Interactions between the intestinal microbiome and helminth parasites.

Throughout evolution, both helminths and bacteria have inhabited our intestines. As intestinal helminths and bacteria inhabit the same environmental niche, it is likely that these organisms interact with, and impact on, each other. In addition, intestinal helminths are well known to alter intestinal physiology, permeability, mucous secretion and the production of antimicrobial peptides - all of which may impact on bacterial survival and spatial organization. Yet despite rapid advances in our understanding of host-intestinal bacteria interactions, the impact of helminths on this relationship has remained largely unexplored. Moreover, although intestinal helminths are generally accepted to possess potent immuno-modulatory activity, it is unknown whether this capacity requires interactions with intestinal bacteria. We propose that this 'ménage à trois' situation is likely to have exerted a strong selective pressure on the development of our metabolic and immune systems. Whilst such pressures remain in developing countries, the eradication of helminths in industrialized countries has shifted this evolutionary balance, possibly underlying the increased development of chronic inflammatory diseases. Thus, helminth-bacteria interactions may represent a key determinant of healthy homoeostasis.

Thymic stromal lymphopoietin plays divergent roles in murine models of atopic and nonatopic airway inflammation.

BACKGROUND: Thymic stromal lymphopoietin (TSLP) is a cytokine primarily produced by epithelial cells, which has been shown to be a potent inducer of T-helper 2 (Th2)-type responses. However, TSLP has pleiotropic effects upon immune cells, and although extensively studied in the context of atopic asthma, its relevance as a therapeutic target and its role in the pathogenesis of nonatopic asthma remains unknown. We sought to investigate the role of TSLP in atopic, nonatopic and viral-induced exacerbations of pulmonary inflammation. METHODS: Using stringently defined murine models of atopic, nonatopic and virally exacerbated forms of pulmonary inflammation, we compared inflammatory responses of C57BL/6 wild-type (WT) and TSLP receptor-deficient (TSLPR KO) mice. RESULTS: Thymic stromal lymphopoietin receptor (TSLPR) signaling was crucial for the development of atopic asthma. Specifically, TSLPR signaling to lung recruited CD4+ T cells enhanced eosinophilia, goblet cell hyperplasia, and overall inflammation within the airways. In contrast, the absence of TSLPR signaling was associated with strikingly exaggerated pulmonary neutrophilic inflammation in a nonatopic model of airway inflammation. The inflammation was associated with excessive levels of interleukin (IL)-17A in the lungs, indicating that TSLP negatively regulates IL-17A. In addition, in a model of influenza-induced exacerbation of atopic airway inflammation, the absence of TSLPR signaling also led to exaggerated neutrophilic inflammation. CONCLUSION: Thymic stromal lymphopoietin plays divergent roles in the pathogenesis of atopic and nonatopic asthma phenotypes by either enhancing Th2 responses or curtailing T-helper 17 responses. These findings raise important caveats for the design of therapeutic interventions targeting TSLP in asthma.

Mucosal immune responses following intestinal nematode infection.

In most natural environments, the large majority of mammals harbour parasitic helminths that often live as adults within the intestine for prolonged periods (1-2 years). Although these organisms have been eradicated to a large extent within westernized human populations, those living within rural areas of developing countries continue to suffer from high infection rates. Indeed, recent estimates indicate that approximately 2.5 billion people worldwide, mainly children, currently suffer from infection with intestinal helminths (also known as geohelminths and soil-transmitted helminths) . Paradoxically, the eradication of helminths is thought to contribute to the increased incidence of autoimmune diseases and allergy observed in developed countries. In this review, we will summarize our current understanding of host-helminth interactions at the mucosal surface that result in parasite expulsion or permit the establishment of chronic infections with luminal dwelling adult worms. We will also provide insight into the adaptive immune mechanisms that provide immune protection against re-infection with helminth larvae, a process that is likely to be key to the future development of successful vaccination strategies. Lastly, the contribution of helminths to immune modulation and particularly to the treatment of allergy and inflammatory bowel disease will be discussed.

