BackgroundAnkylosing spondylitis (AS) is a sort of inflammatory arthritis that affects axial skeleton, peripheral joints, and certain extra-articular organs, including the eyes, skin, and gut. Recently, many attempts have been made to use parasite administration (e.g., ingestion of eggs of the nematode Trichuris suis) as a new modality for treating inflammatory disorders. Our group published that Clonorchis sinensis protein attenuated inflammation in AS.ObjectivesThus, this study aimed to assess the therapeutic potential of Clonorchis sinensis-Excretory/Secretory protein (Cs-ESP) for AS.MethodsCytotoxicity of Cs-ESP at different doses was assessed by MTS and flow cytometry before performing experiments. Peripheral blood mononuclear cells (PBMCs) and synovial fluid mononuclear cells (SFMCs) were obtained from AS patients. Inflammatory cytokine-producing cells were analyzed using flow cytometry. The levels of INF-g, IL-17A, TNF-a, and IL-6 were measured by enzyme-linked immunosorbent assay (ELISA). SKG mice were treated with Cs-ESP or vehicles. Inflammation was evaluated using immunohistochemistry.ResultsTreatment with Cs-ESP resulted in no reduced cell viability of PBMCs or SFMCs. In experiments culturing PBMCs and SFMCs, the frequencies of IFN-g and IL-17A producing cells were significantly reduced after Cs-ESP treatment. In the SKG mouse model, Cs-ESP treatment significantly suppressed arthritis and enthesitis.ConclusionWe provide the evidence demonstrating that Cs-ESP can ameliorate clinical signs and cytokine derangements in AS.Figure 1.Clonorchis sinensis-Excretory/Secretory protein (Cs-ESP) ameliorates clinical symptoms in SKG miceReferences[1]Kim TJ, Kim TH. Clinical spectrum of ankylosing spondylitis in Korea. Joint Bone Spine (2010) 77(3):235–40.[2]Martinez FD. The coming-of-age of the hygiene hypothesis. Respir Res (2001) 2(3):129–32.[3]Summers RW, Elliott DE, Urban JF Jr., Thompson RA, Weinstock JV. Trichuris suis therapy for active ulcerative colitis: a randomized controlled trial. Gastroenterology (2005) 128(4):825–32.[4]Osada Y, Shimizu S, Kumagai T, Yamada S, Kanazawa T. Schistosoma mansoni infection reduces severity of collagen-induced arthritis via downregulation of pro-inflammatory mediators. Int J Parasitol (2009) 39(4):457– 64.[5]Song X, Shen J, Wen H, Zhong Z, Luo Q, Chu D, et al. Impact of Schistosoma japonicum infection on collagen-induced arthritis in DBA/1 mice: a murine model of human rheumatoid arthritis. PloS One (2011) 6(8):e23453.Acknowledgements:NIL.Disclosure of InterestsNone Declared.