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Damås JK, Otterdal K, Astrup E, Lekva T, Janardhanan J, Michelsen A, Aukrust P, Varghese GM, Ueland T. Canonical notch activation in patients with scrub typhus: association with organ dysfunction and poor outcome. Infection 2024; 52:1357-1365. [PMID: 38502427 PMCID: PMC11288987 DOI: 10.1007/s15010-024-02192-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2023] [Accepted: 01/19/2024] [Indexed: 03/21/2024]
Abstract
PURPOSE The mechanisms that control inflammation in scrub typhus are not fully elucidated. The Notch pathways are important regulators of inflammation and infection, but have not been investigated in scrub typhus. METHODS Plasma levels of the canonical Notch ligand Delta-like protein 1 (DLL1) were measured by enzyme immunoassay and RNA expression of the Notch receptors (NOTCH1, NOTCH2 and NOTCH4) in whole blood was analyzed by real-time PCR in patients with scrub typhus (n = 129), in patients with similar febrile illness without O. tsutsugamushi infection (n = 31) and in healthy controls (n = 31); all from the same area of South India. RESULTS Our main results were: (i) plasma DLL1 was markedly increased in scrub typhus patients at hospital admission with a significant decrease during recovery. (ii) RNA expression of NOTCH4 was decreased at admission in whole blood. (iii) A similar pattern for DLL1 and NOTCH4 was seen in febrile disease controls. (iv) Admission DLL1 in plasma was associated with disease severity and short-term survival. (vi) Regulation of Notch pathways in O. tsutsugamushi-infected monocytes as evaluated by public repository data revealed enhanced canonical Notch activation with upregulation of DLL1 and downregulation of NOTCH4. CONCLUSION Our findings suggest that scrub typhus patients are characterized by enhanced canonical Notch activation. Elevated plasma levels of DLL1 were associated with organ dysfunction and poor outcomes in these patients.
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Affiliation(s)
- Jan K Damås
- Department of Clinical and Molecular Medicine, Norwegian University of Science and Technology, Trondheim, Norway
- Department of Infectious Diseases, St. Olavs Hospital, Trondheim, Norway
- Department of Medicine, Christian Medical College, Vellore, Tamil Nadu, India
| | - Kari Otterdal
- Research Institute of Internal Medicine, Oslo University Hospital Rikshospitalet, Oslo, Norway
- Department of Medicine, Christian Medical College, Vellore, Tamil Nadu, India
| | - Elisabeth Astrup
- Research Institute of Internal Medicine, Oslo University Hospital Rikshospitalet, Oslo, Norway
- Institute of Clinical Medicine, Akershus University Hospital, Lørenskog, Norway
- Department of Medicine, Christian Medical College, Vellore, Tamil Nadu, India
| | - Tove Lekva
- Research Institute of Internal Medicine, Oslo University Hospital Rikshospitalet, Oslo, Norway
- Department of Medicine, Christian Medical College, Vellore, Tamil Nadu, India
| | - Jeshina Janardhanan
- Department of Medicine, Christian Medical College, Vellore, Tamil Nadu, India
- Department of Infectious Diseases, Christian Medical College, Vellore, Tamil Nadu, India
| | - Annika Michelsen
- Research Institute of Internal Medicine, Oslo University Hospital Rikshospitalet, Oslo, Norway
- Department of Medicine, Christian Medical College, Vellore, Tamil Nadu, India
| | - Pål Aukrust
- Research Institute of Internal Medicine, Oslo University Hospital Rikshospitalet, Oslo, Norway
- Section of Clinical Immunology and Infectious Diseases, Oslo University Hospital Rikshospitalet, Oslo, Norway
- Faculty of Medicine, University of Oslo, Oslo, Norway
- Department of Medicine, Christian Medical College, Vellore, Tamil Nadu, India
| | - George M Varghese
- Department of Medicine, Christian Medical College, Vellore, Tamil Nadu, India
- Department of Infectious Diseases, Christian Medical College, Vellore, Tamil Nadu, India
| | - Thor Ueland
- Research Institute of Internal Medicine, Oslo University Hospital Rikshospitalet, Oslo, Norway.
- Faculty of Medicine, University of Oslo, Oslo, Norway.
- Thrombosis Research Center (TREC), Division of Internal Medicine, University Hospital of North Norway, Tromsø, Norway.
- Department of Medicine, Christian Medical College, Vellore, Tamil Nadu, India.
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Dolley A, Goswami HB, Dowerah D, Dey U, Kumar A, Hmuaka V, Mukhopadhyay R, Kundu D, Varghese GM, Doley R, Chandra Deka R, Namsa ND. Reverse vaccinology and immunoinformatics approach to design a chimeric epitope vaccine against Orientia tsutsugamushi. Heliyon 2024; 10:e23616. [PMID: 38187223 PMCID: PMC10767154 DOI: 10.1016/j.heliyon.2023.e23616] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2023] [Revised: 12/06/2023] [Accepted: 12/07/2023] [Indexed: 01/09/2024] Open
Abstract
Scrub typhus is a vector-borne infectious disease caused by Orientia tsutsugamushi and it is reportedly associated with up to 20 % of hospitalized cases of febrile illnesses. The major challenge of vaccine development is the lack of identified antigens that can induce both heterotypic and homotypic immunity including the production of antibodies, cytotoxic T lymphocyte, and helper T lymphocytes. We employed a comprehensive immunoinformatic prediction algorithm to identify immunogenic epitopes of the 56-kDa type-specific cell membrane surface antigen and surface cell antigen A of O. tsutsugamushi to select potential candidates for developing vaccines and diagnostic assays. We identified 35 linear and 29 continuous immunogenic B-cell epitopes and 51 and 27 strong-binding T-cell epitopes of major histocompatibility complex class I and class II molecules, respectively, in the conserved and variable regions of the 56-kDa type-specific surface antigen. The predicted B- and T-cell epitopes were used to develop immunogenic multi-epitope candidate vaccines and showed to elicit a broad-range of immune protection. A stable interactions between the multi-epitope vaccines and the host fibronectin protein were observed using docking and simulation methods. Molecular dynamics simulation studies demonstrated that the multi-epitope vaccine constructs and fibronectin docked models were stable during simulation time. Furthermore, the multi-epitope vaccine exhibited properties such as antigenicity, non-allergenicity and ability to induce interferon gamma production and had strong associations with their respective human leukocyte antigen alleles of world-wide population coverage. A correlation of immune simulations and the in-silico predicted immunogenic potential of multi-epitope vaccines implicate for further investigations to accelerate designing of epitope-based vaccine candidates and chimeric antigens for development of serological diagnostic assays for scrub typhus.
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Affiliation(s)
- Anutee Dolley
- Department of Molecular Biology and Biotechnology, Tezpur University, Napaam, 784028, Assam, India
| | - Himanshu Ballav Goswami
- Department of Molecular Biology and Biotechnology, Tezpur University, Napaam, 784028, Assam, India
| | - Dikshita Dowerah
- Department of Chemical Sciences, Tezpur University, Napaam, 784028, Assam, India
| | - Upalabdha Dey
- Department of Molecular Biology and Biotechnology, Tezpur University, Napaam, 784028, Assam, India
| | - Aditya Kumar
- Department of Molecular Biology and Biotechnology, Tezpur University, Napaam, 784028, Assam, India
| | - Vanlal Hmuaka
- Entomology and Biothreat Management Division, Defence Research Laboratory, Tezpur, 784001, Assam, India
| | - Rupak Mukhopadhyay
- Department of Molecular Biology and Biotechnology, Tezpur University, Napaam, 784028, Assam, India
| | - Debasree Kundu
- Department of Infectious Diseases, Christian Medical College, Vellore, 632002, Tamil Nadu, India
| | - George M. Varghese
- Department of Infectious Diseases, Christian Medical College, Vellore, 632002, Tamil Nadu, India
| | - Robin Doley
- Department of Molecular Biology and Biotechnology, Tezpur University, Napaam, 784028, Assam, India
| | - Ramesh Chandra Deka
- Department of Chemical Sciences, Tezpur University, Napaam, 784028, Assam, India
| | - Nima D. Namsa
- Department of Molecular Biology and Biotechnology, Tezpur University, Napaam, 784028, Assam, India
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Thiriot JD, Liang Y, Gonzales C, Sun J, Yu X, Soong L. Differential cellular immune responses against Orientia tsutsugamushi Karp and Gilliam strains following acute infection in mice. PLoS Negl Trop Dis 2023; 17:e0011445. [PMID: 38091346 PMCID: PMC10752558 DOI: 10.1371/journal.pntd.0011445] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2023] [Revised: 12/27/2023] [Accepted: 12/06/2023] [Indexed: 12/28/2023] Open
Abstract
Scrub typhus is a leading cause of febrile illness in endemic countries due to infection with Orientia tsutsugamushi (Ot), a seriously understudied intracellular bacterium. Pulmonary involvement associated with vascular parasitism in patients is common and can develop into life threatening interstitial pneumonia. The diverse antigenicity of Ot genotypes and inter-strain differences in genome content are connected to varied virulence and clinical outcomes; however, detailed studies of strain-related pulmonary immune responses in human patients or small animal models of infection are lacking. In this study, we have used two clinically prevalent bacterial strains (Karp and Gilliam) to reveal cellular immune responses in inflamed lungs and potential biomarkers of disease severity. The results demonstrate that outbred CD-1 mice are highly susceptible to both Karp and Gilliam strains; however, C57BL/6 (B6) mice were susceptible to Karp, but resistant to Gilliam (with self-limiting infection), corresponding to their tissue bacterial burdens and lung pathological changes. Multicolor flow cytometric analyses of perfused B6 mouse lungs revealed robust and sustained influx and activation of innate immune cells (macrophages, neutrophils, and NK cells), followed by CD4+ and CD8+ T cells, during Karp infection, but such responses were greatly attenuated during Gilliam infection. The robust cellular responses in Karp-infected B6 mice positively correlated with significantly early and high levels of serum cytokine/chemokine protein levels (CXCL1, CCL2/3/5, and G-CSF), as well as pulmonary gene expression (Cxcl1/2, Ccl2/3/4, and Ifng). In vitro infection of B6 mouse-derived primary macrophages also revealed bacterial strain-dependent immune gene expression profiles. This study provided the lines of evidence that highlighted differential tissue cellular responses against Karp vs. Gilliam infection, offering a framework for future investigation of Ot strain-related mechanisms of disease pathogenesis vs. infection control.
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Affiliation(s)
- Joseph D. Thiriot
- Department of Microbiology & Immunology, University of Texas Medical Branch, Galveston, Texas, United States of America
| | - Yuejin Liang
- Department of Microbiology & Immunology, University of Texas Medical Branch, Galveston, Texas, United States of America
- Institute for Human Infection and Immunity, University of Texas Medical Branch, Galveston, Texas, United States of America
| | - Casey Gonzales
- Institute for Human Infection and Immunity, University of Texas Medical Branch, Galveston, Texas, United States of America
| | - Jiaren Sun
- Department of Microbiology & Immunology, University of Texas Medical Branch, Galveston, Texas, United States of America
- Institute for Human Infection and Immunity, University of Texas Medical Branch, Galveston, Texas, United States of America
- Department of Pathology, University of Texas Medical Branch, Galveston, Texas, United States of America
| | - Xiaoying Yu
- Department of Biostatistics & Data Science, University of Texas Medical Branch, Galveston, Texas, United States of America
| | - Lynn Soong
- Department of Microbiology & Immunology, University of Texas Medical Branch, Galveston, Texas, United States of America
- Institute for Human Infection and Immunity, University of Texas Medical Branch, Galveston, Texas, United States of America
- Department of Pathology, University of Texas Medical Branch, Galveston, Texas, United States of America
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Gonzales C, Liang Y, Fisher J, Card G, Sun J, Soong L. Alterations in germinal center formation and B cell activation during severe Orientia tsutsugamushi infection in mice. PLoS Negl Trop Dis 2023; 17:e0011090. [PMID: 37146079 PMCID: PMC10191367 DOI: 10.1371/journal.pntd.0011090] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2023] [Revised: 05/17/2023] [Accepted: 04/17/2023] [Indexed: 05/07/2023] Open
Abstract
Scrub typhus is a poorly studied but life-threatening disease caused by the intracellular bacterium Orientia tsutsugamushi (Ot). Cellular and humoral immunity in Ot-infected patients is not long-lasting, waning as early as one-year post-infection; however, its underlying mechanisms remain unclear. To date, no studies have examined germinal center (GC) or B cell responses in Ot-infected humans or experimental animals. This study was aimed at evaluating humoral immune responses at acute stages of severe Ot infection and possible mechanisms underlying B cell dysfunction. Following inoculation with Ot Karp, a clinically dominant strain known to cause lethal infection in C57BL/6 mice, we measured antigen-specific antibody titers, revealing IgG2c as the dominant isotype induced by infection. Splenic GC responses were evaluated by immunohistology, co-staining for B cells (B220), T cells (CD3), and GCs (GL-7). Organized GCs were evident at day 4 post-infection (D4), but they were nearly absent at D8, accompanied by scattered T cells throughout splenic tissues. Flow cytometry revealed comparable numbers of GC B cells and T follicular helper (Tfh) cells at D4 and D8, indicating that GC collapse was not due to excessive death of these cell subtypes at D8. B cell RNAseq analysis revealed significant differences in expression of genes associated with B cell adhesion and co-stimulation at D8 versus D4. The significant downregulation of S1PR2 (a GC-specific adhesion gene) was most evident at D8, correlating with disrupted GC formation. Signaling pathway analysis uncovered downregulation of 71% of B cell activation genes at D8, suggesting attenuation of B cell activation during severe infection. This is the first study showing the disruption of B/T cell microenvironment and dysregulation of B cell responses during Ot infection, which may help understand the transient immunity associated with scrub typhus.
