Distinct cellular immune profiles in the airways and blood of critically ill patients with COVID-19

  1. Anno Saris
  2. Tom D Y Reijnders
  3. Esther J Nossent
  4. Alex R Schuurman
  5. Jan Verhoeff
  6. Saskia van Asten
  7. Hetty Bontkes
  8. Siebe Blok
  9. Janwillem Duitman
  10. Harm-Jan Bogaard
  11. Leo Heunks
  12. Rene Lutter
  13. Tom van der Poll
  14. Juan J Garcia Vallejo

Reviewed by

Read the full article See related articles

Listed in

Log in to save this article

Abstract

Knowledge of the pathophysiology of COVID-19 is almost exclusively derived from studies that examined the immune response in blood. We here aimed to analyse the pulmonary immune response during severe COVID-19 and to compare this with blood responses.

Methods

This was an observational study in patients with COVID-19 admitted to the intensive care unit (ICU). Mononuclear cells were purified from bronchoalveolar lavage fluid (BALF) and blood, and analysed by spectral flow cytometry; inflammatory mediators were measured in BALF and plasma.

Findings

Paired blood and BALF samples were obtained from 17 patients, four of whom died in the ICU. Macrophages and T cells were the most abundant cells in BALF, with a high percentage of T cells expressing the ƴδ T cell receptor. In the lungs, both CD4 and CD8 T cells were predominantly effector memory cells (87·3% and 83·8%, respectively), and these cells expressed higher levels of the exhaustion marker programmad death-1 than in peripheral blood. Prolonged ICU stay (>14 days) was associated with a reduced proportion of activated T cells in peripheral blood and even more so in BALF. T cell activation in blood, but not in BALF, was higher in fatal COVID-19 cases. Increased levels of inflammatory mediators were more pronounced in BALF than in plasma.

Interpretation

The bronchoalveolar immune response in COVID-19 has a unique local profile that strongly differs from the immune profile in peripheral blood. Fully elucidating COVID-19 pathophysiology will require investigation of the pulmonary immune response.

Article activity feed

  1. Version published to 10.1136/thoraxjnl-2020-216256
  2. ScreenIT

    SciScore for 10.1101/2020.10.29.360586: (What is this?)

    Please note, not all rigor criteria are appropriate for all manuscripts.

    Table 1: Rigor

    Institutional Review Board StatementConsent: Informed consent for the use of samples and data was deferred until discharge from the ICU.
    IRB: Study procedure was approved by the Review Committee Biobank of the Amsterdam UMC (2020-065).
    Randomizationnot detected.
    Blindingnot detected.
    Power Analysisnot detected.
    Sex as a biological variablenot detected.

    Table 2: Resources

    Antibodies
    SentencesResources
    Next, 1 million cells (or as many as available in case of BALFMCs) were stained with live/dead stain, and subsequently monoclonal antibodies added sequentially: CCR7, ⍰δ T cell receptor, all non-brilliant (ultra) violet (BV/BUV) or non-brilliant blue (BB) labelled markers and finally all BV, BUV and BB labelled antibodies.
    CCR7
    suggested: None
    Anti-RBD and anti-NP IgG antibodies were measured in EDTA plasma samples at 100-1200 fold dilutions using ELISA as previously described.
    Anti-RBD
    suggested: None
    anti-NP IgG
    suggested: None
    11 Plates were coated with RBD or N protein and specific IgG antibodies were detected using anti-human IgG (MH16, Sanquin).
    specific IgG
    suggested: None
    anti-human IgG
    suggested: (Cell Sciences Cat# MON5009, RRID:AB_419547)
    MH16
    suggested: None
    Software and Algorithms
    SentencesResources
    Correlations are represented using hierarchical edge bundling plot generated using the circlize package in R as previously described.18.
    circlize
    suggested: (circlize, RRID:SCR_002141)
    Statistical analysis was performed in the R statistical framework (Version 4.0.1, Vienna, Austria) or Graphad Prism v7.01 (GraphPad Software, San Diego, California, USA).
    Graphad Prism
    suggested: None
    Graphical presentation was performed using Graphpad Prism v7.01 (GraphPad Software), Adobe Illustrator CC v22.1 (Adobe, San Jose, California, USA), and R (Version 4.0.1).
    Graphpad Prism
    suggested: (GraphPad Prism, RRID:SCR_002798)
    GraphPad
    suggested: (GraphPad Prism, RRID:SCR_002798)
    Adobe Illustrator
    suggested: (Adobe Illustrator, RRID:SCR_010279)

    Results from OddPub: We did not detect open data. We also did not detect open code. Researchers are encouraged to share open data when possible (see Nature blog).

    Results from LimitationRecognizer: We detected the following sentences addressing limitations in the study:
    The present study is limited by its relatively low sample size – due to a rapidly declining incidence of SARS-CoV-2 infections after governmental measures were introduced – and variation in time of sampling, and these limitations necessitate caution when drawing conclusions. In conclusion, immune composition in the lungs of COVID-19 patients admitted to the ICU was substantially different than in peripheral blood. BALF mainly comprised macrophages and T cells, with high percentages of inflammatory monocyte-like macrophages and ⍰δ T cells especially after prolonged ICU stay. Both CD4 and CD8 T cells expressed higher levels of PD-1 in BALF as compared with PBMCs. Surprisingly, total CD8 T cell activation in BALF was lower than in peripheral blood. Reduced CD4 and CD8 T cell activation associated with extended ICU stay, especially in BALF, while peripheral activation of T cells (CD4 EM3 and EM4 as well as CD8 TEMRA) associated with mortality.

    Results from TrialIdentifier: No clinical trial numbers were referenced.

    Results from Barzooka: We did not find any issues relating to the usage of bar graphs.

    Results from JetFighter: We did not find any issues relating to colormaps.

    Results from rtransparent:
    • Thank you for including a conflict of interest statement. Authors are encouraged to include this statement when submitting to a journal.
    • Thank you for including a funding statement. Authors are encouraged to include this statement when submitting to a journal.
    • No protocol registration statement was detected.

    About SciScore

    SciScore is an automated tool that is designed to assist expert reviewers by finding and presenting formulaic information scattered throughout a paper in a standard, easy to digest format. SciScore checks for the presence and correctness of RRIDs (research resource identifiers), and for rigor criteria such as sex and investigator blinding. For details on the theoretical underpinning of rigor criteria and the tools shown here, including references cited, please follow this link.

  3. Version published to 10.1101/2020.10.29.360586v1 on bioRxiv