Аsessment of relationships of cytotoxic Т-lymphocyte disturbances with other compartments of the immune system in post-COVID patients
Authors:   Institute of Immunology and Physiology of the Ural Branch of the Russian Academy of Sciences, Yekaterinburg, Dobrynina Maria A. , Zurochka Alexandr V. ,   Institute of Immunology and Physiology of the Ural Branch of the Russian Academy of Sciences, Yekaterinburg, Komelkova Mariia V. ,   Institute of Immunology and Physiology of the Ural Branch of the Russian Academy of Sciences, Yekaterinburg, Luo Shanshan ,   Institute of Hematology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Semenova Daria A. ,   Federal State Budgetary Educational Institution of Higher Education «Academician I.P. Pavlov First St. Petersburg State Medical University» of the Ministry of Healthcare of Russian Federation
Published: January 2023

Assessment of the state of the cells of the immune system in post-COVID patients currently remains little studied. The consequences of the influence of the virus itself, as well as drugs received by patients in the treatment of infection, on various body systems, including the immune system, contribute to disorders leading to post-COVID syndrome. The aim of the study was to study the level of cytotoxic T cells and features of immune system disorders in patients who had undergone SARS-CoV-2 infection. Materials and methods of research: 78 patients were examined 6 months after suffering COVID-19; studied 25 parameters of the blood system (general blood test), 50 parameters of the immune system, including T-lymphocytes, B-lymphocytes and their functional markers, NK, TNK cells, phagocytic part of the immune system, and humoral factors, including general and specific immunoglobulins and complement fragments. Results and discussion: when analyzing the results obtained, it was found that 44.8% of the examined individuals had a 1.7-fold decrease in the number of cytotoxic T-cells. This phenomenon was accompanied by a decrease in the level of T-lymphocytes in general, TNK-lymphocytes, some growth of T-helpers, an increase in the ratio of CD4/CD8 cells, levels of B-lymphocytes, due to B-total and B1, B2-lymphocytes of non-memory cells related to plasma cells (or otherwise the most actively producing immunoglobulins B cells). All these data indicate that in such patients, an immune response is formed to a greater extent according to the TH2 type (increased production of antibodies), and not according to the TH1 type (formation of cellular immune responses). In addition, in such patients, a violation of the TH1 response is observed and the likelihood of developing pathological processes associated with an inadequate response to viral antigens (including re-infection with the SARS-CoV-2 virus, exacerbations of chronic infections) increases. It is possible that the disorders we have identified in such patients may contribute to the occurrence or exacerbation of allergic and autoimmune processes in case of impaired functioning (hyperactivation) of the B-cell link of the immune system. All this requires further more detailed research, both in terms of further clinical observations of these patients, and the development of methods for correcting the identified disorders of the immune system.