-
Virulence 2018Streptococcus suis is a major porcine bacterial pathogen and emerging zoonotic agent. S. suis 5'-nucleotidase is able to convert adenosine monophosphate to adenosine,...
Streptococcus suis is a major porcine bacterial pathogen and emerging zoonotic agent. S. suis 5'-nucleotidase is able to convert adenosine monophosphate to adenosine, resulting in inhibiting neutrophil functions in vitro and it is an important virulence factor. Here, we show that S. suis 5'-nucleotidase not only enables producing 2'-deoxyadenosine from 2'-deoxyadenosine monophosphate by the enzymatic assay and reversed-phase high performance liquid chromatography (RP-HPLC) analysis in vitro, but also synthesizes both 2'-deoxyadenosine and adenosine in mouse blood in vivo by RP-HPLC and liquid chromatography with tandem mass spectrometry analyses. Cellular cytotoxicity assay and Western blot analysis indicated that the production of 2'-deoxyadenosine by 5'-nucleotidase triggered the death of mouse macrophages RAW 264.7 in a caspase-3-dependent way. The in vivo infection experiment showed that 2'-deoxyadenosine synthesized by 5'-nucleotidase caused monocytopenia in mouse blood. The in vivo transcriptome analysis in mouse blood showed the inhibitory effect of 5'-nucleotidase on neutrophil functions and immune responses probably mediated through the generation of adenosine. Taken together, these findings indicate that S. suis synthesizes 2'-deoxyadenosine and adenosine by 5'-nucleotidase to dampen host immune responses, which represents a new mechanism of S. suis pathogenesis.
Topics: 5'-Nucleotidase; Adenosine; Animals; Bacterial Proteins; Deoxyadenosines; Female; Gene Expression Profiling; Host-Pathogen Interactions; Macrophages; Mice; Neutrophils; RAW 264.7 Cells; Streptococcal Infections; Streptococcus suis; Virulence Factors
PubMed: 30221577
DOI: 10.1080/21505594.2018.1520544 -
Biology of Blood and Marrow... Jan 2019Parainfluenza virus (PIV) infection can progress from upper respiratory tract infection (URTI) to lower respiratory tract disease (LRTD) in immunocompromised hosts. Risk... (Clinical Trial)
Clinical Trial
Parainfluenza virus (PIV) infection can progress from upper respiratory tract infection (URTI) to lower respiratory tract disease (LRTD) in immunocompromised hosts. Risk factors for progression to LRTD and presentation with LRTD without prior URTI are poorly defined. Hematopoietic cell transplant (HCT) recipients with PIV infection were retrospectively analyzed using standardized definitions of LRTD. PIV was detected in 540 HCT recipients; 343 had URTI alone and 197 (36%) had LRTD (possible, 76; probable, 19; proven, 102). Among 476 patients with positive nasopharyngeal samples, the cumulative incidence of progression to probable/proven LRTD by day 40 was 12%, with a median time to progression of 7 days (range, 2 to 40). In multivariable analysis monocytopenia (hazard ratio, 2.22; P = .011), steroid use ≥1mg/kg prior to diagnosis (hazard ratio, 1.89; P = .018), co-pathogen detection in blood (hazard ratio, 3.21; P = .027), and PIV type 3 (hazard ratio, 3.57; P = .032) were associated with increased progression risk. In the absence of all 4 risk factors no patients progressed to LRTD, whereas progression risk increased to >30% if 3 or more risk factors were present. Viral load or ribavirin use appeared to have no effect on progression. Among 121 patients with probable/proven LRTD, 64 (53%) presented LRTD without prior URTI, and decreased lung function before infection and lower respiratory co-pathogens were risk factors for this presentation. Mortality was unaffected by the absence of prior URTI. We conclude that the risk of progression to probable/proven LRTD exceeded 30% with ≥3 risk factors. To detect all cases of LRTD, virologic testing of lower respiratory samples is required regardless of URTI symptoms.
