Höfundar:
Arna Kristbjornsdottir, Hildur Sigurgrimsdottir, Marit Grimsdottir, Siggeir Brynjólfsson, Bjorn R. Ludviksson
Introduction: The COVID-19 disease, caused by SARS-CoV-2, has been a worldwide pandemic since early 2020. As of March 2023, there have been 209,137 confirmed cases in Iceland, causing 259 fatalities. T cells are divided into CD4+ T helper cells and CD8+ T cytotoxic cells with the viral response characterized by Th1 cell response along with IFN-y production. T cells, along with B cells, form the immunological memory.
Aims: To investigate cell mediated immune response in SARS-CoV-2 in COVID-19 patients 16-66 weeks post infection.
Methods: PBMCs from 83 patients were stimulation with SARS-CoV-2 specific proteins (S1, RBD and N) and stained for flow cytometry with CD3, CD4, CD8, IL-2, IL-6, IFN-y and TNF-.
Results: When patients that were hospitalized during their COVID-19 infection were compared to outpatients, outpatients had a higher prevalence of CD4 T cells expressing IL2 and IL6 after N stimulation. Polyfunctional CD4+IL2+IFNy+IL6+ T cells, CD4+IL2+TNF+IL6+ T cells, CD4+IL6+IFNy+IL2+ T cells and CD4+IL6+IL2+TNF+ were also more prevalent in outpatients. No statistical significance was seen when comparing weeks post symptoms onset.
Discussion/Conclusion: T cell specific memory response is seen with individuals previously infected with SARS-CoV-2 for up to 15 months post infection. While no difference was seen between weeks post symptoms onset, we can conclude that the memory T cell response is stable for quite some time. A specific trend is seen that outpatients are showing a higher expression than inpatients, with CD4+ T secreting IL-2 and IL-6 as well as polyfunctional T cells being more prevalent in outpatients.