CONTENTS OF CD4⁺ AND CD8⁺ EFFECTOR MEMORY CELLS AND 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 pathogenesis of this allergic disease. The reduction in number of naïve T cells and the accumulation of memory T cells in bronchial asthma are accompanied by dysregulation of T lymphocyte function. In present study, we have investigated the contents of different T lymphocyte subpopulations in peripheral blood as well as in resting and PHA-stimulated cultures, along with 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 state, the others having been at the stage of clinical exacerbation. The group of donors was formed by healthy individuals matched by gender and age to the patients. Based on expression of cell surface markers CD45R0, CD62L and CD197 (CCR7), the CD4+ and CD8+T lymphocytes were divided into central (Tcm) and effector memory cells (Tem), naïve T lymphocytes (Tnaïve) and terminally differentiated effector cells (Temra) using flow cytometry technique. The proliferative activity of Tcm, Tem and Tnaïve was evaluated in response to PHA as a functional marker of T cells. We have found that the percentage of peripheral CD4+TemCD62L+ and CD8+TemCD62L+ cells in the patients with asthma exacerbation was significantly reduced, if compared to the donors. Following PHA stimulation, these differences in T cell subsets between the groups of patients and donors were not detectable. We performed a correlation analysis between the memory T cell contents and age of the subjects studied. It was shown that the relative amounts of CD4+ and CD8+ memory cells increased with age in asthmatics, but not in healthy donors. Analysis of mitogen-induced proliferation showed that Tcm and Tnaïve cells proliferated more actively than other subpopulations in both groups. Meanwhile, the proliferative activity of CD4+T lymphocytes and subsets of CD8+Tcm, CD4+Tcm and CD4+Tem62L was higher in the group of asthma patients in remission state than in the patients with exacerbating disease, and healthy donors. The revealed increase in the relative number of memory T cells with age suggests that these cells participate in development of bronchial asthma. Proliferative response of the studied subpopulations, which was comparable to the donor values, suggests a functional maintenance of memory T cells and naïve T lymphocytes in bronchial asthma. The increased proliferation of some T-cell subpopulations in asthmatics in remission suggests an activated state of memory T cells. The observed decrease in the number of CD4+TemCD62L+ and CD8+TemCD62L+ in patients with asthma exacerbation may be, by our opinion, associated with an active inflammatory process in the airways

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

Telomere length distribution on individual chromosome arms in patients with bronchial asthma

Objective. The purpose of this study was to evaluate the length of telomeres in the arms of individual chromosomes in patients with bronchial asthma (BA).Materials and methods. The study included patients with BA (n = 10, the mean age (44 ± 8.2) years) and healthy donors (n = 10, the mean age (44 ± 8.4) years). Metaphase spreads obtained from peripheral blood mononuclear cells were used. At the time of sampling BA patients received treatment at the Clinic of Immunopathology, Novosibirsk. BA was diagnosed by physicians according to GINA-2016. For measurement of telomere length on individual chromosome arms we used quantitative fluorescent in situ hybridization with a PNA-probe specific for telomeres. We used inverted DAPI banding for chromosome identification (according to ISCN-2013). For each individual 5 metaphase cells were analyzed. We applied the newly developed MeTeLen software to estimate the telomere repeats quantity (http:// www.bionet.nsc.ru/en/development/application-development/development-of-a-computer/metelen.html) in metaphase images. For enhanced image analysis compared with the previously developed programs, we included estimation of background signal and correction of defects of the optical system.Results. Comparing of telomere length show, that telomeres in the certain chromosome arms (4q, 5q, 9p, 10 q, 11p, 13p, 15q, 18q, 19q) in BA are significantly shorter than in corresponding group of donors (p < 0.05, Mann – Whitney U-test). For both studied groups we also evaluated telomere sequences shortened and elongated relative to the average telomere length in the group (p < 0.05, Wilcoxon-signed-runk test). The following differences and similarities between the telomere profiles of patients and donors were determined: the telomere sequences 4p, 6q, 8p were elongated and 2q, 9q, 11p, 15q were shortened relative to the average telomere length in BA patients. Moreover, this telomere sequences did not differ from the average telomere length in the group of donors. At the same time, the telomere sequences 12p, 16p, 17p, 19p were significantly shorter, and 3p was longer than the average telomere length in both groups.Conclusions. We guess, that the observed significant shortening of telomere length on individual chromosome arms in BA, as compared to donors, is relevant in pathogenesis of this disorder. The revealed features of telomere profile of patients with BA may be a result of different telomere length maintenance mechanisms and may influence to the development of asthma that needs further study