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Affiliation(s)
- Casey Gonzales
- Department of Pathology, University of Texas Medical Branch, Galveston, Texas, United States of America
| | - Yuejin Liang
- Department of Microbiology and Immunology, University of Texas Medical Branch, Galveston, Texas, United States of America
- Institute of Human Infections and Immunity, University of Texas Medical Branch, Galveston, Texas, United States of America
| | - James Fisher
- Department of Microbiology and Immunology, University of Texas Medical Branch, Galveston, Texas, United States of America
| | - Galen Card
- Department of Pathology, University of Texas Medical Branch, Galveston, Texas, United States of America
| | - Jiaren Sun
- Department of Pathology, University of Texas Medical Branch, Galveston, Texas, United States of America
- Department of Microbiology and Immunology, University of Texas Medical Branch, Galveston, Texas, United States of America
- Institute of Human Infections and Immunity, University of Texas Medical Branch, Galveston, Texas, United States of America
| | - Lynn Soong
- Department of Pathology, University of Texas Medical Branch, Galveston, Texas, United States of America
- Department of Microbiology and Immunology, University of Texas Medical Branch, Galveston, Texas, United States of America
- Institute of Human Infections and Immunity, University of Texas Medical Branch, Galveston, Texas, United States of America
- Sealy Institute for Vaccine Sciences, University of Texas Medical Branch, Galveston, Texas, United States of America
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Multiple Orientia clusters and Th1-skewed chemokine profile: a cross-sectional study in patients with scrub typhus from Nepal. Int J Infect Dis 2023; 128:78-87. [PMID: 36566774 DOI: 10.1016/j.ijid.2022.12.022] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2022] [Revised: 12/13/2022] [Accepted: 12/18/2022] [Indexed: 12/24/2022] Open
Abstract
OBJECTIVES Scrub typhus is an emerging infectious disease in Asia caused by Orientia tsutsugamushi (Ot). From Nepal, only scant data on the genetic epidemiology of this agent is available, and determinants of immunoregulation are poorly understood. METHODS Patients (n = 238) referred to the National Public Health Laboratory (Kathmandu, Nepal) from all over Nepal for suspected scrub typhus were enrolled upon positive immunoglobulin (Ig)M testing between July and October 2015. From Ot 16S and 47 kD polymerase chain reaction (PCR)-positive samples, the variable domain I of the 56 kD gene was sequenced and phylogenetically analyzed. T helper (Th) cell-associated cytokines (n = 13) and chemokines (n = 12) were quantified by multiplex bead arrays. RESULTS In 93/238 (39.1%) IgM-positive samples, Ot DNA was detected by quantitative PCR. Phylogenetic analysis of 56 kD sequences revealed seven distinct clusters, six of them with high homologies to strains detected in other countries. The Th1-related cytokines interferon-γ and C-X-C motif chemokine ligand 10 were strongly upregulated and correlated with bacteremia, while levels of Th2-associated chemokines were reduced. Bacteremia also correlated with concentrations of interleukin (IL)-6 and IL-10 but not tumor necrosis factor-α. CONCLUSION We identified a considerable genetic heterogeneity of human-pathogenic Ot strains circulating in Nepal. Acute Nepalese scrub typhus patients showed strong Th1 but impaired Th2 responses, especially on the chemokine level.
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Thiriot J, Liang Y, Fisher J, Walker DH, Soong L. Host transcriptomic profiling of CD-1 outbred mice with severe clinical outcomes following infection with Orientia tsutsugamushi. PLoS Negl Trop Dis 2022; 16:e0010459. [PMID: 36417363 PMCID: PMC9683618 DOI: 10.1371/journal.pntd.0010459] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2022] [Accepted: 10/28/2022] [Indexed: 11/24/2022] Open
Abstract
Orientia tsutsugamushi is an obligately intracellular bacterium with endothelial tropism and can cause mild to lethal scrub typhus in humans. No vaccine is available for this reemerging and severely neglected infection. Previous scrub typhus studies have utilized inbred mice, yet such models have intrinsic limitations. Thus, the development of suitable mouse models that better mimic human diseases is in great need for immunologic investigation and future vaccine studies. This study is aimed at establishing scrub typhus in outbred CD-1 mice and defining immune biomarkers related to disease severity. CD-1 mice received O. tsutsugamushi Karp strain via the i.v. route; major organs were harvested at 2-12 days post-infection for kinetic analyses. We found that for our given infection doses, CD-1 mice were significantly more susceptible (90-100% lethal) than were inbred C57BL/6 mice (0-10% lethal). Gross pathology of infected CD-1 mouse organs revealed features that mimicked human scrub typhus, including pulmonary edema, interstitial pneumonia, perivascular lymphocytic infiltrates, and vasculitis. Alteration in angiopoietin/receptor expression in inflamed lungs implied endothelial dysfunction. Lung immune gene profiling using NanoString analysis displayed a Th1/CD8-skewed, but Th2 repressed profile, including novel biomarkers not previously investigated in other scrub typhus models. Bio-plex analysis revealed a robust inflammatory response in CD-1 mice as evidenced by increased serum cytokine and chemokine levels, correlating with immune cell recruitment during the severe stages of the disease. This study provides an important framework indicating a value of CD-1 mice for delineating host susceptibility to O. tsutsugamushi, immune dysregulation, and disease pathogenesis. This preclinical model is particularly useful for future translational and vaccine studies for severe scrub typhus.
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Affiliation(s)
- Joseph Thiriot
- Department of Microbiology and Immunology, University of Texas Medical Branch, Galveston, Texas, United States of America
| | - Yuejin Liang
- Department of Microbiology and Immunology, University of Texas Medical Branch, Galveston, Texas, United States of America
- Institute for Human Infection and Immunity, University of Texas Medical Branch, Galveston, Texas, United States of America
| | - James Fisher
- Department of Microbiology and Immunology, University of Texas Medical Branch, Galveston, Texas, United States of America
| | - David H. Walker
- Department of Pathology, University of Texas Medical Branch, Galveston, Texas, United States of America
| | - Lynn Soong
- Department of Microbiology and Immunology, University of Texas Medical Branch, Galveston, Texas, United States of America
- Institute for Human Infection and Immunity, University of Texas Medical Branch, Galveston, Texas, United States of America
- Department of Pathology, University of Texas Medical Branch, Galveston, Texas, United States of America
- * E-mail:
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Panda S, Swain SK, Sahu BP, Sarangi R. Gene expression and involvement of signaling pathways during host-pathogen interplay in Orientia tsutsugamushi infection. 3 Biotech 2022; 12:180. [PMID: 35860421 PMCID: PMC9295102 DOI: 10.1007/s13205-022-03239-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2022] [Accepted: 06/18/2022] [Indexed: 11/22/2022] Open
Abstract
Scrub typhus is a neglected tropical disease that affects one-third of the world’s population. The disease is caused by Orientia tsutsugamushi (OT), an obligate intracellular Gram-negative bacterium. OT efficiently escapes from the endosomal pathway after entering the host cell and replicates inside cytosol. OT infection promotes cellular autophagy, the autonomous defense mechanism unlike other bacteria. This study has discussed the bacterial invasion process through the extracellular matrix and the immune response activated by the bacterium within the hosts. Furthermore, we have emphasized the importance of extracellular matrix and their cross-talk with the immune cells, such as, macrophages, neutrophils, and dendritic cells followed by their inflammatory response. We have also put an insight into the host factors associated with signaling pathways during scrub typhus disease with a special focus on the OT-induced stress response, autophagy, apoptosis, and innate immunity. Multiple cytokines and chemokines play a significant role in activating different immune-related signaling pathways. Due to the presence of high antigenic diversity among strains, the signaling pathways during the host–pathogen interplay of OT with its host is very complicated. Thus, it hinders to mitigate the severity of the pandemic occurred by the respective pathogen. Our investigation will provide a useful guide to better understand the virulence and physiology of this intracellular pathogen which will lead towards a better therapeutic diagnosis and vaccine development.
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Affiliation(s)
- Subhasmita Panda
- Department of Pediatrics, IMS and SUM Hospital, Siksha 'O' Anusandhan Deemed to be University, K8, Kalinga Nagar, Bhubaneswar, Odisha 751003 India
| | - Subrat Kumar Swain
- Centre for Genomics and Biomedical Informatics, IMS and SUM Hospital, Siksha 'O' Anusandhan Deemed to be University, K8, Kalinga Nagar, Bhubaneswar, Odisha 751003 India
| | - Basanta Pravas Sahu
- Discipline of Biosciences and Biomedical Engineering, Indian Institute of Technology Indore, Simrol, Indore 453552 India
| | - Rachita Sarangi
- Department of Pediatrics, IMS and SUM Hospital, Siksha 'O' Anusandhan Deemed to be University, K8, Kalinga Nagar, Bhubaneswar, Odisha 751003 India
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Liang Y, Fisher J, Gonzales C, Trent B, Card G, Sun J, Tumanov AV, Soong L. Distinct Role of TNFR1 and TNFR2 in Protective Immunity Against Orientia tsutsugamushi Infection in Mice. Front Immunol 2022; 13:867924. [PMID: 35479068 PMCID: PMC9035742 DOI: 10.3389/fimmu.2022.867924] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2022] [Accepted: 03/21/2022] [Indexed: 02/05/2023] Open
Abstract
Infection with Orientia tsutsugamushi, an obligate intracellular bacterium, can cause mild or severe scrub typhus. Some patients develop acute lung injury, multi-organ failure, and fatal infection; however, little is known regarding key immune mediators that mediate infection control or disease pathogenesis. Using murine models of scrub typhus, we demonstrated in this study the requirement of TNF-TNFR signaling in protective immunity against this infection. Mice lacking both TNF receptors (TNFR1 and TNFR2) were highly susceptible to O. tsutsugamushi infection, displaying significantly increased tissue bacterial burdens and succumbing to infection by day 9, while most wild-type mice survived through day 20. This increased susceptibility correlated with poor activation of cellular immunity in inflamed tissues. Flow cytometry of lung- and spleen-derived cells revealed profound deficiencies in total numbers and activation status of NK cells, neutrophils, and macrophages, as well as CD4 and CD8 T cells. To define the role of individual receptors in O. tsutsugamushi infection, we used mice lacking either TNFR1 or TNFR2. While deficiency in either receptor alone was sufficient to increase host susceptibility to the infection, TNFR1 and TNFR2 played a distinct role in cellular responses. TNF signaling through TNFR1 promoted inflammatory responses and effector T cell expansion, while TNFR2 signaling was associated with anti-inflammatory action and tissue homeostasis. Moreover, TNFRs played an intrinsic role in CD8+ T cell activation, revealing an indispensable role of TNF in protective immunity against O. tsutsugamushi infection.
