13 research outputs found
Modulation of the mouse immune microenvironment by infections with Lactate Dehydrogenase-elevating Virus and Plasmodium parasite : consequences on septic shock and cancer immunosurveillance
No full textAlthough the immune system has evolved to eliminate pathogenic microorganisms, excessive immune responses elicited by these pathogens can lead to immunopathology, as is the case in septic shock. In mice, the parasite Plasmodium, as "Lactate Dehydrogenase-elevating Virus" (LDV), strongly modifies responses to secondary endotoxin exposure. Increased sensitivity is reflected in the production of cytokines such as TNF and of soluble endotoxin receptors (LBP, CD14s). However, the immune surveillance of certain cancers is modulated, at least in part, by concomitant infections. Immunosurveillance of plasmacytoma (myeloma counterpart) was observed in mice infected with Plasmodium yoelii 265 BY. Inhibition of tumor development by this parasite, similar to that induced by LDV, is mediated by ASGM1+ cells. During Plasmodium infection, production of interleukin-12 and interferon-gamma is increased, but it has not been possible to demonstrate an effect on plasmacytoma development of antibodies neutralising these cytokines. In addition, a limited clinical study conducted in Myanmar revealed an increased risk of developing multiple myeloma after exposure to agricultural chemicals, but on the contrary, a reduced risk associated with infections, including malaria. Our results indicate that Plasmodium infection has an indirect effect on the exacerbation of endotoxin shock but inhibits the early development of plasmacytoma.(BIFA - Sciences biomédicales et pharmaceutiques) -- UCL, 202
Enhanced Mouse Susceptibility to Endotoxin Shock after Plasmodium yoelii Infection Is Correlated with Increased Serum Levels of Lipopolysaccharide Soluble Receptors
No full textSepsis is a common disease in sub-Saharan Africa and Asia, where malaria is also prevalent. To determine whether Plasmodium infection might enhance susceptibility to endotoxin shock, we used a mouse model of lipopolysaccharide (LPS) administration. Our results indicated that Plasmodium yoelii infection in mice strongly enhanced the susceptibility of the host to develop endotoxin shock. This increased susceptibility to endotoxin shock was correlated with a synergistic effect of Plasmodium and LPS on the secretion of Tumor Necrosis Factor (TNF). TNF contributed mostly to lethality after the dual challenge since neutralization with an anti-TNF antibody provided protection from death. Plasmodium infection also induced an enhancement of the serum levels of LPS soluble ligands, sCD14 and Lipopolysaccharide Binding Protein. In this regard, our data confirm that Plasmodium infection can profoundly modify responses to secondary bacteria challenges, resulting in dysregulated cytokine expression and pathological effects. If confirmed in humans, LPS soluble receptors might serve as markers of susceptibility to septic shock
Inhibition of IL-12 heterodimers impairs TLR9-mediated prevention of early mouse plasmacytoma cell growth.
No full textINTRODUCTION: Natural prevention of cancer development depends on an efficient immunosurveillance that may be modulated by environmental factors, including infections. Innate lymphoid cytotoxic cells have been shown to play a major role in this immunosurveillance. Interleukin-12 (IL-12) has been suggested to be a key factor in the activation of innate cytotoxic cells after infection, leading to the enhancement of cancer immunosurveillance. METHODS: The aim of this work was to analyze in mouse experimental models by which mechanisms the interaction between infectious agent molecules and the early innate responses could enhance early inhibition of cancer growth and especially to assess the role of IL-12 by using novel antibodies specific for IL-12 heterodimers. RESULTS: Ligation of toll-like receptor (TLR)9 by CpG-protected mice against plasmacytoma TEPC.1033.C2 cell early growth. This protection mediated by innate cytolytic cells was strictly dependent on IL-12 and partly on gamma-interferon. Moreover, the protective effect of CpG stimulation, and to a lesser extent of TLR3 and TLR7/8, and the role of IL-12 in this protection were confirmed in a model of early mesothelioma AB1 cell growth. DISCUSSION: These results suggest that modulation of the mouse immune microenvironment by ligation of innate receptors deeply modifies the efficiency of cancer immunosurveillance through the secretion of IL-12, which may at least partly explain the inhibitory effect of previous infections on the prevalence of some cancers
Lactate Dehydrogenase-Elevating Virus Infection Inhibits MOG Peptide Presentation by CD11b+CD11c+ Dendritic Cells in a Mouse Model of Multiple Sclerosis
No full textInfections may affect the course of autoimmune inflammatory diseases of the central nervous system (CNS), such as multiple sclerosis (MS). Infections with lactate dehydrogenase-elevating virus (LDV) protected mice from developing experimental autoimmune encephalomyelitis (EAE), a mouse counterpart of MS. Uninfected C57BL/6 mice immunized with the myelin oligodendrocyte glycoprotein peptide (MOG35–55) experienced paralysis and lost weight at a greater rate than mice who had previously been infected with LDV. LDV infection decreased the presentation of the MOG peptide by CD11b+CD11c+ dendritic cells (DC) to pathogenic T lymphocytes. When comparing non-infected mice to infected mice, the histopathological examination of the CNS showed more areas of demyelination and CD45+ and CD3+, but not Iba1+ cell infiltration. These results suggest that the protective effect of LDV infection against EAE development is mediated by a suppression of myelin antigen presentation by a specific DC subset to autoreactive T lymphocytes. Such a mechanism might contribute to the general suppressive effect of infections on autoimmune diseases known as the hygiene hypothesis
Lactate dehydrogenase-elevating virus enhances natural killer cell-mediated immunosurveillance of mouse mesothelioma development.
