Fig. 4

CD163⁺ macrophages in the infrapatellar fat pad (IFP) are pro-inflammatory. Total macrophage population (left), and CD163⁺ (red) and CD163^- CD14⁺ (green) macrophages (right) are depicted against the forward scatter-area (FSC-a) (a). Differences between CD163⁺ and CD163^- CD14⁺ macrophages in surface marker expression (N = 7–12) (b) and ex vivo intracellular cytokine production (N = 7–8) (c). Each line indicates one patient sample. A P value <0.05, determined by the Wilcoxon signed rank test (b) or paired Student’s t test (c) was considered significant