传染性非典型肺炎(SARS)患者外周血树突状细胞亚群的变化及临床意义

目的观察传染性非典型肺炎(SARS)患者外周血树突状细胞(DC)亚群的变化趋势,并评价其在SARS免疫发病机制中的作用。方法利用流式细胞技术对30例SARS重症及一般患者外周血DC1和DC2的百分比和绝对数进行跟踪观察,同时分析SARS患者DC细胞亚群变化的原因及其临床意义。结果研究发现,SARS患者发病初期外周血DC细胞亚群数量就明显下降,并在随后4～5周维持低水平、甚至消失;重症患者病程较长,约持续9周以上,而一般患者病程约持续6周;前者在发病6周后DC亚群数量才恢复至正常值,而后者在发病4周后DC亚群数量就开始回升。结论SARS患者发病期间体内DC细胞亚群数量明显下降,提示DC细胞抗病毒能力降低;这既与SARS冠状病毒的直接攻击密切相关,又与临床大剂量激素的使用有关。

Characterization of peripheral dendritic cell subsets and its implication in patients infected with severe acute respiratory syndrome

OBJECTIVE: To investigate the dynamic changes of dendritic cell subsets in peripheral blood of patients infected with severe acute respiratory syndrome (SARS) and evaluate their roles in the immunopathogenesis of SARS. METHODS: Flow cytometry was applied to study the dynamic alteration of the number and frequencies in circulating DC cell subsets in 30 SARS patients including critical SARS (n = 11) and general SARS (n = 19). The reasons and clinic significances of the peripheral blood DC subsets changes in SARS patients were also analyzed in our study. RESULTS: The patients in critical status had a 9-week course of disease, longer than the 6-week course observed in subjects in general status. The frequency of peripheral DC cell subsets significantly dropped beginning from the onset of symptom in SARS patients and was maintained at significant low levels during the following 4 - 5 weeks, 1.7 +/- 1.8, 5.3 +/- 5.0/ micro l for DC1, 0.57 +/- 1.02, 0.98 +/- 1.11/ micro l for DC2 for cases in critical and general statuses, respectively, compared with healthy subjects; more importantly, the pDC2 even disappeared in the patients who died from SARS diseases. The possible reasons responsible for the alteration of DC subsets in peripheral blood is likely to be the direct attack of SARS-CoVin circulation and be partially involved the application of large dose of steroid. The frequency in DC cell subsets returned to normal level in convalescent stage. CONCLUSION: Our results showed SARS patients had a significant decrease of circulating DC cell subset frequency, which maybe lead to the host immunodeficiency response to SARS-associated coronavirus (SARS-CoV).