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Affiliation(s)
- Yuejin Liang
- Department of Microbiology and Immunology, University of Texas Medical Branch, Galveston, TX, United States
- Institute for Human Infections and Immunity, University of Texas Medical Branch, Galveston, TX, United States
| | - James Fisher
- Department of Microbiology and Immunology, University of Texas Medical Branch, Galveston, TX, United States
| | - Casey Gonzales
- Department of Pathology, University of Texas Medical Branch, Galveston, TX, United States
| | - Brandon Trent
- Department of Pathology, University of Texas Medical Branch, Galveston, TX, United States
| | - Galen Card
- Department of Pathology, University of Texas Medical Branch, Galveston, TX, United States
| | - Jiaren Sun
- Department of Microbiology and Immunology, University of Texas Medical Branch, Galveston, TX, United States
- Institute for Human Infections and Immunity, University of Texas Medical Branch, Galveston, TX, United States
- Department of Pathology, University of Texas Medical Branch, Galveston, TX, United States
| | - Alexei V. Tumanov
- Department of Microbiology, Immunology and Molecular Genetics, University of Texas Health Science Center at San Antonio, San Antonio, TX, United States
| | - Lynn Soong
- Department of Microbiology and Immunology, University of Texas Medical Branch, Galveston, TX, United States
- Institute for Human Infections and Immunity, University of Texas Medical Branch, Galveston, TX, United States
- Department of Pathology, University of Texas Medical Branch, Galveston, TX, United States
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Hong K, Shu Z, Li L, Zhong Y, Chen W, Nong C, Kong J. Diagnostic Value of CD4/CD8 in Scrub Typhus. Am J Trop Med Hyg 2022; 106:792-797. [PMID: 34902835 PMCID: PMC8922489 DOI: 10.4269/ajtmh.21-0531] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2021] [Accepted: 10/20/2021] [Indexed: 11/07/2022] Open
Abstract
Scrub typhus is often misdiagnosed in febrile patients, leading to antibiotic abuse and multiple complications. We conducted a retrospective record review at the Fourth Affiliated Hospital of Guangxi Medical University in China. Data were collected on 52 patients with a confirmed diagnosis of scrub typhus and complete clinical data. In addition, data were collected on 52 patients with bloodstream infection, 25 patients with HIV infection, 112 patients with common community-acquired pneumonia (CCAP), and 36 patients with severe community-acquired pneumonia (SCAP) to serve as control groups. The peripheral blood CD4 and CD8 counts, CD4/CD8 ratio, C-reactive protein, procalcitonin, alanine aminotransferase, aspartate aminotransferase, creatinine, and β2 microglobulin levels; and the white blood cell count and neutrophil percentage were compared between the scrub typhus and the control groups. The value of these biomarkers in the diagnosis of scrub typhus was assessed using receiver-operating characteristic curve analysis. The scrub typhus group had a significantly lower CD4 count and CD4/CD8 ratio than the bloodstream infection, CCAP, and SCAP groups, and a significantly greater CD4 count and CD4/CD8 ratio than the HIV infection group. In contrast, the scrub typhus group had a significantly greater CD8 count than the bloodstream infection and CCAP and SCAP groups, and it had a lower level of CD8 than the HIV infection group. The areas under the curve of CD4/CD8 were more than 0.93 in the receiver-operating characteristic curve analysis. These findings suggest that the CD4/CD8 ratio is a useful ancillary test for diagnosing scrub typhus.
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Affiliation(s)
- Kangkang Hong
- Pulmonary and Critical Care Medicine Ward, The First Affiliated Hospital of Guangxi Medical University, Nanning, Guangxi, China;,Department of Geriatric Medicine, The Fourth Affiliated Hospital of Guangxi Medical University, Liuzhou, Guangxi, China
| | - Ziping Shu
- Pulmonary and Critical Care Medicine Ward, The Fourth Affiliated Hospital of Guangxi Medical University, Liuzhou, Guangxi, China
| | - Laodong Li
- Pulmonary and Critical Care Medicine Ward, The Fourth Affiliated Hospital of Guangxi Medical University, Liuzhou, Guangxi, China
| | - Yu Zhong
- Department of Emergency, The Fourth Affiliated Hospital of Guangxi Medical University, Liuzhou, Guangxi, China
| | - Weiqian Chen
- Department of Geriatric Medicine, The Fourth Affiliated Hospital of Guangxi Medical University, Liuzhou, Guangxi, China
| | - Cunli Nong
- Department of Infectious Diseases, The Fourth Affiliated Hospital of Guangxi Medical University, Liuzhou, Guangxi, China
| | - Jinliang Kong
- Pulmonary and Critical Care Medicine Ward, The First Affiliated Hospital of Guangxi Medical University, Nanning, Guangxi, China;,Address correspondence to Jinliang Kong, The First Affiliated Hospital of Guangzi Medical University, Shuangyong Rd., Nanning, China 540000. E-mail:
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Sim JH, Kim JH, Park AK, Lee J, Kim KM, Shin HM, Kim M, Choi K, Choi EY, Kang I, Lee DS, Kim HR. IL-7Rα low CD8 + T Cells from Healthy Individuals Are Anergic with Defective Glycolysis. THE JOURNAL OF IMMUNOLOGY 2020; 205:2968-2978. [PMID: 33106337 DOI: 10.4049/jimmunol.1901470] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/12/2019] [Accepted: 09/22/2020] [Indexed: 11/19/2022]
Abstract
Effector memory (EM) CD8+ T cells expressing lower levels of IL-7R α (IL-7Rαlow) from healthy individuals are partly compromised in vitro, but the identity of these cells has remained unclear. In this study, we demonstrate that human IL-7Rαlow EM CD8+ T cells are naturally occurring anergic cells in vivo and impaired in proliferation and IL-2 production but competent in IFN-γ and TNF-α production, a state that can be restored by IL-2 stimulation. IL-7Rαlow EM CD8+ T cells show decreased expression of GATA3 and c-MYC and are defective in metabolic reprogramming toward glycolysis, a process required for the proliferation of T cells. However, IL-7Rαlow EM CD8+ T cells can proliferate with TCR stimulation in the presence of IL-2 and IL-15, suggesting that these cells can be restored to normality or increased activity by inflammatory conditions and may serve as a reservoir for functional immunity.
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Affiliation(s)
- Ji Hyun Sim
- Department of Anatomy and Cell Biology, Seoul National University College of Medicine, Seoul 03080, Republic of Korea
| | - Jin-Hee Kim
- Department of Anatomy and Cell Biology, Seoul National University College of Medicine, Seoul 03080, Republic of Korea.,Medical Research Institute, Seoul National University College of Medicine, Seoul 03080, Republic of Korea.,Department of Biomedical Laboratory Science, College of Health Science, Cheongju University, Cheongju 28150, Chungbuk, Republic of Korea
| | - Ae Kyung Park
- College of Pharmacy and Research Institute of Life and Pharmaceutical Sciences, College of Pharmacy, Sunchon National University, Suncheon 57922, Jeonnam, Republic of Korea
| | - Jeeyun Lee
- Department of Medicine, Division of Hematology-Oncology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul 06351, Republic of Korea
| | - Kyoung-Mee Kim
- Department of Pathology and Translational Genomics, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul 06351, Republic of Korea
| | - Hyun Mu Shin
- Department of Biomedical Sciences, Seoul National University College of Medicine, Seoul 03080, Republic of Korea.,Wide River Institute of Immunology, Seoul National University, Hongcheon 25159, Republic of Korea
| | - Minji Kim
- Department of Biomedical Sciences, Seoul National University College of Medicine, Seoul 03080, Republic of Korea.,BK21Plus Biomedical Science Project, Seoul National University College of Medicine, Seoul 03080, Republic of Korea
| | - Kyungho Choi
- Department of Biomedical Sciences, Seoul National University College of Medicine, Seoul 03080, Republic of Korea.,BK21Plus Biomedical Science Project, Seoul National University College of Medicine, Seoul 03080, Republic of Korea.,Department of Biochemistry and Molecular Biology, Seoul National University College of Medicine, Seoul 03080, Republic of Korea; and
| | - Eun Young Choi
- Department of Biomedical Sciences, Seoul National University College of Medicine, Seoul 03080, Republic of Korea.,BK21Plus Biomedical Science Project, Seoul National University College of Medicine, Seoul 03080, Republic of Korea
| | - Insoo Kang
- Department of Internal Medicine, Yale University School of Medicine, New Haven, CT 06520
| | - Dong-Sup Lee
- Department of Anatomy and Cell Biology, Seoul National University College of Medicine, Seoul 03080, Republic of Korea.,Medical Research Institute, Seoul National University College of Medicine, Seoul 03080, Republic of Korea.,Department of Biomedical Sciences, Seoul National University College of Medicine, Seoul 03080, Republic of Korea.,Wide River Institute of Immunology, Seoul National University, Hongcheon 25159, Republic of Korea.,BK21Plus Biomedical Science Project, Seoul National University College of Medicine, Seoul 03080, Republic of Korea
| | - Hang-Rae Kim
- Department of Anatomy and Cell Biology, Seoul National University College of Medicine, Seoul 03080, Republic of Korea; .,Medical Research Institute, Seoul National University College of Medicine, Seoul 03080, Republic of Korea.,Department of Biomedical Sciences, Seoul National University College of Medicine, Seoul 03080, Republic of Korea.,Wide River Institute of Immunology, Seoul National University, Hongcheon 25159, Republic of Korea.,BK21Plus Biomedical Science Project, Seoul National University College of Medicine, Seoul 03080, Republic of Korea
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11
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Abstract
Over the last decades, rickettsioses are emerging worldwide. These diseases are caused by intracellular bacteria. Although rickettsioses can be treated with antibiotics, a vaccine against rickettsiae is highly desired for several reasons. Rickettsioses are highly prevalent, especially in poor countries, and there are indications of the development of antibiotic resistance. In addition, some rickettsiae can persist and cause recurrent disease. The development of a vaccine requires the understanding of the immune mechanisms that are involved in protection as well as in immunopathology. Knowledge about these immune responses is accumulating, and efforts have been undertaken to identify antigenic components of rickettsiae that may be useful as a vaccine. This review provides an overview on current knowledge of adaptive immunity against rickettsiae, which is essential for defense, rickettsial antigens that have been identified so far, and on vaccination strategies that have been used in animal models of rickettsial infections.
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12
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Kang CK, Han GC, Kim M, Kim G, Shin HM, Song KH, Choe PG, Park WB, Kim ES, Kim HB, Kim NJ, Kim HR, Oh MD. Aberrant hyperactivation of cytotoxic T-cell as a potential determinant of COVID-19 severity. Int J Infect Dis 2020; 97:313-321. [PMID: 32492530 PMCID: PMC7261468 DOI: 10.1016/j.ijid.2020.05.106] [Citation(s) in RCA: 60] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2020] [Revised: 05/20/2020] [Accepted: 05/24/2020] [Indexed: 01/08/2023] Open
Abstract
OBJECTIVES We hypothesized that immune response may contribute to progression of coronavirus disease-19 (COVID-19) at the second week of illness. Therefore, we compared cell-mediated immune (CMI) responses between severe and mild COVID-19 cases. METHODS We examined peripheral blood mononuclear cells of laboratory-confirmed COVID-19 patients from their first and third weeks of illness. Severe pneumonia was defined as an oxygen saturation ≤93% at room air. Expressions of molecules related to T-cell activation and functions were analyzed by flow cytometry. RESULTS The population dynamics of T cells at the first week were not different between the two groups. However, total numbers of CD4+ and CD8+ T cells tended to be lower in the severe group at the third week of illness. Expressions of Ki-67, PD-1, perforin, and granzyme B in CD4+ or CD8+ T cells were significantly higher in the severe group than in the mild group at the third week. In contrast to the mild group, the levels of their expression did not decrease in the severe group. CONCLUSIONS Severe COVID-19 had a higher degree of proliferation, activation, and cytotoxicity of T-cells at the late phase of illness without cytotoxic T-cell contraction, which might contribute to the development of severe COVID-19.
