POS0673 TOLEROGENIC DENDRITIC CELLS IN RHEUMATOID ARTHRITIS PATIENTS: NEWS AND PROMISES

Abstract

Background:Dendritic cells (DCs) are known to contribute to the pathogenesis of rheumatoid arthritis (RA) through presentation of cartilage glycoprotein, production of proinflammatory cytokines and activation of Th1/Th17 responses. Along with stimulating activity, DCs may exhibit suppressive functions via capacity to induce T cell apoptosis/anergy and to generate regulatory T cells. Since these DCs have potential to control autoreactive T-lymphocytes, the enhancing of tolerogenic properties of DCs seems to be a new important strategy in treatment of RA. Dexamethasone is widely used in clinical practice and can be used as a tolerogenic substance. Therefore, the properties of DCs generated in presence of dexamethasone are of great clinical interests.Objectives:The aim of our study is to describe the properties of tolerogenic DCs, generated with dexamethasone in patients with RA and their influence on autologous T-cells.Methods:Sixty five patients with RA with high and moderate activity of disease were recruited in this study. All patients follow ACR/EULAR criteria (2010). All studies were performed after receiving informed consent. All patients received conventional synthetic DMARDs. DCs were generated from blood monocytes culturing for 5 days with GM-CSF and IFN-α in the presence dexamethasone (dexDCS), applied on third day. LPS as maturation stimuli was added on fourth day. The expression of CD14, CD83, HLA-DR, TLR-2 on the surface of DCs was measured by flow cytometry. The functions of DCs were evaluated by measuring cytokine production and DCs allostimulatory activity in mixed lymphocyte culture. Mature DCs generated in absence of dexamethasone used as control.Results:We revealed that dexDCs are characterized by enhanced expression of CD14+cells and decreased number of CD83+cells but percent of HLA-DR+cells were constant (about 85). DexDCs show high expression of TLR-2 is seen as tolerogenic molecule (75%vs51%, p=0.05 compared to control). DexDCs also have marked prominent increase of TNFα/IL-10 ratio in contrast to control (0.59 vs 1.8, p=0.03). DexDCs suppressed proliferation of allogenic T-cells (2005 vs 7980 cpm, p=0.0002). To assess the stability of the DC in the proinfflamatory micro-environment after assessing stimulatory activity dexDCs were then cultivated with LPS and allostimulatory activity were evaluated one more. The stimulation activity dexDCs after incubation with LPS were not increase (4692 vs 6053 cpm, p=0.7). Also earlier we showed possibility of dexDCs induse apoptosis of autologous T-cells, activation of CD4+IL10+Tr1 and possession of antigen-specific suppression.Conclusion:The data obtained indicate that dexDCs from RA patients have the main tolerogenic features and stable in inflammatory environment that proves their potential in the treatment of rheumatoid arthritis.Disclosure of Interests:None declared