Defects in the interferon system associated with a deficiency of natural killers and T-cells in patients with COVID-19

Identification of interrelated innate and sensitive immune responses in COVID-19 is an important step in the development of targeted therapeutic approaches, which is relevant. Objective. To clarify the features of the defect in the function of NK cells, T lymphocytes, the interferon system in patients with moderate and severe COVID-19. Patients and methods. Tests of the peripheral blood of 50 COVID-19 patients aged 61(57–71) and having the moderate and severe disease were performed. The following parameters were measured: the quantity of CD3+CD19–, CD3+CD4+, CD3+CD8+ T lymphocytes, NK – (CD3–CD16+CD56+), and TNK – CD3+CD16+CD56+ with expression density considered membrane receptors (MFI) (FC 500 Beckman Coulter, USA), the levels of IFN-α, IFN-γ, IL-6, TNF-α cytokines (IFA). Results. Combined immunodeficiency associated with quantitative and functional defects in NK, T lymphocytes and their subsets was revealed in moderate and severe COVID-19. An imbalance of cytokines has been established: blockade of the production of IFN-α and IFN-γ against the background of a significant increase in IL-6 and TNF-α, which negatively affects both the number and functionality of the participants in the immune response and is associated with a severe course and poor prognosis of COVID-19. Conclusion. The data obtained demonstrate the need to develop new strategies and tactics for the treatment of COVID-19, including replacement systemic therapy with recombinant IFN-α2b in combination with antioxidants (Viferon®) in adequate therapeutic doses, aimed at restoring the normal functioning of T lymphocytes, NK and the interferon system. Key words: COVID-19, interferons, moderate and severe disease course, NK cells, T lymphocytes