Understanding the role of antibodies in murine infections with Heligmosomoides (polygyrus) bakeri: 35 years ago, now and 35 years ahead.

The rodent intestinal nematode H.p.bakeri has played an important role in the exploration of the host-parasite relationship of chronic nematode infections for over six decades, since the parasite was first isolated in the 1950s by Ehrenford. It soon became a popular laboratory model providing a tractable experimental system that is easy to maintain in the laboratory and far more cost-effective than other laboratory nematode-rodent model systems. Immunity to this parasite is complex, dependent on antibodies, but confounded by the parasite's potent immunosuppressive secretions that facilitate chronic survival in murine hosts. In this review, we remind readers of the state of knowledge in the 1970s, when the first volume of Parasite Immunology was published, focusing on the role of antibodies in protective immunity. We show how our understanding of the host-parasite relationship then developed over the following 35 years to date, we propose testable hypotheses for future researchers to tackle, and we speculate on how the new technologies will be applied to enable an increasingly refined understanding of the role of antibodies in host-protective immunity, and its evasion, to be achieved in the longer term.

Intestinal eosinophils: multifaceted roles in tissue homeostasis and disease.

Intestinal eosinophils are largely considered to be one of the central immune effector cells during helminth infection and disorders such as eosinophilic oesophagitis and food allergies. Given the abundance of these cells present in the gastrointestinal tract at homeostasis, emerging studies now reveal novel roles for eosinophils in the development and regulation of immunity, and during tissue repair. In addition, the identification of distinct eosinophil subsets indicates that we must consider the heterogeneity of these cells and how they differentially participate in mucosal immunity at steady state and during disease. Here, we summarise the literature on intestinal eosinophils, and how they contribute to mucosal homeostasis through immune regulation and interactions with the microbiome. We then explore the divergent roles of eosinophils in the context of eosinophilic gastrointestinal disorders and during helminth infection, whereby we discuss key observations and differences that have emerged from animal models and human studies. Lastly, we consider the possible interactions of eosinophils with the enteric nervous system, and how this represents an exciting area for future research which may inform future therapeutic targets.

Comparative genomics of the eukaryotes.

A comparative analysis of the genomes of Drosophila melanogaster, Caenorhabditis elegans, and Saccharomyces cerevisiae-and the proteins they are predicted to encode-was undertaken in the context of cellular, developmental, and evolutionary processes. The nonredundant protein sets of flies and worms are similar in size and are only twice that of yeast, but different gene families are expanded in each genome, and the multidomain proteins and signaling pathways of the fly and worm are far more complex than those of yeast. The fly has orthologs to 177 of the 289 human disease genes examined and provides the foundation for rapid analysis of some of the basic processes involved in human disease.

SerpinB2 regulates stromal remodelling and local invasion in pancreatic cancer.

Pancreatic cancer has a devastating prognosis, with an overall 5-year survival rate of ~8%, restricted treatment options and characteristic molecular heterogeneity. SerpinB2 expression, particularly in the stromal compartment, is associated with reduced metastasis and prolonged survival in pancreatic ductal adenocarcinoma (PDAC) and our genomic analysis revealed that SERPINB2 is frequently deleted in PDAC. We show that SerpinB2 is required by stromal cells for normal collagen remodelling in vitro, regulating fibroblast interaction and engagement with collagen in the contracting matrix. In a pancreatic cancer allograft model, co-injection of PDAC cancer cells and SerpinB2-/- mouse embryonic fibroblasts (MEFs) resulted in increased tumour growth, aberrant remodelling of the extracellular matrix (ECM) and increased local invasion from the primary tumour. These tumours also displayed elevated proteolytic activity of the primary biochemical target of SerpinB2-urokinase plasminogen activator (uPA). In a large cohort of patients with resected PDAC, we show that increasing uPA mRNA expression was significantly associated with poorer survival following pancreatectomy. This study establishes a novel role for SerpinB2 in the stromal compartment in PDAC invasion through regulation of stromal remodelling and highlights the SerpinB2/uPA axis for further investigation as a potential therapeutic target in pancreatic cancer.

