Features of peripheral blood cellular immunity parameters in patients with lung damage up to 30 % in COVID-19

Background . The stability of human organism for different kind of infection, including SARS-CoV-2 is significantly defined by the immune system. The mechanisms of the cellular immunity to the SARS-CoV-2 are not exactly defined and are under study. The aim . To study the features of cell immunity parameters in patients with lung damage up to 30 % in COVID-19. Material and methods . 73 people were examined during the 2020–2021 pandemic. The study group consisted of 31 patients with lung damage up to 30 % with COVID-19, the comparison group consisted of 42 people not infected with SARS-CoV-2. A complete clinical blood count was carried out using a Medonic M20 hematological analyzer (Boule Medical, Sweden), the level of lymphocyte subpopulations was determined using a FACS Calibur cytometer (BD, USA) and FITC- and phycoerythrin-labeled monoclonal antibodies (Sorbent, Russia). Differences were considered statistically significant at p < 0.05. Results . Patients with COVID-19 with lung damage according to computed tomography (CT) ≤ 30 % before the treatment had a restructuring in the ratio of lymphocyte subpopulations in 67.7 % of cases. Lymphopenia (< 1.1 × 10 9 cells/l) was detected in 34.4 % of patients: a decrease in the absolute count of CD3 + lymphocytes by 30.8 %, CD3 + CD4 + – by 35 %, CD3 + CD8 + – by 6.7 % (p < 0.05), CD16 + CD56 + natural killer (NK) cells – by 29.4 % (p = 0.009). The level of CD95 + lymphocytes in COVID-19 is 3.2 times higher than in healthy individuals. Elevated levels of HLA-DR + - (> 20 %) and CD3 + HLADR + lymphocytes (> 6 %) are recorded in 60 % and 86.7 % of patients, respectively. Elevated levels of CD19 + B lymphocytes (> 17 %) in COVID-19 are 2.6 times more common than in healthy individuals. Correlation dependences of the count of NK cells with a wide range of T lymphocyte subpopulations were revealed. Conclusion . Cellular immunity indicators in COVID-19 have a number of features that can serve as predictors of the progression of the severity of the disease.