Immune responses and COVID-19 severity
Open Forum Infectious Diseases
; 7(SUPPL 1):S325, 2020.
Article
in English
| EMBASE | ID: covidwho-1185880
ABSTRACT
Background:
The coronavirus-19-disease (COVID-19) pandemic caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has spread to >200 countries and surpassed 7 million cases. There is a broad range of COVID-19 illness, ranging from milder disease to a rapidly progressive respiratory disease and ARDS. The causes of this different clinical course and the drivers for severe disease are currently unknown. A fulminant increase of pro-inflammatory cytokines is thought to play a role in causing a rapid disease evolution, however the immune correlates of severe COVID-19 remain unclear.Methods:
To gain insight into relationship between immune responses and disease severity we built a longitudinal cohort of 40 adult patients with known COVID- 19. Samples were collected at diagnosis and every 7 days until hospital discharge or death. As controls we also included a group of convalescent patients, and subjects who tested negative for COVID-19 by PCR. Clinical and laboratory data and were also collected. Multicolor flow cytometry was used to determine the presence and phenotype of B, T and natural killer (NK) cells. We also identified specific sub-populations (Tfh, activated/cytotoxic CD8 and NK) and assessed lymphoid exhaustion of different cell types such as naïve, memory T cells, or NK over time. Anti-Sars-CoV2 IgG and IgM antibody were detected using lateral flow method.Results:
We found that the absolute number of lymphocytes and monocytes was decreased starting at diagnosis and correlated with disease severity. Disease severity correlated with decreased NK and T cell. In severe COVID-19 cases, NK cell populations were strongly decreased over time in intubated patients while they recovered in patients who improved and were discharged. CD8+ were also decreased at disease onset and seemed to correlate with disease severity. A high percentage of CD4+ and CD8+ T cells showed an exhausted phenotype. All patients tested at admission had IgM antibody responses irrespective of the course of the disease. Further analyses are ongoing.Conclusion:
The characterization and role of the immune responses in COVID- 19 evolution is still under investigation. Further characterization of viral and immune factors will help in identifying subjects at high risk of severe disease and targets for intervention.
Full text:
Available
Collection:
Databases of international organizations
Database:
EMBASE
Type of study:
Prognostic study
Language:
English
Journal:
Open Forum Infectious Diseases
Year:
2020
Document Type:
Article
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