PROPORTION OF NAIVE CD45RA+ AND CD31+T-CELLS IN PATIENTS WITH RHEUMATOID ARTHRITIS UNDER STIMULATION WITH HOMEOSTATIC FACTORS IN VITRO

Much attention of researchers is directed to study the role of factors of homeostatic proliferation in the pathogenesis of autoimmune diseases, however, the effect of IL-7 and IL-15 on the phenotype of naive T cells  has not yet been sufficiently investigated in the pathology. The aim of this study was to investigate the proportion of CD45RA⁺ and CD31⁺ naive cells among CD4⁺ and CD8⁺ lymphocytes from healthy individuals and patients with rheumatoid arthritis (RA) upon stimulation with IL-7, IL-15 in vitro. In peripheral blood, we did not find any differences in the number of CD45RA⁺ and CD31⁺ cells between the group of donors and group of RA patients. In donors, stimulation by a combination of IL-7 with IL-15 promoted an increase in the proportion of CD4⁺CD45RA⁺ and CD8⁺CD45RA⁺  relative to their level in the peripheral blood. Whereas in RA patients the number of CD8⁺CD45RA⁺ cells decreased under IL-15 and the combination of IL-15 with IL-7 compared to the control without stimulation, and it, as a proportion of CD4⁺CD45RA⁺ cells, significantly differed from the content of these cells  under the same conditions in donors. There were no significant differences in the content of CD31⁺ cells and the number of CD31⁺ cells proliferating to cytokines, both between the groups of donors and patients with RA, and between different culture conditions. Thus, we can say that under the factors of homeostatic proliferation, there is a proportional increase in CD31⁺ T cells number, both in donors and in patients with RA. At the same time, naive T cells from donors  retain the expression of CD45RA during cultivation, while naive T cells from patients partially lose it. The obtained data  indicate that in RA, under  factors of  homeostatic proliferation  the phenotype of naive T cells is converted into the phenotype of memory T cells.

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