Browsing by Author "Balcells, Maria Elvira"

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    Identification of Recent Tuberculosis Exposure Using QuantiFERON-TB Gold Plus, a Multicenter Study
    (2021) Perez-Recio, Sandra; Pallares, Natalia; Grijota-Camino, Maria D.; Sanchez-Montalva, Adrian; Barcia, Laura; Campos-Gutierrez, Silvia; Pomar, Virginia; Rabunal-Rey, Ramon; Balcells, Maria Elvira; Gazel, Deniz; Montiel, Natalia; Vicente, Diego; Goic-Barisic, Ivana; Schon, Thomas; Paues, Jakob; Marekovic, Ivana; Cacho-Calvo, Juana; Barac, Aleksandra; Goletti, Delia; Garcia-Gasalla, Mercedes; Maria Barcala, Jose; Teresa Tortola, Maria; Anibarro, Luis; Suarez-Toste, Isabel; Moga, Esther; Gude-Gonzalez, Maria J.; Naves, Rodrigo; Karsligil, Tekin; Martin-Penaranda, Tania; Stevanovic, Goran; Trigo, Matilde; Rubio, Veronica; Karaoglan, Ilkay; Bayram, Nazan; Alcaide, Fernando; Tebe, Cristian; Santin, Miguel
    We investigated whether the difference of antigen tube 2 (TB2) minus antigen tube 1 (TB1) (TB22TB1) of the QuantiFERON-TB gold plus test, which has been postulated as a surrogate for the CD81 T-cell response, could be useful in identifying recent tuberculosis (TB) exposure. We looked at the interferon gamma (IFN-g) responses and differences in TB2 and TB1 tubes for 686 adults with QFT-plus positive test results. These results were compared among groups with high (368 TB contacts), low (229 patients with immune-mediated inflammatory diseases [IMID]), and indeterminate (89 asylum seekers or people from abroad [ASPFA]) risks of recent TB exposure. A TB2-TB1 value.0.6 IU.ml(-1) was deemed to indicate a true difference between tubes. In the whole cohort, 13.6%, 10.9%, and 11.2% of cases had a TB2>TB1 result in the contact, IMID, and ASPFA groups, respectively (P = 0.591). The adjusted odds ratios (aORs) for an association between a TB2-TB1 result of >0.6 IU.ml(-1) and risk of recent exposure versus contacts were 0.71 (95% confidence interval [CI], 0.31 to 1.61) for the IMID group and 0.86 (95% CI, 0.49 to 1.52) for the ASPFA group. In TB contact subgroups, 11.4%, 15.4%, and 17.7% with close, frequent, and sporadic contact had a TB2>TB1 result (P = 0.362). The aORs versus the close subgroup were 1.29 (95% CI, 0.63 to 2.62) for the frequent subgroup and 1.55 (95% CI, 0.67 to 3.60) for the sporadic subgroup. A TB2-TB1 difference of.0.6 IU.ml(-1) was not associated with increased risk of recent TB exposure, which puts into question the clinical potential as a proxy marker for recently acquired TB infection.
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    SARS-CoV-2 infectivity and antigenic evasion: spotlight on isolated Omicron sub-lineages
    (2024) Barrera, Aldo; Martinez-Valdebenito, Constanza; Angulo, Jenniffer; Palma, Carlos; Hormazabal, Juan; Vial, Cecilia; Aguilera, Ximena; Castillo-Torres, Pablo; Pardo-Roa, Catalina; Balcells, Maria Elvira; Nervi, Bruno; Le Corre, Nicole; Ferres, Marcela
    Since the SARS-CoV-2 outbreak in 2019, a diversity of viral genomic variants has emerged and spread globally due to increased transmissibility, pathogenicity, and immune evasion. By the first trimester of 2023 in Chile, as in most countries, BQ and XBB were the predominant circulating sub-lineages of Omicron. The molecular and antigenic characteristics of these variants have been mainly determined using non-authentic spike pseudoviruses, which is often described as a limitation. Additionally, few comparative studies using isolates from recent Omicron sub-lineages have been conducted. In this study, we isolated SARS-CoV-2 variants from clinical samples, including the ancestral B.1.1, Delta, Omicron BA.1, and sub-lineages of BA.2 and BA.5. We assessed their infectivity through cell culture infections and their antibody evasion using neutralization assays. We observed variations in viral plaque size, cell morphology, and cytotoxicity upon infection in Vero E6-TMPRSS2 cells for each variant compared to the ancestral B.1.1 virus. BA.2-derived sub-variants, such as XBB.1.5, showed attenuated viral replication, while BA.5-derived variants, such as BQ.1.1, exhibited replication rates similar to the ancestral SARS-CoV-2 virus. Similar trends were observed in intestinal Caco-2 cells, except for Delta. Antibody neutralization experiments using sera from individuals infected during the first COVID-19 wave (FWI) showed a consistent but moderate reduction in neutralization against Omicron sub-lineages. Interestingly, despite being less prevalent, BQ.1.1 showed a 6.1-fold greater escape from neutralization than XBB.1.5. Neutralization patterns were similar when tested against sera from individuals vaccinated with 3xBNT162b2 (PPP) or Coronavac-Coronavac-BNT162b2 (CCP) schedules. However, CCP sera showed 2.3-fold higher neutralization against XBB.1.5 than FWI and PPP sera. This study provides new insights into the differences between BA.2 and BA.5-derived variants, leading to their eventual outcompetition. Our analysis offers important evidence regarding the balance between infectivity and antigenic escape that drives the evolution of second-generation SARS-CoV-2 variants in the population.