应伊丽　袁远

[摘要] 目的 探讨IDO/TTS介导的色氨酸代谢途径在免疫性血小板减少症患者的发病和治疗中的作用。 方法 选取2015年7月～2017年8月我院收治的36例免疫性血小板减少症患者和36例来我院体检的健康人为研究对象，分别为观察组和对照组，观察组给予地塞米松40 mg/d进行治疗，对照组不采取任何处理。通过液相-质谱分析仪检测血浆中犬尿氨酸（Kyn）和色氨酸（Trp）的浓度；通过流式细胞仪检测T淋巴细胞中IDO和TTS的表达。 结果 与对照组相比，治疗前免疫性血小板减少症患者血浆中Kyn、Trp、Kyn/Trp的表达量较高，IDO的表达量较低，而TTS的表达量则明显较高，差异有统计学意义（P<0.05）；观察组经有效治疗后，患者血浆中Trp的浓度降低，而Kyn浓度及Kyn/Trp比值则明显升高，差异有统计学意义（P<0.05）；患者IDO表达量明显上升，而TTS的表达量则明显下降，差异有统计学意义（P<0.05）。 结论 地塞米松对免疫性血小板减少症患者疗效显著，主要通过IDO/TTS介导的色氨酸代谢途径发挥作用，临床可以通过监测IDO、TTS的水平指导其治疗。

[关键词] IDO；TTS；免疫性血小板减少症；发病；治疗

[中图分类号] R593.2 [文献标识码] A [文章编号] 1673-9701（2017）36-0006-04

[Abstract] Objective To investigate the role of IDO/TTS-mediated tryptophan metabolic pathway in the pathogenesis and treatment of patients with immune thrombocytopenia. Methods A total of 36 patients with immune thrombocytopenia admitted in our hospital from July 2015 to August 2016 and 36 healthy volunteers who were in our hospital for physical examination were divided into observation group and control group. The observation group was given dexamethasone 40 mg/d. The control group was not given any treatment. Plasma concentrations of Kyn and Tryptophan were measured by liquid chromatography-mass spectrometry. The expression of IDO and TTS in T lymphocytes was detected by flow cytometry. Results Compared with that of the control group， the Kyn， Trp and Kyn/Trp plasma level in patients with pre-immune thrombocytopenia was higher， and the expression of IDO was lower， and the expression of TTS was significantly higher， and the difference was significant（P<0.05）. After effective treatment， the concentration of Trp in the plasma of the observation group was decreased， while the Kyn concentration and Kyn/Trp ratio of the observation group was significantly increased， and the difference was statistically significant（P<0.05）. The IDO expression level significantly increased， while the expression of TTS was significantly decreased， and the difference was statistically significant（P<0.05）. Conclusion Dexamethasone has a significant effect on patients with immune thrombocytopenia. It plays a role mainly through the tryptophan metabolic pathway mediated by IDO/TTS. Dexamethasone can monitor the level of IDO and TTS in order to guide its treatment. Clinically， IDO and TTS levels can be monitored to guide the treatment.

[Key words] IDO； TTS； Immune thrombocytopenia； Incidence； Treatment

免疫性血小板減少症（primary immune thrombocytopenia，ITP）又称特发性血小板减少性紫癜，属于获得性自身免疫性疾病[1，2]，是由于自身反应性B和T细胞被自身血小板抗原所激活[3]，而发生免疫介导的单核巨噬细胞系统过度破坏被自身抗体致敏的血小板或免疫介导的巨核细胞抑制血小板的释放，导致患者产生血小板减少或破坏的免疫性疾病[2，4]，主要表现为血小板减少、皮肤黏膜出血、乏力等症状[5]。地塞米松属于肾上腺糖皮质激素，具有抗炎、抗过敏、抗病毒的多种功效，主要用于治疗严重过敏[6]、哮喘、皮肤病和慢性阻塞性肺部疾病[7]、结核病[8]、免疫性疾病[9，10]，作为治疗免疫性血小板减少症的首选药物，其临床有效率可达70%[11]。色氨酸（Trp）是细胞生存和周期进展中的必须氨基酸，T细胞的周期进程对细胞内Trp含量很敏感，当Trp浓度降低时，T细胞周期发生阻滞，T细胞的增殖会发生抑制[12]。……