Publications by authors named "Cesar M Rueda"

18 Publications

  • Page 1 of 1

POLD1 Deficiency Reveals a Role for POLD1 in DNA Repair and T and B Cell Development.

J Clin Immunol 2021 Jan 2;41(1):270-273. Epub 2020 Nov 2.

Laboratory of Clinical Immunology and Microbiology, Division of Intramural Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Building 10, Room 5-3950, 10 Center Dr, Bethesda, MD, 20892, USA.

View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1007/s10875-020-00903-6DOI Listing
January 2021

Severe SARS-CoV-2 disease in the context of a NF-κB2 loss-of-function pathogenic variant.

J Allergy Clin Immunol 2021 Feb 30;147(2):532-544.e1. Epub 2020 Sep 30.

Department of Pediatrics, Nationwide Children's Hospital and The Ohio State University College of Medicine, Columbus, Ohio; Center for Vaccines and Immunity, The Abigail Wexner Research Institute, Nationwide Children's Hospital, Columbus, Ohio; Division of Infectious Diseases, Nationwide Children's Hospital, Columbus, Ohio.

Background: Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is a novel coronavirus that emerged recently and has created a global pandemic. Symptomatic SARS-CoV-2 infection, termed coronavirus disease 2019 (COVID-19), has been associated with a host of symptoms affecting numerous organ systems, including the lungs, cardiovascular system, kidney, central nervous system, gastrointestinal tract, and skin, among others.

Objective: Although several risk factors have been identified as related to complications from and severity of COVID-19, much about the virus remains unknown. The host immune response appears to affect the outcome of disease. It is not surprising that patients with intrinsic or secondary immune compromise might be particularly susceptible to complications from SARS-CoV-2 infection. Pathogenic loss-of-function or gain-of-function heterozygous variants in nuclear factor-κB2 have been reported to be associated with either a combined immunodeficiency or common variable immunodeficiency phenotype.

Methods: We evaluated the functional consequence and immunologic phenotype of a novel NFKB2 loss of function variant in a 17-year-old male patient and describe the clinical management of SARS-CoV-2 infection in this context.

Results: This patient required a 2-week hospitalization for SARS-CoV-2 infection, including 7 days of mechanical ventilation. We used biologic therapies to avert potentially fatal acute respiratory distress syndrome and treat hyperinflammatory responses. The patient had an immunologic phenotype of B-cell dysregulation with decreased switched memory B cells. Despite the underlying immune dysfunction, he recovered from the infection with intense management.

Conclusions: This clinical case exemplifies some of the practical challenges in management of patients with SARS-CoV-2 infection, especially in the context of underlying immune dysregulation.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.jaci.2020.09.020DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7525247PMC
February 2021

A Novel Pathogenic Variant in () Causing CARMIL2 Deficiency and EBV-Associated Smooth Muscle Tumors.

Front Immunol 2020 18;11:884. Epub 2020 Jun 18.

Department of Pathology and Laboratory Medicine, Nationwide Children's Hospital, Columbus, OH, United States.

CARMIL2 deficiency is a rare combined immunodeficiency (CID) characterized by defective CD28-mediated T cell co-stimulation, altered cytoskeletal dynamics, and susceptibility to Epstein Barr Virus smooth muscle tumors (EBV-SMTs). Case reports associated with EBV-SMTs are limited. We describe herein a novel homozygous variant (c.1364_1393del) in two Saudi Arabian male siblings born to consanguineous parents who developed EBV-SMTs. CARMIL2 protein expression was significantly reduced in CD4+ T cells and CD8+ T cells. T cell proliferation on stimulation with soluble (s) anti-CD3 or (s) anti-CD3 plus anti-CD28 antibodies was close to absent in the proband, confirming altered CD28-mediated co-signaling. CD28 expression was substantially reduced in the proband's T cells, and was diminished to a lesser degree in the T cells of the younger sibling, who has a milder clinical phenotype. Defects in both T and B cell compartments were observed, including absent central memory CD8+ T cells, and decreased frequencies of total and class-switched memory B cells. FOXP3+ regulatory T cells (Treg) were also quantitatively decreased, and furthermore CD25 expression within the Treg subset was substantially reduced. These data confirm the pathogenicity of this novel loss-of-function (LOF) variant in and expand the genotypic and phenotypic spectrum of CIDs associated with EBV-SMTs.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.3389/fimmu.2020.00884DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7314954PMC
June 2020

IL-1 signaling mediates intrauterine inflammation and chorio-decidua neutrophil recruitment and activation.

