Quantitative and qualitative composition of the main populations of lymphocytes in patients with community-acquired pneumonia during the COVID-19 pandemic

Ivanova I.A., Filippenko A.V., Pavlovich N.V., Aronova N.V., Tsimbalistova M.V., Anisimova A.S., Omelchenko N.D., Trufanova A.A., Chemisova O.S., Noskov A.K.

Rostov-on-Don Anti-Plague Institute of Rospotrebnadzor, Rostov-on-Don, Russia

The aim of the study was comparative assessment of the content of the main populations and subpopulations of T- and B-lymphocytes in patients with new coronavirus infection caused by genovariant 1.617.2 (Delta), as well as in patients with community-acquired pneumonia of mixed etiology. The experiment involved 70 people (37 women, 33 men) aged 53,5±19,4, diagnosed with community-acquired pneumonia (5-7 days after the onset of the disease, lung damage from 2 to 12%), of which, according to identified pathogens of viral, bacterial or fungal nature, seven target groups were formed. In these patients, the percentage and absolute content of CD3+lymphocytes (CD45+CD3+), CD4+lymphocytes (CD45+CD3+CD4+), CD8+lymphocytes (CD45+CD3+CD8+), T-NK cells (CD45+CD3+CD16-CD56+), natural killer cells (NK) (CD45+CD3-CD16+CD56+), activated/memory T-lymphocytes (CD45+CD45RO+CD45RA-), naive T-lymphocytes (CD45+CD45RO-CD45RA+), memory B-cells (CD45+CD19+CD5-CD27+), CD19+lymphocytes (CD45+CD19+), B1- (CD45+CD5+CD19-CD27-) and B2-cells (CD45+CD19+CD5-CD27-). It was shown that in all patients with community-acquired pneumonia, regardless of the nature of the pathogen, T-lymphocytopenia and an increase in the content of naive and activated/memory T-lymphocytes were observed. In infected with SARS-CoV-2, as well as in covidpositive patients with identified other pathogens of viral and bacterial-viral nature, a decrease in the number of T cells occurred due to a decrease in the percentage and absolute number of cytotoxic lymphocytes, and in patients with COVID-19, burdened with bacterial or bacterial-fungal infection, T helper cells. Similar results were obtained in groups of covidnegative patients. In these patients, in contrast to covidpositive, there was an increase in the relative and absolute number of B- and B2-lymphocytes, as well as the total population of memory B-cells. Thus, in the immune status of patients with community-acquired pneumonia, we identified changes characteristic of all groups of subjects and of those directly dependent on the nature of the pathogens causing this disease.