THE INFLUENCE OF IL-7 AND IL-15 ON T-REGULATORY CELLS OF DONORS AND PATIENTS WITH RHEUMATOID ARTHRITIS IN VITRO

The aim of this study was to assess the infl uence of homeostatic factors IL-7 and IL-15, that induced homeostatic proliferation (HP), on the phenotypic characteristics of T-regulatory cells (Treg) from healthy donors and patients with rheumatoid arthritis (RA) in vitro. Analysis of Treg phenotype was performed by fl ow cytometry, using Foxp3, CD127, CD4 and CD25. Isolated from the blood cells were cultured with and without stimulation during 7 days. IL-7, IL-15 and anti-CD3 antibodies supplemented IL-2 were chosen as activators. Purifi ed Treg cells were labeled with CFSE dye to assess proliferation. We estimated that HP factors eff ectively maintain the number and phenotype (CD25⁺FoxP3⁺) of Treg in vitro. Also, in patients group we showed an increasing of CD4⁺CD25⁺FoxP3⁺ cells under all stimulation condition that may indicate the induction of Treg from conventional T cells. Herewith under IL-7 and IL-15 Treg cells from RA patients had a low proliferative activity than Treg from donors. The reduced proliferative activity of Treg in the group of RA-patients under IL-7 and IL-15 perhaps make a signifi - cant contribution to the development of the disease due to the delay of Treg pool reconstitution in the lymphopenia conditions on the initial stage. Furthermore, increased induction of CD4⁺CD25⁺FoxP3⁺ cells in PBMC cultures in patients group associated with pathogenesis of RA, since induced Treg have transient and unstable expression of FoxP3.