T-regulatory cells from patients with rheumatoid arthritis retain suppressor functions in vitro

Daniil Shevyrev; Valeriy Tereshchenko; Vladimir Kozlov; Alexey Sizikov; Oksana Chumasova; Veroniсa Koksharova

doi:10.3892/etm.2021.9641

T-regulatory cells from patients with rheumatoid arthritis retain suppressor functions in vitro

Exp Ther Med. 2021 Mar;21(3):209. doi: 10.3892/etm.2021.9641. Epub 2021 Jan 14.

Authors

Daniil Shevyrev¹, Valeriy Tereshchenko², Vladimir Kozlov¹, Alexey Sizikov³, Oksana Chumasova³, Veroniсa Koksharova³

Affiliations

¹ Laboratory of Clinical Immunopathology, Federal State Budgetary Scientific Institution, Research Institute of Fundamental and Clinical Immunology, Novosibirsk 630099, Russia.
² Laboratory of Molecular Immunology, Federal State Budgetary Scientific Institution, Research Institute of Fundamental and Clinical Immunology, Novosibirsk 630099, Russia.
³ Rheumatology Department, Federal State Budgetary Scientific Institution, Research Institute of Fundamental and Clinical Immunology, Novosibirsk 630099, Russia.

Abstract

Rheumatoid arthritis (RA) is a chronic disease of connective tissue caused by intolerance to self-antigens. Regulatory T cells (Tregs) are key players in maintaining autotolerance through a variety of suppressor mechanisms. RA is generally believed to develop due to disorders in Tregs; however, there is no consensus on this issue. Thus, the present study focused on phenotypical analysis of Treg cells and their ability to suppress CD4⁺ and CD8⁺ cell proliferation. The present study used peripheral blood samples from 21 patients with RA and 22 healthy donors. The CD25⁺FoxP3⁺ subpopulation of Tregs was analyzed using flow cytometry to evaluate the expression of CTLA-4, PD-L1, HLA-DR, CCR4, CD86 and RORyt. Tregs suppressor activity was calculated in terms of suppression of the proliferation of CD4⁺ and CD8⁺ lymphocytes in vitro. Suppressor activity of the total Treg population did not differ between patients with RA and healthy donors. However, the patients had elevated CD25^loFoxP3⁺ levels and lower CD25^hiFoxP3⁺ levels; in addition, they had more activated Tregs expressing PD-L1, HLA-DR, CCR4 and CD86. The surface expression of CTLA-4 was below the reference level. The patients also had transitional FoxP3⁺RORyt⁺ cells and elevated CD4⁺RORyt⁺ levels, which were highly correlated with disease activity. These results show that in RA, Treg cells are activated and have an immunosuppressive activity. However, it is the transitional FoxP3⁺RORyt⁺ cells and increased CD4⁺RORyt⁺ percentages in peripheral blood that appear to be associated with the pathological conversion of some Treg cells into Th-17. This process appears to be key in RA pathogenesis.

Keywords: RORyt+ lymphocytes; regulatory T cells; rheumatoid arthritis; suppressor activity.