Balancing autoaggressive and protective T cell responses

A finely orchestrated balance between activating and inhibitory signals is fundamental for the ability of the immune system to effectively attack and eliminate pathogenic microbes but to not react against self-antigens. Derangements of this balance underlie the pathogenesis of autoimmune diseases. Conversely, elucidating the mechanisms of this balance may provide rational strategies for manipulating it in order to enhance the efficacy of vaccines and tumor immunotherapy. One of the clearest illustrations of precise regulation is in the generation of effector and regulatory T cells. In order to analyze the mechanisms of this regulation, we have developed a transgenic mouse model in which a single population of T cells reacts against its known cognate antigen in vivo. Here we summarize our studies with this experimental model, illustrating the sequence of T cell responses that develop and attempting to dissect the stimuli that control these responses.

Role of IL-17 and regulatory T lymphocytes in a systemic autoimmune disease

To explore the interactions between regulatory T cells and pathogenic effector cytokines, we have developed a model of a T cell–mediated systemic autoimmune disorder resembling graft-versus-host disease. The cytokine responsible for tissue inflammation in this disorder is interleukin (IL)-17, whereas interferon (IFN)-γ produced by Th1 cells has a protective effect in this setting. Because of the interest in potential therapeutic approaches utilizing transfer of regulatory T cells and inhibition of the IL-2 pathway, we have explored the roles of these in the systemic disease. We demonstrate that the production of IL-17 and tissue infiltration by IL-17–producing cells occur and are even enhanced in the absence of IL-2. Regulatory T cells favor IL-17 production but prevent the disease when administered early in the course by suppressing expansion of T cells. Thus, the pathogenic or protective effects of cytokines and the therapeutic capacity of regulatory T cells are crucially dependent on the timing and the nature of the disease.

Regulatory T cells in the periphery

Recognition of a systemic antigen by CD4+ T cells in a lymphopenic host leads to the sequential generation of pathogenic effector cells and protective CD25+ forkhead box protein (Foxp3+) regulatory T cells (Tregs) in the periphery. Such an experimental model is potentially valuable for defining the stimuli that determine the balance of effector and regulatory T cells. Our studies have shown that interleukin-2 (IL-2) enhances the development of effector cells and is essential for the peripheral generation of regulatory cells. Other models of peripheral Treg generation suggest that the concentration of antigen, the nature of the antigen-presenting cells, and cytokines such as transforming growth factor-beta and IL-10 may all influence the peripheral generation of Tregs.

Functional and Molecular Comparison of Anergic and Regulatory T Lymphocytes

Tolerance in vivo is maintained by multiple mechanisms that function to prevent autoimmunity. An encounter of CD4+ T cells with a circulating self-Ag leads to partial thymic deletion, the development of CD25+ regulatory T cells (Tregs), and functional anergy in the surviving CD25- population. We have compared anergic and regulatory T cells of the same Ag specificity generated in vivo by the systemic self-Ag. Anergic cells are unresponsive to the self-Ag that induces tolerance, but upon transfer into a new host and immunization, anergic cells can induce a pathologic autoimmune reaction against tissue expressing the same Ag. Tregs, in contrast, are incapable of mediating harmful reactions. To define the basis of this functional difference, we have compared gene expression profiles of anergic and regulatory T cells. These analyses show that Tregs express a distinct molecular signature, but anergic cells largely lack such a profile. Anergic cells express transcripts that are associated with effector differentiation, e.g., the effector cytokines IL-4 and IFN-gamma. Anergic cells do not produce these cytokines in response to self-Ag, because the cells exhibit a proximal signaling block in response to TCR engagement. Thus, anergy reflects an aborted activation pathway that can readily be reversed, resulting in pathologic effector cell responses, whereas Treg development follows a distinct developmental pathway that extinguishes effector functions.

