236例SARS患者外周血中幼稚和记忆CD4T细胞亚群变化

目的：研究严重急性呼吸综合征(SARS)患者外周血T淋巴细胞及CD4细胞中幼稚亚群(Tn)和记忆亚群(Tm)的异常变化，以期更好地了解SARS患者细胞免疫功能，从而建立新的实验室指标。方法：采用多色荧光标记流式细胞术结合血液分析仪检测236例不同病程的SARS患者(包括50例重型患者和186例普通型患者)的外周血T淋巴细胞及CD45RA和CD45RO分子在CD4细胞中的表达情况。结果：与正常对照组比较，SARS患者的外周血T淋巴细胞及CD4细胞中Tn和Tm绝对值明显减低，其百分比无明显改变，重型尤其明显。其中，重型组CD4细胞中的Tm百分比高于普通型；各病程SARS患者比较，三个病程组的T淋巴细胞计数均明显低于正常对照组，以I组为最低，CD4、CD8亚群的绝对值均低于正常对照组；在CD4细胞中，各病程Tn和Tm的百分比无明显差异，绝对值以Ⅱ组最高，但均低于正常对照组。结论：伴随着全面低下的细胞免疫功能，SARS患者的CD4^ T细胞的Tn和Tm均明显减少，重型尤其明显，但是在病程中可有轻度回升。相对于百分比而言，CD4细胞中Tn和Tm表面标志分子(分别为CD45RA和CD45RO分子)表达绝对值对于明确机体细胞免疫功能的意义更为重要。

Abnormal changes of T lymphocyte and its naive and memory subsets of CD4 cells in the patients with severe acute respiratory syndrome

Objective:To study abnormal changes of T lymphocyte and its naive subset (Tn) and memory subset (Tm) of CD_4 cells in severe acute respiratory syndrome (SARS) patients in order to find out cellular immune function of SARS patients,to establish a new laboratory parameter and which may contribute to the preliminary pathogenesis.Methods:Flow cytometer with multi color fluorescence and hematology analyzer were used to detected T lymphocyte and its expression of CD_45RA/CD_4 and CD_45RO/CD_4 which indicating naive and memory subsets in 236 cases of SARS including 50 cases of severe type (ST) of patients and 186 cases of common type (CT) of patients. According to the different duration of the illness,patients were divided into three groups,i.e.,group I (0 to 14 days of illness),group II (15 to 35 days) and group III (> 35 days). Results:Statistical analysis by means of SAS software showed that there was significant decrease in absolute counts (AC) of T lymphocyte and its subsets in SARS patients in comparison with those of normal control group,especially ST patients. There was,however,no change of the ratio of CD_4 and CD_8 and the ratio of the subsets of CD_4. There was significant increase in the ratio of Tm of CD_4 subset in ST group compared with that of CT group. The ACs of CD_4 and CD_8 in different groups of duration were lower than normal control group,group I was the lowest. Among CD_4 cells,the ACs of naive and memory subsets in groupa! was the highest,however,they were all lower than those of normal control group. Conclusion:Along with the reduction of cellular immunity,the number of Tm and Tn subsets of CD_4 T lymphocytes were decreased obviously in SARS patients,especially for ST patients. However,the above decrease could be slightly raised in process of SARS. Absolute count of T lymphocyte subpopulation showed more significant meaning than its percentage as a parameter of cellular immune function for laboratory diagnosis and therapy.