Extended Data Fig. 2. HLA-DR and trogocytosis of synovial Mϕ.

a. HLA-DR protein expression was measured by flow cytometry in CD206⁺CD163⁺ cells and CD206⁻CD163^low cells isolated from low- and high-grade synovitis (n=5).

b. Identification of trogocytic Mϕ in the synovial tissue. Single cell suspensions were prepared from synovial tissues collected from RA patients. Multiparametric flow cytometry identified CD68⁺ Mϕ, which had integrated T cell-derived membrane fragments. Captured membrane fragments stained positive with two independent anti-CD3 antibodies (UCHT clone (clone 2) and SK7 clone (clone 1)). CD68⁺ CD3/UCHTI⁺CD3/SK7⁺ cells were considered trogocytic macrophages. Gating strategy and a representative dot plot overlaying CD68⁺ cells from a tissue with low-grade and high-grade synovitis.