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Affiliation(s)
- Chang Kyung Kang
- Department of Internal Medicine, Seoul National University College of Medicine, Seoul 03080, Republic of Korea
| | - Gi-Chan Han
- Department of Biomedical Sciences, Seoul National University College of Medicine, Seoul 03080, Republic of Korea; Department of Anatomy & Cell Biology, Seoul National University College of Medicine, Seoul 03080, Republic of Korea; BK21 Plus Biomedical Science Project, Seoul National University College of Medicine, Seoul 03080, Republic of Korea
| | - Minji Kim
- Department of Biomedical Sciences, Seoul National University College of Medicine, Seoul 03080, Republic of Korea; Department of Anatomy & Cell Biology, Seoul National University College of Medicine, Seoul 03080, Republic of Korea; BK21 Plus Biomedical Science Project, Seoul National University College of Medicine, Seoul 03080, Republic of Korea
| | - Gwanghun Kim
- Department of Biomedical Sciences, Seoul National University College of Medicine, Seoul 03080, Republic of Korea; Department of Anatomy & Cell Biology, Seoul National University College of Medicine, Seoul 03080, Republic of Korea; BK21 Plus Biomedical Science Project, Seoul National University College of Medicine, Seoul 03080, Republic of Korea
| | - Hyun Mu Shin
- Wide River Institute of Immunology, Seoul National University, Hongcheon 25159, Republic of Korea
| | - Kyoung-Ho Song
- Department of Internal Medicine, Seoul National University College of Medicine, Seoul 03080, Republic of Korea; Department of Internal Medicine, Seoul National University Bundang Hospital, Seongnam 13620, Republic of Korea
| | - Pyoeng Gyun Choe
- Department of Internal Medicine, Seoul National University College of Medicine, Seoul 03080, Republic of Korea
| | - Wan Beom Park
- Department of Internal Medicine, Seoul National University College of Medicine, Seoul 03080, Republic of Korea
| | - Eu Suk Kim
- Department of Internal Medicine, Seoul National University College of Medicine, Seoul 03080, Republic of Korea; Department of Internal Medicine, Seoul National University Bundang Hospital, Seongnam 13620, Republic of Korea
| | - Hong Bin Kim
- Department of Internal Medicine, Seoul National University College of Medicine, Seoul 03080, Republic of Korea; Department of Internal Medicine, Seoul National University Bundang Hospital, Seongnam 13620, Republic of Korea
| | - Nam-Joong Kim
- Department of Internal Medicine, Seoul National University College of Medicine, Seoul 03080, Republic of Korea
| | - Hang-Rae Kim
- Department of Biomedical Sciences, Seoul National University College of Medicine, Seoul 03080, Republic of Korea; Department of Anatomy & Cell Biology, Seoul National University College of Medicine, Seoul 03080, Republic of Korea; BK21 Plus Biomedical Science Project, Seoul National University College of Medicine, Seoul 03080, Republic of Korea; Wide River Institute of Immunology, Seoul National University, Hongcheon 25159, Republic of Korea; Medical Research Institute, Seoul National University College of Medicine, Seoul 03080, Republic of Korea.
| | - Myoung-Don Oh
- Department of Internal Medicine, Seoul National University College of Medicine, Seoul 03080, Republic of Korea.
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13
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Kang SJ, Jin HM, Cho YN, Oh TH, Kim SE, Kim UJ, Park KH, Jang HC, Jung SI, Kee SJ, Park YW. Dysfunction of Circulating Natural Killer T Cells in Patients With Scrub Typhus. J Infect Dis 2019; 218:1813-1821. [PMID: 29982731 DOI: 10.1093/infdis/jiy402] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2018] [Accepted: 06/28/2018] [Indexed: 01/01/2023] Open
Abstract
Background Human natural killer T (NKT) cells are known to serve as regulatory and/or effector cells in infectious diseases. However, little is known about the role of NKT cells in Orientia tsutsugamushi infection. Accordingly, the objective of this study was to examine the level and function of NKT cells in patients with scrub typhus. Methods This study included 62 scrub typhus patients and 62 healthy controls (HCs). NKT cell level and function in peripheral blood samples were measured by flow cytometry. Results Proliferation of NKT cells and their ability to produce interferon-γ and interleukin-4 (IL-4) were significantly lower in scrub typhus patients compared to those in HCs. However, circulating NKT cell levels were comparable between patients and HCs. Expression levels of CD69, programmed death-1 (PD-1), lymphocyte activation gene-3 (LAG-3), and T-cell immunoglobulin domain and mucin domain-containing molecule-3 (TIM-3) were significantly increased in scrub typhus patients. Elevated expression of CD69, PD-1, LAG-3, and TIM-3, impaired proliferation, and decreased IL-4 production by NKT cells were recovered in the remission phase. Conclusions This study demonstrates that circulating NKT cells are numerically preserved but functionally impaired in scrub typhus patients. In addition, NKT cell dysfunction is recovered in the remission phase.
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Affiliation(s)
- Seung-Ji Kang
- Department of Infectious Diseases, Chonnam National University Medical School and Hospital, Gwangju, Republic of Korea
| | - Hye-Mi Jin
- Department of Rheumatology, Chonnam National University Medical School and Hospital, Gwangju, Republic of Korea
| | - Young-Nan Cho
- Department of Rheumatology, Chonnam National University Medical School and Hospital, Gwangju, Republic of Korea
| | - Tae-Hoon Oh
- Department of Infectious Diseases, Chonnam National University Medical School and Hospital, Gwangju, Republic of Korea
| | - Seong Eun Kim
- Department of Infectious Diseases, Chonnam National University Medical School and Hospital, Gwangju, Republic of Korea
| | - Uh Jin Kim
- Department of Infectious Diseases, Chonnam National University Medical School and Hospital, Gwangju, Republic of Korea
| | - Kyung-Hwa Park
- Department of Infectious Diseases, Chonnam National University Medical School and Hospital, Gwangju, Republic of Korea
| | - Hee-Chang Jang
- Department of Infectious Diseases, Chonnam National University Medical School and Hospital, Gwangju, Republic of Korea
| | - Sook-In Jung
- Department of Infectious Diseases, Chonnam National University Medical School and Hospital, Gwangju, Republic of Korea
| | - Seung-Jung Kee
- Department of Laboratory Medicine, Chonnam National University Medical School and Hospital, Gwangju, Republic of Korea
| | - Yong-Wook Park
- Department of Rheumatology, Chonnam National University Medical School and Hospital, Gwangju, Republic of Korea
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14
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Trent B, Fisher J, Soong L. Scrub Typhus Pathogenesis: Innate Immune Response and Lung Injury During Orientia tsutsugamushi Infection. Front Microbiol 2019; 10:2065. [PMID: 31555249 PMCID: PMC6742975 DOI: 10.3389/fmicb.2019.02065] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2019] [Accepted: 08/22/2019] [Indexed: 01/28/2023] Open
Abstract
Scrub typhus is an understudied, potentially lethal disease caused by infection with Orientia tsutsugamushi. Despite causing an estimated 1 million cases per year and an increasing global presence, mechanisms of scrub typhus pathogenesis remain unclear. One of the most life-threatening conditions that can arise in scrub typhus patients is acute respiratory distress syndrome (ARDS). The development of ARDS is a complex process; some of its pathological hallmarks, including prolonged recruitment of inflammatory immune cells to the lung and vasculature damage, have been observed in humans and/or animal models of O. tsutsugamushi infection. Although different cell types and mechanisms may contribute to ARDS development during O. tsutsugamushi infection, this review highlights our current evidence of pulmonary endothelial activation and damage, the potential roles of neutrophils and macrophages in the lung, and the knowledge gaps in this field. Continued investigation of the lung microenvironment and cellular interactions will help elucidate disease pathogenesis and possible treatment during scrub typhus.
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Affiliation(s)
- Brandon Trent
- Department of Pathology, University of Texas Medical Branch, Galveston, TX, United States
| | - James Fisher
- Department of Microbiology and Immunology, University of Texas Medical Branch, Galveston, TX, United States
| | - Lynn Soong
- Department of Pathology, University of Texas Medical Branch, Galveston, TX, United States.,Department of Microbiology and Immunology, University of Texas Medical Branch, Galveston, TX, United States
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15
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Soong L. Dysregulated Th1 Immune and Vascular Responses in Scrub Typhus Pathogenesis. THE JOURNAL OF IMMUNOLOGY 2019; 200:1233-1240. [PMID: 29431689 DOI: 10.4049/jimmunol.1701219] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/25/2017] [Accepted: 11/30/2017] [Indexed: 12/25/2022]
Abstract
Scrub typhus is an emerging, insect-transmitted disease caused by Orientia tsutsugamushi, a Gram- and LPS-negative bacterium that replicates freely within professional phagocytes and endothelial cells. Scrub typhus is prevalent with high mortality rates, but information regarding its molecular pathogenesis, microbial virulence determinants, and key immune responses is limited. Improved animal models have recently been developed that respectively resemble the pathological features of self-limiting or severe scrub typhus in humans. Strong activation of Th1 and CD8, but not Th2 and regulatory T, immune responses, accompanied by altered angiopoietin/Tie2-related regulation, are hallmarks of lethal infection in murine models. This review, based primarily on recent advances from clinical and experimental studies, highlights tissue- and endothelial cell-specific biomarkers that are indicative of immune dysregulation. The potential roles of neutrophils and damage-associated molecular pattern molecules at late stages of disease are discussed in the context of vascular leakage, pulmonary and renal injury, and scrub typhus pathogenesis.
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Affiliation(s)
- Lynn Soong
- Department of Microbiology and Immunology, Center for Tropical Diseases, Center for Biodefense and Emerging Infectious Diseases, Sealy Center for Vaccine Development, Institute of Human Infections and Immunity, University of Texas Medical Branch, Galveston, TX 77555; and .,Department of Pathology, Center for Tropical Diseases, Center for Biodefense and Emerging Infectious Diseases, Sealy Center for Vaccine Development, Institute of Human Infections and Immunity, University of Texas Medical Branch, Galveston, TX 77555
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16
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Min CK, Kim HI, Ha NY, Kim Y, Kwon EK, Yen NTH, Youn JI, Jeon YK, Inn KS, Choi MS, Cho NH. A Type I Interferon and IL-10 Induced by Orientia tsutsugamushi Infection Suppresses Antigen-Specific T Cells and Their Memory Responses. Front Immunol 2018; 9:2022. [PMID: 30233599 PMCID: PMC6131522 DOI: 10.3389/fimmu.2018.02022] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2018] [Accepted: 08/16/2018] [Indexed: 12/31/2022] Open
Abstract
Despite the various roles of type I interferon (type I IFN) responses during bacterial infection, its specific effects in vivo have been poorly characterized in scrub typhus caused by Orientia tsutsugamushi infection. Here, we show that type I IFNs are primarily induced via intracellular nucleic acids sensors, including RIG-I/MAVS and cGAS/STING pathways, during O. tsutsugamushi invasion. However, type I IFN signaling did not significantly affect pathogenesis, mortality, or bacterial burden during primary infection in vivo, when assessed in a mice model lacking a receptor for type I IFNs (IFNAR KO). Rather, it significantly impaired the induction of antigen-specific T cells and reduced memory T cell responses. IFNAR KO mice that recovered from primary infection showed stronger antigen-specific T cell responses, especially Th1, and more efficiently controlled bacteremia during secondary infection than wild type mice. Enhanced IL-10 expression by macrophages in the presence of type I IFN signaling might play a significant role in the suppression of antigen-specific T cell responses as neutralization or knock-out (KO) of IL-10 increased T cell responses in vitro. Therefore, induction of the type I IFN/IL-10 axis by O. tsutsugamushi infection might play a significant role in the suppression of T cell responses and contribute to the short longevity of cell-mediated immunity, often observed in scrub typhus patients.
