The Experts below are selected from a list of 7818 Experts worldwide ranked by ideXlab platform
Stephen R Walsh - One of the best experts on this subject based on the ideXlab platform.
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safety and immunogenicity of modified vaccinia ankara in hematopoietic stem cell transplant recipients a randomized controlled trial
The Journal of Infectious Diseases, 2013Co-Authors: Stephen R Walsh, David J Dominguez, Shringkhala Bajimaya, Lisa S Gagne, Elise Zablowsky, Marissa B Wilck, Kelly VerrillAbstract:Less than 200 years after the introduction of the smallpox vaccine, variola virus (VARV) was successfully eradicated by use of vaccines produced with vaccinia virus (VACV) [1]. However, along with the dramatic success of the vaccination program, frequent and sometimes severe adverse reactions to VACV vaccine were encountered, particularly in subjects with immunologic defects or dermatopathologic conditions. Since eradication, VACV vaccine has been reserved for highly selected individuals at risk for orthopoxvirus infections, but there are ongoing concerns over the potential use of VARV as a biological weapon. The development of safer, yet effective vaccines for future use against smallpox therefore remains of considerable interest. Modified vaccinia Ankara (MVA), an attenuated strain of VACV [2, 3], is much less reactogenic than widely used vaccinia strains, such as Dryvax or Elstree [4–8]. MVA was administered to approximately 120 000 persons [9] but was never used in a VARV-endemic area, and its effectiveness at preventing clinical smallpox is unknown. MVA is severely host restricted, and it is either unable to replicate in mammalian cell lines or replicates at a very low level [3, 10, 11]. Approximately 15% of the MVA genome was deleted during in vitro passage, compared with the parental strain [10, 12], but the block in replication in nonpermissive mammalian cells occurs late in the viral life cycle. Thus, because MVA-infected cells express very high levels of virally encoded proteins [13–15], including those encoded by foreign transgenes, there is considerable interest in using MVA as a vector in vaccines to prevent human immunodeficiency virus (HIV) infection, malaria, and infectious diseases due to other pathogens [16–18]. There is also substantial interest in the use of MVA as a vector to deliver tumor-specific antigens to induce immune responses that may help control malignancies, and several of these therapeutic vaccines have advanced to clinical trials [18–20]. Because preliminary studies suggested MVA was safe in Immunocompromised hosts [21–24], we hypothesized that MVA would be safe, well-tolerated, and immunogenic in an important, well-characterized Immunocompromised Population—recipients of a hematopoietic stem cell transplant (HSCT). Vaccination with either traditional calf lymph–derived VACV (such as Dryvax or Elstree) or modern tissue culture-grown strains (the recently approved ACAM2000) are contraindicated for HSCT recipients [25]. Thus, establishing safety and immunogenicity of MVA in this group has implications for pre-event smallpox vaccine contingency planning, as well as for potential therapeutic vaccines against malignancies. We therefore conducted a randomized, placebo-controlled, double-blind study of MVA-BN (IMVAMUNE; Bavarian Nordic A/S, Kvistgaard, Denmark) in 24 individuals who received a HSCT >2 years previously.
Thomas B. Nutman - One of the best experts on this subject based on the ideXlab platform.
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Strongyloides stercoralis in the Immunocompromised Population
Clinical microbiology reviews, 2004Co-Authors: Paul B. Keiser, Thomas B. NutmanAbstract:Strongyloides stercoralis is an intestinal nematode of humans that infects tens of millions of people worldwide. S. stercoralis is unique among intestinal nematodes in its ability to complete its life cycle within the host through an asexual autoinfective cycle, allowing the infection to persist in the host indefinitely. Under some conditions associated with immunocompromise, this autoinfective cycle can become amplified into a potentially fatal hyperinfection syndrome, characterized by increased numbers of infective filariform larvae in stool and sputum and clinical manifestations of the increased parasite burden and migration, such as gastrointestinal bleeding and respiratory distress. S. stercoralis hyperinfection is often accompanied by sepsis or meningitis with enteric organisms. Glucocorticoid treatment and human T-lymphotropic virus type 1 infection are the two conditions most specifically associated with triggering hyperinfection, but cases have been reported in association with hematologic malignancy, malnutrition, and AIDS. Anthelmintic agents such as ivermectin have been used successfully in treating the hyperinfection syndrome as well as for primary and secondary prevention of hyperinfection in patients whose exposure history and underlying condition put them at increased risk.