JCI Insight 2018 03 22;3(6). Epub 2018 Mar 22.

Division of Neonatology/Pulmonary Biology.

Neutrophil infiltration of the chorioamnion-decidua tissue at the maternal-fetal interface (chorioamnionitis) is a leading cause of prematurity, fetal inflammation, and perinatal mortality. We induced chorioamnionitis in preterm rhesus macaques by intraamniotic injection of LPS. Here, we show that, during chorioamnionitis, the amnion upregulated phospho-IRAK1-expressed neutrophil chemoattractants CXCL8 and CSF3 in an IL-1-dependent manner. IL-1R blockade decreased chorio-decidua neutrophil accumulation, neutrophil activation, and IL-6 and prostaglandin E2 concentrations in the amniotic fluid. Neutrophils accumulating in the chorio-decidua had increased survival mediated by BCL2A1, and IL-1R blockade also decreased BCL2A1+ chorio-decidua neutrophils. Readouts for inflammation in a cohort of women with preterm delivery and chorioamnionitis were similar to findings in the rhesus macaques. IL-1 is a potential therapeutic target for chorioamnionitis and associated morbidities.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1172/jci.insight.98306DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5926925PMC
March 2018

High density lipoproteins selectively promote the survival of human regulatory T cells.

J Lipid Res 2017 08 4;58(8):1514-1523. Epub 2017 Apr 4.

Division of Immunobiology, Cincinnati Children's Hospital Research Foundation, Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, OH

HDLs appear to affect regulatory T cell (Treg) homeostasis, as suggested by the increased Treg counts in HDL-treated mice and by the positive correlation between Treg frequency and HDL-cholesterol levels in statin-treated healthy adults. However, the underlying mechanisms remain unclear. Herein, we show that HDLs, not LDLs, significantly decreased the apoptosis of human Tregs in vitro, whereas they did not alter naïve or memory CD4 T cell survival. Similarly, oleic acid bound to serum albumin increased Treg survival. Tregs bound and internalized high amounts of HDL compared with other subsets, which might arise from the higher expression of the scavenger receptor class B type I by Tregs; accordingly, blocking this receptor hindered HDL-mediated Treg survival. Mechanistically, we showed that HDL increased Treg ATP concentration and mitochondrial activity, enhancing basal respiration, maximal respiration, and spare respiratory capacity. Blockade of FA oxidation by etoxomir abolished the HDL-mediated enhanced survival and mitochondrial activity. Our findings thus suggest that Tregs can specifically internalize HDLs from their microenvironment and use them as an energy source. Furthermore, a novel implication of our data is that enhanced Treg survival may contribute to HDLs' anti-inflammatory properties.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1194/jlr.M072835DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5538275PMC
August 2017

IL-1β induced HIF-1α inhibits the differentiation of human FOXP3 T cells.

Sci Rep 2017 03 28;7(1):465. Epub 2017 Mar 28.

Department of Infectious Diseases and Microbiology, University of Lübeck, Lübeck, Germany.

Differentiation of regulatory Treg (Treg) in the periphery is critical to control inflammatory processes. Although polarization of inducible Treg (iTreg) often occurs in an inflammatory environment, the effects exerted by inflammation on human iTreg differentiation have not been extensively studied. We observed that IL-1β significantly reduced the frequency of FOXP3 T cells under iTreg-polarizing conditions. Mechanistically, we show that IL-1β activated mTORC1 and downstream upregulated hypoxia inducible factor-1 (HIF-1α) expression. Using specific inhibitors, we demonstrated that both steps were critical in the deleterious effect of IL-1β on Treg differentiation. Chemical stabilization of HIF-1α by Dimethyloxalylglycine (DMOG) also significantly impaired iTreg differentiation. Interestingly, while IL-1β-treated cells exhibited only minor changes in metabolism, DMOG treatment decreased iTreg mitochondrial respiration and increased their glycolytic capacity. In conclusion, exposure to inflammatory stimuli profoundly inhibits human Treg differentiation HIF-1α dependent, suggesting that targeting HIF-1α could be a strategy to foster iTreg differentiation in an inflammatory milieu. However, IL-1β deleterious effect does not appear to be completely driven by metabolic changes. These data thus suggest that several mechanisms contribute to the regulation of iTreg differentiation, but the timing and respective requirement for each pathway vary depending on the milieu in which iTreg differentiate.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1038/s41598-017-00508-xDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5428734PMC
March 2017

Type I interferons regulate susceptibility to inflammation-induced preterm birth.

