Figure 2

CD68 positive myeloid cells in muscle tissue from JDM patients express MRP14 and MRP8/14. (A) Immunohistochemical staining for CD68 (left) and MRP 8/14 (right) on muscle tissue from JDM patient (top panel) and controls (bottom panel). Positive cells stain brown as indicated by arrows. Bar represents 50 microns. (B) Two-colour immunofluorescence staining for infiltrating cells, lineage markers (green), MRP14 (red), double positive cells show as yellow. Bar represents 50 microns. Bar graph illustrates %MRP14+ cells expressing specific lineage markers, based on counting 10 fields at x10 magnification for each marker, bars and lines represent median and IQR respectively. (C) Immunohistochemical staining for CD3 and CD68 from JDM patients with a predominant macrophage infiltration, histological score of 0 for T cells and 2 for monocytes (upper panel), and mixed T cell-macrophage infiltrate, scores 2 for T-cells and 2 for macrophage (lower panel). Bar represents 100 microns. (D) Percentage of patients with histology scores 0, 1 and 2 for CD68 (macrophage) and CD3 (T cell) frequency in JDM muscle biopsies (n = 28, Chi square test for trend, P < 0.001). JDM, juvenile dermatomyositis; MRP, myeloid-related protein.