Publications by authors named "Ana Victoria Ibarra-Meneses"

6 Publications

  • Page 1 of 1

Loop-Mediated Isothermal Amplification Allows Rapid, Simple and Accurate Molecular Diagnosis of Human Cutaneous and Visceral Leishmaniasis Caused by When Compared to PCR.

Microorganisms 2021 Mar 16;9(3). Epub 2021 Mar 16.

WHO Collaborating Centre for Leishmaniasis, National Center for Microbiology, Instituto de Salud Carlos III, 28220 Majadahonda, Spain.

Loop-mediated isothermal amplification allows the rapid, sensitive and specific amplification of DNA without complex and expensive equipment. We compared the diagnostic performance of Loopamp™ Detection Kit (Eiken Chemical Co., Ltd., Tokyo, Japan) with conventional and real-time polymerase chain reaction (PCR) for human cutaneous and visceral leishmaniasis caused by . A total of 230 DNA samples from cutaneous (CL) and visceral (VL) leishmaniasis cases and controls from Spain, characterized by nested PCR (LnPCR) were tested by: (i) the Loopamp™ Detection Kit (Loopamp), run on Genie III real-time fluorimeter (OptiGene, UK); and (ii) real-time quantitative PCR (qPCR). The Loopamp test returned 98.8% (95% confidence interval-CI: 96.0-100.00) sensitivity and specificity of 97.7% (95% CI: 92.2-100) on VL samples, and 100% (95% CI: 99.1-100) sensitivity and 100.0% (95% CI: 98.8-100.0) specificity on CL samples. The Loopamp time-to-positivity () obtained by real-time fluorimetry showed excellent concordance (C = 97.91%) and strong correlation (r = 0.799) with qPCR's cycle threshold (). The performance of Loopamp is comparable to that of LnPCR and qPCR in the diagnosis of cutaneous and visceral leishmaniasis due to . The excellent correlation between the and should be further investigated to determine the accuracy of Loopamp to quantify parasite load in tissues.
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http://dx.doi.org/10.3390/microorganisms9030610DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7999953PMC
March 2021

Whole Blood Stimulation Assay as a Treatment Outcome Monitoring Tool for VL Patients in Ethiopia: A Pilot Evaluation.

J Immunol Res 2020 23;2020:8385672. Epub 2020 Jan 23.

Unit of Neglected Tropical Diseases, Department of Clinical Sciences, Institute of Tropical Medicine, Antwerp, Belgium.

Visceral leishmaniasis (VL) is a lethal disease if left untreated. Current treatments produce variable rates of treatment failure and toxicity without sterile cure, rendering treatment efficacy monitoring essential. To avoid repeated invasive tissue aspirates as well as empirical treatment, there is a need for new tools that allow a less-invasive and early assessment of treatment efficacy in the field. Cross-sectional studies have suggested levels of cytokines/chemokines after whole blood stimulation as good markers of cure, but longitudinal studies are lacking. In this study, we followed 13 active VL cases in an endemic area in Ethiopia by measuring the production of IFN-, TNF-, IP-10, IL-2, IL-10, MCP-1, and MIG before, during, and at the end of treatment. After 24 hours of stimulation of whole blood with soluble antigen, we observed an early, robust, and incremental increase of IFN-, TNF-, and IP-10 levels in all patients during treatment. Moreover, based on the IFN- levels that showed an average 13-fold increase from the time of diagnosis until the end of treatment, we could almost perfectly discriminate active from cured status. Similar concentrations and patterns were found in stimulation assays with the two main species. The levels of IFN-, IP-10, or TNF- also seemed to be inversely associated with the parasite load at baseline. Despite a 1/10 drop in concentrations, similar patterns were observed in IFN- and IP-10 levels when dried plasma spots were stored at 4°C for an average of 225 days. All the above evidence suggests a detectable restoration of cell-mediated immunity in VL and its association with parasite clearance. With a potential application in rural settings by means of dried plasma spots, we recommend to further explore the early diagnostic value of such assays for treatment efficacy monitoring in large cohort studies including treatment failure cases.
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http://dx.doi.org/10.1155/2020/8385672DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7193677PMC
February 2021

Prevalence of asymptomatic infection and associated risk factors, after an outbreak in the south-western Madrid region, Spain, 2015.