JCI Insight 2017 03 9;2(5):e91288. Epub 2017 Mar 9.

Division of Immunobiology.

Preterm birth (PTB) is a leading worldwide cause of morbidity and mortality in infants. Maternal inflammation induced by microbial infection is a critical predisposing factor for PTB. However, biological processes associated with competency of pathogens, including viruses, to induce PTB or sensitize for secondary bacterial infection-driven PTB are unknown. We show that pathogen/pathogen-associated molecular pattern-driven activation of type I IFN/IFN receptor (IFNAR) was sufficient to prime for systemic and uterine proinflammatory chemokine and cytokine production and induction of PTB. Similarly, treatment with recombinant type I IFNs recapitulated such effects by exacerbating proinflammatory cytokine production and reducing the dose of secondary inflammatory challenge required for induction of PTB. Inflammatory challenge-driven induction of PTB was eliminated by defects in type I IFN, TLR, or IL-6 responsiveness, whereas the sequence of type I IFN sensing by IFNAR on hematopoietic cells was essential for regulation of proinflammatory cytokine production. Importantly, we also show that type I IFN priming effects are conserved from mice to nonhuman primates and humans, and expression of both type I IFNs and proinflammatory cytokines is upregulated in human PTB. Thus, activation of the type I IFN/IFNAR axis in pregnancy primes for inflammation-driven PTB and provides an actionable biomarker and therapeutic target for mitigating PTB risk.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1172/jci.insight.91288DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5333966PMC
March 2017

Intra-amniotic Ureaplasma parvum-Induced Maternal and Fetal Inflammation and Immune Responses in Rhesus Macaques.

J Infect Dis 2016 11 6;214(10):1597-1604. Epub 2016 Sep 6.

Perinatal Institute.

Background: Although Ureaplasma species are the most common organisms associated with prematurity, their effects on the maternal and fetal immune system remain poorly characterized.

Methods: Rhesus macaque dams at approximately 80% gestation were injected intra-amniotically with 10 colony-forming units of Ureaplasma parvum or saline (control). Fetuses were delivered surgically 3 or 7 days later. We performed comprehensive assessments of inflammation and immune effects in multiple fetal and maternal tissues.

Results: Although U. parvum grew well in amniotic fluid, there was minimal chorioamnionitis. U. parvum colonized the fetal lung, but fetal systemic microbial invasion was limited. Fetal lung inflammation was mild, with elevations in CXCL8, tumor necrosis factor (TNF) α, and CCL2 levels in alveolar washes at day 7. Inflammation was not detected in the fetal brain. Significantly, U. parvum decreased regulatory T cells (Tregs) and activated interferon γ production in these Tregs in the fetus. It was detected in uterine tissue by day 7 and induced mild inflammation and increased expression of connexin 43, a gap junction protein involved with labor.

Conclusions: U. parvum colonized the amniotic fluid and caused uterine inflammation, but without overt chorioamnionitis. It caused mild fetal lung inflammation but had a more profound effect on the fetal immune system, decreasing Tregs and polarizing them toward a T-helper 1 phenotype.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1093/infdis/jiw408DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6392471PMC
November 2016

Regulatory T-Cell-Mediated Suppression of Conventional T-Cells and Dendritic Cells by Different cAMP Intracellular Pathways.

Front Immunol 2016 2;7:216. Epub 2016 Jun 2.

Division of Immunobiology, Department of Pediatrics, Cincinnati Children's Hospital Research Foundation, University of Cincinnati College of Medicine , Cincinnati, OH , USA.