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Affiliation(s)
- Chan-Ki Min
- Department of Microbiology and Immunology,Seoul National University College of Medicine, Seoul, South Korea.,Department of Biomedical Sciences,Seoul National University College of Medicine, Seoul, South Korea
| | - Hong-Ii Kim
- Department of Microbiology and Immunology,Seoul National University College of Medicine, Seoul, South Korea.,Department of Biomedical Sciences,Seoul National University College of Medicine, Seoul, South Korea
| | - Na-Young Ha
- Department of Microbiology and Immunology,Seoul National University College of Medicine, Seoul, South Korea.,Department of Biomedical Sciences,Seoul National University College of Medicine, Seoul, South Korea
| | - Yuri Kim
- Department of Microbiology and Immunology,Seoul National University College of Medicine, Seoul, South Korea.,Department of Biomedical Sciences,Seoul National University College of Medicine, Seoul, South Korea
| | - Eun-Kyung Kwon
- Department of Microbiology and Immunology,Seoul National University College of Medicine, Seoul, South Korea.,Department of Biomedical Sciences,Seoul National University College of Medicine, Seoul, South Korea
| | - Nguyen Thi Hai Yen
- Department of Microbiology and Immunology,Seoul National University College of Medicine, Seoul, South Korea.,Department of Biomedical Sciences,Seoul National University College of Medicine, Seoul, South Korea
| | - Je-In Youn
- Department of Biomedical Sciences,Seoul National University College of Medicine, Seoul, South Korea.,Wide River Institute of Immunology, Seoul National University College of Medicine, Gangwon-do, South Korea
| | - Yoon Kyung Jeon
- Department of Pathology, Seoul National University College of Medicine, Seoul, South Korea
| | - Kyung-Soo Inn
- Department of Pharmaceutical Science, College of Pharmacy, Kyung Hee University, Seoul, South Korea
| | - Myung-Sik Choi
- Department of Microbiology and Immunology,Seoul National University College of Medicine, Seoul, South Korea
| | - Nam-Hyuk Cho
- Department of Microbiology and Immunology,Seoul National University College of Medicine, Seoul, South Korea.,Department of Biomedical Sciences,Seoul National University College of Medicine, Seoul, South Korea.,Wide River Institute of Immunology, Seoul National University College of Medicine, Gangwon-do, South Korea.,Institute of Endemic Disease, Seoul National University Medical Research Center and Bundang Hospital, Seoul, South Korea
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17
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Jiang L, Morris EK, Aguilera-Olvera R, Zhang Z, Chan TC, Shashikumar S, Chao CC, Casares SA, Ching WM. Dissemination of Orientia tsutsugamushi, a Causative Agent of Scrub Typhus, and Immunological Responses in the Humanized DRAGA Mouse. Front Immunol 2018; 9:816. [PMID: 29760694 PMCID: PMC5936984 DOI: 10.3389/fimmu.2018.00816] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2017] [Accepted: 04/04/2018] [Indexed: 12/23/2022] Open
Abstract
Scrub typhus is caused by Orientia tsutsugamushi, an obligated intracellular bacterium that affects over one million people per year. Several mouse models have been used to study its pathogenesis, disease immunology, and for testing vaccine candidates. However, due to the intrinsic differences between the immune systems in mouse and human, these mouse models could not faithfully mimic the pathology and immunological responses developed by human patients, limiting their value in both basic and translational studies. In this study, we have tested for the first time, a new humanized mouse model through footpad inoculation of O. tsutsugamushi in DRAGA (HLA-A2.HLA-DR4.Rag1KO.IL2RγcKO.NOD) mice with their human immune system reconstituted by infusion of HLA-matched human hematopoietic stem cells from umbilical cord blood. Upon infection, Orientia disseminated into various organs of DRAGA mice resulted in lethality in a dose-dependent manner, while all C3H/HeJ mice infected by the same route survived. Tissue-specific lesions associated with inflammation and/or necroses were observed in multiple organs of infected DRAGA mice. Consistent with the intracellular nature of Orientia, strong Th1, but subdued Th2 responses were elicited as reflected by the human cytokine profiles in sera from infected mice. Interestingly, the percentage of both activated and regulatory (CD4+FOXP3+) human T cells were elevated in spleen tissues of infected mice. After immunization with irradiated whole cell Orientia, humanized DRAGA mice showed a significant activation of human T cells as evidenced by increased number of human CD4+ and CD8+ T cells. Specific human IgM and IgG antibodies were developed after repetitive immunization. The humanized DRAGA mouse model represents a new pre-clinical model for studying Orientia-human interactions and also for testing vaccines and novel therapeutics for scrub typhus.
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Affiliation(s)
- Le Jiang
- Viral and Rickettsial Diseases Department, Naval Medical Research Center, Silver Spring, MD, United States
| | - Erin K Morris
- Veterinary Services Program, Department of Pathology Services, Walter Reed Army Institute of Research, Silver Spring, MD, United States
| | - Rodrigo Aguilera-Olvera
- US Military Malaria Vaccine Program, Naval Medical Research Center, Walter Reed Army Institute of Research, Silver Spring, MD, United States
| | - Zhiwen Zhang
- Viral and Rickettsial Diseases Department, Naval Medical Research Center, Silver Spring, MD, United States
| | - Teik-Chye Chan
- Viral and Rickettsial Diseases Department, Naval Medical Research Center, Silver Spring, MD, United States
| | - Soumya Shashikumar
- US Military Malaria Vaccine Program, Naval Medical Research Center, Walter Reed Army Institute of Research, Silver Spring, MD, United States
| | - Chien-Chung Chao
- Viral and Rickettsial Diseases Department, Naval Medical Research Center, Silver Spring, MD, United States.,Uniformed Services University of the Health Sciences, Bethesda, MD, United States
| | - Sofia A Casares
- US Military Malaria Vaccine Program, Naval Medical Research Center, Walter Reed Army Institute of Research, Silver Spring, MD, United States.,Uniformed Services University of the Health Sciences, Bethesda, MD, United States
| | - Wei-Mei Ching
- Viral and Rickettsial Diseases Department, Naval Medical Research Center, Silver Spring, MD, United States.,Uniformed Services University of the Health Sciences, Bethesda, MD, United States
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18
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Díaz FE, Abarca K, Kalergis AM. An Update on Host-Pathogen Interplay and Modulation of Immune Responses during Orientia tsutsugamushi Infection. Clin Microbiol Rev 2018; 31:e00076-17. [PMID: 29386235 PMCID: PMC5967693 DOI: 10.1128/cmr.00076-17] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
The obligate intracellular bacterium Orientia tsutsugamushi is the causative agent of scrub typhus in humans, a serious mite-borne disease present in a widespread area of endemicity, which affects an estimated 1 million people every year. This disease may exhibit a broad range of presentations, ranging from asymptomatic to fatal conditions, with the latter being due to disseminated endothelial infection and organ injury. Unique characteristics of the biology and host-pathogen interactions of O. tsutsugamushi, including the high antigenic diversity among strains and the highly variable, short-lived memory responses developed by the host, underlie difficulties faced in the pursuit of an effective vaccine, which is an imperative need. Other factors that have hindered scientific progress relative to the infectious mechanisms of and the immune response triggered by this bacterium in vertebrate hosts include the limited number of mechanistic studies performed on animal models and the lack of genetic tools currently available for this pathogen. However, recent advances in animal model development are promising to improve our understanding of host-pathogen interactions. Here, we comprehensively discuss the recent advances in and future perspectives on host-pathogen interactions and the modulation of immune responses related to this reemerging disease, highlighting the role of animal models.
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Affiliation(s)
- Fabián E Díaz
- Millennium Institute on Immunology and Immunotherapy, Departamento de Genética Molecular y Microbiología, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Katia Abarca
- Departamento en Enfermedades Infecciosas e Inmunología Pediátricas, Facultad de Medicina, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Alexis M Kalergis
- Millennium Institute on Immunology and Immunotherapy, Departamento de Genética Molecular y Microbiología, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago, Chile
- Departamento de Endocrinología, Facultad de Medicina, Pontificia Universidad Católica de Chile, Santiago, Chile
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19
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Sunyakumthorn P, Somponpun SJ, Im-erbsin R, Anantatat T, Jenjaroen K, Dunachie SJ, Lombardini ED, Burke RL, Blacksell SD, Jones JW, Mason CJ, Richards AL, Day NPJ, Paris DH. Characterization of the rhesus macaque (Macaca mulatta) scrub typhus model: Susceptibility to intradermal challenge with the human pathogen Orientia tsutsugamushi Karp. PLoS Negl Trop Dis 2018. [PMID: 29522521 PMCID: PMC5862536 DOI: 10.1371/journal.pntd.0006305] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023] Open
Abstract
BACKGROUND Scrub typhus is an important endemic disease in tropical Asia caused by Orientia tsutsugamushi for which no effective broadly protective vaccine is available. The successful evaluation of vaccine candidates requires well-characterized animal models and a better understanding of the immune response against O. tsutsugamushi. While many animal species have been used to study host immunity and vaccine responses in scrub typhus, only limited data exists in non-human primate (NHP) models. METHODOLOGY/PRINCIPLE FINDINGS In this study we evaluated a NHP scrub typhus disease model based on intradermal inoculation of O. tsutsugamushi Karp strain in rhesus macaques (n = 7). After an intradermal inoculation with 106 murine LD50 of O. tsutsugamushi at the anterior thigh (n = 4) or mock inoculum (n = 3), a series of time course investigations involving hematological, biochemical, molecular and immunological assays were performed, until day 28, when tissues were collected for pathology and immunohistochemistry. In all NHPs with O. tsutsugamushi inoculation, but not with mock inoculation, the development of a classic eschar with central necrosis, regional lymphadenopathy, and elevation of body temperature was observed on days 7-21 post inoculation (pi); bacteremia was detected by qPCR on days 6-18 pi; and alteration of liver enzyme function and increase of white blood cells on day 14 pi. Immune assays demonstrated raised serum levels of soluble cell adhesion molecules, anti-O. tsutsugamushi-specific antibody responses (IgM and IgG) and pathogen-specific cell-mediated immune responses in inoculated macaques. The qPCR assays detected O. tsutsugamushi in eschar, spleen, draining and non-draining lymph nodes, and immuno-double staining demonstrated intracellular O. tsutsugamushi in antigen presenting cells of eschars and lymph nodes. CONCLUSIONS/SIGNIFICANCE These data show the potential of using rhesus macaques as a scrub typhus model, for evaluation of correlates of protection in both natural and vaccine induced immunity, and support the evaluation of future vaccine candidates against scrub typhus.
