A longitudinal study of immune cells in severe COVID-19 patients
Running title: Monocytes and antigen-specific T-cells in severe COVID-19.
Authors:Payen D et al.
Tags: Clincal, Immunology/Immunity
No significant differences in monocyte subset populations over time in severe COVID19 hospitalised patients
Although a reduction of CD4 and CD8 T cells was observed, the CD4/CD8 T cells ratio remain the same throughout
SARS-CoV2 specific CD4 T cells were more potent in secreting cytokines (IFNg, TNFa, IL-2) than CD8 T cells after in vitro stimulation.
A longitudinal study following 15 severe COVID-19 patients, not on immunomodulatory treatment, to assess lymphocyte subsets and their functionality and monocyte phenotyping in serial peripheral blood samples. As previously reported, a decrease in CD4 and CD8 T cells was observed in severe patients, however no disruption of the CD4/CD8 ratio is shown. Isolation of SARS-COv2-specific T cells showed that after in vitro stimulation CD4 T cells were more capable of secreting cytokines (IFNg, TNFa, IL-2) with higher TNFa, IL-2 positive cells. Overall this study lacks a strong correlation/explanation between their observations.
Impact for SARS-CoV2/COVID19 research efforts
Understand the immune response to SARS-CoV2/COVID19
Clinical Cohort study (15 patients followed overtime with blood collections)
Strengths and limitations of the paper
Novelty: The authors assess the functional potential of the cells by looking at expression of multiple cytokines and monocyte populations overtime.
Standing in the field: This study does not add crucial data to the field.
Appropriate statistics: Yes, but small sample size
Viral model used: Severe COVID-19 hospitalized patients (confirmed by RT-PCR)
Translatability: It would be very interesting to deeper phenotype innate and adaptive immune responses overtime in different disease stages in patients. However, the translational implications of the research are limited.
Study lacks details of monocyte subsets and their potential roles. Moreover, the study was confined to analyses of peripheral blood and did not look at macrophages.
Did not show the gating strategy neither the MFI for cytokine production for instance.
Limited sample size (n=5 patients for cytokine experiments)
Did not entirely functionally characterise the cells. It would have been valuable if they had phenotyped SARS-Cov2 specific T cells by FACS over time.