Topics: Adult; Allografts; Female; Hematopoietic Stem Cell Transplantation; Humans; Immunocompromised Host; Male; Middle Aged; Paramyxoviridae Infections; Respiratory Tract Infections; Retrospective Studies; Ribavirin; Risk Factors
PubMed: 30149147
DOI: 10.1016/j.bbmt.2018.08.021 -
Hematology/oncology Clinics of North... Aug 2018GATA2 deficiency is an immunodeficiency and bone marrow failure disorder caused by pathogenic variants in GATA2. It is inherited in an autosomal-dominant pattern or can... (Review)
Review
GATA2 deficiency is an immunodeficiency and bone marrow failure disorder caused by pathogenic variants in GATA2. It is inherited in an autosomal-dominant pattern or can be due to de novo sporadic germline mutation. Patients commonly have B-cell, dendritic cell, natural killer cell, and monocytopenias, and are predisposed to myelodysplastic syndrome, acute myeloid leukemia, and chronic myelomonocytic leukemia. Patients may suffer from disseminated human papilloma virus and mycobacterial infections, pulmonary alveolar proteinosis, and lymphedema. The bone marrow eventually takes on a characteristic hypocellular myelodysplasia with loss of monocytes and hematogones, megakaryocytes with separated nuclear lobes, micromegakaryocytes, and megakaryocytes with hypolobated nuclei.
Topics: Anemia, Aplastic; Bone Marrow Diseases; Bone Marrow Failure Disorders; GATA2 Deficiency; GATA2 Transcription Factor; Genetic Predisposition to Disease; Germ-Line Mutation; Hemoglobinuria, Paroxysmal; Humans; Leukemia, Myelogenous, Chronic, BCR-ABL Positive; Leukemia, Myeloid, Acute; Myelodysplastic Syndromes
PubMed: 30047422
DOI: 10.1016/j.hoc.2018.04.004 -
Modern Pathology : An Official Journal... Nov 2018Hairy cell leukemia-variant is rare. Only a small number of cases have been reported in the literature with little cytogenetic or molecular data available. In this...
Hairy cell leukemia-variant is rare. Only a small number of cases have been reported in the literature with little cytogenetic or molecular data available. In this study, we describe the clinicopathologic and genetic features of 23 patients with hairy cell leukemia-variant (16 men and 7 women) with a median age of 70 years. Most patients had splenomegaly (90%), leukocytosis (77%), and lymphocytosis (82%); no patients had monocytopenia. Histologically, the bone marrow biopsy specimens showed a mixed pattern of predominantly interstitial and lesser intrasinusoidal infiltration by leukemic cells. In bone marrow aspirate smears most cells had villous cytoplasmic features and a small nucleolus. We describe unusual sites of hairy cell leukemia-variant involvement in 4 patients, including brain, omentum, terminal ileum, and skin at the time of initial presentation. Immunophenotyping showed monotypic B-cells positive for pan B-cell antigens, CD11c, and CD103, and negative for CD25 and annexin A1. Conventional cytogenetic or fluorescence in situ hybridization analysis showed deletions of 17p13/TP53 and 11q22/ATM gene in 5/12 (42%) and 2/9 (22%) cases, respectively. Sequencing of the variable region of IGVH showed mutations (>2% deviation from germline) in 40% of the cases assessed. MAP2K1 mutation (p.C121S) was seen in 1 of 14 (7%) patients tested. No BRAF V600E mutations were detected. The patients were treated in a heterogeneous manner, but most often with therapies designed for classical hairy cell leukemia and the 5-year overall survival was 84%. In summary, hairy cell leukemia-variant exhibits a heterogeneous spectrum of clinical, morphologic, immunophenotypic, and genetic features that may overlap with classic hairy cell leukemia and other hairy cell-like B-cell neoplasms. A subset of patients can have an aggressive clinical course. In our experience MAP2K1 mutations are uncommon in this disease.
Topics: Aged; Aged, 80 and over; Female; Humans; Immunophenotyping; Leukemia, Hairy Cell; Male; Middle Aged; Retrospective Studies
PubMed: 29955146
DOI: 10.1038/s41379-018-0093-8 -
Blood Aug 2018Heparin-induced thrombocytopenia (HIT) is a prothrombotic disorder initiated by antibodies to platelet factor 4 (PF4)/heparin complexes. PF4 released from platelets...
