Features of T cell immunity depending on the content of natural killer cells in patients with acute coronary syndrome following COVID-19

We examined 65 men with unstable angina and acute myocardial infarction (acute coronary syndrome - ACS) from 40 to 65 years old who had previously had COVID-19 and 20 people with ACS who had not undergone COVID-19. All persons also had hypertension, and they required stenting of the coronary arteries within the next 3 days after admission to the hospital. From the immunological parameters by flow cytometry on the Navios cytofluorimeter (BeckmanCoulter, USA), according to the standardized technology for assessing the lymphocytic link of immunity [1], the following were determined: ), CD45+ CD3+ CD8+ (cytotoxic T-lymphocytes), CD45+CD3-CD19+ (B-lymphocytes), CD45+CD3+CD16+CD56+ (TNK cells), CD45+CD3-CD16+CD56+ (natural killer cells), CD45+ CD3+CD4+CD25+CD127- (T-regulatory cells), CD45+ CD3+CD4+CD25+ (T-lymphocytes - early activation), CD45+CD3+HLA-DR (T-lymphocytes - late activation). All patients were divided into groups depending on the content of NK cells (natural killer cells). Patients who have had COVID-19 have 3 phenotypes of disorders (decreased NK cell count, normal and increased), while non-survivors have 2 phenotypes (decreased NK cell count and normal). The most severe condition and severity of immune disorders were found in patients who had undergone COVID-19. In patients with acute coronary syndrome and COVID-19, predominantly with normal and elevated levels of NK cells, compared with ACS patients without COVID-19, a more severe course of the disease was observed - patients with acute myocardial infarction prevailed, they had a higher mortality rate, the duration of treatment was increased, and stent thrombosis was also more common. In persons with ACS and COVID-19 with elevated NK cells, the maximum decrease in the T-cell immunity was observed: T-lymphocytes of general, T-lymphocytes-helpers, T-cytotoxic lymphocytes, T-lymphocytes of early activation, T-regulatory cells in absolute numbers compared to other groups. The lowest immunoregulatory index and, at the same time, the maximum number of T-NK-lymphocytes were observed in persons who had undergone COVID-19 and had reduced NK cells. The minimum number of T-NK lymphocytes was recorded in patients with low NK cells who did not have COVID-19. Minimal T-lymphocytes (CD45+CD3+CD4+HLA-DR+) of late activation were found in people who recovered from COVID-19 with elevated and normal NK cells. The lowest number of late activation regulatory T cells was observed in patients who did not have COVID-19, but were vaccinated, and had a normal content of NK cells. The study also allows us to more clearly define the groups of patients with ACS who need additional immunocorrection.