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Affiliation(s)
- Piyanate Sunyakumthorn
- Department of Veterinary Medicine, United States Army Medical Directorate, Armed Forces Research Institute of Medical Sciences (USAMD-AFRIMS), Bangkok, Thailand
- Mahidol Oxford Tropical Medicine Research Unit, Mahidol University, Bangkok, Thailand
| | - Suwit J. Somponpun
- Department of Veterinary Medicine, United States Army Medical Directorate, Armed Forces Research Institute of Medical Sciences (USAMD-AFRIMS), Bangkok, Thailand
| | - Rawiwan Im-erbsin
- Department of Veterinary Medicine, United States Army Medical Directorate, Armed Forces Research Institute of Medical Sciences (USAMD-AFRIMS), Bangkok, Thailand
| | - Tippawan Anantatat
- Mahidol Oxford Tropical Medicine Research Unit, Mahidol University, Bangkok, Thailand
| | - Kemajittra Jenjaroen
- Mahidol Oxford Tropical Medicine Research Unit, Mahidol University, Bangkok, Thailand
| | - Susanna J. Dunachie
- Mahidol Oxford Tropical Medicine Research Unit, Mahidol University, Bangkok, Thailand
| | - Eric D. Lombardini
- Department of Veterinary Medicine, United States Army Medical Directorate, Armed Forces Research Institute of Medical Sciences (USAMD-AFRIMS), Bangkok, Thailand
| | - Robin L. Burke
- Department of Veterinary Medicine, United States Army Medical Directorate, Armed Forces Research Institute of Medical Sciences (USAMD-AFRIMS), Bangkok, Thailand
| | - Stuart D. Blacksell
- Mahidol Oxford Tropical Medicine Research Unit, Mahidol University, Bangkok, Thailand
- Nuffield Department of Medicine, Oxford University, Oxford, United Kingdom
| | - James W. Jones
- Department of Veterinary Medicine, United States Army Medical Directorate, Armed Forces Research Institute of Medical Sciences (USAMD-AFRIMS), Bangkok, Thailand
| | - Carl J. Mason
- Department of Veterinary Medicine, United States Army Medical Directorate, Armed Forces Research Institute of Medical Sciences (USAMD-AFRIMS), Bangkok, Thailand
| | - Allen L. Richards
- Viral & Rickettsial Diseases Department, Naval Medical Research Center, Silver Spring, MD, United States of America
- Preventive Medicine and Biostatistics Department, Uniformed Services University of the Health Sciences, Bethesda, MD, United States of America
| | - Nicholas P. J. Day
- Mahidol Oxford Tropical Medicine Research Unit, Mahidol University, Bangkok, Thailand
- Nuffield Department of Medicine, Oxford University, Oxford, United Kingdom
| | - Daniel H. Paris
- Mahidol Oxford Tropical Medicine Research Unit, Mahidol University, Bangkok, Thailand
- Nuffield Department of Medicine, Oxford University, Oxford, United Kingdom
- Department of Medicine, Swiss Tropical and Public Health Institute, Basel, Switzerland
- Faculty of Medicine, University of Basel, Basel, Switzerland
- * E-mail:
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Ha NY, Kim Y, Min CK, Kim HI, Yen NTH, Choi MS, Kang JS, Kim YS, Cho NH. Longevity of antibody and T-cell responses against outer membrane antigens of Orientia tsutsugamushi in scrub typhus patients. Emerg Microbes Infect 2017; 6:e116. [PMID: 29259327 PMCID: PMC5750460 DOI: 10.1038/emi.2017.106] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2017] [Revised: 11/01/2017] [Accepted: 11/07/2017] [Indexed: 01/30/2023]
Abstract
Scrub typhus, caused by Orientia tsutsugamushi infection, has been a serious public health issue in the Asia-Pacific region, with rising incidence and sporadic outbreaks. However, human protective immunity against specific antigens has been poorly characterized for this bacterium. In addition, immunity produced in early vaccine trials or even after natural infections, did not last long and had poor cross-reactivity among various genotypes. Here, we systematically investigated the kinetics and magnitude of specific adaptive immunity against two membrane antigens, 56 kDa type-specific antigen (TSA56) and surface cell antigen A (ScaA), that are involved in bacterial adhesion and invasion of the host in 64 recovered scrub typhus patients. Antibody responses to the bacterial antigens in patients were generally short-lived and waned to baseline levels 2 years after recovery. The anti-TSA56 IgG responses were predominantly composed of the IgG1 and IgG3 subclasses and persisted for up to 1 year after recovery, whereas IgG specific to ScaA primarily consisted of more transient IgG1, with limited responses by other subclasses. Cellular immunity, including CD4 and CD8 T-cells specific to membrane antigens, also rapidly declined from 1 year after infection, as measured by enzyme-linked immunospot (ELISPOT) assays and flow cytometry. The short longevity of antigen-specific adaptive immunity might be attributable to limited memory responses, as observed in earlier vaccine studies using whole bacterial antigens. Finally, we identified HLA-A*0201-restricted and highly conserved CD8 T-cell epitopes in the TSA56 antigen, which may be valuable tools for assessing cellular immunity against O. tsutsugamushi and developing an effective scrub typhus vaccine.
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Affiliation(s)
- Na-Young Ha
- Department of Microbiology and Immunology, Seoul National University College of Medicine, Seoul 03080, Republic of Korea.,Department of Biomedical Sciences, Seoul National University College of Medicine, Seoul 03080, Republic of Korea
| | - Yuri Kim
- Department of Microbiology and Immunology, Seoul National University College of Medicine, Seoul 03080, Republic of Korea.,Department of Biomedical Sciences, Seoul National University College of Medicine, Seoul 03080, Republic of Korea
| | - Chan-Ki Min
- Department of Microbiology and Immunology, Seoul National University College of Medicine, Seoul 03080, Republic of Korea.,Department of Biomedical Sciences, Seoul National University College of Medicine, Seoul 03080, Republic of Korea
| | - Hong-Il Kim
- Department of Microbiology and Immunology, Seoul National University College of Medicine, Seoul 03080, Republic of Korea.,Department of Biomedical Sciences, Seoul National University College of Medicine, Seoul 03080, Republic of Korea
| | - Nguyen Thi Hai Yen
- Department of Microbiology and Immunology, Seoul National University College of Medicine, Seoul 03080, Republic of Korea.,Department of Biomedical Sciences, Seoul National University College of Medicine, Seoul 03080, Republic of Korea
| | - Myung-Sik Choi
- Department of Microbiology and Immunology, Seoul National University College of Medicine, Seoul 03080, Republic of Korea
| | - Jae-Seung Kang
- Department of Microbiology, Inha University School of Medicine, Incheon 22212, Republic of Korea
| | - Yeon-Sook Kim
- Division of Infectious Diseases, Department of Internal Medicine, Chungnam National University School of Medicine, Daejeon 35015, Republic of Korea
| | - Nam-Hyuk Cho
- Department of Microbiology and Immunology, Seoul National University College of Medicine, Seoul 03080, Republic of Korea.,Department of Biomedical Sciences, Seoul National University College of Medicine, Seoul 03080, Republic of Korea.,Institute of Endemic Disease, Seoul National University Medical Research Center and Bundang Hospital, Seoul 03080, Republic of Korea
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Bonell A, Lubell Y, Newton PN, Crump JA, Paris DH. Estimating the burden of scrub typhus: A systematic review. PLoS Negl Trop Dis 2017; 11:e0005838. [PMID: 28945755 PMCID: PMC5634655 DOI: 10.1371/journal.pntd.0005838] [Citation(s) in RCA: 187] [Impact Index Per Article: 26.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2017] [Revised: 10/10/2017] [Accepted: 07/28/2017] [Indexed: 01/30/2023] Open
Abstract
BACKGROUND Scrub typhus is a vector-borne zoonotic disease that can be life-threatening. There are no licensed vaccines, or vector control efforts in place. Despite increasing awareness in endemic regions, the public health burden and global distribution of scrub typhus remains poorly known. METHODS We systematically reviewed all literature from public health records, fever studies and reports available on the Ovid MEDLINE, Embase Classic + Embase and EconLit databases, to estimate the burden of scrub typhus since the year 2000. FINDINGS In prospective fever studies from Asia, scrub typhus is a leading cause of treatable non-malarial febrile illness. Sero-epidemiological data also suggest that Orientia tsutsugamushi infection is common across Asia, with seroprevalence ranging from 9.3%-27.9% (median 22.2% IQR 18.6-25.7). A substantial apparent rise in minimum disease incidence (median 4.6/100,000/10 years, highest in China with 11.2/100,000/10 years) was reported through passive national surveillance systems in South Korea, Japan, China, and Thailand. Case fatality risks from areas of reduced drug-susceptibility are reported at 12.2% and 13.6% for South India and northern Thailand, respectively. Mortality reports vary widely around a median mortality of 6.0% for untreated and 1.4% for treated scrub typhus. Limited evidence suggests high mortality in complicated scrub typhus with CNS involvement (13.6% mortality), multi-organ dysfunction (24.1%) and high pregnancy miscarriage rates with poor neonatal outcomes. INTERPRETATION Scrub typhus appears to be a truly neglected tropical disease mainly affecting rural populations, but increasingly also metropolitan areas. Rising minimum incidence rates have been reported over the past 8-10 years from countries with an established surveillance system. A wider distribution of scrub typhus beyond Asia is likely, based on reports from South America and Africa. Unfortunately, the quality and quantity of the available data on scrub typhus epidemiology is currently too limited for any economical, mathematical modeling or mapping approaches.
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Affiliation(s)
- Ana Bonell
- Oxford University Clinical Research Unit, National Hospital of Tropical Diseases, Hanoi, Vietnam
| | - Yoel Lubell
- Mahidol Oxford Tropical Medicine Research Unit, Mahidol University, Bangkok, Thailand
- Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, United Kingdom
| | - Paul N. Newton
- Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, United Kingdom
- Lao-Oxford-Mahosot Hospital-Wellcome Trust Research Unit, Microbiology Laboratory, Mahosot Hospital, Vientiane, Laos
| | - John A. Crump
- Centre for International Health, University of Otago, Dunedin, New Zealand
| | - Daniel H. Paris
- Mahidol Oxford Tropical Medicine Research Unit, Mahidol University, Bangkok, Thailand
- Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, United Kingdom
- Department of Medicine, Swiss Tropical and Public Health Institute, Basel, Switzerland
- Faculty of Medicine, University Basel, Basel, Switzerland
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22
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Sumonwiriya M, Paris DH, Sunyakumthorn P, Anantatat T, Jenjaroen K, Chumseng S, Im-erbsin R, Tanganuchitcharnchai A, Jintaworn S, Blacksell SD, Chowdhury FR, Kronsteiner B, Teparrukkul P, Burke RL, Lombardini ED, Richards AL, Mason CJ, Jones JW, Day NPJ, Dunachie SJ. Strong interferon-gamma mediated cellular immunity to scrub typhus demonstrated using a novel whole cell antigen ELISpot assay in rhesus macaques and humans. PLoS Negl Trop Dis 2017; 11:e0005846. [PMID: 28892515 PMCID: PMC5608426 DOI: 10.1371/journal.pntd.0005846] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2017] [Revised: 09/21/2017] [Accepted: 08/01/2017] [Indexed: 01/30/2023] Open
Abstract
Scrub typhus is a febrile infection caused by the obligate intracellular bacterium Orientia tsutsugamushi, which causes significant morbidity and mortality across the Asia-Pacific region. The control of this vector-borne disease is challenging due to humans being dead-end hosts, vertical maintenance of the pathogen in the vector itself, and a potentially large rodent reservoir of unclear significance, coupled with a lack of accurate diagnostic tests. Development of an effective vaccine is highly desirable. This however requires better characterization of the natural immune response of this neglected but important disease. Here we implement a novel IFN-γ ELISpot assay as a tool for studying O. tsutsugamushi induced cellular immune responses in an experimental scrub typhus rhesus macaque model and human populations. Whole cell antigen for O. tsutsugamushi (OT-WCA) was prepared by heat inactivation of Karp-strain bacteria. Rhesus macaques were infected intradermally with O. tsutsugamushi. Freshly isolated peripheral blood mononuclear cells (PBMC) from infected (n = 10) and uninfected animals (n = 5) were stimulated with OT-WCA, and IFN-γ secreting cells quantitated by ELISpot assay at five time points over 28 days. PBMC were then assayed from people in a scrub typhus-endemic region of Thailand (n = 105) and responses compared to those from a partially exposed population in a non-endemic region (n = 14), and to a naïve population in UK (n = 12). Mean results at Day 0 prior to O. tsutsugamushi infection were 12 (95% CI 0-25) and 15 (2-27) spot-forming cells (SFC)/106 PBMC for infected and control macaques respectively. Strong O. tsutsugamushi-specific IFN-γ responses were seen post infection, with ELISpot responses 20-fold higher than baseline at Day 7 (mean 235, 95% CI 200-270 SFC/106 PBMC), 105-fold higher at Day 14 (mean 1261, 95% CI 1,097-1,425 SFC/106 PBMC), 125-fold higher at Day 21 (mean 1,498, 95% CI 1,496-1,500 SFC/106 PBMC) and 118-fold higher at Day 28 (mean 1,416, 95% CI 1,306-1,527 SFC/106 PBMC). No significant change was found in the control group at any time point compared to baseline. Humans from a scrub typhus endemic region of Thailand had mean responses of 189 (95% CI 88-290) SFC/106 PBMC compared to mean responses of 40 (95% CI 9-71) SFC/106 PBMC in people from a non-endemic region and 3 (95% CI 0-7) SFC/106 PBMC in naïve controls. In summary, this highly sensitive assay will enable field immunogenicity studies and further characterization of the host response to O. tsutsugamushi, and provides a link between human and animal models to accelerate vaccine development.
