Immunological imprint of COVID-19 on human peripheral blood leukocyte populations

Bernhard Kratzer, Doris Trapin, Paul Ettel, Ulrike Körmöczi, Arno Rottal, Friedrich Tuppy, Melanie Feichter, Pia Gattinger, Kristina Borochova, Yulia Dorofeeva, Inna Tulaeva, Milena Weber, Katharina Grabmeier-Pfistershammer, Peter A Tauber, Marika Gerdov, Bernhard Mühl, Thomas Perkmann, Ingrid Fae, Sabine Wenda, Harald FührerRainer Henning, Rudolf Valenta, Winfried F Pickl

Research output: Journal article (peer-reviewed)Journal article

60 Citations (Scopus)


BACKGROUND: SARS-CoV-2 has triggered a pandemic that is now claiming many lives. Several studies have investigated cellular immune responses in COVID-19-infected patients during disease but little is known regarding a possible protracted impact of COVID-19 on the adaptive and innate immune system in COVID-19 convalescent patients.

METHODS: We used multiparametric flow cytometry to analyze whole peripheral blood samples and determined SARS-CoV-2-specific antibody levels against the S-protein, its RBD-subunit, and viral nucleocapsid in a cohort of COVID-19 convalescent patients who had mild disease ~10 weeks after infection (n = 109) and healthy control subjects (n = 98). Furthermore, we correlated immunological changes with clinical and demographic parameters.

RESULTS: Even ten weeks after disease COVID-19 convalescent patients had fewer neutrophils, while their cytotoxic CD8+ T cells were activated, reflected as higher HLA-DR and CD38 expression. Multiparametric regression analyses showed that in COVID-19-infected patients both CD3+ CD4+ and CD3+ CD8+ effector memory cells were higher, while CD25+ Foxp3+ T regulatory cells were lower. In addition, both transitional B cell and plasmablast levels were significantly elevated in COVID-19-infected patients. Fever (duration, level) correlated with numbers of central memory CD4+ T cells and anti-S and anti-RBD, but not anti-NC antibody levels. Moreover, a "young immunological age" as determined by numbers of CD3+ CD45RA+ CD62L+ CD31+ recent thymic emigrants was associated with a loss of sense of taste and/or smell.

CONCLUSION: Acute SARS-CoV-2 infection leaves protracted beneficial (ie, activation of T cells) and potentially harmful (ie, reduction of neutrophils) imprints in the cellular immune system in addition to induction of specific antibody responses.

Original languageEnglish
Pages (from-to)751-765
Number of pages15
JournalAllergy: European Journal of Allergy and Clinical Immunology
Issue number3
Publication statusPublished - Mar 2021


  • Adolescent
  • Adult
  • Aged
  • Antibodies, Viral/blood
  • COVID-19/immunology
  • Convalescence
  • Female
  • Humans
  • Logistic Models
  • Lymphocytes/immunology
  • Male
  • Middle Aged
  • Neutrophils/metabolism
  • SARS-CoV-2/immunology
  • Spike Glycoprotein, Coronavirus/immunology
  • Young Adult


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