Figure 7. IL-1β induces an osteoclastogenic Treg population in humans.

(A and B) Naive CD4⁺ cells from peripheral blood of healthy adult donors were cultured under iTreg-polarizing conditions, with or without supplemental IL-1β. After 5 days of differentiation, cells were cocultured with peripheral blood CD14⁺ cells isolated from the same donors. After 15 days of coculture, cells were stained for tartrate-resistant acid phosphatase (TRAP) and TRAP⁺ osteoclasts were measured (surface area). Scale bars: 1 mm. (C) viSNE plots of synovial CD4⁺FOXP3⁺ T cells from 8 patients with OA and 8 patients with RA. The dashed red outline (in gray in panel D) indicates RANKL^hi cells. (D) viSNE map colored by density. (E and F) CD4⁺FOXP3⁺RANKL^hi T cell frequencies in synovial tissue from RA patients (n = 8) and OA patients (n = 8). (G) Expression of indicated proteins by mass cytometry of CD4⁺FOXP3⁺RANKL^lo populations and CD4⁺FOXP3⁺RANKL^hi cells from 8 patients with OA and 8 patients with RA. MFI, mean fluorescence intensity. Data are expressed as mean ± SEM. Statistical significance was determined using 3-way ANOVA (B), Mann-Whitney U test (F), or 1-way ANOVA (G).