Effect of allyl alcohol-induced sublethal hepatic damage upon doxorubicin metabolism and toxicity in the rabbit.

A model of hepatic dysfunction in vivo has been developed in rabbits to determine the effects of sublethal hepatocellular necrosis upon doxorubicin pharmacology. Eight New Zealand white rabbits were given 3 mg/kg doxorubicin i.v. Plasma doxorubicin and metabolite pharmacokinetics were determined and toxicity assessed by nadir complete blood counts. Hepatic function was assessed by the pulmonary excretion rate of 14CO2 from [14C]aminopyrine. Hepatocellular necrosis was produced by i.v. injection of 1.35 mg/kg of a 2% allyl alcohol solution. Doxorubicin administration and pharmacokinetics were repeated. Doxorubicin enhances the hepatotoxicity of allyl alcohol. Hepatocellular necrosis does not alter the plasma pharmacokinetics of doxorubicin but does increase the plasma exposure of doxorubicinol. Doxorubicin-induced myelosuppression is enhanced by allyl alcohol pretreatment. These data suggest that in circumstances of reduced hepatocellular volume or acute hepatocellular necrosis, a key plasma marker of doxorubicin-induced acute toxicity may be doxorubicinol.

Breakpoints of the t(11;18)(q21;q21) in mucosa-associated lymphoid tissue (MALT) lymphoma lie within or near the previously undescribed gene MALT1 in chromosome 18.

Lymphomas arising in mucosa-associated lymphoid tissue (MALT) are indolent B-cell tumors that have a predilection for epithelial sites and often develop in a setting of chronic inflammation or autoimmunity. As many as 50% of low-grade MALT lymphomas contain an (11;18)(q21; q21) chromosomal translocation. Using fluorescence in situ hybridization, we have analyzed the position of recombination within chromosome 18 DNA in three examples of MALT lymphoma bearing this translocation. In all three cases, the breakpoint maps to DNA in BAC b357H2, covering about 150 kb of sequence. A previously undescribed, ubiquitously expressed gene, which we refer to as MALT1, was identified within this sequence and was found to be broken in one case for which we have definitively located the position of recombination between chromosomes 18 and 11. The sequence of this gene indicates the presence of two immunoglobulin-like C2 domains and a region of partial homology to caspases, suggesting a possible role for MALT1 in the regulation of apoptosis.

Attribution of net carbon change by disturbance type across forest lands of the conterminous United States.

BACKGROUND: Locating terrestrial sources and sinks of carbon (C) will be critical to developing strategies that contribute to the climate change mitigation goals of the Paris Agreement. Here we present spatially resolved estimates of net C change across United States (US) forest lands between 2006 and 2010 and attribute them to natural and anthropogenic processes. RESULTS: Forests in the conterminous US sequestered -460 ± 48 Tg C year-1, while C losses from disturbance averaged 191 ± 10 Tg C year-1. Combining estimates of net C losses and gains results in net carbon change of -269 ± 49 Tg C year-1. New forests gained -8 ± 1 Tg C year-1, while deforestation resulted in losses of 6 ± 1 Tg C year-1. Forest land remaining forest land lost 185 ± 10 Tg C year-1 to various disturbances; these losses were compensated by net carbon gains of -452 ± 48 Tg C year-1. C loss in the southern US was highest (105 ± 6 Tg C year-1) with the highest fractional contributions from harvest (92%) and wind (5%). C loss in the western US (44 ± 3 Tg C year-1) was due predominantly to harvest (66%), fire (15%), and insect damage (13%). The northern US had the lowest C loss (41 ± 2 Tg C year-1) with the most significant proportional contributions from harvest (86%), insect damage (9%), and conversion (3%). Taken together, these disturbances reduced the estimated potential C sink of US forests by 42%. CONCLUSION: The framework presented here allows for the integration of ground and space observations to more fully inform US forest C policy and monitoring efforts.

