RT Journal Article
SR Electronic
T1 Distinct cellular immune profiles in the airways and blood of critically ill patients with COVID-19
JF Thorax
JO Thorax
FD BMJ Publishing Group Ltd and British Thoracic Society
SP 1010
OP 1019
DO 10.1136/thoraxjnl-2020-216256
VO 76
IS 10
A1 Anno Saris
A1 Tom D Y Reijnders
A1 Esther J Nossent
A1 Alex R Schuurman
A1 Jan Verhoeff
A1 Saskia van Asten
A1 Hetty Bontkes
A1 Siebe Blok
A1 Janwillem Duitman
A1 Harm-Jan Bogaard
A1 Leo Heunks
A1 Rene Lutter
A1 Tom van der Poll
A1 Juan J Garcia Vallejo
A1 ,
YR 2021
UL http://thorax.bmj.com/content/76/10/1010.abstract
AB Background 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.The data that support the findings of this study are available from the corresponding author, AS, upon reasonable request.