ASSOCIATIONS BETWEEN BLOOD CONCENTRATIONS OF CYTOTOXIC CD8+ CELLS AND LYMPHOCYTE APOPTOSIS IN HEALTHY HUMANS

Abstract

Introduction: Cytotoxic T-lymphocytes play an important role in a specific immune response via a lytic effect in relation to abnormal cells. The number of these cells greatly increases sin pathological states. In addition, an increased cytotoxic activity is a characteristic of the immune response of people living in the Far NorthTherefore, it is important to understand what function cytotoxic T-lymphocytes predominantly perform in healthy people in the North - cytolytic or suppressor? Aim: To assess associations between CD8+ concentration and immune response and apoptotic deaths of the lymphocytes in healthy individuals. Methods: Ninety-three healthy adult residents of the Russian North comprised the sample. Apoptotic lymphocyte death was studied by flow cytometry. FITC-annexine-V and propidium iodide labelled cells were detected. Concentrations of cytokines and apoptosis mediators were assessed by a solid-phase enzyme immunoassay. Neutrophiles, monocytes and phagocytic activity of neutrophils were studied in blood smears stained by Romanowsky's - Giemsa. The level of phenotypic activity of lymphocytes was assessed by double peroxidase labeling using monoclonal antibodies. The data were presented using means, standard deviations, medians, the 1st and the 3rd quartiles. All study participants were divided into two groups: with normal- (0.2-0,4 х109 kl/l) and elevated (more 0,6 х109 kl/l) blood cytotoxic lymphocyte levels. The groups were similar in terms of by age- and gender distribution. Continuous variables were analyzed using Mann-Whitney tests. Results: In individuals with an increased level of cytotoxic CD8+ lymphocytes in peripheral venous blood had greater concentrations of leukocytes (7.4 ± 0.49 х109 cells/l vs. 5.5 ± 0.23 х109, p = 0.003), lymphocytes (2.8 ± 0.17 х109 cells/l vs.1.8 ± 0.07 х109 cells/t p = 0.005), and mature neutrophils (4.1 ± 0.19 х109 cells/l vs. 3.4 ± 0.49 х109 cells/l, p = 0.013). No associations between the level of apoptosis of lymphocytes (AnV+/PI-) and concentrations of sFasL, TRAIL, TNFa, and cytochrome C were observed. Conclusions: Lymphocytes CD8+ in healthy residents of the Russian North perform mainly cytotoxic function, which is not related to apoptotic cellular death.