The Dynamic Immunological Parameter Landscape in Coronavirus Disease 2019 Patients With Different Outcomes

Front Immunol. 2021 Oct 29:12:697622. doi: 10.3389/fimmu.2021.697622. eCollection 2021.


Objectives: The longitudinal and systematic evaluation of immunity in coronavirus disease 2019 (COVID-19) patients is rarely reported.

Methods: Parameters involved in innate, adaptive, and humoral immunity were continuously monitored in COVID-19 patients from onset of illness until 45 days after symptom onset.

Results: This study enrolled 27 mild, 47 severe, and 46 deceased COVID-19 patients. Generally, deceased patients demonstrated a gradual increase of neutrophils and IL-6 but a decrease of lymphocytes and platelets after the onset of illness. Specifically, sustained low numbers of CD8+ T cells, NK cells, and dendritic cells were noted in deceased patients, while these cells gradually restored in mild and severe patients. Furthermore, deceased patients displayed a rapid increase of HLA-DR expression on CD4+ T cells in the early phase, but with a low level of overall CD45RO and HLA-DR expressions on CD4+ and CD8+ T cells, respectively. Notably, in the early phase, deceased patients showed a lower level of plasma cells and antigen-specific IgG, but higher expansion of CD16+CD14+ proinflammatory monocytes and HLA-DR-CD14+ monocytic-myeloid-derived suppressor cells (M-MDSCs) than mild or severe patients. Among these immunological parameters, M-MDSCs showed the best performance in predicting COVID-19 mortality, when using a cutoff value of ≥10%. Cluster analysis found a typical immunological pattern in deceased patients on day 9 after onset, which was characterized as the increase of inflammatory markers (M-MDSCs, neutrophils, CD16+CD14+ monocytes, and IL-6) but a decrease of host immunity markers.

Conclusions: This study systemically characterizes the kinetics of immunity of COVID-19, highlighting the importance of immunity in patient prognosis.

Keywords: COVID-19; adaptive immunity; humoral immunity; innate immunity; outcome.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adaptive Immunity
  • Aged
  • Aged, 80 and over
  • Antibodies, Viral / blood
  • B-Lymphocytes / immunology
  • COVID-19 / blood
  • COVID-19 / classification
  • COVID-19 / immunology*
  • COVID-19 / physiopathology
  • Cytokines / blood
  • Dendritic Cells / immunology
  • Female
  • Humans
  • Immunity, Innate
  • Immunoglobulin G / blood
  • Killer Cells, Natural / immunology
  • Lymphocyte Count
  • Male
  • Middle Aged
  • SARS-CoV-2* / immunology
  • Severity of Illness Index
  • T-Lymphocytes / immunology


  • Antibodies, Viral
  • Cytokines
  • Immunoglobulin G