老年重症脓毒症患者树突状细胞的功能变化

The functional alteration of dendritic cells in severe septic old patients

目的 初步探讨老年脓毒症患者树突状细胞（DC）的功能变化。方法取广州军区广州总医院干部内科及内科重症监护病房（MICU）同一时间收治的老年患者共20例，排除既往有恶性肿瘤、血液系统疾病、免疫性疾病、干扰免疫功能药物治疗史的患者，按美国胸科医师协会／危重病医学会的定义分为非脓毒症组（A组）、脓毒症组（B组）、严重脓毒症组（C组）、脓毒症休克组（D组）；分别分离每例患者的外周血单个核细胞（PBMC），在体外用人重组粒-巨噬细胞集落刺激因子（GM-CSF）及白细胞介素4（IL4）培养10d后，倒置显微镜、扫描电镜以及流式细胞仪鉴定，采用配对t检验比较培养前后各组细胞表面标志物的变化，并使用MTT比色法观察各组患者树突状细胞在体外刺激同种异体T淋巴细胞反应的能力。结果四组患者的外周血单个核细胞在体外经组合细胞因子培养后均可分化为具有典型树突状形态的细胞，培养后细胞表面CD40，CD80，CD86及HLA-DR的表达较培养前明显增高，分别为（43．2±12．5）％／（27．3±9．3）％、（31．44±10．1）％／（22．5±8．7）％、（39．3±15．7）％／（21．9±7．7）％及（75．4±25．6）％／（58．7±16．7）％；四组患者培养后获得的树突状细胞体外刺激同种异体T淋巴细胞反应的能力（刺激指数）分别为（23．3±7．9）、（18．9±8．3）、（11．4±5．1）、（5．5±3．7），随患者脓毒症严重程度的增加而减低，其中D组树突状细胞体外刺激同种异体T淋巴细胞反应的能力最低。结论老年脓毒症患者随着脓毒症严重程度的增加，其树突状细胞的免疫功能逐渐减退。

Objective To investigate the functional changes of dendritic cells （DC） in elderly patients with sepsis. Method Elderly patients （ n = 20）, ages 75 to 86 years, treated in the department of internal medicine for cadres and the medical intensive care unit （MICU）, were selected to participate in the study. Patients with malignant tumors, hematological diseases, immune diseases, or a history of receiving drugs known to interfere with immune functions were excluded. Using the American College of Chest Physicians/Society of Critical Care Medicine （ACCP/SCCM） definition of sepsis, the patients were categorized into four groups： non-sepsis （group A） （ n = 5） ; sepsis （group B） （ n = 5） ; severe sepsis （group C） （ n = 5） ; and septic shock （group D） （ n = 5）. The peripheral blood mononuclear cells （PBMCs） of each patient were isolated and cultured with human recombinant granulocyte-macrophage colony-stimulating factor （GM-CSF） and interleukin-4 （IL-4） in vitro for 10 days. The cells were examined under an inverted microscope, scanning electron microscopy, and flow cytometry. The MTT colorimetric assay was used to observe the abilities of the dendritic cells to stimulate an allogeneic T lymphocyte response in vitro. Paired t -test was used to compare changes in the surface markers among the different groups. Results The PBMCs in the four groups of patients differentiated into cells with typical dendritic configurations after in vitro culture with combined cytokines. The CD40, CD80, CD86, and HLA-DR expressions on the cell surfaces increased after culture,with （43.2±12.5）%/（27.3± 9.3）%, （31.4 ±10.1）%/（22.5 ± 8.7）%, （39.3±15.7） % / （ 21.9 ± 7.7） %, and （75.4 ± 25.6） % / （58.7 ± 16.7） %, respectively. The stimulation index （the abilities of the dendritic ceils to stimulate the allogeneic T lymphocyte response in vitro） in the four groups of patients after culture were （23.3± 7.9） in group A, （18.9 ±8.3） in group B, （11.4± 5.1） in Group C, and （5.5 ± 3.7） in Group D. Conclusions The immune functions of the dendritic ceils of elderly patients with sepsis decrease in a linear manner with the severity of their septic state.