Heparin-induced thrombocytopenia (HIT) is a prothrombotic disorder initiated by antibodies to platelet factor 4 (PF4)/heparin complexes. PF4 released from platelets binds to surface glycosaminoglycans on hematopoietic and vascular cells that are heterogenous in composition and differ in affinity for PF4. PF4 binds to monocytes with higher affinity than to platelets, and depletion of monocytes exacerbates thrombocytopenia in a murine HIT model. Here we show that the expression of PF4 on platelets and development of thrombocytopenia are modulated by the (re)distribution of PF4 among hematopoietic and endothelial cell surfaces. Binding of PF4 to platelets in whole blood in vitro varies inversely with the white cell count, likely because of the greater affinity of monocytes for PF4. In mice, monocyte depletion increased binding of PF4 to platelets by two- to three-fold. Induction of HIT in mice caused a transient >80-fold increase in binding of HIT antibody to monocytes vs 3.5-fold increase to platelets and rapid transient monocytopenia. Normalization of monocyte counts preceded the return in platelet counts. Exposure of blood to endothelial cells also depletes PF4 from platelet surfaces. These studies demonstrate a dynamic interchange of surface-bound PF4 among hematopoetic and vascular cells that may limit thrombocytopenia at the expense of promoting prothrombotic processes in HIT.
Topics: Animals; Antigens; Blood Platelets; Gene Expression Regulation; Heparin; Human Umbilical Vein Endothelial Cells; Humans; Mice; Monocytes; Platelet Factor 4; Thrombocytopenia
PubMed: 29914979
DOI: 10.1182/blood-2018-02-830737 -
Biology of Blood and Marrow... Nov 2018Recent publications note an association between antibiotic exposure and respiratory viral infections (RVIs). Antibiotics affect microbiota and impair immune response...
Antibiotic Exposure Prior to Respiratory Viral Infection Is Associated with Progression to Lower Respiratory Tract Disease in Allogeneic Hematopoietic Cell Transplant Recipients.
Recent publications note an association between antibiotic exposure and respiratory viral infections (RVIs). Antibiotics affect microbiota and impair immune response against RVIs in mice, and low microbiome diversity is associated with pulmonary complications including viral lower respiratory tract disease (LRTD) in hematopoietic cell transplantation (HCT) recipients. In this study, we examined whether antibiotic exposure was associated with increased risk of disease progression in RVIs post-transplantation. We analyzed patients who underwent allogeneic HCT (June 2008 to February 2016) and had their first RVI due to parainfluenza virus (PIV), respiratory syncytial virus (RSV), or human metapneumovirus (MPV) during the initial 100 days post-transplantation. Antibiotic exposure in the 3 weeks before RVI onset was defined as (1) use of specific antibiotics versus none of these antibiotics and (2) number of antibiotic-days. Cox proportional hazards models were used to examine associations between antibiotic exposures and risk of viral disease progression to proven/probable/possible LRTD. Ninety HCT recipients (84 adults, 6 children) fulfilled study criteria; 33 progressed to LRTD. The number of antibiotic-days was associated with progression to LRTD after adjusting for neutropenia, steroid use, and either lymphopenia (hazard ratio, 1.41 [95% confidence interval, 1.04 to 1.92], P = .027) or monocytopenia (hazard ratio, 1.46 [95% confidence interval, 1.11 to 1.91], P = .006). Specific antibiotic classes was not associated with the outcome. Cumulative antibiotic exposure immediately before RVI onset is a risk factor for disease progression following PIV, RSV, and MPV infections post-transplantation. Larger cohort studies are needed to determine the impact of specific antibiotics or antibiotic classes on disease severity.
Topics: Adolescent; Adult; Anti-Bacterial Agents; Child; Child, Preschool; Female; Hematopoietic Stem Cell Transplantation; Humans; Male; Middle Aged; Respiratory Syncytial Virus Infections; Respiratory Tract Infections; Retrospective Studies; Transplantation Conditioning; Transplantation, Homologous; Young Adult
PubMed: 29777867
DOI: 10.1016/j.bbmt.2018.05.016 -
Cancer Research and Treatment Jan 2019Extranodal natural killer/T-cell lymphoma, nasal type (ENKTL) is a rare subtype of non-Hodgkin lymphoma, and asparaginase-based regimens are the best first-line...
PURPOSE
Extranodal natural killer/T-cell lymphoma, nasal type (ENKTL) is a rare subtype of non-Hodgkin lymphoma, and asparaginase-based regimens are the best first-line treatments. Data on the role of specific circulating lymphocyte subsets in the progression of ENKTL are limited. The aim of this study was to investigate the clinical correlation and distribution of circulating absolute CD4+ T-cell counts (ACD4Cs) in ENKTL.