Sequential development of interleukin 2-dependent effector and regulatory T cells in response to endogenous systemic antigen

Transfer of naive antigen-specific CD4(+) T cells into lymphopenic mice that express an endogenous antigen as a systemic, secreted protein results in severe autoimmunity resembling graft-versus-host disease. T cells that respond to this endogenous antigen develop into effector cells that cause the disease. Recovery from this disease is associated with the subsequent generation of FoxP3(+)CD25(+) regulatory cells in the periphery. Both pathogenic effector cells and protective regulatory cells develop from the same antigen-specific T cell population after activation, and their generation may occur in parallel or sequentially. Interleukin (IL)-2 plays a dual role in this systemic T cell reaction. In the absence of IL-2, the acute disease is mild because of reduced T cell effector function, but a chronic and progressive disease develops late and is associated with a failure to generate FoxP3(+) regulatory T (T reg) cells in the periphery. Thus, a peripheral T cell reaction to a systemic antigen goes through a phase of effector cell-mediated pathology followed by T reg cell-mediated recovery, and both require the growth factor IL-2.

Cutting Edge: The Link between Lymphocyte Deficiency and Autoimmunity: Roles of Endogenous T and B Lymphocytes in Tolerance

We demonstrate that transfer of OVA-specific DO11 CD4(+) T cells into mice that lack T and B cells and produce secreted OVA as an endogenous self-protein results in a severe systemic autoimmune reaction with skin inflammation, wasting, and death. The transferred DO11 T cells undergo massive expansion and produce IL-2 and IFN-gamma abundantly. Transfer of DO11 cells into OVA-expressing animals in which T cells are absent but B cells are present, leads to mild disease with no death. In this situation, the DO11 cells undergo similar expansion but show poor Th1 differentiation. This regulatory effect of B cells correlates with profound TCR down-regulation. If T cells are present, the DO11 cells fail to expand independent of B cells. These results suggest that both endogenous T and B lymphocytes control T cell tolerance induction and pathogenicity, but at different stages of an anti-self response. Although endogenous T cells prevent expansion and maintain homeostasis, endogenous B cells limit subsequent effector responses of autoreactive CD4(+) T cells.

T cell tolerance and autoimmunity

CD4 T cells are the master controllers of immune responses to protein antigens, and many autoimmune diseases are thought to arise from a breakdown of immunological tolerance in CD4 cells. Peripheral tolerance in CD4 T cells is maintained by several mechanisms, including functional anergy, deletion (death) by apoptosis and suppression by regulatory T lymphocytes (Treg). Using transgenic mouse models, we have explored the roles of these mechanisms in tolerance to cell-associated tissue-restricted self-antigens and secreted systemic self-antigens. Tolerance to a membrane form of the antigen expressed in islet beta cells is maintained by Treg, which block T cell differentiation into pathogenic effectors, and by CTLA-4, which increases the activation threshold of T cells and prevents responses to the self-antigen. A systemically produced soluble form of the antigen induces rapid T cell anergy followed by deletion. The induction of anergy does not require either CTLA-4 or Treg, although in the absence of Treg tolerance can be broken more readily by potent immunogenic signals. Encounter with circulating antigen in T cells induces a state of antigen receptor "desensitization" that is associated with a block in proximal receptor-triggered signals. Thus, different mechanisms play dominant roles in T cell tolerance to different types of self-antigens.

T-cell tolerance and autoimmunity to systemic and tissue-restricted self-antigens

We have used transgenic mouse models to examine the mechanisms of tolerance in CD4(+) T lymphocytes to soluble, systemic and cell-associated, tissue-restricted self-antigens. Anergy to an islet antigen, as a model of a tissue antigen, is dependent on the inhibitory receptor cytotoxic T-lymphocyte antigen-4 (CTLA-4), and tissue-restricted autoimmunity is inhibited by regulatory T lymphocytes. Anergy to a circulating systemic antigen can occur independently of CTLA-4 signals, and it is induced primarily by a block in proximal receptor-initiated signals. CD4(+)CD25(+) regulatory T cells are generated in response to both forms of self-antigens, but the induction is much more efficient with the tissue antigen. Receptor desensitization can be induced by the systemic antigen even in the absence of regulatory T cells, but tolerance can be broken by immunization much more easily if these cells are absent. Deletion of mature T cells is striking with the systemic antigen; there is little evidence to support peripheral deletion as a mechanism of tolerance to the tissue antigen. Thus, both distinct and overlapping mechanisms account for unresponsiveness to different forms of self-antigens. These results establish a foundation for searching for genetic influences and pathogenic mechanisms in organ-specific and systemic autoimmune diseases.