Regulatory T-cells (Tregs) mediate their suppressive action by acting directly on conventional T-cells (Tcons) or dendritic cells (DCs). One mechanism of Treg suppression is the increase of cyclic adenosine 3',5'-monophosphate (cAMP) levels in target cells. Tregs utilize cAMP to control Tcon responses, such as proliferation and cytokine production. Tregs also exert their suppression on DCs, diminishing DC immunogenicity by downmodulating the expression of costimulatory molecules and actin polymerization at the immunological synapse. The Treg-mediated usage of cAMP occurs through two major mechanisms. The first involves the Treg-mediated influx of cAMP in target cells through gap junctions. The second is the conversion of adenosine triphosphate into adenosine by the ectonucleases CD39 and CD73 present on the surface of Tregs. Adenosine then binds to receptors on the surface of target cells, leading to increased intracellular cAMP levels in these targets. Downstream, cAMP can activate the canonical protein kinase A (PKA) pathway and the exchange protein activated by cyclic AMP (EPAC) non-canonical pathway. In this review, we discuss the most recent findings related to cAMP activation of PKA and EPAC, which are implicated in Treg homeostasis as well as the functional alterations induced by cAMP in cellular targets of Treg suppression.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.3389/fimmu.2016.00216DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4889573PMC
June 2016

Lipopolysaccharide-Induced Chorioamnionitis Promotes IL-1-Dependent Inflammatory FOXP3+ CD4+ T Cells in the Fetal Rhesus Macaque.

J Immunol 2016 05 1;196(9):3706-15. Epub 2016 Apr 1.

Division of Immunobiology, Cincinnati Children's Hospital Research Foundation, Cincinnati, OH 45229; Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, OH 45229;

Chorioamnionitis is associated with preterm labor and fetal inflammatory response syndrome (FIRS), causing fetal organ injury and morbidity, particularly in extremely premature infants. However, the effects of inflammation on the fetal immune system remain poorly understood, due to the difficulty of studying immune development in infants. Therefore, we used the model of intra-amniotic LPS administered at ∼80% gestation in rhesus monkeys to cause chorioamnionitis and FIRS that is similar in human pathology. Importantly, the frequency of IL-17(+) and IL-22(+) CD4(+) T cells increased in the spleen of LPS-exposed fetuses, whereas regulatory T cell (Treg) frequency decreased. These changes persisted for at least 48 h. Notably, Th17 cytokines were predominantly expressed by FOXP3(+)CD4(+) T cells and not by their FOXP3(-) counterparts. Bifunctional IL-17(+)FOXP3(+) exhibited a phenotype of inflammatory Tregs (RORc(High/+), Helios(Low/-), IL-2(+), IFN-γ(+), and IL-8(+)) compared with typical FOXP3(+) cells. Diminished splenic Treg frequency in LPS-exposed fetuses was associated with inadequate Treg generation in the thymus. Mechanistically, the emergence of inflammatory Tregs was largely dependent on IL-1 signaling. However, blockage of IL-1R signaling did not abolish the deleterious effects of LPS on Treg frequency in the thymus or spleen. Collectively, we demonstrate that a prenatal inflammatory environment leads to inadequate Treg generation in the thymus with a switch of splenic Tregs toward an inflammatory phenotype. Both processes likely contribute to the pathogenesis of chorioamnionitis. Approaches to manipulate Treg numbers and function could thus be useful therapeutically to alleviate FIRS in preterm infants.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.4049/jimmunol.1502613DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4868637PMC
May 2016

AUTOIMMUNE DISEASE. Patients with LRBA deficiency show CTLA4 loss and immune dysregulation responsive to abatacept therapy.

Science 2015 Jul;349(6246):436-40

Division of Bone Marrow Transplantation and Immune Deficiency, Department of Pediatrics, Cincinnati Children's Hospital Medical Center, University of Cincinnati, Cincinnati, OH, USA. Division of Immunobiology, Department of Pediatrics, Cincinnati Children's Hospital Medical Center/ University of Cincinnati, Cincinnati, OH, USA.

Mutations in the LRBA gene (encoding the lipopolysaccharide-responsive and beige-like anchor protein) cause a syndrome of autoimmunity, lymphoproliferation, and humoral immune deficiency. The biological role of LRBA in immunologic disease is unknown. We found that patients with LRBA deficiency manifested a dramatic and sustained improvement in response to abatacept, a CTLA4 (cytotoxic T lymphocyte antigen-4)-immunoglobulin fusion drug. Clinical responses and homology of LRBA to proteins controlling intracellular trafficking led us to hypothesize that it regulates CTLA4, a potent inhibitory immune receptor. We found that LRBA colocalized with CTLA4 in endosomal vesicles and that LRBA deficiency or knockdown increased CTLA4 turnover, which resulted in reduced levels of CTLA4 protein in FoxP3(+) regulatory and activated conventional T cells. In LRBA-deficient cells, inhibition of lysosome degradation with chloroquine prevented CTLA4 loss. These findings elucidate a mechanism for CTLA4 trafficking and control of immune responses and suggest therapies for diseases involving the CTLA4 pathway.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1126/science.aaa1663DOI Listing
July 2015

Neonatal regulatory T cells have reduced capacity to suppress dendritic cell function.

