外周血CD4^-CD8^-双阴性T细胞在小儿传染性单核细胞增多症患者中的表达

Expression of peripheral blood CD4^- CD8^- double negative T cells in children with infectious mononu-cleosis

目的分析小儿传染性单核细胞增多症(infectiousmononucleosis,IM)患者外周血淋巴细胞亚群T、B和自然杀伤细胞(natural killer cells,NK)以及CD4^-CD8^-双阴性T细胞(double negative T cells,DNT)的表达水平,探讨DNT在IM发病中的作用.方法收集2017年12月1日至2018年4月30日在苏州九龙医院治疗并明确诊断为IM住院患者65例作为病例组,同时收集在本院健康体检儿童65名作为对照.采用流式细胞术,分析IM患儿及健康儿童外周血淋巴细胞亚群T、B和NK以及DNT细胞的表达.结果与健康对照组相比,IM患儿组总T淋巴细胞(CD3^+T细胞)表达率、细胞毒性T细胞(CD8^+T细胞)表达率高于健康对照组(t值分别为4.60和4.74,P值均<0.05).辅助性T细胞(CD4+T细胞)表达率、B细胞(CD19^+T细胞)表达率、NK细胞(CD56+T细胞)表达率、CD4/CD8比率均低于健康对照组,差异具有统计学意义(t值分别为5.28,2.57,4.61和4.16,P值均<0.05).IM患儿和健康儿童体内均有DNT细胞的表达,为γδ-T细胞表面受体(T cell receptor,TCR)型,且IM患儿体内高表达γδ-TCR型DNT细胞与健康儿童组相比,差异具有统计学意义(t=9.22,P<0.05).结论 IM患儿体内各淋巴亚群比例变化显著,IM患儿体内存在高表达γδ-TCR型DNT细胞,这有可能为传染性单核细胞增多症的实验室诊断提供新的方法.

Objective To analyze the expression levels of peripheral blood lymphocyte subsets,T cells,B cells,natural killer cells (NK)and CD4^-CD8^- double negative T cells (DNT)in children with infec-tious mononucleosis (IM),and to explore the role of DNT in the pathogenesis of IM. Methods Total of 65 in-patient children diagnosed with IM in Suzhou Kowloon Hospital from December 1,2017 to April 30,2018 were collected,and another 65 healthy children were collected as controls. The expression of peripheral blood lympho-cyte subsets T,B and NK and DNT cells in children with and without IM were analyzed by flow cytometry. Results Compared with the healthy control group,the expression rates of total T lymphocyte (CD3^+ T cells) and cytotoxic T cells (CD8^+ T cells)in the IM group were higher than those of the healthy control group (t val-ues were 4. 60 and 4. 74,both P values < 0. 05),and the expression rates of helper T cells (CD4^+ T cells),B cells (CD19^+ T cells),NK cells (CD56^+ T cells)and CD4 / CD8 ratio were significantly lower than those of the healthy control group (t values were 5. 28,2. 57,4. 61 and 4. 16 respectively,all P values < 0. 05). DNT cells expressed in both group were γδ- T cell receptor(TCR)type,and the γδ-TCR type DNT cells were highly ex-pressed in children with IM,which was statistically different from healthy children (t = 9. 22,P < 0. 05). Conclusion The lymphocyte subsets in IM children were observed imbalanced and dysfunctional. Meanwhile,there was a high expression level of the γδ-TCR type DNT cells in children,which may provide a new method for laboratory diagnosis of infectious mononucleosis.