Adaptive immune response in women from the Russian Arctic region after COVID-19 infection

BACKGROUND: The Arctic region of Russia is characterized by disproportionately high rates of morbidity and mortality from COVID-19 during the pandemic. The harsh climatic and environmental conditions in this area impede the development of self-regulation processes resulting in activation and strain of both cellular and humoral immunity. This leads to a depletion of the body’s reserve capacities. At present, there is lack of research examining how individuals who have recovered from COVID-19 are affected by the extreme conditions of Arctic Russia.

AIM: To study the ratio of immunocompetent cells involved in the adaptive immune response following COVID-19 infection.

MATERIAL AND METHODS: A total of 29 women aged 20 – 40 years were examined in Arkhangelsk as part of a comprehensive immunological study. This study involved assessment of the number of leukocytes, lymphocytes, and their phenotypes (CD5+, CD8+, CD10+, CD95+), as well as determination of phagocytic activity and phagocytic number.

RESULTS: The cellular adaptive immune response in observed individuals 6 months after experiencing moderate COVID-19 disease was characterized by a very low concentration of T cells (CD5⁺) in all cases, CD10⁺ lymphocytes (44.83%) alongside with a high concentration of cytotoxic lymphocytes (CD8⁺) in 48.27% of individuals and lymphocytes with receptors for apoptosis (CD95⁺) in 51.72%, with relatively high phagocytic activity ranging from 90 to 100%. A correlation was found in 11.29% of women between the low content of CD10⁺ and CD95⁺ cells with the activity of phagocytosis. In 40% of women with high phagocytic activity, the concentrations of cytotoxic cells (CD8⁺) were found to be at a minimum level.

CONCLUSIONS: Women with high phagocytic activity were found to have the lowest concentrations of cytotoxic cells, suggesting a potentially positive prognosis for reducing the risk of complications. This indicates that cellular immunity may play a role in determining the severity of COVID-19 infection in individuals with high phagocytic activity.