Interleukin-17 acts in synergy with B cell-activating factor to influence B cell biology of primary Sj（o）gren' s syndrome / 中华风湿病学杂志

ABSTRACT

Objective To identify interleukin 17 (IL-17) and B cell activating factor (BAFF) that could influence B cell biology by detecting the expression of BAFF in the serum and labial salivary glands from primary Sj(o)gren's syndrome (pSS) patients and to test the apoptosis rates of B cells cultured with Th17 cells which were transfected with IL-17-siRNA,BAFF-siRNA.Methods A total of 40 patients with pSS who were referred to the Department of Rheumatology and Immunology at Anhui Provincial Hospital from June 2011 to June 2012 were enrolled into this study.The expression of BAFF on salivary gland and serum from pSS patients and healthy controls were detected by ELISA and immunohistochemical examination (22 patients with pSS).Flow cytometry was used to detect B cell's apoptosis,BAFF and IL-17 interfered with amplified Th17 cells,and co-cultured with B cells.Immunoblot was used to detect supernatant antibody in 5 patients with pSS.Independent samples t test was used for statistical analysis.Results In all pSS specimens,infiltrating inflammatory cells expressed BAFF,so did some ductual cells,but acinar cells did not express these markers.There was no expression of BAFF in the controls.BAFF-positive cell numbers in the labial salivary glands of pSS patients with focal infiltrating lymphocytes were more than that with non-focal infiltrating lymphocytes (888±372 vs 164±161,t=5.94,P＜0.05),and the percentage of BAFF-positive lymphocytes over the total infiltrating lymphocytes in the salivary glands of pSS patients with focal infiltrating lymphocytes [(0.18 ±0.08) ％] was higher than those with non-focal infiltrating lymphocytes [(0.09 ±0.07) ％] (t =3.03,P＜0.05).The level of soluble BAFF in patients with pSS [(6.0±2.8) ng/ml] was significantly higher than the controls [(3.8±1.7) ng/ml,t=3.26,P＜0.05].BAFF or IL-17 transfected group,B cell apoptosis rate [(24± 5)％,(23±5)％] were significantly higher than the non-transfected group [(7±4)％],t=4.6,4.4; P＜0.05].And there was no significant difference when compared with cultured B cells (P＞0.05).Compared with the controls,no antibody could be detected in the supernatants.Conclusion BAFF may be involved in the process of local inflammatory damage of the pSS,it may have a synergistic effect with IL-17 on abnormal B cell function.