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Affiliation(s)
| | - Daniel H. Paris
- Mahidol Oxford Tropical Medicine Research Unit, Mahidol University, Bangkok, Thailand
- Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, United Kingdom
- Department of Medicine, Swiss Tropical and Public Health Institute, Basel, Switzerland
- Faculty of Medicine, University of Basel, Basel, Switzerland
| | - Piyanate Sunyakumthorn
- Department of Veterinary Medicine, Armed Forces Research Institute of Medical Sciences (AFRIMS), Bangkok, Thailand
| | - Tippawan Anantatat
- Mahidol Oxford Tropical Medicine Research Unit, Mahidol University, Bangkok, Thailand
| | - Kemajittra Jenjaroen
- Mahidol Oxford Tropical Medicine Research Unit, Mahidol University, Bangkok, Thailand
| | - Suchintana Chumseng
- Mahidol Oxford Tropical Medicine Research Unit, Mahidol University, Bangkok, Thailand
| | - Rawiwan Im-erbsin
- Department of Veterinary Medicine, Armed Forces Research Institute of Medical Sciences (AFRIMS), Bangkok, Thailand
| | | | - Suthatip Jintaworn
- Mahidol Oxford Tropical Medicine Research Unit, Mahidol University, Bangkok, Thailand
| | - Stuart D. Blacksell
- Mahidol Oxford Tropical Medicine Research Unit, Mahidol University, Bangkok, Thailand
| | - Fazle R. Chowdhury
- Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, United Kingdom
- Peter Medawar Building for Pathogen Research, University of Oxford, Oxford, United Kingdom
| | - Barbara Kronsteiner
- Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, United Kingdom
- Peter Medawar Building for Pathogen Research, University of Oxford, Oxford, United Kingdom
| | - Prapit Teparrukkul
- Department of Medicine, Sappasithiprasong Hospital, Ubon Ratchathani, Thailand
| | - Robin L. Burke
- Department of Veterinary Medicine, Armed Forces Research Institute of Medical Sciences (AFRIMS), Bangkok, Thailand
| | - Eric D. Lombardini
- Department of Veterinary Medicine, Armed Forces Research Institute of Medical Sciences (AFRIMS), Bangkok, Thailand
| | - Allen L. Richards
- Department of Viral & Rickettsial Diseases, Naval Medical Research Center, Silver Spring, Maryland, United States of America
- Preventive Medicine and Biometrics Department, Uniformed Services University of the Health Sciences, Bethesda, Maryland, United States of America
| | - Carl J. Mason
- Department of Enteric Diseases, Armed Forces Research Institute of Medical Sciences (AFRIMS), Bangkok, Thailand
| | - James W. Jones
- Department of Veterinary Medicine, Armed Forces Research Institute of Medical Sciences (AFRIMS), Bangkok, Thailand
- Department of Enteric Diseases, Armed Forces Research Institute of Medical Sciences (AFRIMS), Bangkok, Thailand
| | - Nicholas P. J. Day
- Mahidol Oxford Tropical Medicine Research Unit, Mahidol University, Bangkok, Thailand
- Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, United Kingdom
| | - Susanna J. Dunachie
- Mahidol Oxford Tropical Medicine Research Unit, Mahidol University, Bangkok, Thailand
- Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, United Kingdom
- Peter Medawar Building for Pathogen Research, University of Oxford, Oxford, United Kingdom
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Increased level and interferon-γ production of circulating natural killer cells in patients with scrub typhus. PLoS Negl Trop Dis 2017; 11:e0005815. [PMID: 28750012 PMCID: PMC5549767 DOI: 10.1371/journal.pntd.0005815] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2017] [Revised: 08/08/2017] [Accepted: 07/19/2017] [Indexed: 12/27/2022] Open
Abstract
Background Natural killer (NK) cells are essential immune cells against several pathogens. Not much is known regarding the roll of NK cells in Orientia tsutsugamushi infection. Thus, this study aims to determine the level, function, and clinical relevance of NK cells in patients with scrub typhus. Methodology/Principal findings This study enrolled fifty-six scrub typhus patients and 56 health controls (HCs). The patients were divided into subgroups according to their disease severity. A flow cytometry measured NK cell level and function in peripheral blood. Circulating NK cell levels and CD69 expressions were significantly increased in scrub typhus patients. Increased NK cell levels reflected disease severity. In scrub typhus patients, tests showed their NK cells produced higher amounts of interferon (IFN)-γ after stimulation with interleukin (IL)-12 and IL-18 relative to those of HCs. Meanwhile, between scrub typhus patients and HCs, the cytotoxicity and degranulation of NK cells against K562 were comparable. CD69 expressions were recovered to the normal levels in the remission phase. Conclusions This study shows that circulating NK cells are activated and numerically increased, and they produced more IFN-γ in scrub typhus patients. Orientia tsutsugamushi is an obligate intracellular bacterium. It primarily invades endothelial cells, macrophages, monocytes, and dendritic cells. Plasma concentrations of interferon (IFN)-γ, several cytokines and chemokines, which are known to recruit natural killer (NK) cells and T cells, were found to be increased in scrub typhus patients. NK cells are known as essential immune cells against several pathogens. In murine models of Rickettsial infection, the clearance of bacteria was found to be significantly associated with NK cell activity. Not much is known regarding NK cells’ role in O. tsutsugamushi infection in humans. This study is very possibly the first to measure NK cells’ level and function of in scrub typhus patients, or to examine NK cell levels’ clinical relevance. This study’s results demonstrate that circulating NK cells are activated and numerically increased in scrub typhus patients. Notably, increased production IFN-γ by NK cells of scrub typhus patients suggests their contribution to enhancement of intracellular bacterial killing in infected antigen presenting cells. Moreover, disease severity corresponded to increased NK cell levels. These findings importantly suggest that NK cells play a role in protecting the host against O. tsutsugamushi infection.
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24
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Hauptmann M, Kolbaum J, Lilla S, Wozniak D, Gharaibeh M, Fleischer B, Keller CA. Protective and Pathogenic Roles of CD8+ T Lymphocytes in Murine Orientia tsutsugamushi Infection. PLoS Negl Trop Dis 2016; 10:e0004991. [PMID: 27606708 PMCID: PMC5015871 DOI: 10.1371/journal.pntd.0004991] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2016] [Accepted: 08/19/2016] [Indexed: 01/12/2023] Open
Abstract
T cells are known to contribute to immune protection against scrub typhus, a potentially fatal infection caused by the obligate intracellular bacterium Orientia (O.) tsutsugamushi. However, the contribution of CD8+ T cells to protection and pathogenesis during O. tsutsugamushi infection is still unknown. Using our recently developed BALB/c mouse model that is based on footpad inoculation of the human-pathogenic Karp strain, we show that activated CD8+ T cells infiltrate spleen and lung during the third week of infection. Depletion of CD8+ T cells with monoclonal antibodies resulted in uncontrolled pathogen growth and mortality. Adoptive transfer of CD8+ T cells from infected animals protected naïve BALB/c mice from lethal outcome of intraperitoneal challenge. In C57Bl/6 mice, the pulmonary lymphocyte compartment showed an increased percentage of CD8+ T cells for at least 135 days post O. tsutsugamushi infection. Depletion of CD8+ T cells at 84 days post infection caused reactivation of bacterial growth. In CD8+ T cell-deficient beta 2-microglobulin knockout mice, bacterial replication was uncontrolled, and all mice succumbed to the infection, despite higher serum IFN-γ levels and stronger macrophage responses in liver and lung. Moreover, we show that CD8+ T cells but not NKT cells were required for hepatocyte injury: elevated concentrations of serum alanine aminotransferase and infection-induced subcapsular necrotic liver lesions surrounded by macrophages were found in C57Bl/6 and CD1d-deficient mice, but not in beta 2-microglobulin knockout mice. In the lungs, peribronchial macrophage infiltrations also depended on CD8+ T cells. In summary, our results demonstrate that CD8+ T cells restrict growth of O. tsutsugamushi during acute and persistent infection, and are required to protect from lethal infections in BALB/c and C57BL/6 mice. However, they also elicit specific pathologic tissue lesions in liver and lung.
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Affiliation(s)
- Matthias Hauptmann
- Department of Immunology, Bernhard Nocht Institute for Tropical Medicine, Hamburg, Germany
| | - Julia Kolbaum
- Department of Immunology, Bernhard Nocht Institute for Tropical Medicine, Hamburg, Germany
| | - Stefanie Lilla
- Department of Immunology, Bernhard Nocht Institute for Tropical Medicine, Hamburg, Germany
| | - David Wozniak
- Department of Immunology, Bernhard Nocht Institute for Tropical Medicine, Hamburg, Germany
| | - Mohammad Gharaibeh
- Department of Immunology, Bernhard Nocht Institute for Tropical Medicine, Hamburg, Germany
| | - Bernhard Fleischer
- Department of Immunology, Bernhard Nocht Institute for Tropical Medicine, Hamburg, Germany
- Institute for Immunology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Christian A. Keller
- Department of Immunology, Bernhard Nocht Institute for Tropical Medicine, Hamburg, Germany
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Kang SJ, Jin HM, Won EJ, Cho YN, Jung HJ, Kwon YS, Kee HJ, Ju JK, Kim JC, Kim UJ, Jang HC, Jung SI, Kee SJ, Park YW. Activation, Impaired Tumor Necrosis Factor-α Production, and Deficiency of Circulating Mucosal-Associated Invariant T Cells in Patients with Scrub Typhus. PLoS Negl Trop Dis 2016; 10:e0004832. [PMID: 27463223 PMCID: PMC4963088 DOI: 10.1371/journal.pntd.0004832] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2016] [Accepted: 06/17/2016] [Indexed: 01/10/2023] Open
Abstract
BACKGROUND Mucosal-associated invariant T (MAIT) cells contribute to protection against certain microorganism infections. However, little is known about the role of MAIT cells in Orientia tsutsugamushi infection. Hence, the aims of this study were to examine the level and function of MAIT cells in patients with scrub typhus and to evaluate the clinical relevance of MAIT cell levels. METHODOLOGY/PRINCIPAL FINDINGS Thirty-eight patients with scrub typhus and 53 health control subjects were enrolled in the study. The patients were further divided into subgroups according to disease severity. MAIT cell level and function in the peripheral blood were measured by flow cytometry. Circulating MAIT cell levels were found to be significantly reduced in scrub typhus patients. MAIT cell deficiency reflects a variety of clinical conditions. In particular, MAT cell levels reflect disease severity. MAIT cells in scrub typhus patients displayed impaired tumor necrosis factor (TNF)-α production, which was restored during the remission phase. In addition, the impaired production of TNF-α by MAIT cells was associated with elevated CD69 expression. CONCLUSIONS This study shows that circulating MAIT cells are activated, numerically deficient, and functionally impaired in TNF-α production in patients with scrub typhus. These abnormalities possibly contribute to immune system dysregulation in scrub typhus infection.
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Affiliation(s)
- Seung-Ji Kang
- Department of Infectious Diseases, Chonnam National University Medical School and Hospital, Gwangju, Republic of Korea
| | - Hye-Mi Jin
- Department of Rheumatology, Chonnam National University Medical School and Hospital, Gwangju, Republic of Korea
| | - Eun Jeong Won
- Department of Laboratory Medicine, Chonnam National University Medical School and Hospital, Gwangju, Republic of Korea
| | - Young-Nan Cho
- Department of Rheumatology, Chonnam National University Medical School and Hospital, Gwangju, Republic of Korea
| | - Hyun-Ju Jung
- Department of Rheumatology, Chonnam National University Medical School and Hospital, Gwangju, Republic of Korea
| | - Yong-Soo Kwon
- Department of Pulmonary and Critical Care Medicine, Chonnam National University Medical School and Hospital, Gwangju, Republic of Korea
| | - Hae Jin Kee
- Heart Research Center, Chonnam National University Hospital, Gwangju, Republic of Korea
| | - Jae Kyun Ju
- Department of Surgery, Chonnam National University Medical School and Hospital, Gwangju, Republic of Korea
| | - Jung-Chul Kim
- Department of Surgery, Chonnam National University Medical School and Hospital, Gwangju, Republic of Korea
| | - Uh Jin Kim
- Department of Infectious Diseases, Chonnam National University Medical School and Hospital, Gwangju, Republic of Korea
| | - Hee-Chang Jang
- Department of Infectious Diseases, Chonnam National University Medical School and Hospital, Gwangju, Republic of Korea
| | - Sook-In Jung
- Department of Infectious Diseases, Chonnam National University Medical School and Hospital, Gwangju, Republic of Korea
| | - Seung-Jung Kee
- Department of Laboratory Medicine, Chonnam National University Medical School and Hospital, Gwangju, Republic of Korea
| | - Yong-Wook Park
- Department of Rheumatology, Chonnam National University Medical School and Hospital, Gwangju, Republic of Korea
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CNS Manifestations in Orientia tsutsugamushi Disease (Scrub Typhus) in North India. Indian J Pediatr 2016; 83:634-9. [PMID: 26817467 DOI: 10.1007/s12098-015-2001-2] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/25/2015] [Accepted: 12/16/2015] [Indexed: 02/06/2023]
Abstract
OBJECTIVE To present the clinical, lab profile and outcome of a series of six children who had features of meningoencephalitis (median age of 10.5 y) diagnosed as confirmed scrub typhus (ST) by using a lgM ELISA commercial kit (InBiOS International Inc. USA). METHODS This was a prospective observational study conducted at a tertiary care hospital, over a period of 7 mo through April 2014. All the patients with undifferentiated febrile illness (aged 1-18 y) with fever of 5-21 d duration were evaluated. After thorough physical examination they were subjected to blood investigations such as complete blood count (CBC), blood culture, hepatic and kidney function tests, serum electrolytes, cerebrospinal fluid (CSF) analysis and IgM ELISA for scrub typhus, coagulogram and chest radiograph, wherever indicated. RESULTS During this period, of the total 81 confirmed cases based on a positive scrub IgM ELISA and/or eschar, 6 (7.4 %), had neurological involvement in the form of presence of neck stiffness, altered sensorium and/or seizures and the CSF findings were suggestive of meningoencephalitis and all had evidence of multiple organ dysfunction syndrome (MODS) needing intensive care. The CECT could be performed in four patients only showing evidence of effacement of sulci and evidence of brain edema. CONCLUSIONS This communication highlights that variable central nervous system (CNS) involvement is not uncommon in patients with scrub typhus with high mortality. CSF and neuro-radiology findings are nonspecific as these are also observed in patients with aseptic meningitis or encephalitis. Early suspection and institution of appropriate therapy without delay will lead to substantial reduction in the morbidity and mortality.
