Endothelialization occurs in HJD synovium. (A) HJD synovium coexpressed VEGFR2/CD 11b (indicated by yellow staining with red arrows), late EPC markers. (B) VEGFR2 mRNA (labeled kdr, mouse equivalent of human VEGFR2) levels as quantified by quantitative PCR were increased in the peripheral blood of HJD subjects compared with control groups A and B (CNTRLs). (C) Significantly increased numbers of VEGFR2⁺/AC133⁺ early EPCs were also observed in the peripheral blood of HJD subjects compared with control groups A and B (CNTRLs). These data are expressed as a percentage of total peripheral blood mononuclear cells analyzed by flow cytometry.