AB0080 IMBALANCE OF MONOCYTE/MACROPHAGE POLARIZATION IN PERIPHERAL BLOOD AND SYNOVIAL FLUID OF RHEUMATOID ARTHRITIS PATIENTS

Background Macrophages strongly contribute to the pathogenesis of rheumatoid arthritis (RA), initiating inflammatory response, join damage, but also may promote resolution inflammation and restoration tissue immune-homeostasis [1,2]. This seems be related an unbalanced immunological response mediated by macrophages through their polarization into “classically” “alternatively” activated phenotypes (M1 or M2) [3,4]. However, little is known about M1 M2 phenotype circulating precursors (monocytes) in peripheral blood (PB) synovial fluid (SF) RA patients. Objectives To characterise status PB SF monocytes patients together with distribution monocyte subsets flow cytometry (FC). Methods Nineteen not yet treated biological DMARDs (mean age 62±14 years), who fulfilled 2010 ACR/EULAR classification criteria for accordance EULAR recommendation, as well 19 age-matched healthy subjects (HSs) were enrolled after signed informed consent. cells collected from each patient, whereas only HSs. The expression CD14 CD16 surface markers allowed identify population subsets: “classical”(CD14++CD16-), “intermediate”(CD14++CD16+), “non-classical”(CD14-CD16+). monocytes) was identified evaluation CD80, CD86, TLR2 TLR4, (M2 evaluating CD204, CD163 CD206 markers. Results expressed percentage positive over total leukocytes SF. Statistical analysis carried out Mann-Whitney non-parametric test. In patients, CD14++CD16+monocytes significantly higher compared that HS (p<0.001), it (p<0.05). CD14-CD16+monocytes increased RA-PB HS-PB RA-SF (p<0.01; p<0.05). characterized (CD80 + CD86 TLR4 CD204 - cells) HSs RA-SF. (CD204 CD80 RA-SF, this increase lower significant than observed monocytes. Moreover, M1-M2 ratio 8:1in RA-PB. Therefore, belonged “non-classical” subset, “classical” subset. mixed M1/M2 these they primarily “intermediate” Interestingly, highest receiving a daily (25mg) cumulative glucocorticoid dosages. Conclusion results confirm immune-inflammatory disease mainly both macrophages, demonstrated Glucocorticoids might transition, which characterizes under remission increasing percentage. References [1]Okabe Y et al. Nat Immunol. 2016;17:9–17. [2]Kurowska-Stolarska M, Rev Rheumatol. 2022;18:384-97. [3]Cutolo Front 2022;13:867260. [4]Ross EA, 2021;12:708186. Acknowledgements: NIL. Disclosure Interests Stefano Soldano: None declared, Emanuele Gotelli: Paola Montagna: Rosanna Campitiello: Alberto Sulli: Vanessa Smith: Maurizio Cutolo Grant/research support from: BMS, Boehringer, Amgen.