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Krooniset bakteeri-infektiot (Luettu 199858 kertaa)
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Re: Krooniset bakteeri-infektiot
Vastaus #330 - 19.12.2017 - 22:15:11
 
Lyme bacteria survive 28-day course of antibiotics months after infection

https://www.sciencedaily.com/releases/2017/12/171213143613.htm

December 13, 2017

Bay Area Lyme Foundation, a leading sponsor of Lyme disease research in the US, today announced results of two papers published in the peer-reviewed journals PLOS ONE and American Journal of Pathology, that seem to support claims of lingering symptoms reported by many patients who have already received antibiotic treatment for the disease.

Based on a single, extensive study of Lyme disease designed by Tulane University researchers, the study employed multiple methods to evaluate the presence of Borrelia burgdorferi spirochetes, the bacteria that cause Lyme disease, before and after antibiotic treatment in primates. The study also measured the antibody immune response to the bacteria both pre- and post- treatment, as this is how current diagnostics typically evaluate Lyme disease in humans.

The data show that living B. burgdorferi spirochetes were found in ticks that fed upon the primates and in multiple organs after treatment with 28 days of oral doxycycline. The results also indicated that the immune response to the bacteria varied widely in both treated and untreated subjects.

"It is apparent from these data that B. burgdorferi bacteria, which have had time to adapt to their host, have the ability to escape immune recognition,tolerate the antibiotic doxycycline and invade vital organs such as the brain and heart," said lead author Monica Embers, PhD, assistant professor of microbiology and immunology at Tulane University School of Medicine.

"In this study, we were able to observe the existence of microscopic disease and low numbers of bacteria, which would be difficult to 'see' in humans but could possibly be the cause of the variable and nonspecific symptoms that are characteristic of post-treatment Lyme disease syndrome. Although current antibiotic regimens may cure most patients who are treated early, if the infection is allowed to progress, the 28-day treatment may be insufficient, based on these findings," Embers said.

The findings also demonstrated:

*  All subjects treated with antibiotics were found to have some level of infection 7 -- 12 months post treatment.
*  Despite testing negative by antibody tests for Lyme disease, two of 10 subjects were still infected with Lyme bacteria in heart and bladder.
*  Lyme bacteria which persist are still viable.

To better elucidate previous animal studies demonstrating that some B. burgdorferi bacteria survive antibiotics, the study explored Lyme disease infection in rhesus macaque primates treated with antibiotics and a control group who were also infected but not treated. This species has been shown to demonstrate a progression of Lyme disease most similar to humans, particularly related to erythema migrans, carditis, arthritis, and neuropathy of the peripheral and central nervous systems.

"Clearly, some medical practices governing diagnosis and treatment of Lyme disease should be reconsidered in light of this study. This study shows that we must reevaluate the current paradigm of antibody response tests for diagnosis and move away from the one size fits all approach to Lyme treatment," said Wendy Adams, Research Grant Director, Bay Area Lyme Foundation. "Every day, patients with Lyme disease are told their symptoms cannot be caused by Lyme, because they test negative on antibody tests or because they have received a single course of antibiotics. More research and funding are imperative."

In the study, ticks carrying B. burgdorferi spirochetes fed on ten primates. Four months post infection, half of the primates (five) received the antibiotic doxycycline orally for 28 days at a proportional dose to that used in human treatment. Five subjects were treated with placebo and all ten were evaluated by more than five different diagnostic methods to characterize any remaining infection. The researchers used several important techniques, including xenodiagnoses, to determine if the spirochete bacteria persisted.

