BACKGROUND:Ankylosing spondylitis is an autoimmune disease at high inflammatory state, and its pathogenesis is stil unclear. Besides, there is a lack of entirely satisfactory curative strategies. OBJECTIVE: To explore the immunoregulation capability of bone marrow mesenchymal stem cels from ankylosing spondylitis patients on macrophages and the potential therapeutic use of bone marrow mesenchymal stem cels from healthy donors on ankylosing spondylitis. METHODS: Bone marrow mesenchymal stem cels were extracted from 21 healthy donors and 25 ankylosing spondylitis patients respectively, and passage 4 cels were used in subsequent experiments. A human monocytic cel line was induced to differentiate into macrophages. The phenotypic markers of bone marrow mesenchymal stem cels and macrophages were detected by flow cytometry. Expressions of tumor necrosis factor-α and tumor necrosis factor-α-stimulated gene 6 (TSG-6) proteins in the supernatant of co-culture system were detected by ELISA. Quantitative real-time PCR was applied to detect the mRNA level of cytokines secreted by bone marrow mesenchymal stem cels and macrophages. RESULTS AND CONCLUSION:The typical mesenchymal stem cel surface markers were expressed in both bone marrow mesenchymal stem cels from healthy donors and patients with ankylosing spondylitis, and CD68 was detected positively in induced macrophages. The protein and mRNA levels of tumor necrosis factor-α secreted by macrophages co-cultured with bone marrow mesenchymal stem cels from patients with ankylosing spondylitis were obviously higher than those from healthy donors (P < 0.05). TSG-6 secreted by bone marrow mesenchymal stem cels from patients with ankylosing spondylitis was lower than that by bone marrow mesenchymal stem cels from healthy donors in both RNA transcriptional and protein levels (P < 0.05). Our study demonstrates that bone marrow mesenchymal stem cels from patients with ankylosing spondylitis shows abnormal immunoregulatory function on inhibiting the tumor necrosis factor-α secretion from macrophages, which reveals a mechanism of immune disorder in ankylosing spondylitis. The therapeutic mechanism of bone marrow mesenchymal stem cels from healthy donors may work by secreting enough TSG-6 to inhibit the activation of macrophages in patients with ankylosing spondylitis, and thereby to decrease the secretion of tumor necrosis factor-α. Cite this article:Sun SH, Wang P, Su CY, Xie ZY, Li YX, Li D, Wang S, Su HJ, Wu XH, Deng W, Wu YF, Shen HY. Bone marrow mesenchymal stem cels derived from patients with ankylosing spondylitis show abnormal immunoregulation capability on macrophages. Zhongguo Zuzhi Gongcheng Yanjiu. 2016;20(1):13-19.