Euro Surveill 2019 May;24(22)

WHO Collaborating Centre for Leishmaniasis, National Center for Microbiology, Instituto de Salud Carlos III, Majadahonda, Madrid, Spain.

BackgroundA large outbreak of leishmaniasis with 758 cutaneous and visceral leishmaniasis cases occurred in 2009 in Fuenlabrada, in the south-west of the Madrid region of Spain.AimWe aimed to determine the prevalence of asymptomatic infection after this outbreak, and its associated risk factors.MethodsA cross-sectional study of 804 healthy individuals living in Fuenlabrada who had no history of leishmaniasis, was conducted between January and July 2015. Asymptomatic infections were sought by either a combination of PCR, immunofluorescent antibody titre, and direct agglutination tests, or by whole blood stimulation assay (WBA) with interleukin-2 (IL-2) quantification.ResultsUsing the first approach, prevalence of asymptomatic individuals was 1.1% (9/804), while the second returned a value of 20.7% (143/804). Older age, being male, proximity to the park where the focus of infection was identified, and living in a detached house, were all strongly associated with the prevalence of asymptomatic infection.ConclusionsThe true number of infected individuals may be underestimated if only serological methods are used. The combination of WBA with IL-2 quantification may allow to better determine the prevalence of asymptomatic infection, which would be useful in establishing control measures and in quantifying their impact. In our study, the use of WBA with IL-2 quantification also helped establish the risk factors that influence exposure to and infection by .
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http://dx.doi.org/10.2807/1560-7917.ES.2019.24.22.1800379DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6549460PMC
May 2019

Asymptomatic immune responders to Leishmania among HIV positive patients.

PLoS Negl Trop Dis 2019 06 3;13(6):e0007461. Epub 2019 Jun 3.

WHO Collaborating Centre for Leishmaniasis, National Centre for Microbiology, Instituto de Salud Carlos III, Majadahonda (Madrid), Spain.

Concomitant infection with human immunodeficiency virus (HIV) and the Leishmania parasite is a growing public health problem, the result of the former spreading to areas where the latter is endemic. Leishmania infection is usually asymptomatic in immunocompetent individuals, but the proportion of HIV+ individuals in contact with the parasite who remain asymptomatic is not known. The aim of the present work was to examine the use of cytokine release assays in the detection of asymptomatic immune responders to Leishmania among HIV+ patients with no previous leishmaniasis or current symptomatology. Eighty two HIV+ patients (all from Fuenlabrada, Madrid, Spain, where a leishmaniasis outbreak occurred in 2009) were examined for Leishmania infantum infection using molecular and humoral response-based methods. None returned a positive molecular or serological result for the parasite. Thirteen subjects showed a positive lymphoproliferative response to soluble Leishmania antigen (SLA), although the mean CD4+ T lymphocyte counts of these patients was below the normal range. Stimulation of peripheral blood mononuclear cells (PBMC) or whole blood with SLA (the lymphoproliferative assay and whole blood assay respectively), led to the production of specific cytokines and chemokines. Thus, despite being immunocompromised, HIV+ patients can maintain a Th1-type cellular response to Leishmania. In addition, cytokine release assays would appear to be useful tools for detecting these individuals via the identification of IFN-γ in the supernatants of SLA-stimulated PBMC, and of IFN-γ, MIG and IL-2 in SLA-stimulated whole blood. These biomarkers appear to be 100% reliable for detecting asymptomatic immune responders to Leishmania among HIV+ patients.
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http://dx.doi.org/10.1371/journal.pntd.0007461DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6564048PMC
June 2019

Antigenicity of -Activated C-Kinase Antigen (LACK) in Human Peripheral Blood Mononuclear Cells, and Protective Effect of Prime-Boost Vaccination With pCI-neo-LACK Plus Attenuated LACK-Expressing Vaccinia Viruses in Hamsters.

Front Immunol 2018 23;9:843. Epub 2018 Apr 23.

WHO Collaborating Center for Leishmaniasis, National Center of Microbiology, Instituto de Salud Carlos III, Madrid, Spain.