The results show:

*  Few subjects displayed a rash. Although all subjects were infected, only one of the 10 displayed a rash with central clearing, the classical "bulls-eye" rash. The subject that developed this rash, interestingly, never mounted an immune response to five borrelia antigens throughout the study period, prior to and following treatment.
*  Organs may be infected even if antibody tests are negative. One subject which tested negative for B. burgdorferi by skin biopsy cultures, PCR and in vivo cultures, was found to have B. burgdorferi infecting the heart. Another untreated subject, who was ultimately shown to have residual Lyme bacteria in the bladder, showed a decrease in immune response over the course of infection, with a negative xenodiagnosis test in the late stage, which would signal that the animal self-cured.
*  Intact spirochetes were found in three of five treated and four of five untreated subjects based on xenodiagnosis results 12 months after the tick bite.
*  Immune responses to B. burgdorferi varied greatly post-treatment, with one subject's antibody levels dropping to pre-bite levels for three antigens while another subject experienced elevated antibodies for the same antigens throughout the study period. This is significant because it demonstrates that subjects infected with the same strain of B. burgdorferi may have different immune responses to the same antigen. And, because humans, like primates, are genetically diverse, it underscores that testing antibody responses may be inherently unreliable as a singular diagnostic modality for Lyme disease.
* Widespread and variable microscopic disease was observed in all infected subjects, despite antibiotic treatment. Compared to uninfected subjects of the same age, infected subjects in this study (treated and untreated) demonstrated Inflammation in and around the heart, in skeletal muscles, joints, and the protective sheath that covers the brain, and near peripheral nerves.
*   Rare, but intact B. burgdorferi spirochetes were found in the tissues of both the treated and untreated subjects. In two subjects treated with doxycycline, multiple Lyme bacteria were observed in the brain tissue. Others organs in which the spirochetes were observed included the heart, joints, bladder, skeletal muscle and adjacent to peripheral nerves.

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Ehkä vähitellen järki voittaa. Nykyisin jos potilaalla oireet jatkuvat, se on potilaan syy, sen päässä on vikaa, koska borrelioosi paranee kahden viikon doxy kuurilla..
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Re: Krooniset bakteeri-infektiot
Vastaus #331 - 03.02.2018 - 23:55:48
 
Transcriptional profile and Epstein-Barr virus infection status of laser-cut immune infiltrates from the brain of patients with progressive multiple sclerosis.

https://www.ncbi.nlm.nih.gov/pubmed/29338732

J Neuroinflammation. 2018 Jan 16

Abstract

BACKGROUND:
It is debated whether multiple sclerosis (MS) might result from an immunopathological response toward an active Epstein-Barr virus (EBV) infection brought into the central nervous system (CNS) by immigrating B cells. Based on this model, a relationship should exist between the local immune milieu and EBV infection status in the MS brain. To test this hypothesis, we analyzed expression of viral and cellular genes in brain-infiltrating immune cells.

METHODS:
Twenty-three postmortem snap-frozen brain tissue blocks from 11 patients with progressive MS were selected based on good RNA quality and prominent immune cell infiltration. White matter perivascular and intrameningeal immune infiltrates, including B cell follicle-like structures, were isolated from brain sections using laser capture microdissection. Enhanced PCR-based methods were used to investigate expression of 75 immune-related genes and 6 EBV genes associated with latent and lytic infection. Data were analyzed using univariate and multivariate statistical methods.

RESULTS:
Genes related to T cell activation, cytotoxic cell-mediated (or type 1) immunity, B cell growth and differentiation, pathogen recognition, myeloid cell function, type I interferon pathway activation, and leukocyte recruitment were found expressed at different levels in most or all MS brain immune infiltrates. EBV genes were detected in brain samples from 9 of 11 MS patients with expression patterns suggestive of in situ activation of latent infection and, less frequently, entry into the lytic cycle. Comparison of data obtained in meningeal and white matter infiltrates revealed higher expression of genes related to interferonγ production, B cell differentiation, cell proliferation, lipid antigen presentation, and T cell and myeloid cell recruitment, as well as more widespread EBV infection in the meningeal samples. Multivariate analysis grouped genes expressed in meningeal and white matter immune infiltrates into artificial factors that were characterized primarily by genes involved in type 1 immunity effector mechanisms and type I interferon pathway activation.