MATERIALS AND METHODS
We retrospectively searched medical records for 70 newly diagnosed ENKTL patients treated with pegaspargase-based regimens. Comparison of ACD4Cs as a continuous parameter in different groups was calculated. Univariate and multivariate analyses were used to assess prognostic factors for overall survival (OS) and progression-free survival (PFS).
RESULTS
Stage III/IV, B symptoms, elevated lactate dehydrogenase, monocytopenia, high-intermediate and high risk International Prognostic Index (IPI) and Korean Prognostic Index (KPI), high risk Prognostic Index of Natural Killer Lymphoma (PINK), and lower lymphocytes were significantly associated with low ACD4C at diagnosis. With a median follow-up time of 32 months, patients who had an ACD4C < 0.30×109/L had a worse OS. Median OS was 11 months and median PFS was 5 months in the low ACD4C cohort. There were significant differences in both OS and PFS between the two cohorts. Moreover, multivariate Cox analysis identified ACD4Cs as an independent predictor for OS and PFS.
CONCLUSION
Low ACD4Cs were associated with poorer survival and could act as a negative predictor for ENKTL patients treated with asparaginase-based regimens.
Topics: Adolescent; Adult; Aged; Aged, 80 and over; Antineoplastic Agents; Asparaginase; CD4 Lymphocyte Count; CD4-Positive T-Lymphocytes; Disease Progression; Female; Humans; Lymphoma, Extranodal NK-T-Cell; Male; Middle Aged; Neoplasm Staging; Polyethylene Glycols; Prognosis; Retrospective Studies; Survival Analysis; Treatment Outcome; Young Adult
PubMed: 29764116
DOI: 10.4143/crt.2018.010 -
The Tohoku Journal of Experimental... Jan 2018Hematopoietic stem cells can self-renew and differentiate into all blood cell types. The transcription factor GATA-2 is expressed in hematopoietic stem and progenitor...
Hematopoietic stem cells can self-renew and differentiate into all blood cell types. The transcription factor GATA-2 is expressed in hematopoietic stem and progenitor cells and is essential for cell proliferation and differentiation. Heterozygous germline GATA2 mutations induce GATA-2 deficiency syndrome, characterized by monocytopenia, a predisposition to myelodysplasia and acute myeloid leukemia, and a profoundly reduced dendritic cell (DC) population, which is associated with increased susceptibility to viral infections. Because patients with GATA-2 deficiency syndrome could retain a wild-type copy of GATA-2, boosting residual wild-type GATA-2 activity may represent a novel therapeutic strategy for the disease. Here, we sought to establish a screening system to identify GATA-2 activators using human U937 monocytic cells as a potential model of the DC progenitor. Enforced GATA-2 expression in U937 cells induces CD205 expression, a marker of DC differentiation, indicating U937 cells as a surrogate of human primary DC progenitors. Transient luciferase reporter assays in U937 cells reveals a high promoter activity of the -0.5 kb GATA-2 hematopoietic-specific promoter (1S promoter) fused with two tandemly connected GATA-2 +9.9 kb intronic enhancers. We thus established U937-derived cell lines stably expressing tandem +9.9 kb/-0.5 kb 1S-luciferase. Importantly, forced GATA-1 expression, a repressor for GATA-2 expression, in the stable clones caused significant decreases in the luciferase activities. In conclusion, our system represents a potential tool for identifying novel regulators of GATA-2, thereby contributing to the development of novel therapeutic approaches.
Topics: Base Pairing; Biomarkers; Cell Line, Tumor; Clone Cells; Dendritic Cells; GATA2 Transcription Factor; Gene Expression Regulation; Genetic Testing; Humans; Immune Sera; Luciferases; Promoter Regions, Genetic; Transcription, Genetic
PubMed: 29343653
DOI: 10.1620/tjem.244.41 -
Parasites & Vectors Jan 2018Anaplasma phagocytophilum is an obligate intracellular, tick-transmitted bacterium that causes granulocytic anaplasmosis in humans and several mammalian species...
BACKGROUND
Anaplasma phagocytophilum is an obligate intracellular, tick-transmitted bacterium that causes granulocytic anaplasmosis in humans and several mammalian species including domestic ruminants where it is called tick-borne fever (TBF). Different genetic variants exist but their impact with regard to putative differences in host associations and pathogenicity are not yet completely understood.