Lymphocyte surface markers in orbital lymphoid neoplasms.

Since the malignant nature of many orbital lymphoid infiltrates is difficult to assess from pathologic examination alone, over the past four years lymphocyte surface marker studies have been added to the evaluation of 23 such cases. Only 10 of the 23 could be confidently classified as malignant lymphoma by histology alone. However, monoclonal surface immunoglobulin was found in 15, supporting the pathologic diagnosis of malignancy in eight and adding seven that could not have been diagnosed otherwise. Clinical evaluation, including a median follow-up of 18 months, revealed manifestations of systemic lymphoma in six of those 15; two had been diagnosed only by surface markers. In contrast, only one of eight cases lacking monoclonal surface immunoglobulin exhibited clinical evidence of malignancy (that case was also indeterminate by histologic criteria). The addition of surface marker analysis permits more accurate diagnosis of orbital lymphoma than is possible from pathologic study alone. This technique can suggest the subtype of lymphoma.

World Health Organization classification of neoplastic diseases of the hematopoietic and lymphoid tissues: report of the Clinical Advisory Committee meeting-Airlie House, Virginia, November 1997.

PURPOSE: The European Association of Hematopathologists and the Society for Hematopathology have developed a new World Health Organization (WHO) classification of hematologic malignancies, including lymphoid, myeloid, histiocytic, and mast cell neoplasms. DESIGN: Ten committees of pathologists developed lists and definitions of disease entities. A clinical advisory committee (CAC) of international hematologists and oncologists was formed to ensure that the classification would be useful to clinicians. The CAC met in November 1997 to discuss clinical issues related to the classification. RESULTS: The WHO uses the Revised European-American Lymphoma (REAL) classification, published in 1994 by the International Lymphoma Study Group, to categorize lymphoid neoplasms. The REAL classification is based on the principle that a classification is a list of "real" disease entities, which are defined by a combination of morphology, immunophenotype, genetic features, and clinical features. The relative importance of each of these features varies among diseases, and there is no one gold standard. The WHO Neoplasms recognizes distinct entities defined by a combination of morphology and cytogenetic abnormalities. At the CAC meeting, which was organized around a series of clinical questions, participants reached a consensus on most of the questions posed. They concluded that clinical groupings of lymphoid neoplasms were neither necessary nor desirable. Patient treatment is determined by the specific type of lymphoma, with the addition of grade within the tumor type, if applicable, and clinical prognostic factors, such as the International Prognostic Index. CONCLUSION: The WHO classification has produced a new and exciting degree of cooperation and communication between oncologists and pathologists from around the world, which should facilitate progress in the understanding and treatment of hematologic malignancies.

Marginal zone B-cell lymphoma: A clinical comparison of nodal and mucosa-associated lymphoid tissue types. Non-Hodgkin's Lymphoma Classification Project.

