The investigation of the chemokine CXC chemokine ligand 16 and its receptor CXC chemokine receptor 6 in ankylosing apondylitis

Abstract

Objective To investigate the expression of human CXC chemokine ligand 16 (CXCL16) and its CXC chemokine receptor 6 (CXCR6) in ankylosing spondylitis. Methods The mRNA levels of CXCL16 and CXCR6 in the synovial joints fluid and the peripheral blood of AS patients were respectively measured by Real-time PCR and the protein concentration of CXCL16 in serum was tested by enzyme linked immunosorbent assay (ELISA). The expression of CXCR6 and CXCL16 on lymphocytes and monocytes in the peripheral blood were detected by flow cytometry. A chemotaxis experiment was conducted to test a chemo-attractive activity of different concentration of CXCL16 on mediating lymphocytes trafficking in the synovial joints fluid and the peripheral blood of AS patients. Results CXCL16 protein concentrations expression were significantly increased in the peripheral blood (175.10±13.28) pg/ml and synovial joints fluid (357.90±60.44) pg/ml of the AS patients compared with healthy controls (122.80±21.42) pg/ml, P<0.01; The frequency of CXCR6 in the peripheral blood lymphocytes of AS patients was higher than in the healthy controls (48.63±2.60)% verse (37.70±2.37)%; P<0.01). The chemotaxis activity of CXCL16 in synovial joints fluid was significantly higher than that in the peripheral blood lymphocytes of AS patients. Conclusion The gene and protein expression of CXCL16/CXCR6 is significantly higher in the peripheral blood and synovial joints fluid than those in the control group, these data indicating novel immunotherapeutic and targets of AS. Key words: Chemokine; CXC chemokine ligand 16; Ankylosing apondylitis; CXC chemokine receptor 6