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Evaluation of two fluorescence immunoassays for the rapid detection of SARS-CoV-2 antigen—new tool to detect infective COVID-19 patients

2021 , PORTE TORRE, LORENA ISABEL , LEGARRAGA RADDATZ, PAULETTE , IRURETAGOYENA BRUCE, MIRENTXU INES , Valeska Vollrath , Gabriel Pizarro , MUNITA SEPULVEDA, JOSE MANUEL , ARAOS BRALIC, RAFAEL IGNACIO , WEITZEL, THOMAS

Background Real-Time Reverse-Transcription Polymerase Chain Reaction (RT-PCR) is currently the only recommended diagnostic method for SARS-CoV-2. However, rapid immunoassays for SARS-CoV-2 antigen could significantly reduce the COVID-19 burden currently weighing on laboratories around the world. Methods We evaluated the performance of two rapid fluorescence immunoassays (FIAs), SOFIA SARS Antigen FIA (Quidel Corporation, San Diego, CA, USA) and STANDARD F COVID-19 Ag FIA (SD Biosensor Inc., Gyeonggi-do, Republic of Korea), which use an automated reader. The study used 64 RT-PCR characterized clinical samples (32 positive; 32 negative), which consisted of nasopharyngeal swabs in universal transport medium. Results Of the 32 positive specimens, all from patients within 5 days of symptom onset, the Quidel and SD Biosensor assays detected 30 (93.8%) and 29 (90.6%) samples, respectively. Among the 27 samples with high viral loads (Ct ≤ 25), the two tests had a sensitivity of 100%. Specificity was 96.9% for both kits. Conclusion The high performance of the evaluated FIAs indicates a potential use as rapid and PCR-independent tools for COVID-19 diagnosis in early stages of infection. The excellent sensitivity to detect cases with viral loads above ~106 copies/mL (Ct values ≤ 25), the estimated threshold of contagiousness, suggests that the assays might serve to rapidly identify infective individuals.

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Enfermedad relacionada a IgG4. Serie clínica de pacientes chilenos

2022 , María C. Cuéllar , Miguel Gutiérrez , Alejandra Herrera , Fabián Elgueta , Pamela Wurmann , Natalia Badilla , Bellanides Mansilla , Javier Basualdo , Jorge Vega , Daniel Erlij , Cristian Labarca , Cristian Vergara , Verónica Mezzano , Ignacio Méndez , Lilith Stange , Susana Michalland , Francisco Silva , Aquiles Jara , Annelise Goecke , Paula Burgos , IRURETAGOYENA BRUCE, MIRENTXU INES , Cristina Fernández , Carolina Landeros , Óscar Neira

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Integration of T‐cell clonality screening using TRBC‐1 in lymphoma suspect samples by flow cytometry

2023 , Felipe Castillo , Constanza Morales , Biserka Spralja , Joaquín Díaz‐Schmidt , IRURETAGOYENA BRUCE, MIRENTXU INES , ERNST DIAZ, DANIEL MATIAS

AbstractBackgroundThe diagnosis of T‐cell non‐Hodgkin lymphomas (NHL) is challenging. The development of a monoclonal antibody specific for T‐cell receptor β constant region 1 (TRBC1) provides an alternative to discriminate clonal T cells. The aim of this study was to evaluate the diagnostic potential of an anti‐TRBC1 mAb for the identification of T‐NHL.MethodsWe performed a cross‐sectional diagnostic analytic study of samples tested for lymphoma. All samples sent for lymphoma screening were first evaluated using the standard Euroflow LST, to which a second additional custom‐designed T‐cell clonality assessment tube was added CD45/TRBC1/CD2/CD7/CD4/TCRγδ/CD3. Flow cytometry reports were compared with morphological and molecular tests.ResultsFifty‐nine patient samples were evaluated. Within the T‐cell population, cut‐off percentages in the CD4+ cells were from 29.4 to 54.6% and from 23.9 to 52.1% in CD8+ cells. Cut‐off ratios in CD4+ T cells were from 0.33 to 1.1, and in CD8+ cells between 0.22 and 1.0. Using predefined normal cut‐off values, 18 of 59 (30.5%) samples showed a restricted expression of TRBC1. A final diagnosis of a T‐NHL was confirmed clinically and/or by histopathological studies in 15 of the 18 cases (83.3%). There were no cases of T‐NHL by morphology/IHC with normal TRBC1 expression. Non‐neoplastic patient samples behaved between predefined TRBC1 cut‐off values.ConclusionsExpression of TRBC1 provides a robust method for T‐cell clonality assessment, with very high sensitivity and good correlation with complementary methods. TRBC1 can be integrated into routine lymphoma screening strategies via flow cytometry.

