Immunohistologic analysis of fucosyltransferase 1 (fut1) expression. (A and B) Photomicrographs of ST samples from patients with rheumatoid arthritis (RA). Cryosections were stained with anti-fut1 (A) or control IgG (B). Original magnification is 400×. Arrows indicate fut1 expression. RA synovial tissues (STs) contain a greater percentage of fut1 lining cells (C) compared to OA and NL ST. A significantly elevated percentage of macrophage staining on RA compared to OA or NL STs was also found (D). Expression of fut1 mRNA in TNF-α stimulated or nonstimulated RA synovial fibroblasts was significantly elevated compared to TNF-α stimulated or nonstimulated NL synovial fibroblasts (E). Means are presented with standard error. *P <0.05 was significant. NS = nonstimulated. (n = number of RA patients or patient ST fibroblasts). (F) Left panel, fut1 straining in RA ST (green); middle panel, cadherin-11 staining in RA ST (red); right panel, merge of the previous two figures. The arrow indicates fut1 and cadherin-11-positive cells respectively (yellow), indicating that fut1 is expressed on fibroblasts in RA ST. (G) Left panel, fut1 straining in RA ST (green); middle panel, CD68 staining in RA ST (red); right panel, merge of the previous two panels. The arrows indicate fut1 on CD68-positive cells, validating that fut1 is expressed on macrophages in RA ST (yellow). The blue background is 4′,6-diamidino-2-phenylindole (DAPI) staining. IgG control staining was performed and showed no fluorescence staining (data not shown; all figures are 400× magnification).