Cell-mediated immunity in people with long COVID

 Nerea Montes, Èlia Domènech, Sílvia Guerrero, Bárbara Oliván-Blázquez, Rosa Magallón-Botalla

doi: https://doi.org/10.1101/2021.06.09.21258553

This article is a preprint and has not been certified by peer review [what does this mean?]. It reports new medical research that has yet to be evaluated and so should not be used to guide clinical practice.

https://www.medrxiv.org/content/10.1101/2021.06.09.21258553v1.full.pdf

Abstract

Introduction The objective of this study is to analyse the specific immune response against SARS-CoV-2 in those affected by Long Covid (LC), attributable to T cells (cell-mediated immunity) and to carry out a parallel analysis of the humoral response and lymphocyte typing.

Methodology Descriptive cross-sectional study of 74 patients with LC for at least 4 months since diagnosis. The collected data were: information on the COVID-19 episode and the persistent symptoms, medical history and a specific cell-mediated immunity to SARS-CoV-2 through flow cytometry, assessing the release of interferon-gamma (IFN-Ɣ) by T4 lymphocytes, T8 lymphocytes and NK cells. Descriptive and comparative analyses were carried out.

Results Patients with LC had negative serology for Covid-19 in 89% of cases but 96% showed specific cellular immunity to SARS-CoV-2 an average of 9.5 months after infection: 89% of this response corresponded to T8 lymphocytes, 58% to NK cells, and 51% to T4 lymphocyte (20% negligibly positive). Most of them had altered immune cell typing and we found that T4 lymphocyte counts were low in 34% of cases and NK cell high in 64%. Macrophage populations were detected in the peripheral blood of 7% of them. Patients displayed a higher percentage of illnesses related to &[Prime]abnormal&[Prime] immune responses, either preceding SARS-CoV-2 infection (43%) or following it in 23% of cases.

Conclusion The immune system appears to have an important involvement in the development of LC and viral persistence could be the cause or consequence of it. Further analysis with a control group should be performed.

Competing Interest Statement

The authors have declared no competing interest.

Funding Statement

No funding was granted for this study. Serologic tests were funded by each of the participants themselves. Participants have not received any financial benefit and took part in this study in order to further research into LC.

https://www.medrxiv.org/content/10.1101/2021.06.09.21258553v1