Role of B7 in T cell tolerance

The induction of effective immune responses requires costimulation by B7 molecules, and Ag recognition without B7 is thought to result in no response or tolerance. We compared T cell responses in vivo to the same Ag presented either by mature dendritic cells (DCs) or as self, in the presence or absence of B7. We show that Ag presentation by mature B7-1/2-deficient DCs fails to elicit an effector T cell response but does not induce tolerance. In contrast, using a newly developed adoptive transfer system, we show that naive OVA-specific DO11 CD4+ T cells become anergic upon encounter with a soluble form of OVA, in the presence or absence of B7. However, tolerance in DO11 cells transferred into soluble OVA transgenic recipients can be broken by immunization with Ag-pulsed DCs only in B7-deficient mice and not in wild-type mice, suggesting a role of B7 in maintaining tolerance in the presence of strong immunogenic signals. Comparing two double-transgenic models--expressing either a soluble or a tissue Ag--we further show that B7 is not only essential for the active induction of regulatory T cells in the thymus, but also for their maintenance in the periphery. Thus, the obligatory role of B7 molecules paradoxically is to promote effective T cell priming and contain effector responses when self-Ags are presented as foreign.

[Antitumoral action of interferons and interleukins in combination with radiotherapy. Part II: radiobiological and immunologic strategies]

BACKGROUND

Combined tumor treatment with cytokines, e. g., interferons (IFN), and radiotherapy was initially of phenomenological nature but has increasingly been based on a radiobiological rationale. However, an improved understanding of the complex interactions of the cytokine network within the immune system warrants the rationale for such studies to be reviewed.

METHODS

Based on published clinical studies, the results of treatment with interferons in combination with radiotherapy are reviewed. New strategies for antitumoral application of cytokines, illustrated by interleukin-(IL-)2 and IL-12 in preclinical and clinical studies, are presented.

RESULTS

The initially high expectations regarding the antitumoral action of IFN-alpha, IFN-beta and IFN-gamma in combination with radiotherapy have, with few exceptions, not been fulfilled. In particular, toxicity has been a problem after systemic application. Recent advances in immunology, however, have emphasized the importance of local interactions between antigen-presenting cells and effector cells such as natural killer (NK) cells and cytotoxic T-lymphocytes in the immune reaction against tumors. Preclinical studies with IL-2 und IL-12 have shown efficacy mainly against early metastases, but immune reactions against primary tumors have also been observed. Furthermore, the method and timing of the application have proven to be critical.

CONCLUSION

A few positive clinical studies give cause for hope that a therapeutic benefit may be achieved by targeted, local application of cytokines. Recent preclinical studies indicate the importance of cellular cytokine production in the interaction between the components of the immune system. Gene therapy might contribute to reduce the toxicity associated with cytokine treatment.

Antitumorale Wirkung von Interferonen und Interleukinen in Kombination mit Strahlentherapie

BACKGROUND

During the last 2 decades, cytokines such as interferons (IFN) have been used to modulate tumor response in radiotherapy. Initially, the focus was on antiviral and radiosensitizing effects of interferons but increasingly, the function of interferons and interleukins (IL) within the immune response to tumor cells is becoming important.

METHOD

The cellular immune response toward tumor cells is reviewed. The role of cytokines in antigen presentation and activation of effector cells and their interactions with radiation are described. Preclinical strategies of the antitumor action of cytokines are presented and discussed based on the induction of IFN-gamma by IL-12.