Annemiek A Van Der Eijk - One of the best experts on this subject based on the ideXlab platform.
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whole genome next generation sequencing to study within host evolution of norovirus nov among Immunocompromised patients with chronic nov infection
The Journal of Infectious Diseases, 2017Co-Authors: Janko Van Beek, Annemiek A Van Der Eijk, Miranda De Graaf, Saskia L Smits, Claudia M E Schapendonk, Georges M G M Verjans, Harry Vennema, My V T Phan, Matthew Cotten, Marion KoopmansAbstract:Background. The genus Norovirus comprises large genetic diversity, and new GII.4 variants emerge every 2-3 years. It is unknown in which host these new variants originate. Here we study whether prolonged shedders within the Immunocompromised Population could be a reservoir for newly emerging strains. Methods. Sixty-five fecal samples from 16 Immunocompromised patients were retrospectively selected. Isolated viral RNA was enriched by hybridization with a custom norovirus whole-genome RNA bait set and deep sequenced on the Illumina MiSeq platform. Results. Patients shed virus for average 352 days (range, 76-716 days). Phylogenetic analysis showed distinct GII.4 variants in 3 of 13 patients (23%). The viral mutation rates were variable between patients but did not differ between various immune status groups. All within-host GII.4 viral Populations showed amino acid changes at blocking epitopes over time, and the majority of VP1 amino acid mutations were located at the capsid surface. Conclusions. This study found viruses in Immunocompromised hosts that are genetically distinct from viruses circulating in the general Population, and these patients therefore may contain a reservoir for newly emerging strains. Future studies need to determine whether these new strains are of risk to other Immunocompromised patients and the general Population.
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hepatitis e virus infection among solid organ transplant recipients the netherlands
Emerging Infectious Diseases, 2012Co-Authors: Claudia Mulders, Albertus D M E Osterhaus, Aggie H M M Balk, Willem Weimar, Marion Koopmans, Annemiek A Van Der EijkAbstract:We screened 1,200 living heart, lung, liver, and kidney transplant recipients for hepatitis E virus infection by reverse transcription PCR. In 12 (1%) patients, hepatitis E virus infection was identified; in 11 patients, chronic infection developed. This Immunocompromised Population is at risk for hepatitis E virus infection.
Vijay Johnson - One of the best experts on this subject based on the ideXlab platform.
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Granulomatous amebic encephalitis following hematopoietic stem cell transplantation.
Surgical Neurology International, 2015Co-Authors: Ninh Doan, Gregory Rozansky, Ha Son Nguyen, Michael Gelsomino, Saman Shabani, Wade M. Mueller, Vijay JohnsonAbstract:Background: Granulomatous amebic encephalitis (GAE) is rare, but often fatal. The infection has been documented predominantly among the Immunocompromised Population or among those with chronic disease. To date, however, there have only been eight cases regarding the infection following hematopoietic stem cell transplantation (HSCT).
Paul B. Keiser - One of the best experts on this subject based on the ideXlab platform.
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Strongyloides stercoralis in the Immunocompromised Population
Clinical microbiology reviews, 2004Co-Authors: Paul B. Keiser, Thomas B. NutmanAbstract:Strongyloides stercoralis is an intestinal nematode of humans that infects tens of millions of people worldwide. S. stercoralis is unique among intestinal nematodes in its ability to complete its life cycle within the host through an asexual autoinfective cycle, allowing the infection to persist in the host indefinitely. Under some conditions associated with immunocompromise, this autoinfective cycle can become amplified into a potentially fatal hyperinfection syndrome, characterized by increased numbers of infective filariform larvae in stool and sputum and clinical manifestations of the increased parasite burden and migration, such as gastrointestinal bleeding and respiratory distress. S. stercoralis hyperinfection is often accompanied by sepsis or meningitis with enteric organisms. Glucocorticoid treatment and human T-lymphotropic virus type 1 infection are the two conditions most specifically associated with triggering hyperinfection, but cases have been reported in association with hematologic malignancy, malnutrition, and AIDS. Anthelmintic agents such as ivermectin have been used successfully in treating the hyperinfection syndrome as well as for primary and secondary prevention of hyperinfection in patients whose exposure history and underlying condition put them at increased risk.
