Browsing by Author "Ferres, Marcela"
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Item Comparison of VSV Pseudovirus and Focus Reduction Neutralization Assays for Measurement of Anti-Andes orthohantavirus Neutralizing Antibodies in Patient Samples(2020-09) Vial, Cecilia; Whitaker, Annalis; Wilhelm, Jan; Ovalle, Jimena; Perez, Ruth; Valdivieso, Francisca; Ferres, Marcela; Martínez-Valdebenito, Constanza; Eisenhauer, Philip; Mertz, Gregory J.; Hooper, Jay W.; Botten, Jason W.; Vial, PabloAndes orthohantavirus (ANDV) is the etiologic agent of hantavirus cardiopulmonary syndrome (HCPS), which has a case fatality rate around 35%, with no effective treatment or vaccine available. ANDV neutralizing antibody (NAb) measurements are important for the evaluation of the immune response following infection, vaccination, or passive administration of investigational monoclonal or polyclonal antibodies. The standard assay for NAb measurement is a focus reduction neutralization test (FRNT) featuring live ANDV and must be completed under biosafety level (BSL)-3 conditions. In this study, we compared neutralization assays featuring infectious ANDV or vesicular stomatitis virus (VSV) pseudovirions decorated with ANDV glycoproteins for their ability to measure anti-ANDV NAbs from patient samples. Our studies demonstrate that VSV pseudovirions effectively measure NAb from clinical samples and have greater sensitivity compared to FRNT with live ANDV. Importantly, the pseudovirus assay requires less labor and sample materials and can be conducted at BSL-2.Item Deletions in Genes Participating in Innate Immune Response Modify the Clinical Course of Andes Orthohantavirus Infection(2019) Ribeiro, Grazielle; León, Luis; Pérez, Ruth; Cuiza, Analía; Vial, Pablo; Ferres, Marcela; Mertz, Gregory; Vial, CeciliaAndes orthohantavirus (ANDV) is an important human pathogen causing hantavirus cardiopulmonary syndrome (HCPS) with a fatality rate of 30% in Chile. Around 60% of all cases have a severe clinical course, while the others have a mild clinical course. The main goal of this study was to understand if the genetic variation of patients is associated with the clinical course they develop after ANDV infection. For this, the frequency of copy number variants (CNVs, i.e., deletions and duplications) was studied in 195 patients, 88 with mild and 107 with severe HCPS. CNVs were called from intensity data of the Affymetrix Genome-Wide SNP Array 6.0. The analysis of the data was performed with PennCNV, ParseCNV and R softwares; Results: a deletion of 19, 416 bp in the q31.3 region of chromosome 1 is found more frequently in severe patients (p < 0.05). This region contains Complement Factor H Related (CFHR1) and CFHR3 genes, regulators of the complement cascade. A second deletion of 1.81 kb located in the p13 region of chr20 was significantly more frequent in mild patients (p < 0.05). This region contains the SIRPB1 gene, which participates in the innate immune response, more specifically in neutrophil trans-epithelial migration. Both deletions are associated with the clinical course of HCPS, the first being a risk factor and the second being protective. The participation of genes contained in both deletions in ANDV infection pathophysiology deserves further investigation.Item Etiología viral en la neumonía del adulto adquirida en la comunidad en un hospital del sur de Chile(Sociedad Medica de Santiago, 2012) Rioseco, María Luisa; Riquelme, Raul; Riquelme, Mauricio; Inzunza, Carlos; Oyarzun, Paola; Aguero, Yasna; Ferres, Marcela; Vial, Pablo; Fasce, Rodrigo; Torres, Antoniackground: There is paucity of information about viral etiology of community acquired pneumonia in adults. Aim: To investigate the viral etiology of pneumonia among hospitalized patients. Material and Methods: All adults with pneumonia that were hospitalized were prospectively enrolled at Puerto Montt hospital. A microbiological and viral assessment was carried out. Viral assessment included direct immunofluorescence of nasopharyngeal aspirates for influenza A and B virus and serum samples obtained during the acute phase of the disease and during convalescence for Hanta virus. Results: Between April 1 2005 and March 31 2006,159 adults aged 62 ± 20 years (58 % males), were admitted to the hospital for pneumonia. Mean hospital stay was 11.9 ± 8.6 days. Four patients had Hantavirus acute infection. Other viruses were identified in twelve patients (7.7%). Nine had influenza A, one syncytial respiratory virus, one syncytial and influenza A virus and one varicella zoster virus. Excluding patients with Hantavirus, no significant differences in age, clinical presentation, chest X ray findings, laboratory results and mortality were observed between patients with bacterial or viral etiology of the pneumonia. Conclusions: Viral etiology was confirmed in 10% of adult patients hospitalized with community acquired pneumonia.Item High-dose intravenous methylprednisolone for hantavirus cardiopulmonary syndrome in Chile: a double-blind, randomized controlled clinical trial(Oxford University Press, 2013) Vial, Pablo; Valdivieso, Francisca; Ferres, Marcela; Riquelme, Raul; Rioseco, Maria; Calvo, Mario; Castillo, Constanza; Diaz, Ricardo; Scholz, Luis; Cuiza, Analía; Belmar, Edith; Hernandez, Carla; Martinez, Jessica; Lee, Sang-Joon; Mertz, GregoryBACKGROUND: Andes virus (ANDV)-related hantavirus cardiopulmonary syndrome (HCPS) has a 35% case fatality rate in Chile and no specific treatment. In an immunomodulatory approach, we evaluated the efficacy of intravenous methylprednisolone for HCPS treatment, through a parallel-group, placebo-controlled clinical trial. METHODS: Patients aged >2 years, with confirmed or suspected HCPS in cardiopulmonary stage, admitted to any