No full textBACKGROUND: Viral infections can reduce early cancer development through enhancement of cancer immunosurveillance. This study was performed to analyse this effect of viral infection in a mouse model of solid tumor. METHODS: The experimental model used was the effect of BALB/c mouse infection by lactate dehydrogenase-elevating virus on AB1 mesothelioma cancer development. RESULTS: Acute infection with lactate dehydrogenase-elevating virus strongly reduced in vivo early AB1 mesothelioma growth and death resulting from cancer development. This effect was not due to a direct cytolytic effect of the virus on AB1 cells, but to an in vivo activation of natural killer cells. Gamma-interferon production rather than cytotoxic activity against AB1 cells mediated this protective effect. This gamma-interferon production by natural killer cells was dependent on interleukin-12 production. CONCLUSIONS: Together with other reported effects of infectious agents on cancer development, this observation may support the hypothesis that enhancement of innate immunosurveillance against tumors may result from infection with common infectious agents through modulation of the host immune microenvironment
Impact of Environmental Factors on the Risk of Multiple Myeloma, a Case-Control Study in Myanmar
No full textBACKGROUND: Environmental factors, including exposure to chemicals and certain pathogens, may increase the risk of developing Multiple Myeloma (MM), as indicated by studies conducted primarily in industrialized countries. On the other hand, some epidemiological and experimental data also support the hypothesis that exposure to infections may enhance cancer immunosurveillance, particularly against multiple myeloma. AIM: To improve our understanding of the association between environmental factors and the risk of multiple myeloma, particularly in developing countries, this research was conducted to ascertain, in a South-East Asian setting, if environmental factors can modulate the risk of developing multiple myeloma. METHODOLOGY: A hospital-based case-control study was conducted using simple questionnaires in two large public hospitals in Myanmar from July to September 2020, with 40 multiple myeloma cases and a double control population seeking care in the medical and surgical Units of the same hospitals. RESULTS: Even if not significant, our results suggest an increased risk of developing multiple myeloma after exposure to chemicals used in farming, and a reduced risk for those with a history of infections such as tuberculosis, hepatitis, measles, or pneumonia. The reduction was significant for malaria at the country level. CONCLUSION: These results support the idea that certain infections can improve cancer immunosurveillance, although they still need to be confirmed in other series of patients
ICCHP-AAATE 2022 Open Access Compendium "Assistive Technology, Accessibility and (e)Inclusion" Part II / von Petz, Andrea / Measuring Access to Assistive Technology using the Rapid Assistive Technology Assessment (rATA) Survey in Myanmar
No full textAccess to assistive technology (AT) is essential for many people to maintain and improve function, health and wellbeing, and quality of life. Although the need for Assistive Products (AP) is continue rising, only one in 10 people globally have access the AP they need. Furthermore, there is not sufficient data for AT in many countries around the world yet. We aimed to estimate the prevalence of assessing to AT, need and unmet need of AT, barriers, satisfaction and quality of AT services in Myanmar. Method: A nationwide cross-sectional household survey was conducted from June to August 2021 among 8,209 participants using two-staged cluster sampling methods. Results: In our study 29.4% of the study population needed any type of AP, among which seeing was 26.1% mobility 16.2%, cognition 15%, self-care 13.3%, hearing 9.1%, and 6.4% for communication. The private sector currently used AP accounted for 52.8%, while the public sector contributed only 6.6%. The prevalence of unmet need was 21.5%. It was highest among the elderly. Out-of-pocket payment (67.5%) was the main funding source of AP in Myanmar. Unaffordability was the major barrier to access to AP (38.4%). Majority of the people (66.1%) were satisfied with the assistive products they use. Conclusion: Outcomes of the rATA survey provided key information related to AP in the Myanmar population. Our findings pointed out the importance of formulating and implementing strategies to im-prove the accessibility of AP and enhance the fair financial opportunity for everyone who needs AP.Refereed/Peer-reviewedVersion of recor
