IL-17 expression on T cells within rheumatoid synovium and in synovial fluid CD4+CD3+ T cells. (a) Rheumatoid synovial tissue was examined by immunohistochemistry. IL-17 (red) was found to colocalise with CD3+ T cells (blue) in perivascular cuffs (purple). Blood vessels were localised with von Willebrand factor (vWF) (green). Nuclear staining is shown in grey. (b) IL-17 (red) expression is associated with CD4+ T cells (blue) but not CD8+ (green) T cells. Nuclear staining is shown in grey. (c) flow cytometric analysis of peripheral blood (PB) and synovial fluid (SF) CD3+ T cells demonstrates that IL-17 is expressed in SF CD4+ T cells. PE, phycoerythrin; FITC, fluorescein isothyocyanate.
Parsonage et al. Arthritis Research & Therapy 2008 10:R47 doi:10.1186/ar2406