-activated C-kinase antigen (LACK) is a highly conserved protein among species and is considered a viable vaccine candidate for human leishmaniasis. In animal models, prime-boost vaccination with LACK-expressing plasmids plus attenuated vaccinia viruses (modified vaccinia Ankara [MVA] and mutant M65) expressing LACK, has been shown to protect against cutaneous leishmaniasis (CL). Further, LACK demonstrated to induce the production of protective cytokines in patients with active CL or cured visceral leishmaniasis, as well as in asymptomatic individuals from endemic areas. However, whether LACK is capable to trigger cytokine release by peripheral blood mononuclear cells from patients cured of CL due to () or induce protection in -infected hamsters [visceral leishmaniasis (VL) model], has not yet been analyzed. The present work examines the immunogenicity of LACK in cured VL and CL patients, and asymptomatic subjects from an area. It also evaluates the vaccine potential of LACK against infection in hamsters, in a protocol of priming with plasmid pCI-neo-LACK (DNA-LACK) followed by a booster with the poxvirus vectors MVA-LACK or M65-LACK. LACK-stimulated PBMC from both asymptomatic and cured subjects responded by producing IFN-γ, TNF-α, and granzyme B (Th1-type response). Further, 78% of PBMC samples that responded to soluble antigen showed IFN-γ secretion following stimulation with LACK. In hamsters, the protocol of DNA-LACK prime/MVA-LACK or M65-LACK virus boost vaccination significantly reduced the amount of DNA in the liver and bone marrow, with no differences recorded between the use of MVA or M65 virus vector options. In summary, the Th1-type and cytotoxic responses elicited by LACK in PBMC from human subjects infected with , and the parasite protective effect of prime/boost vaccination in hamsters with DNA-LACK/MVA-LACK and DNA-LACK/M65-LACK, revealed the significance of LACK in activating human and hamster immune responses and support LACK to be a valuable candidate for inclusion in a vaccine against human VL.
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http://dx.doi.org/10.3389/fimmu.2018.00843DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5924775PMC
June 2019

F1 Domain of the Nucleoside Hydrolase Promotes a Th1 Response in Cured Patients and in Asymptomatic Individuals Living in an Endemic Area of Leishmaniasis.

Front Immunol 2017 12;8:750. Epub 2017 Jul 12.

Instituto de Microbiologia Paulo de Góes, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil.

The nucleoside hydrolase NH36 is the main antigen of the Leishmune vaccine and one of the promising candidates for vaccination against visceral leishmaniasis. The antigenicity of the N-terminal (F1), the central (F2), or the C-terminal recombinant domain (F3) of NH36 was evaluated using peripheral blood mononuclear cells (PBMC) from individuals infected with from an endemic area of visceral leishmaniasis of Spain. Both NH36 and F1 domains significantly increased the PBMC proliferation stimulation index of cured patients and infected asymptomatic individuals compared to healthy controls. Moreover, F1 induced a 19% higher proliferative response than NH36 in asymptomatic exposed subjects. In addition, in patients cured from visceral leishmaniasis, proliferation in response to NH36 and F1 was accompanied by a significant increase of IFN-γ and TNF-α secretion, which was 42-43% higher, in response to F1 than to NH36. The interleukin 17 (IL-17) secretion was stronger in asymptomatic subjects, in response to F1, as well as in cured cutaneous leishmaniasis after NH36 stimulation. While no IL-10 secretion was determined by F1, a granzyme B increase was detected in supernatants from cured patients after stimulation with either NH36 or F1. These data demonstrate that F1 is the domain of NH36 that induces a recall cellular response in individuals with acquired resistance to the infection by . In addition, F1 and NH36 discriminated the IgG3 humoral response in patients with active visceral leishmaniasis due to (Ethiopia) and (Spain) from that of endemic and non-endemic area controls. NH36 showed higher reactivity with sera from -infected individuals, indicating species specificity. We conclude that the F1 domain, previously characterized as an inducer of the Th1 and Th17 responses in cured/exposed patients infected with , may also be involved in the generation of a protective response against and represents a potential vaccine candidate for the control of human leishmaniasis alone, or in combination with other HLA epitopes/antigens.
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http://dx.doi.org/10.3389/fimmu.2017.00750DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5506215PMC
July 2017