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Lee J, Kim DM, Yun NR, Kim YD, Park CG, Kim MW. The Correlation of Endoscopic Findings and Clinical Features in Korean Patients with Scrub Typhus: A Cohort Study. PLoS One 2016; 11:e0155810. [PMID: 27195943 PMCID: PMC4873011 DOI: 10.1371/journal.pone.0155810] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2016] [Accepted: 05/04/2016] [Indexed: 11/18/2022] Open
Abstract
Scrub typhus is an infectious disease caused by Orientia tsutsugamushi-induced systemic vasculitis, but the involvement of the gastrointestinal tract and the endoscopic findings associated with scrub typhus are not well understood. We performed a prospective study and recommend performing esophagogastroduodenoscopy (EGD) for all possible scrub typhus patients, regardless of gastrointestinal symptoms. Gastrointestinal symptoms, endoscopic findings and clinical severity based on organ involvement and ICU admission were analyzed. Gastrointestinal symptoms occurred in up to 76.4% of scrub typhus patients. The major endoscopic findings were ulcers (43/127, 33.9%). Interestingly, 7.1% (9/127) of the patients presented with esophageal candidiasis. There was no correlation between the presence or absence of gastrointestinal symptoms and the endoscopic grade (P = 0.995). However, there was a positive correlation between the clinical severity and the endoscopic findings (P = 0.001). Sixty-three percent of the patients presented with erosion or ulcers on prospectively performed endoscopic evaluations, irrespective of gastrointestinal symptoms. Gastrointestinal symptoms did not reflect the need for endoscopy. Scrub typhus patients could have significant endoscopic abnormalities even in the absence of gastrointestinal symptoms.
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Affiliation(s)
- Jun Lee
- Department of Internal Medicine, School of Medicine, Chosun University, Gwangju, Republic of Korea
| | - Dong-Min Kim
- Department of Internal Medicine, School of Medicine, Chosun University, Gwangju, Republic of Korea
- * E-mail:
| | - Na Ra Yun
- Department of Internal Medicine, School of Medicine, Chosun University, Gwangju, Republic of Korea
| | - Young Dae Kim
- Department of Internal Medicine, School of Medicine, Chosun University, Gwangju, Republic of Korea
| | - Chan Guk Park
- Department of Internal Medicine, School of Medicine, Chosun University, Gwangju, Republic of Korea
| | - Man Woo Kim
- Department of Internal Medicine, School of Medicine, Chosun University, Gwangju, Republic of Korea
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Increased Nucleosomes and Neutrophil Activation Link to Disease Progression in Patients with Scrub Typhus but Not Murine Typhus in Laos. PLoS Negl Trop Dis 2015; 9:e0003990. [PMID: 26317419 PMCID: PMC4552835 DOI: 10.1371/journal.pntd.0003990] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2015] [Accepted: 07/15/2015] [Indexed: 11/19/2022] Open
Abstract
Cell-mediated immunity is essential in protection against rickettsial illnesses, but the role of neutrophils in these intracellular vasculotropic infections remains unclear. This study analyzed the plasma levels of nucleosomes, FSAP-activation (nucleosome-releasing factor), and neutrophil activation, as evidenced by neutrophil-elastase (ELA) complexes, in sympatric Lao patients with scrub typhus and murine typhus. In acute scrub typhus elevated nucleosome levels correlated with lower GCS scores, raised respiratory rate, jaundice and impaired liver function, whereas neutrophil activation correlated with fibrinolysis and high IL-8 plasma levels, a recently identified predictor of severe disease and mortality. Nucleosome and ELA complex levels were associated with a 4.8-fold and 4-fold increased risk of developing severe scrub typhus, beyond cut off values of 1,040 U/ml for nucleosomes and 275 U/ml for ELA complexes respectively. In murine typhus, nucleosome levels associated with pro-inflammatory cytokines and the duration of illness, while ELA complexes correlated strongly with inflammation markers, jaundice and increased respiratory rates. This study found strong correlations between circulating nucleosomes and neutrophil activation in patients with scrub typhus, but not murine typhus, providing indirect evidence that nucleosomes could originate from neutrophil extracellular trap (NET) degradation. High circulating plasma nucleosomes and ELA complexes represent independent risk factors for developing severe complications in scrub typhus. As nucleosomes and histones exposed on NETs are highly cytotoxic to endothelial cells and are strongly pro-coagulant, neutrophil-derived nucleosomes could contribute to vascular damage, the pro-coagulant state and exacerbation of disease in scrub typhus, thus indicating a detrimental role of neutrophil activation. The data suggest that increased neutrophil activation relates to disease progression and severe complications, and increased plasma levels of nucleosomes and ELA complexes represent independent risk factors for developing severe scrub typhus. Tropical rickettsial illnesses, especially scrub typhus and murine typhus, are increasingly recognized as a leading cause of treatable undifferentiated febrile illness in Asia, but remain severely neglected and under appreciated diseases in many areas. In this study we investigated the relationship of markers of neutrophil activation and cell death with disease severity in patients with acute scrub typhus and murine typhus in Laos. These easily measurable circulating markers were associated with a 4 to 5-fold increased risk of developing severe clinical disease manifestations in scrub typhus and represent independent predictors of severe disease, and possibly death. We also found strong correlations between circulating markers of cell death and neutrophil activation in patients with scrub typhus, but not murine typhus, providing indirect evidence that neutrophil extracellular traps could contribute to the vascular damage and pro-coagulant state leading to exacerbation of disease in scrub typhus, thus indicating a detrimental role of neutrophil activation. The data suggest that increased neutrophil activation relates to disease progression and severe complications, and increased plasma levels of nucleosomes and ELA complexes represent independent risk factors for developing severe scrub typhus.
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Ha NY, Sharma P, Kim G, Kim Y, Min CK, Choi MS, Kim IS, Cho NH. Immunization with an autotransporter protein of Orientia tsutsugamushi provides protective immunity against scrub typhus. PLoS Negl Trop Dis 2015; 9:e0003585. [PMID: 25768004 PMCID: PMC4359152 DOI: 10.1371/journal.pntd.0003585] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2014] [Accepted: 02/03/2015] [Indexed: 01/14/2023] Open
Abstract
BACKGROUND Scrub typhus is an acute febrile disease caused by Orientia tsutsugamushi infection. Recently, the rapid increase of scrub typhus incidence in several countries within the endemic region has become a serious public health issue. Despite the wide range of preventative approaches that have been attempted in the past 70 years, all have failed to develop an effective prophylactic vaccine. Currently, the selection of the proper antigens is one of the critical barriers to generating cross-protective immunity against antigenically-variable strains of O. tsutsugamushi. METHODOLOGY/PRINCIPAL FINDINGS We examined the potential role of ScaA protein, an autotransporter protein of O. tsutsugamushi, in bacterial pathogenesis and evaluated the protective attributes of ScaA immunization in lethal O. tsutsugamushi infection in mice. Our findings demonstrate that ScaA functions as a bacterial adhesion factor, and anti-ScaA antibody significantly neutralizes bacterial infection of host cells. In addition, immunization with ScaA not only provides protective immunity against lethal challenges with the homologous strain, but also confers significant protection against heterologous strains when combined with TSA56, a major outer membrane protein of O. tsutsugamushi. CONCLUSIONS/SIGNIFICANCE Immunization of ScaA proteins provides protective immunity in mice when challenged with the homologous strain and significantly enhanced protective immunity against infection with heterologous strains. To our knowledge, this is the most promising result of scrub typhus vaccination trials against infection of heterologous strains in mouse models thus far.
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Affiliation(s)
- Na-Young Ha
- Department of Microbiology and Immunology, Seoul National University College of Medicine, Seoul, Republic of Korea
- Department of Biomedical Sciences, Seoul National University College of Medicine, Seoul, Republic of Korea
| | - Prashant Sharma
- Department of Microbiology and Immunology, Seoul National University College of Medicine, Seoul, Republic of Korea
- Department of Biomedical Sciences, Seoul National University College of Medicine, Seoul, Republic of Korea
| | - Gwanghun Kim
- Department of Microbiology and Immunology, Seoul National University College of Medicine, Seoul, Republic of Korea
- Department of Biomedical Sciences, Seoul National University College of Medicine, Seoul, Republic of Korea
| | - Yuri Kim
- Department of Microbiology and Immunology, Seoul National University College of Medicine, Seoul, Republic of Korea
- Department of Biomedical Sciences, Seoul National University College of Medicine, Seoul, Republic of Korea
| | - Chan-Ki Min
- Department of Microbiology and Immunology, Seoul National University College of Medicine, Seoul, Republic of Korea
- Department of Biomedical Sciences, Seoul National University College of Medicine, Seoul, Republic of Korea
| | - Myung-Sik Choi
- Department of Microbiology and Immunology, Seoul National University College of Medicine, Seoul, Republic of Korea
| | - Ik-Sang Kim
- Department of Microbiology and Immunology, Seoul National University College of Medicine, Seoul, Republic of Korea
| | - Nam-Hyuk Cho
- Department of Microbiology and Immunology, Seoul National University College of Medicine, Seoul, Republic of Korea
- Department of Biomedical Sciences, Seoul National University College of Medicine, Seoul, Republic of Korea
- Institute of Endemic Disease, Seoul National University Medical Research Center and Bundang Hospital, Seoul, Republic of Korea
- * E-mail:
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Kim DM, Chung JH, Yun NR, Kim SW, Lee JY, Han MA, Lee YB. Scrub typhus meningitis or meningoencephalitis. Am J Trop Med Hyg 2013; 89:1206-11. [PMID: 24166036 DOI: 10.4269/ajtmh.13-0224] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
Orientia tsutsugamushi induces vasculitis leading to symptoms of systemic organ invasion including meningitis and meningoencephalitis. We conducted a retrospective case-control study of scrub typhus patients to investigate the clinical and laboratory features of patients with scrub typhus meningitis or meningoencephalitis, and the therapeutic outcomes, and to determine the predictor factors. Cases were 22 patients with scrub typhus meningitis or meningoencephalitis, and controls were 303 patients without meningitis or meningoencephalitis. Multivariate analysis showed that the presence of pneumonitis was associated with the occurrence of scrub typhus meningitis and meningoencephalitis (odds ratio [OR] 8.9; P < 0.001; confidence interval [CI] 2.9-27.2). Although appropriate antimicrobials such as doxycycline agents were administered at an early stage, meningitis or meningoencephalitis still occurred in some cases. Physicians should be aware that meningitis or meningoencephalitis may develop during appropriate drug therapy such as doxycycline. Close observation and great care are essential for patients with risk factors, particularly pneumonitis.
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Affiliation(s)
- Dong-Min Kim
- Departments of Internal Medicine, Neurosurgery, Orthopedic Surgery, and Preventive Medicine, School of Medicine, Chosun University, Gwangj, Republic of Korea; College of Pharmacy, Institute of Bioequivalence and Bridging Study, Gwangj, Republic of Korea
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