老年人外周血淋巴细胞的凋亡及CD28和CD95的表达

目的通过对健康老年人与健康成年人外周血淋巴细胞的凋亡率及CD28和CD95表达水平的比较性研究，观察衰老对淋巴细胞凋亡的影响，以及CD28和CD95与淋巴细胞凋亡的关系。方法将实验对象分为2组：成年组（25～59岁）与老年组（60～90岁）各20例，采用免疫荧光标记流式细胞术检测外周血淋巴细胞CD28和CD95的水平；Annexin-v-FITC／PI双染色流式细胞术测定地塞米松诱导的淋巴细胞凋亡。结果老年组：淋巴细胞凋亡率[（14．90±4．12）％]显著高于成年组[（8．12±3．12）％]；CD28^＋CD95[（8．80±4．86）％]及CD28^＋[（36．31±10．38）％]均明显低于成年组[（23．09±3．48）％、（52．29±4．90）％]，而CD28^-CD95^＋[（53．23±8．28）％]、CD95^＋[（80．25±7．19）％]及CD28^-[（63．69±10．38）％]明显高于成年组[（33．58±4．72）％、（63．18±4．12）％、（47．71±4．90）O]；CD28^＋CD95^＋在两组间差异无统计学意义。淋巴细胞凋亡率与CD28（CD28^＋）呈负相关，与CD95（CD95^＋）呈正相关。结论老年人淋巴细胞凋亡率上升；CD28^＋表达下降，CD28^-、CD95^＋表达上升；淋巴细胞的凋亡率与CD28^＋、CD95^＋有相关性。提示老化导致老年人淋巴细胞凋亡增加，CD28和CD95的变化与淋巴细胞凋亡密切相关。

Apoptosis of lymphocytes and expression of CD28 and CD95 on peripheral blood lymphocytes in the elderly

Objective To observe the dexamethasone-induced apoptosis of lymphoeytes in the elderly, and the relationship between lymphocyte apoptosis and the expression of CD28 and CD95. Methods The subjects were divided into two groups： 20 subjects each in healthy adult group with a mean age of （37.2±7.56） years （eight males and twelve females） and healthy elderly group with a mean age of （78.7±9.57） years （twelve males and eight females）. The fluorescent flow cytometry was used to analyze the expression of CD28 and CD95 on peripheral blood lymphocytes and the apoptosis rate of lymphocytes induced by dexamethasone. Results The apoptosis rate was significantly higher in the elderly group[（14. 90±4.12）%] than in the adult group[（8.12±3.12）%]. CD28^＋CD95^- and CD28^＋ cells of the peripheral blood lymphocytes in the elderly group[（8.80±4.86）%, （36.31±10.38）%, respectively] were significantly lower than those in the adult group[ （23.09±3.48）%, （52.29±4.90）%, respectively]. CD28^-CD95^＋ , CD95^＋ and CD28^- cells in the elderly group[（53.23±8.28）%, （80.25±7.19）%, （63.69±10.38）%, respectively] were significantly higher than those in the adult group [（33. 58±4. 72）%, （63. 18±4.12） %, （47.71±4.90）%, respectively]. There was no statistically significant difference in the CD28^＋ CD95^＋ cells between the two groups. The apoptosis rate of lymphocyte was negatively correlated with CD28^＋ and positively corre lated with CD95^＋. Conclusion The apoptosis rate and the expression of CD28^＋ ,CD28^- and CD95^＋ change signifi-cantly with aging. The apoptosis rate of lymphocyte is correlated with CD28 and CD95, suggesting that apoptosis of lymphocyte plays an important role in the immunosenescence.