RESULTS

Recent advances in immunology have demonstrated the importance of local interactions between antigen-presenting cells (APC) and effector cells such as natural killer (NK) cells and T-lymphocytes for an effective immune reaction against tumors. Interferons stimulate such interactions, while IL-2 plays a central role in the activation of NK cells and T-lymphocytes. The interactions between APC and effector cells are suppressed by many tumors but can be stimulated by irradiation. Since systemic application of interferons is quite toxic, present strategies aim at local expression, e. g., the induction of IFN-gamma expression in Th1 cells by IL-12.

CONCLUSION

The improved understanding of immunologic mechanisms has emphasized the role of the cytokine network in the interaction between tumor cells and effector cells such as NK cells and T-lymphocytes. This opens new possibilities for the application of cytokines as biological response modifiers, which may eventually help widening the therapeutic window in radiotherapy.

Fatal outcome in a patient with metastatic prostate cancer and acquired severe hypogammaglobulinemia with complete absence of mature peripheral blood B-cells

Common variable immunodeficiency (CVID) is the second most common immunodeficiency and may be classified according to the presence or absence of mature B-cells, the latter subgroup being exceedingly rare. We describe a 66-year-old patient who over six months developed profound hypogammaglobulinemia associated with a complete absence of circulating B-lymphocytes and had a fatal outcome. Immunophenotypic analysis of a bone marrow aspirate demonstrated a strongly reduced number of B-cell precursors (CD34+/CD19+) but normal numbers of CD34+/CD45+ hematopoietic progenitor cells. This case is remarkable with respect to its documented rapid evolution. Possible triggers are discussed, a combination of drug toxicities being the most likely.

The inhibitory function of B7 costimulators in T cell responses to foreign and self-antigens

When antigen-presenting cells (APCs) encounter inflammatory stimuli, they up-regulate their expression of B7. A small amount of B7 is also constitutively expressed on resting APCs, but its function is unclear. Here we show that initiation of T cell responses requires the expression of B7 on immunizing APCs, but the responses are much greater in the absence of basal B7 expression. Transfer of antigen-specific CD4+CD25+ cells reverses the increased responsiveness, and tolerance to a self-protein is broken by immunization in the absence of basal B7, thereby inducing autoimmunity. Similar loss of self-tolerance is seen on depletion of CD25+ cells. Thus, constitutively expressed B7 costimulators function to suppress T cell activation and maintain self-tolerance, principally by sustaining a population of regulatory T cells.

Modification of the current profile in high-performance plasmas using off-axis electron-cyclotron-current drive in DIII-D

Recent DIII-D experiments using off-axis electron cyclotron current drive (ECCD) have demonstrated the ability to modify the current profile in a plasma with toroidal beta near 3%. The resulting plasma simultaneously sustains the key elements required for Advanced Tokamak operation: high bootstrap current fraction, high beta, and good confinement. More than 85% of the plasma current is driven by noninductive means. ECCD is observed to produce strong negative central magnetic shear, which in turn acts to trigger confinement improvements in all transport channels in the plasma core.

Paris-Trousseau syndrome platelets in a child with Jacobsen's syndrome

The thrombocytopenia in an infant with clinical features of Jacobsen's syndrome characterized by multiple congenital anomalies, cardiac defects, psychomotor retardation, and deletion of chromosome 11 at 11q23.3 has been evaluated. Study of his platelets in the electron microscope revealed giant alpha granules in his cells identical in appearance to those reported in the family with Paris-Trousseau syndrome. As a result, the Paris-Trousseau syndrome appears to be a variant of the Jacobsen syndrome, and the thrombocytopenia observed in all cases of chromosome 11q23.3 deletion due to dysmegakaryopoieses. Giant alpha granules are frequently observed in normal platelets during long-term storage and may form in Jacobsen and Paris-Trousseau platelets during prolonged residence in the bone marrow.