Objectives:The arm of this study was to systematically study the immunopathology of bone and cartilage of sacroiliitis in patients with spondyloarthropathy(SpA).Methods:193 patients with SpA accepted CT-guided needle biopsy in the SIJ.Patientss clinical,laboratory,and imaging data were collected.Immunohistochemistry was performed to detect CD34+microvessels,CD68+osteoclasts/macrophages,Receptor activator of NF-κB ligand(RANKL),osteoprotegerin(OPG),vascular endothelial growth factor(VEGF),metalloproteinase-3(MMP-3),tumor necrosis factor-α(TNF-α)and Caspase-3.27 autopsy subjects were gained as normal controls.