Immunohistochemical detection of VEGF in NR (A, and C) and in I (B and D) synovial biopsies. At the time of surgery, synovial biopsies coming from NR or I areas were macroscopically selected as described in Materials and methods. NR and I synovial biopsies were stained with anti-VEGF antibody. Positive staining was detected as brown peroxidase reaction product. (A) and (B) global image of the section, (C) and (D) magnification (×10) of intima lining and vessel lumen.