Studies of non-autonomous effects of apoptosis in the course of in vitro apoptotic cell death initiation in healthy persons and patients with rheumatoid arthritis

The process of apoptosis is known that play an important role in cellular homeostasis, and the altered cell death may lead to development of pathological disorders. Evolving autoimmune conditions, in particular, rheumatoid arthritis, are associated with decreased rates of apoptosis as a form of programmed cell death. The aim of this study was to evaluate expression of activation and proliferation markers on T lymphocytes during initiation of apoptotic cell death under the conditions of “cell neighborhood” in healthy individuals and patients with rheumatoid arthritis. Patients and methods. The study was performed with blood samples of the patients with rheumatoid arthritis (RA) and healthy women of comparable age. During the study, we conducted experiments aimed to identify the in vitro influence of non-stimulated apoptosis-induced cells, as well as aCD3- and dexamethasone (Dexa)-stimulated apoptosis-induced cells upon autologous T lymphocytes cultured under physiological conditions. Development of a “cell neighborhood” model, i.e., co-cultures of CFSE- T cells subjected to incubation under crowding condition and depletion of the culture medium which is the most physiological variant of apoptosis activation, and CFSE+ autologous cells placed in the complete culture medium, has revealed some relationships. We have revealed an opportunity of secondary induction of early and late apoptosis by means of humoral and cellular components of autologous cell culture subjected to activation apoptosis. We determined the features of apoptosis in unstimulated, as well as aCD3- and dexamethasone-stimulated cultures, compared with controls. There were no differences in these parameters of apoptosis between RA patients and healthy people for all variants of cultures. An increased proportion of viale cells was found in the CFSE- culture of patients with RA when compared to donors. The donor group had more lymphocytes with activation parameters CD25+, CD69+ and low level of proliferation marker Ki-67 than patients. In contrast to healthy, the RA patients demonstrated a significantly increased expression of Ki 67 in T lymphocytes when co-culturing CFSE- and CFSE+ cells. An increased number of living cells in apoptotic cultures of patients with RA relative to healthy people, in absence of significant differences in the parameters of apoptosis and activation markers in dynamics, as well as pattern of changes in the Ki-67+ cell contents suggested a contribution of the non-autonomous effects of apoptosis to cellular homeostasis in RA patients.