Frontiers in Immunology (Oct 2021)

Dysregulated Immune Responses in COVID-19 Patients Correlating With Disease Severity and Invasive Oxygen Requirements

  • Paulina García-González,
  • Fabián Tempio,
  • Camila Fuentes,
  • Consuelo Merino,
  • Leonardo Vargas,
  • Valeska Simon,
  • Mirliana Ramirez-Pereira,
  • Verónica Rojas,
  • Eduardo Tobar,
  • Glauben Landskron,
  • Glauben Landskron,
  • Juan Pablo Araya,
  • Juan Pablo Araya,
  • Mariela Navarrete,
  • Mariela Navarrete,
  • Carla Bastias,
  • Rocío Tordecilla,
  • Macarena A. Varas,
  • Macarena A. Varas,
  • Pablo Maturana,
  • Andrés E. Marcoleta,
  • Miguel L. Allende,
  • Rodrigo Naves,
  • Marcela A. Hermoso,
  • Flavio Salazar-Onfray,
  • Flavio Salazar-Onfray,
  • Mercedes Lopez,
  • María Rosa Bono,
  • Fabiola Osorio

DOI
https://doi.org/10.3389/fimmu.2021.769059
Journal volume & issue
Vol. 12

Abstract

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The prognosis of severe COVID-19 patients has motivated research communities to uncover mechanisms of SARS-CoV-2 pathogenesis also on a regional level. In this work, we aimed to understand the immunological dynamics of severe COVID-19 patients with different degrees of illness, and upon long-term recovery. We analyzed immune cellular subsets and SARS-CoV-2-specific antibody isotypes of 66 COVID-19 patients admitted to the Hospital Clínico Universidad de Chile, which were categorized according to the WHO ten-point clinical progression score. These included 29 moderate patients (score 4-5) and 37 severe patients under either high flow oxygen nasal cannula (18 patients, score 6), or invasive mechanical ventilation (19 patients, score 7-9), plus 28 convalescent patients and 28 healthy controls. Furthermore, six severe patients that recovered from the disease were longitudinally followed over 300 days. Our data indicate that severe COVID-19 patients display increased frequencies of plasmablasts, activated T cells and SARS-CoV-2-specific antibodies compared to moderate and convalescent patients. Remarkably, within the severe COVID-19 group, patients rapidly progressing into invasive mechanical ventilation show higher frequencies of plasmablasts, monocytes, eosinophils, Th1 cells and SARS-CoV-2-specific IgG than patients under high flow oxygen nasal cannula. These findings demonstrate that severe COVID-19 patients progressing into invasive mechanical ventilation show a distinctive type of immunity. In addition, patients that recover from severe COVID-19 begin to regain normal proportions of immune cells 100 days after hospital discharge and maintain high levels of SARS-CoV-2-specific IgG throughout the study, which is an indicative sign of immunological memory. Thus, this work can provide useful information to better understand the diverse outcomes of severe COVID-19 pathogenesis.

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