CONCLUSION:
These results confirm profound in situ EBV deregulation and suggest orchestration of local antiviral function in the MS brain, lending support to a model of MS pathogenesis that involves EBV as possible antigenic stimulus of the persistent immune response in the central nervous system.
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Re: Krooniset bakteeri-infektiot
Vastaus #332 - 10.02.2018 - 22:47:13
 
Epstein-Barr virus is present in the brain of most cases of multiple sclerosis and may engage more than just B cells

https://www.ncbi.nlm.nih.gov/pubmed/29394264#

PLoS One. 2018 Feb 2

Abstract

Multiple sclerosis (MS) is a chronic neuroinflammatory condition of the central nervous system (CNS). It is a major cause of neurological disability in young adults, particularly women. What triggers the destruction of myelin sheaths covering nerve fibres is unknown. Both genetic and infectious agents have been implicated. Of the infectious agents, Epstein-Barr virus (EBV), a common herpesvirus, has the strongest epidemiological and serological evidence. However, the presence of EBV in the CNS and demonstration of the underlying mechanism(s) linking EBV to the pathogenesis of MS remain to be elucidated. We aimed at understanding the contribution of EBV infection in the pathology of MS. We examined 1055 specimens (440 DNA samples and 615 brain tissues) from 101 MS and 21 non-MS cases for the presence of EBV using PCR and EBER-in situ hybridization (EBER-ISH). EBV was detected by PCR and/or EBER-ISH in 91/101 (90%) of MS cases compared to only 5/21 (24%) of non-MS cases with other neuropathologies. None of the samples were PCR positive for other common herpesviruses (HSV-1, CMV, HHV-6). By quantitative PCR, EBV viral load in MS brain was mainly low to moderate in most cases. However, in 18/101 (18%) of MS cases, widespread but scattered presence of EBV infected cells was noted in the affected tissues by EBER-ISH. Immunohistochemical analysis of EBV gene expression in the 18 heavily infected cases, revealed that the EBV latent protein EBNA1, and to a lesser extent the early lytic protein BZLF1 were expressed. Furthermore, using double-staining we show for the first time that astrocytes and microglia, in addition to B-cells can also be infected. To the best of our knowledge, this is the most comprehensive study demonstrating that EBV is present and transcriptionally active in the brain of most cases of MS and supports a role for the virus in MS pathogenesis. Further studies are required to address the mechanism of EBV involvement in MS pathology.
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Re: Krooniset bakteeri-infektiot
Vastaus #333 - 12.02.2018 - 21:32:24
 
How viruses disarm the immune system

https://www.sciencedaily.com/releases/2018/02/180205134245.htm

February 5, 2018
How do viruses that cause chronic infections, such as HIV or hepatitis c virus, manage to outsmart their hosts' immune systems?

The answer to that question has long eluded scientists, but new research from McGill University has uncovered a molecular mechanism that may be a key piece of the puzzle. The discovery could provide new targets for treating a wide range of diseases.

Fighting off infections depends largely on our bodies' capacity to quickly recognize infected cells and destroy them, a job carried out by a class of immune cells known as CD8+ T cells. These soldiers get some of their orders from chemical mediators known as cytokines that make them more or less responsive to outside threats. In most cases, CD8+ T cells quickly recognize and destroy infected cells to prevent the infection from spreading.

"When it comes to viruses that lead to chronic infection, immune cells receive the wrong set of marching orders, which makes them less responsive," says Martin Richer, an assistant professor at McGill's Department of Microbiology & Immunology and senior author of the study, published recently in the journal Immunity.

The research, conducted in Richer's lab by graduate student Logan Smith, revealed that certain viruses persist by driving the production of a cytokine that leads to modification of glycoproteins on the surface of the CD8+ T cells, making the cells less functional. That maneuver buys time for the pathogen to outpace the immune response and establish a chronic infection. Importantly, this pathway can be targeted to restore some functionality to the T cells and enhance the capacity to control infection.

The discovery of this regulatory pathway could help identify new therapeutic targets for a variety of diseases. "We might be able to take advantage of the pathways induced by these signals to fight chronic viral infections by making the immune system more responsive," Richer says. "The findings might also prove useful for diseases like cancer and autoimmunity, where T cells function is poorly regulated."
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