METHODS
Natural infections with A. phagocytophilum in a dairy cattle herd in Germany were investigated over one pasture season by using serology, haematology, blood chemistry and polymerase chain reaction (PCR). Sequence analysis of partial 16S rRNA, groEL, msp2 and msp4 genes of A. phagocytophilum was carried out in order to trace possible genetic variants and their relations between cattle, roe deer (Capreolus capreolus) and ticks (Ixodes ricinus) in this area.
RESULTS
In total 533 samples from 58 cattle, 310 ticks, three roe deer and one wild boar were examined. Our results show (i) typical clinical symptoms of TBF in first-time infected heifers, such as high fever, reduced milk yield, lower limb oedema and typical haematological and biochemical findings such as severe leukopenia, erythropenia, neutropenia, lymphocytopenia, monocytopenia, a significant increase in creatinine and bilirubin and a significant decrease in serum albumin, γ-GT, GLDH, magnesium and calcium; (ii) a high overall prevalence of A. phagocytophilum infections in this herd as 78.9% (15/19) of the naïve heifers were real-time PCR-positive and 75.9% (44/58) of the entire herd seroconverted; and (iii) a high level of sequence variation in the analysed genes with five variants of the 16S rRNA gene, two variants of the groEL gene, three variants of the msp2 gene and four variants in the msp4 gene with certain combinations of these variants.
CONCLUSIONS
In cattle particular combinations of the genetic variants of A. phagocytophilum occurred, whereas three roe deer showed different variants altogether. This is indicative for a sympatric circulation of variants in this small geographical region (< 1 km). Both re- and superinfections with A. phagocytophilum were observed in five cattle showing that infection does not result in sterile immunity. For prevention of clinical cases we suggest pasturing of young, not pregnant heifers to reduce economical losses.
Topics: Anaplasma phagocytophilum; Animals; Bacterial Proteins; Blood Cell Count; Blood Chemical Analysis; Cattle; Cattle Diseases; Cluster Analysis; DNA, Bacterial; DNA, Ribosomal; Ehrlichiosis; Genetic Variation; Germany; Molecular Epidemiology; Phylogeny; Polymerase Chain Reaction; Prevalence; RNA, Ribosomal, 16S; Sequence Analysis, DNA; Serology; Tick Infestations
PubMed: 29310697
DOI: 10.1186/s13071-017-2570-1 -
The Journal of Allergy and Clinical... Jun 2018The homozygous K108E mutation of interferon regulatory factor 8 (IRF8) is reported to cause dendritic cell (DC) and monocyte deficiency. However, more widespread immune...
BACKGROUND
The homozygous K108E mutation of interferon regulatory factor 8 (IRF8) is reported to cause dendritic cell (DC) and monocyte deficiency. However, more widespread immune dysfunction is predicted from the multiple roles ascribed to IRF8 in immune cell development and function.
OBJECTIVE
We sought to describe the effect on hematopoiesis and immunity of the compound heterozygous R83C/R291Q mutation of IRF8, which is present in a patient with recurrent viral infection, granuloproliferation, and intracerebral calcification.
METHODS
Variant IRF8 alleles were identified by means of exome sequencing, and their function was tested by using reporter assays. The cellular phenotype was studied in detail by using flow cytometry, functional immunologic assay transcriptional profiling, and antigen receptor profiling.
RESULTS
Both mutations affected conserved residues, and R291Q is orthologous to R294, which is mutated in the BXH2 IRF8-deficient mouse. R83C showed reduced nuclear translocation, and neither mutant was able to regulate the Ets/IRF composite element or interferon-stimulated response element, whereas R291Q retained BATF/JUN interactions. DC deficiency and monocytopenia were observed in blood, dermis, and lung lavage fluid. Granulocytes were consistently increased, dysplastic, and hypofunctional. Natural killer cell development and maturation were arrested. T1, T17, and CD8 memory T-cell differentiation was significantly reduced, and T cells did not express CXCR3. B-cell development was impaired, with fewer memory cells, reduced class-switching, and lower frequency and complexity of somatic hypermutation. Cell-specific gene expression was widely disturbed in interferon- and IRF8-regulated transcripts.
CONCLUSIONS
This analysis defines the clinical features of human biallelic IRF8 deficiency, revealing a complex immunodeficiency syndrome caused by DC and monocyte deficiency combined with widespread immune dysregulation.
Topics: Dendritic Cells; Humans; Immunologic Deficiency Syndromes; Interferon Regulatory Factors; Male; Monocytes; Mutation
PubMed: 29128673
DOI: 10.1016/j.jaci.2017.08.044