Eur J Immunol 2015 Sep 25;45(9):2582-92. Epub 2015 Jun 25.

Division of Immunobiology, Cincinnati Children's Hospital Research Foundation, Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, OH, USA.

Regulatory T cells (Treg cells) limit contact between dendritic cells (DCs) and conventional T cells (Tcons), decreasing the formation of aggregates as well as down-modulating the expression of co-stimulatory molecules by DCs, thus decreasing DC immunogenicity and abrogating T-cell activation. Despite the importance of this Treg-cell function, the capacity of Treg cells from term and preterm neonates to suppress DCs, and the suppressive mechanisms they use, are still undefined. We found that, relative to adult Treg cells, activated Treg cells from human neonates expressed lower FOXP3 and CTLA-4, but contained higher levels of cAMP. We developed an in vitro model in which Treg function was measured at a physiological ratio of 1 Treg for 10 Tcon and 1 monocyte-derived DC, as Treg target. Term and preterm Treg cells failed to suppress the formation of DC-Tcon aggregates, in contrast to naïve and memory Treg cells from adults. However, neonatal Treg cells diminished DC and Tcon activation as well as actin polymerization at the immunological synapses. In addition, CTLA-4 and cAMP were the main suppressive molecules used by neonatal Treg. Altogether, both preterm and term neonatal Treg cells appear less functional than adult Treg cells, and this defect is consistent with the general impairment of CD4 cell function in newborns.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1002/eji.201445371DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4666291PMC
September 2015

Neutrophil recruitment and activation in decidua with intra-amniotic IL-1beta in the preterm rhesus macaque.

Biol Reprod 2015 Feb 23;92(2):56. Epub 2014 Dec 23.

Perinatal Institute, Cincinnati Children's Hospital Medical Center, University of Cincinnati, Cincinnati, Ohio

Chorioamnionitis, an infection/inflammation of the fetomaternal membranes, is frequently associated with preterm delivery. The mechanisms of inflammation in chorioamnionitis are poorly understood. We hypothesized that neutrophils recruited to the decidua would be the major producers of proinflammatory cytokines. We injected intra-amniotic (IA) interleukin 1beta (IL-1beta) at ∼80% gestation in rhesus macaque monkeys, Macaca mulatta, delivered the fetuses surgically 24 h or 72 h after IA injections, and investigated the role of immune cells in the chorion-amnion decidua. IA IL-1beta induced a robust infiltration of neutrophils and significant increases of proinflammatory cytokines in the chorioamnion decidua at 24 h after exposure, with a subsequent decrease at 72 h. Neutrophils in the decidua were the major source of tumor necrosis factor alpha (TNFalpha) and IL-8. Interestingly, IA IL-1beta also induced a significant increase in anti-inflammatory indoleamine 2,3-dioxygenase (IDO) expression in the decidua neutrophils. The frequency of regulatory T cells (Tregs) and FOXP3 mRNA expression in the decidua did not change after IA IL-1beta injection. Collectively, our data demonstrate that in this model of sterile chorioamnionitis, the decidua neutrophils cause the inflammation in the gestational tissues but may also act as regulators to dampen the inflammation. These results help to understand the contribution of neutrophils to the pathogenesis of chorioamnionitis-induced preterm labor.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1095/biolreprod.114.124420DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4342792PMC
February 2015

Effect of chorioamnionitis on regulatory T cells in moderate/late preterm neonates.

Hum Immunol 2015 Jan 8;76(1):65-73. Epub 2014 Nov 8.

