Ankylosing spondylitis (AS) is an inflammatory arthritis of the axial skeleton that predominantly affects young men. HLA-B27 has remained the major genetic risk factor in AS. Recently, more non-MHC genes has been discoverd to be involved in AS pathogenesis, especially IL-23 signalling pathway related genes. We performed a proteomic study of the peripheral blood mononuclear cells from AS patients and healthy donors.