Chemokine binding to CD68+ monocyte/macrophages (red) in the synovium. (a) CCL5 binding to CD68+ cells around a venule in the subintima of inflamed, nonrheumatoid synovium. (b) CXCL8 (IL-8) binding to macrophages in a macrophage-rich infiltrate in rheumatoid tissue. (c) CXCL8 binding to macrophages in a lymphocyte-rich infiltrate in rheumatoid synovium. (d) CCL3 (macrophage inflammatory protein-1α) binding to macrophages in the inflamed intimal layer of rheumatoid synovium. Magnification × 470 (a)–(d).