Division of Immunobiology, Cincinnati Children's Hospital Research Foundation, Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, OH, USA. Electronic address:

Regulatory T-cells (Treg) have a protective role for the control of immune activation and tissue damage. The effects of chorioamnionitis (chorio) on Treg in moderate/late preterm newborns are not known. We hypothesized that infants exposed to chorio would have decreased Treg frequency and/or function. We isolated mononuclear cells from adult peripheral blood and cord blood from term and moderate/late preterm infants who were classified for severity of chorio exposure. Mononuclear cells were analyzed by flow cytometry for Treg frequency and phenotype. Treg suppression of activation of conventional T-cells (Tcon) was also quantified. Treg frequencies were similar in all groups of neonates, but lower than that found in adults. Newborn Treg had a naïve phenotype, with decreased levels of CD45RO, HLA-DR, CD39 and TIGIT compared to adult Treg and chorio did not affect the phenotype. Treg from preterm newborns exposed to severe chorio had higher expression of Ki67 compared to the other groups. Treg from preterm newborns were less suppressive than Treg from adults or term, and the level of suppression was reduced with severe chorio. Relative to term, Treg frequency and phenotype were not affected by prematurity and chorio but their functionality was decreased. Lower Treg activity may contribute to inflammation in newborns that is often associated with chorioamnionitis.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.humimm.2014.10.016DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4282957PMC
January 2015

Fetal immune response to chorioamnionitis.

Semin Reprod Med 2014 Jan 3;32(1):56-67. Epub 2014 Jan 3.

Division of Immunobiology, The Perinatal Institute, Cincinnati Children's Hospital Medical Center, University of Cincinnati, Cincinnati, Ohio.

Chorioamnionitis is a frequent cause of preterm birth and is associated with an increased risk for injury responses in the lung, gastrointestinal tract, brain, and other fetal organs. Chorioamnionitis is a polymicrobial nontraditional infectious disease because the organisms causing chorioamnionitis are generally of low virulence and colonize the amniotic fluid often for extended periods, and the host (mother and the fetus) does not have typical infection-related symptoms such as fever. In this review, we discuss the effects of chorioamnionitis in experimental animal models that mimic the human disease. Our focus is on the immune changes in multiple fetal organs and the pathogenesis of chorioamnionitis-induced injury in different fetal compartments. As chorioamnionitis disproportionately affects preterm infants, we discuss the relevant developmental context for the immune system. We also provide a clinical context for the fetal responses.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1055/s-0033-1361823DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4118297PMC
January 2014

Incomplete normalization of regulatory t-cell frequency in the gut mucosa of Colombian HIV-infected patients receiving long-term antiretroviral treatment.

PLoS One 2013 15;8(8):e71062. Epub 2013 Aug 15.

Grupo Inmunovirologia, Universidad de Antioquia, Medellín, Antioquia, Colombia.

Introduction: To evaluate the effect of late initiation of HAART and poor immune reconstitution on the frequency of regulatory T-cells (Treg) in the peripheral blood and gut of HIV-infected patients, we studied Colombian HIV-infected patients who had been on suppressive HAART for at least one year. They had undetectable viremia but were either immunological responders (HIR); (CD4 counts >500 cells/µl) or non-immunological responders (NIR); (CD4 T-cell count <300 cells/µl). Untreated HIV-infected patients and uninfected controls from the same region were also evaluated.

Methods: Frequency and phenotype of regulatory T-cells (Treg) were analyzed in gut biopsies and blood samples. The functional effect of Treg depletion on CMV and HIV responses was determined. Markers of immune activation and circulating LPS levels were quantified.

Results: Untreated patients exhibited high Treg frequency in PBMC and gut, and their Treg express high levels of CTLA-4 and PD-1. Although HAART significantly decreased mucosal Treg frequency, it did not normalize it in any of the treated groups (HIR and NIR patients). Treg normalization was observed in the blood of HIR patients following HAART, but did not occur in NIR patients. Treg from HIV-infected patients (treated or not) suppressed HIV and hCMV-specific T-cells from gut and blood. Plasma LPS levels and percentage of HLA-DR+CD38+ T-cells were significantly elevated in all infected groups compared to controls.

Conclusions: These findings suggest that control of viral replication is not sufficient to normalize gut Treg frequency in patients, independent of their response to HAART. Furthermore, persistence of functional Treg in the gut appears to be associated with the failure of HAART to repair mucosal damage.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0071062PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3744540PMC
September 2014

Characterization of CD4 and CD8 T cells producing IFN-γ in human latent and active tuberculosis.

Tuberculosis (Edinb) 2010 Nov 8;90(6):346-53. Epub 2010 Oct 8.

Grupo de Inmunología Celular e Inmunogenética, Instituto de Investigaciones Médicas, Universidad de Antioquia, Medellín, Colombia.

