CD8＋ T细胞在肠道病毒71型感染重症手足口病中的作用研究

目的：检测分析肠道病毒71型（EV71）感染手足口病患儿外周血CD8＋T细胞数量变化与患儿年龄以及病情严重程度之间的关系，进而分析探讨CD8＋T细胞在EV71感染神经系统并发症发生中的潜在作用。方法收集2014年3月至9月昆明市儿童医院感染科确诊的手足口病患儿138例，其中普通型33例，重型45例，危重型60例。患儿年龄9个月~5岁。采用流式细胞术对外周血中CD8＋T细胞亚群进行检测。结果与各年龄段健康儿童CD8＋T细胞参考值相比，除~2岁年龄段普通型手足口病患儿CD8＋T细胞百分比增高明显，~5岁年龄段危重型手足口病患儿CD8＋T细胞减低外，其他各年龄段各病情患儿中CD8＋T细胞均增高或略高。其中，9~15个月普通型、重型患儿外周血CD8＋T细胞百分比增高均较明显，而危重型患儿略增高；~2岁患儿随病情加重CD8＋T细胞增高幅度逐渐减低；~5岁年龄段患儿，普通型增高不明显，重型略高，危重型减低。~2岁年龄段普通型与重型、危重型手足口病患儿CD8＋T细胞百分比均存在显著差异（ P均﹤0.05）；而其他年龄段手足口病患儿，不同病情严重程度者CD8＋T细胞的表达无显著差异（ P均﹥0.05）。结论 CD8＋T细胞的表达变化与患儿年龄及病情严重程度间存在一定的关系；尤其是~2岁年龄段手足口病患儿体内CD8＋T细胞的表达减低与患儿病情发展至重症相关，推测CD8＋T细胞在~2岁年龄段手足口病患儿很可能发挥重要的抗病毒免疫反应。

The function of CD8 +T cells in severe hand,foot and mouth disease infected by enterovirus 71

Objective To investigate the correlation between the expression of peripheral blood CD8 + T lymphocytes and the severity degree of hand,foot and mouth disease( HFMD)in children infected by enterovirus( EV)71 at different ages,and further to predict the role of the expression of CD8+ T lympho-cytes played in the occurrence of neurological complications infected by EV71. Methods A total of 138 pe-ripheral blood samples derived from the confirmed HFMD cases were collected in the department of infectious disease at Kunming Children′s Hospital between March and September in 2014,including 33 mild cases,45 severe cases,and 60 critical cases. Patient ages were 9 months to 5 years old. Flow cytometry was used to detect the expression of peripheral blood CD8 + T lymphocytes in all of above patients. Results Compared to the reference value of CD8 + T lymphocytes in normal healthy children at different age groups,the percentage of peripheral blood CD8 + T lymphocytes elevated or increased slightly in patients of all ages,except the obvi-ously increasing expression in the age group of ~2 years and decreasing expression in critical cases of the age group of ~5 years. The expression of peripheral blood CD8+ T lymphocytes significantly increased in mild and severe patients but slightly increased in critical patients of the age group of 9 to 15 months,gradually de-creased in the age group of ~2 years and slightly increased in mild and severe cases but decreased in critical patients of the age group of ~5 years. There were significant differences between the patients in mild condi-tion and in severe condition or critical condition respectively within the age group of ~2 years( P﹤0. 05 ), and there were no significant differences in other age groups between different severity of disease. Conclusion
There are correlations between the expression of CD8+ T cells and the severity of HFMD in patients at different ages. Especially,the patient′s condition developing into severe degree is associated with the rapid decreasing of CD8 + T cells in HFMD patients of the age group of ~2 years. CD8+T cells play an important role in antiviral immune response in HFMD patients of ~2 years old.