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Vitamin D supplementation reduces TLR7 and TLR9 expression in B cells from systemic lupus erythematosus patients

2019 , IRURETAGOYENA BRUCE, MIRENTXU INES , Naves, R. , Hirigoyen, D , Burgos, P. I.

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First Report of Tocilizumab Use in a Cohort of Latin American Patients Hospitalized for Severe COVID-19 Pneumonia

2020 , VALENZUELA LETELIER, OMAR ANTONIO , IBAÑEZ, SEBASTIAN , M. Cecilia Poli , ROESSLER VERGARA, PATRICIA ANDREA , AYLWIN RAMIREZ, MABEL CRISTINA , Gigia Roizen , IRURETAGOYENA BRUCE, MIRENTXU INES , Vivianne Agar , Javiera Donoso , Margarita Fierro , José Montes

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Evaluation of a novel antigen-based rapid detection test for the diagnosis of SARS-CoV-2 in respiratory samples

2020 , PORTE TORRE, LORENA ISABEL , LEGARRAGA RADDATZ, PAULETTE , Sabine Dittrich , Valeska Vollrath , AGUILERA SANHUEZA, XIMENA PAZ , MUNITA SEPULVEDA, JOSE MANUEL , ARAOS BRALIC, RAFAEL IGNACIO , Gabriel Pizarro , VIAL CLARO, PABLO AGUSTIN , IRURETAGOYENA BRUCE, MIRENTXU INES , WEITZEL, THOMAS

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Respuesta inmunitaria al SARS-CoV-2 y factores asociados previo a la vacunación, en personal de salud de atención primaria en una comuna de Santiago, Chile

2022 , OLEA NORMANDIN, ANDREA MARIA , Elena Pedroni , HIRMAS ADAUY, MACARENA SOLEDAD , MATUTE WILLEMSEM, MARIA ISABEL , IRURETAGOYENA BRUCE, MIRENTXU INES , MUNITA SEPULVEDA, JOSE MANUEL , GONZALEZ WIEDMAIER, CLAUDIA MARTA , María Inés Gómez , Manuel Nájera

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Longitudinal assessment of SARS-CoV-2 IgG seroconversionamong front-line healthcare workers during the first wave of the Covid-19 pandemic at a tertiary-care hospital in Chile

2021 , IRURETAGOYENA BRUCE, MIRENTXU INES , Macarena R. Vial , Maria Spencer-Sandino , Pablo Gaete , Anne Peters , DELGADO BECERRA, OROZIMBA IRIS , Inia Perez , Claudia Calderon , PORTE TORRE, LORENA ISABEL , Alicia Anderson , MUNITA SEPULVEDA, JOSE MANUEL , LEGARRAGA RADDATZ, PAULETTE , AGUILERA SANHUEZA, XIMENA PAZ , VIAL CLARO, PABLO AGUSTIN , WEITZEL, THOMAS

Abstract Background Healthcare workers (HCWs) are at high risk of exposure to SARS-CoV-2. Cross-sectional studies have provided variable rates of seroprevalence in HCWs. Longitudinal assessments of the serological response to Covid-19 among HCWs are crucial to understanding the risk of infection and changes in antibody titers over time. We aimed to investigate seroprevalence and risk factors associated with seroconversion in a prospective cohort of HCWs during the peak of the first wave of the Covid-19 pandemic. Methods We conducted a longitudinal study among 446 front-line HCWsin a tertiary-care hospital in Chile from April to July 2020. IgG was determined monthly using two different ELISAs in serum samples of HCWs, during the three-month period. In each visit, demographic data, symptoms, risk factors, and exposure risks were also assessed. Results The overall seroprevalence at the end of the study period was 24% (95% CI20.2–28.3), with 43% of seropositive HCWs reporting no prior symptoms. Seroconversion rates significantly differed over the study period, from 2.1% to as high as 8.8% at the peak of the epidemic. There were no statistically significant differences observed between HCWs in direct clinical care of patients with Covid-19 and those working in low risk areas. Antibody titers appeared to wane over time. Conclusions HCWs were severely affected with a high rate of seroconversion that appeared to mirror the local epidemiological situation. A significant amount of participants underwent an asymptomatic infection, highlighting the need for improved surveillance policies. Antibody titers appear to wane over time; further studies to understand this finding’s impact on the risk of reinfection are warranted.

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Comparative evaluation of four rapid SARS-CoV-2 antigen detection tests using universal transport medium

2021 , WEITZEL, THOMAS , LEGARRAGA RADDATZ, PAULETTE , IRURETAGOYENA BRUCE, MIRENTXU INES , Gabriel Pizarro , Valeska Vollrath , ARAOS BRALIC, RAFAEL IGNACIO , MUNITA SEPULVEDA, JOSE MANUEL , PORTE TORRE, LORENA ISABEL