Emerg Infect Dis
No full textWe developed surveillance guidance for COVID-19 in 9 temporary camps for displaced persons along the Thailand-Myanmar border. Arrangements were made for testing of persons presenting with acute respiratory infection, influenza-like illness, or who met the Thailand national COVID-19 Person Under Investigation case definition. In addition, testing was performed for persons who had traveled outside of the camps in outbreak-affected areas or who departed Thailand as resettling refugees. During the first 18 months of surveillance, May 2020-October 2021, a total of 6,190 specimens were tested, and 15 outbreaks (i.e., >1 confirmed COVID-19 cases) were detected in 7 camps. Of those, 5 outbreaks were limited to a single case. Outbreaks during the Delta variant surge were particularly challenging to control. Adapting and implementing COVID-19 surveillance measures in the camp setting were successful in detecting COVID-19 outbreaks and preventing widespread disease during the initial phase of the pandemic in Thailand
Lipid profiles and determinants of total cholesterol and hypercholesterolaemia among 25–74 year-old urban and rural citizens of the Yangon Region, Myanmar: a cross-sectional study
No full textObjectiveThe first is to estimate the prevalence of dyslipidaemia (hypercholesterolaemia, hypertriglyceridaemia, high low-density lipoprotein (LDL) level and low high-density lipoprotein (HDL) level), as well as the mean levels of total cholesterol, triglyceride, LDL and HDL, in the urban and rural Yangon Region, Myanmar. The second is to investigate the association between urban-rural location and total cholesterol.DesignTwo cross-sectional studies using the WHO STEPS methodology.SettingBoth the urban and rural areas of the Yangon Region, Myanmar.ParticipantsA total of 1370 men and women aged 25–74 years participated based on a multistage cluster sampling. Physically and mentally ill people, monks, nuns, soldiers and institutionalised people were excluded.ResultsCompared with rural counterparts, urban dwellers had a significantly higher age-standardised prevalence of hypercholesterolaemia (50.7% vs 41.6%; p=0.042) and a low HDL level (60.6% vs 44.4%; p=0.001). No urban-rural differences were found in the prevalence of hypertriglyceridaemia and high LDL. Men had a higher age-standardised prevalence of hypertriglyceridaemia than women (25.1% vs 14.8%; p<0.001), while the opposite pattern was found in the prevalence of a high LDL (11.3% vs 16.3%; p=0.018) and low HDL level (35.3% vs 70.1%; p<0.001).Compared with rural inhabitants, urban dwellers had higher age-standardised mean levels of total cholesterol (5.31 mmol/L, SE: 0.044 vs 5.05 mmol/L, 0.068; p=0.009), triglyceride (1.65 mmol/L, 0.049 vs 1.38 mmol/L, 0.078; p=0.017), LDL (3.44 mmol/L, 0.019 vs 3.16 mmol/L, 0.058; p=0.001) and lower age-standardised mean levels of HDL (1.11 mmol/L, 0.010 vs 1.25 mmol/L, 0.012; p<0.001). In linear regression, the total cholesterol was significantly associated with an urban location among men, but not among women.ConclusionThe mean level of total cholesterol and the prevalence of hypercholesterolaemia were alarmingly high in men and women in both the urban and rural areas of Yangon Region, Myanmar. Preventive measures to reduce cholesterol levels in the population are therefore needed.</jats:sec
Enhancing Respiratory Disease Surveillance to Detect COVID-19 in Shelters for Displaced Persons, Thailand–Myanmar Border, 2020–2021
No full textWe developed surveillance guidance for COVID-19 in 9 temporary camps for displaced persons along the Thailand–Myanmar border. Arrangements were made for testing of persons presenting with acute respiratory infection, influenza-like illness, or who met the Thailand national COVID-19 Person Under Investigation case definition. In addition, testing was performed for persons who had traveled outside of the camps in outbreak-affected areas or who departed Thailand as resettling refugees. During the first 18 months of surveillance, May 2020–October 2021, a total of 6,190 specimens were tested, and 15 outbreaks (i.e., >1 confirmed COVID-19 cases) were detected in 7 camps. Of those, 5 outbreaks were limited to a single case. Outbreaks during the Delta variant surge were particularly challenging to control. Adapting and implementing COVID-19 surveillance measures in the camp setting were successful in detecting COVID-19 outbreaks and preventing widespread disease during the initial phase of the pandemic in Thailand