PURPOSE: In the International Lymphoma Study Group classification of lymphoma, extranodal marginal zone B-cell lymphoma (MZL) of mucosa-associated lymphoid tissue (MALT) type is listed as a distinctive entity. However, nodal MZL is listed as a provisional entity because of questions as to whether it is truly a disease or just an advanced stage of MALT-type MZL. To resolve the issue of whether primary nodal MZL without involvement of mucosal sites exists and whether it is clinically different from extranodal MALT-type lymphoma, we compared the clinical features of these two lymphomas. PATIENTS AND METHODS: Five expert hematopathologists reached a consensus diagnosis of MZL in 93 patients. Seventy-three were classified as having MALT-type MZL because of involvement of a mucosal site at the time of diagnosis, and 20 were classified as having nodal MZL because of involvement of lymph nodes without involvement of a mucosal site. RESULTS: A comparison of the clinical features of nodal MZL and MALT-type MZL showed that more patients with nodal MZL presented with advanced-stage disease (71% v 34%; P =. 02), peripheral lymphadenopathy (100% v 8%; P <.001), and para-aortic lymphadenopathy (56% v 14%; P <.001) than those with MALT-type MZL. However, fewer patients with nodal MZL had a large mass (> or = 5 cm) than those with MALT-type MZL (31% v 68%; P =.03). The 5-year overall survival of patients with nodal MZL was lower than that for patients with MALT-type MZL (56% v 81%; P =.09), with a similar result for failure-free survival (28% v 65%; P =.01). Comparisons of patients with International Prognostic Index scores of 0 to 3 showed that those with nodal MZL had lower 5-year overall survival (52% v 88%; P =.025) and failure-free survival (30% v 75%; P =.007) rates than those with MALT-type MZL. CONCLUSION: Nodal MZL seems to be a distinctive disease entity rather than an advanced stage of MALT-type MZL because the clinical presentations and survival outcomes are different in these two types of MZL. Clinically, nodal MZL is similar to other low-grade, node-based B-cell lymphomas, such as follicular and small lymphocytic lymphomas.

Report of an international workshop to standardize response criteria for non-Hodgkin's lymphomas. NCI Sponsored International Working Group.

Standardized guidelines for response assessment are needed to ensure comparability among clinical trials in non-Hodgkin's lymphomas (NHL). To achieve this, two meetings were convened among United States and international lymphoma experts representing medical hematology/oncology, radiology, radiation oncology, and pathology to review currently used response definitions and to develop a uniform set of criteria for assessing response in clinical trials. The criteria that were developed include anatomic definitions of response, with normal lymph node size after treatment of 1.5 cm in the longest transverse diameter by computer-assisted tomography scan. A designation of complete response/unconfirmed was adopted to include patients with a greater than 75% reduction in tumor size after therapy but with a residual mass, to include patients-especially those with large-cell NHL-who may not have residual disease. Single-photon emission computed tomography gallium scans are encouraged as a valuable adjunct to assessment of patients with large-cell NHL, but such scans require appropriate expertise. Flow cytometric, cytogenetic, and molecular studies are not currently included in response definitions. Response rates may be the most important objective in phase II trials where the activity of a new agent is important and may provide support for approval by regulatory agencies. However, the goals of most phase III trials are to identify therapies that will prolong the progression-free survival, if not the overall survival, of the treated patients. We hope that these guidelines will serve to improve communication among investigators and comparability among clinical trials until clinically relevant laboratory and imaging studies are identified and become more widely available.

Four helix bundle diversity in globular proteins.

Four helix bundles are a common structural motif that can be observed both independently and as components of larger folding units. We examined 221 globular proteins of known structure for possible four helix bundles. Previous computational studies of four helix bundles have placed arbitrary restrictions on interhelical packing angles. In this study we develop a geometric definition of four helix bundles based in part on solvent accessibility criteria that permits the removal of constraints on interhelical packing. Based on the observed pattern of interhelical angles, a bundle taxonomy is presented. This formalism should provide a useful categorization method for future structural studies of proteins rich in alpha-helices. The helix-helix interactions within bundles were studied in detail. Central residues, contact normals, and skew angles all were observed to have non-random distributions. A simple geometric model was developed for the helix-helix interface to explain these findings. Analysis of the helix-helix interaction data collected in this work confirms the importance of including skew angles in models of helix packing, and should improve the accuracy of combinatorial strategies for the prediction of the tertiary structure of all-helical proteins. Additionally, the geometric properties observed in globular proteins provide insight into the structural organization of membrane spanning proteins.

Systemic salmonellosis in patients with disseminated histoplasmosis. Case for 'macrophage blockade' caused by Histoplasma capsulatum.

