A. STs from NL, OA and RA were stained with anti-IL-11 Ab (original magnification x 200) and (B) staining was scored on a scale of 0–5 in the lining, sublining and endothelial cells, n=8−9. C. IL-11 protein concentration was determined in RA SF (n=40) and OA SF (n=40) as well as in plasma from RA (n=40), OA (n=35) and NL (n=35) individuals. D. RA ST serial sections were stained with Abs to anti-IL-11, CD68, VWF or Vimentin to establish which cell types produce IL-11, n=5. E. To confirm serial section studies, individual (red or green) as well as the overlapping (yellow) immunofluorescence staining was shown of RA STs that were stained with Abs to anti-IL-11 (green) or cell markers per slide including CD68 (red), VWF (red) or Vimentin (red) (original magnification x 400), n=5. Values are the mean ± SE. * represents p <0.05.