THE CONTENT OF CD4+ AND CD8+ EFFECTOR MEMORY CELLS AND THE PROLIFERATIVE ACTIVITY OF T LYMPHOCYTES IN BRONCHIAL ASTHMA

Bronchial asthma is a chronic inflammatory disease of the respiratory tract. T-lymphocytes play a key role in the pathogenesis of this allergic disease. The reduction in number of naive T cells and the accumulation of memory T cells in bronchial asthma are accompanied by dysregulation of T lymphocytes function. In present study, it was investigated the content of different subpopulations of T lymphocytes in the peripheral blood, in unstimulated and PHA-stimulated cultures, as well as their proliferative capacity in patients with bronchial asthma and healthy donors. The study included 10 patients with bronchial asthma (age 45.4 ± 11.8 years). One half of patients was in remission and the other half - in the stage of exacerbation of the underlying disease. The group of donors was formed by healthy individuals matched by gender and age to patients. Based on the expression of cell surface markers CD45R0, CD62L and CD197 (CCR7) CD4+ and CD8+ T lymphocytes were divided into central (Tcm) and effector memory cells (Tem), naive T-lymphocytes (Tnaive) and terminal-differentiated effectors (Temra) using flow cytometric technique. The proliferative activity of Tcm, Tem and Tnaive was evaluated in response to PHA as a functional marker of T cells. It was found that the percentage of CD4+TemCD62L+ and CD8+TemCD62L+ in the peripheral blood of patients in the exacerbation of asthma was significantly reduced compared to donors. After stimulation with PHA, these differences in T cell subsets between the groups of patients and donors were disappeared. We performed a correlation analysis between memory T cells and age . It was determined that the relative amount of CD4+ and CD8+ memory cells increased with age in asthmatics, but not in healthy donors. The analysis of mitogen-induced proliferation showed that Tcm and Tnaive cells divided more actively compared to other subpopulations in both groups. At the same time, the proliferative activity of CD4+ T lymphocytes and subsets of CD8+Tcm, CD4+Tcm and CD4+Tem62L- was higher in the group of patients in remission of asthma, than in groups of patients in exacerbation of the disease, and healthy donors. The revealed increase in the relative number of memory T cells with age suggests that these cells participate in the development of bronchial asthma. The proliferative response of the studied subpopulations, which was comparable with the donor values, indicates the retention of the functional characteristics of memory T cells and naive T lymphocytes in bronchial asthma. The increased proliferation of some T-cell subpopulations in asthmatics in remission points to the activated state of memory T cells. The observed decrease in the number of CD4+TemCD62L+ and CD8+TemCD62L+ in patients in exacerbation of asthma, by our opinion, may be associated with an active inflammatory process in the airways