of 13 study sites in Chile, were randomized by study center in blocks of 4 with a 1:1 allocation and assigned through sequentially numbered envelopes to receive placebo or methylprednisolone 16 mg/kg/day (≤1000 mg) for 3 days. All personnel remained blinded except the local pharmacist. Infection was confirmed by immunoglobulin M antibodies or ANDV RNA in blood. The composite primary endpoint was death, partial pressure of arterial oxygen/fraction of inspired oxygen ratio ≤55, cardiac index ≤2.2, or ventricular tachycardia or fibrillation within 28 days. Safety endpoints included the number of serious adverse events (SAEs) and quantification of viral RNA in blood. Analysis was by intention to treat. RESULTS: Infection was confirmed in 60 of 66 (91%) enrollees. Fifteen of 30 placebo-treated patients and 11 of 30 methylprednisolone-treated patients progressed to the primary endpoint (P = .43). We observed no significant difference in mortality between treatment groups (P = .41). There was a trend toward more severe disease in placebo recipients at entry. More subjects in the placebo group experienced SAEs (P = .02). There were no SAEs clearly related to methylprednisolone administration, and methylprednisolone did not increase viral load. CONCLUSIONS: Although methylprednisolone appears to be safe, it did not provide significant clinical benefit to patients. Our results do not support the use of methylprednisolone for HCPS. CLINICAL TRIALS REGISTRATION: NCT00128180.Item Highly Differentiated, Resting Gn-Specific Memory CD8+ T Cells Persist Years after Infection by Andes Hantavirus(2010) Manigold, Tobias; Mori, Andres; Graumann, Rebecca; Llop, Elena; Simon, Valeska; Ferres, Marcela; Valdivieso, Francisca; Castillo, Constanza; Hjelle, Brian; Vial, PabloIn man, infection with South American Andes virus (ANDV) causes hantavirus cardiopulmonary syndrome (HCPS). HCPS due to ANDV is endemic in Southern Chile and much of Argentina and increasing numbers of cases are reported all over South America. A case-fatality rate of about 36% together with the absence of successful antiviral therapies urge the development of a vaccine. Although T-cell responses were shown to be critically involved in immunity to hantaviruses in mouse models, no data are available on the magnitude, specificity and longevity of ANDV-specific memory T-cell responses in patients. Using sets of overlapping peptides in IFN-c ELISPOT assays, we herein show in 78 Chilean convalescent patients that Gnderived epitopes were immunodominant as compared to those from the N- and Gc-proteins. Furthermore, while the relative contribution of the N-specific response significantly declined over time, Gn-specific responses remained readily detectable ex vivo up to 13 years after the acute infection. Tetramer analysis further showed that up to 16.8% of all circulating CD3+ CD8+ T cells were specific for the single HLA-B*3501-restricted epitope Gn465–473 years after the acute infection. Remarkably, Gn465–473–specific cells readily secreted IFN-c, granzyme B and TNF-a but not IL-2 upon stimulation and showed a ‘revertant’ CD45RA+ CD272CD282CCR72CD1272 effector memory phenotype, thereby resembling a phenotype seen in other latent virus infections. Most intriguingly, titers of neutralizing antibodies increased over time in 10/17 individuals months to years after the acute infection and independently of whether they were residents of endemic areas or not. Thus, our data suggest intrinsic, latent antigenic stimulation of Gn-specific T-cells. However, it remains a major task for future studies to proof this hypothesis by determination of viral antigen in convalescent patients. Furthermore, it remains to be seen whether Gn-specific T cells are critical for viral control and protective immunity. If so, Gn-derived immunodominant epitopes could be of high value for future ANDV vaccinesItem Molecular method for the detection of Andes hantavirus infection: validation for clinical diagnostics(Elsevier, 2016) Vial, Cecilia; Martinez-Valdebenito, Constanza; Rios, Susana; Martinez, Jessica; Vial, Pablo; Ferres, Marcela; Rivera, Juan; Perez, Ruth; Valdivieso, FranciscaHantavirus cardiopulmonary syndrome is a severe disease caused by exposure to New World hantaviruses. Early diagnosis is difficult due to the lack of specific initial symptoms. Antihantavirus antibodies are usually negative until late in the febrile prodrome or the beginning of cardiopulmonary phase, while Andes hantavirus (ANDV) RNA genome can be detected before symptoms onset. We analyzed the effectiveness of quantitative reverse transcription polymerase chain reaction (RT-qPCR) as a diagnostic tool detecting ANDV-Sout genome in peripheral blood cells from 78 confirmed hantavirus patients and 166 negative controls. Our results indicate that RT-qPCR had a low detection limit (~10 copies), with a specificity of 100% and a sensitivity of 94.9%. This suggests the potential for establishing RT-qPCR as the assay of choice for early diagnosis, promoting early effective care of patients, and improving other important aspects of ANDV infection management, such as compliance of biosafety recommendations for health personnel in order to avoid nosocomial transmission.Item Neutralizing antibodies in survivors of Sin Nombre and Andes hantavirus infection(Centers for Disease Control and Prevention, 2006) Valdivieso, Francisca; Vial, Pablo; Ferres, Marcela; Ye, Chunyan; Goade, Diane; Cuiza, Analía; Hjelle, BrianWe evaluated titers of homotypic and heterotypic neutralizing antibodies (NAbs) to Andes and Sin Nombre hantaviruses in plasma samples from 20 patients from Chile and the United States. All but 1 patient had high titers of NAb. None of the plasma samples showed high titers against the heterologous virus.