Five patients are described with disseminated histoplasmosis and systemic salmonellosis. Four of these patients were also immunocompromised because of the acquired immunodeficiency syndrome in two patients and renal transplantation in another two patients. Histologic studies in two patients showed histiocytes that were heavily laden with Histoplasma capsulatum yeast-phase organisms. We postulate that diffuse parasitization of the reticuloendothelial system (RES) by Histoplasma organisms may cause "RES blockade," which then predisposes to systemic salmonellosis, as reported in certain other infections and in sickle cell anemia.

Hodgkin's lymphomas: classification, diagnosis, and grading.

Much has been learned in the past decade from the study of tissues involved by the disorder long known as Hodgkin's disease. Two important discoveries have prompted changes in classification and nomenclature: first, the recognition that there are two distinct lymphomas encompassed within this category (classical and nodular lymphocyte-predominant [NLP] types), and second, the discovery that the Reed-Sternberg (RS) cells in most cases are monoclonal B cells. Thus "Hodgkin's disease" comprises two distinct lymphomas, deserving of a name change, to "Hodgkin's lymphomas" (HLs). The immunophenotype and genetic features of both classical HL and NLPHL have been defined. These are useful in the subclassification of HL and in distinguishing HL from two recently described, aggressive lymphomas that were in the past often diagnosed as HL: anaplastic large-cell lymphoma, T-cell type (ALCL), and T-cell/histiocyte-rich large B-cell lymphoma (T/HRBCL). Despite the advances of recent years, many questions remain to be answered, and these will provide the challenges of the next decade.

Relapsing central and peripheral demyelinating diseases. Unusual pathologic features.

We treated a patient who had a demyelinating peripheral neuropathy and a central nervous system inflammatory demyelinating disease. The unusual pathologic feature of dense infiltrates of atypical macrophages was observed in many areas of the brain; otherwise the process had several features in common with either multiple sclerosis or chronic relapsing experimental allergic encephalomyelitis. The illness followed "swine-flu" inoculation; exacerbation followed pneumococcal vaccination.

Primary T-cell lymphoma of the brainstem.

Most primary CNS lymphomas are non-Hodgkin's lymphomas of B-cell lineage. We report a case of a small lymphocytic-type T-cell lymphoma localized primarily to the brainstem and compare the characteristics of primary CNS T-cell lymphomas with those of primary CNS B-cell lymphomas.

Detection of Epstein-Barr virus in CNS lymphomas by in-situ hybridization.

We used an optimized in-situ hybridization technique employing a biotinylated Epstein-Barr (EB) virus sequence, BamH1V (3.1 kb), to detect this sequence in 2 EB virus-infected cell lines (B95-8 and Namalwa) and 8 CNS lymphomas. We obtained a good hybridization signal from cytospins of B95-8 (EB virus productively infected) and Namalwa (EB virus latently infected, 1 copy per cell) cell lines. We were able to detect signal from both cell lines after overnight fixation in 10% formalin and paraffin embedding, but development time in the detection chromogen required longer incubation and the signal intensity was lower than in cytospin cells. We then used the technique to examine formalin-fixed, paraffin-embedded primary CNS lymphoma tissue from 4 patients who were immunocompromised (1 renal transplant, 3 acquired immune deficiency syndrome) and 4 patients who were not. All 4 CNS lymphomas from immunocompromised patients hybridized well with BamH1V, exhibiting a pattern of staining similar to Namalwa cells and nonlytically infected B95-8 cells. There was no relationship between the intensity and degree of reaction and the patients' survival. None of the 4 CNS lymphomas in immunocompetent patients or uninvolved brain showed any reactivity with BamH1V. We suggest that low-abundance targets are detectable in paraffin-embedded tissue by in-situ hybridization using biotinylated probes. Detection of EB viral sequences in CNS lymphomas in immunocompromised patients suggests a role for the virus in the pathogenesis of this tumor.