Fig. 1

Circulating CD45⁺/Col-1⁺ fibrocytes are contaminated with polymorphonuclear leukocytes. a Representative gating strategy for identification of circulating CD45⁺/Collagen-1⁺ fibrocytes from PBMCs. Isotype control for collagen-1 (Col-1) was used to set the gate for Col-1+ cells within alive CD45⁺ cells. Red cells are CD45⁺Col-1⁺. b FSC and SSC characteristics of CD45⁺/Col-1⁺ cells (in red) compared to all alive cells (blue) showing that most CD45⁺/Col-1⁺ cells are found in the polymorphonuclear leukocytes fraction. c Histogram overlay showing surface expression of CD15 assessed by flow cytometry on CD45⁺/Col-1⁺ cells (red), CD14+ monocytes (black) and T cells (gray). d CD45⁺/Col-1⁺ cell enriched fraction and PBMC cultured fibrocytes were analyzed with immunocytochemistry (ICC) for CD15 and collagen-1 expression. Magnification for all ICC figures was 200× and sections were counterstained with hematoxylin. This is representative of 7 experiments

CD14+ Mo = CD14+ monocytes, PBMC = peripheral blood mononuclear cells, FSC = forward scatter, SSC = side scatter.