Resistance of SFMCs to suppression is not caused by activation status of APCs. (A-B) Monocytes from paired PBMCs and SFMCs of JIA patients were analyzed for CD80, CD86, and HLA-DR expression by flow cytometry. (A) Histograms showing CD80 (left panel), CD86 (middle panel), and HLA-DR (right panel) fluorescence intensity in paired PBMCs (solid gray) and SFMCs (black line), one representative of n = 4. (B) MFI of CD80 (left panel), CD86 (middle panel) and HLA-DR (right panel) in monocytes from paired PBMCs and SFMCs of n = 4. (C-D) CD3⁺ T cells, CD3⁻ APCs and CD4⁺CD25⁺CD127^low Tregs were sorted by flow cytometry. PB T cells were cocultured with PB APCs (black bars) and SF T cells were cocultured with SF APCs (gray bars) or PB APCs (white bars) in the absence or presence of SF Tregs at a 1:8 and 1:4 ratio or additional effector cells (+eff) at a 1:4 ratio. Suppression of CD4⁺ (C) and CD8⁺ T cell proliferation (D) was measured. The results show percentage of suppression in the presence of Tregs or additional effector cells relative to effector cells alone. Bars represent mean ± SEM of n = 3.