Patients with pulmonary tuberculosis (PTB) frequently have reduced IFN-γ production in response to mycobacterial antigens, compared to individuals with latent Mycobacterium tuberculosis infection (LTBi). However, it is not clear whether this reduced responsiveness is restricted to a particular T cell subset. Herein, PBMCs from 26 PTB patients, 30 household contacts (HHCs) of PTB, and 30 tuberculin positive (TST+) healthy subjects not recently exposed to PTB, were stained with CFSE and stimulated non-specific (PPD) for 120 h, and specific (CFP-10/ESAT-6) and latency (HSpX) mycobacterial antigens for 144 h and the percentage of CD4(+) and CD8(+)IFN-γ(+) T cells responding determined by flow cytometry, in addition to their memory phenotype by the CD45RO and CD27 expression. PTB had decreased frequency of both CD4(+) and CD8(+) precursor cells, as well as decreased number of CD4(+)IFN-γ(+) cells in response to all antigens, whereas CD8(+)IFN-γ(+) cells were decreased in response to PPD and ESAT-6, but not to CFP-10 and HSpX. HHCs exhibited the highest precursor frequencies and IFN-γ responses, irrespective of the antigen employed. The CD4(+)/CD8(+) cell ratios showed that in response to PPD CD4(+) precursor and IFN-γ-producer cells are more frequent than their CD8(+) counterparts, and that PTB have a decreased CD4(+)IFN-γ(+)/CD8(+)IFN-γ(+) ratio in response to PPD, CFP-10, and ESAT-6. CD4(+)IFN-γ(+) and CD8(+)IFN-γ(+) cells exhibited a central memory phenotype (CD45RO(+)CD27(+)), irrespective of the group of subjects and the antigen used for stimulation. In conclusion, PTB patients had a decreased percentage of CD4(+) and CD8(+) precursor cells and CD4(+)IFN-γ(+). HHCs exhibited the highest frequency of CD4(+) and CD8(+) precursors and CD4(+)IFN-γ(+)-producing cells.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.tube.2010.09.003DOI Listing
November 2010

Photodynamic activity of aluminium (III) and zinc (II) phthalocyanines in Leishmania promastigotes.

Biomedica 2006 Oct;26 Suppl 1:49-56

Centro de Investigación de Enfermedades Tropicales (CINTROP), Facultad de Salud, Escuela de Medicina, Departamento de Ciencias Básicas, Universidad Industrial de Santander, Bucaramanga, Colombia.

Introduction: Photodynamic therapy is a two-step procedure, involving the use of photosensitizing agents followed by selective illumination of the target lesion with visible light. It produces highly reactive oxygen species and subsequent cellular damage.

Objective: This study was designed to determine whether Leishmania chagasi and L. panamensis promastigotes were sensitive to photodynamic therapy in vitro.

Material And Methods: Leishmania promastigotes were treated with aluminium phthalocyanine chloride and zinc phthalocyanine photosensitizers before illumination with visible light at 670 nm. The parasite photoactivity was calculated by sigmoidal regression analysis.

Results: Leishmania chagasi promastigotes were highly photosensitive to aluminium phthalocyanine chloride treatment with effective inhibitory dose50 (ED50) concentration values of 0.0033, 0.0083 and 0.0093 microM upon exposure to 10.0, 5.0, and 2.5 J/cm2 light intensities respectively. By contrast, the activity of aluminium phthalocyanine chloride on L. panamensis was significantly lower (P < 0.01) with ED50 values of 0.17, 0.25, 0.34 microM at the same light intensities. Zinc phthalocyanine activity was significantly (P < 0.01) less active than aluminium phthalocyanine chloride on both strains of these two species and no differences in zinc phthalocyanine activity were found between them. A dose-response phototoxic effect with both phthalocyanines was observed. Parasite inhibition was not observed after aluminium phthalocyanine chloride or zinc phthalocyanine treatment in the dark. The reference drugs hexadecylphosphocholine and amphotericin B were not photoactive.

Conclusion: Treatment of Leishmania promastigotes with aluminium phthalocyanine chloride and zinc phthalocyanine followed by illumination with visible light at 670 nm inhibited in vitro growth of promastigotes of L. chagasi and L. panamensis. Photodynamic therapy against Leishmania could be a promising strategy for leishmaniasis treatment.
View Article and Find Full Text PDF

Download full-text PDF

Source
October 2006