CD19^+CD24^(high)CD27^+调节性B细胞在儿童传染性单核细胞增多症中的表达及意义

Role of CD19^+ CD24highCD27^+ Regulatory B Cells in Children with Infectious Mononucleosis

目的探讨调节性B细胞(Breg)在儿童传染性单核细胞增多症(IM)中的作用。方法应用流式细胞术检测53例IM患儿外周血T淋巴细胞亚群,CD19^+CD24^(high)CD27^+Breg细胞表达情况。用荧光定量PCR检测血浆EBV-DNA。同时用ELISA方法分析血清IL-10、TGF-β分泌水平。以50例健康儿童为对照。结果 IM急性期组与对照组比较CD3^+CD4^+T细胞明显降低(t=19.99,P<0.01),CD3^+CD8^+T细胞明显增高(t=17.47,P<0.01),CD4/CD8比值降低(t=16.79,P<0.01)。IM恢复期组与急性期组比较,CD3^+CD4^+T细胞明显增高(t=21.54,P<0.01),CD3^+CD8^+T细胞明显降低(t=17.47,P<0.01),CD4/CD8比值增高(t=16.68,P<0.01)。IM急性期组CD19^+CD24^(high)CD27^+Breg细胞表达水平13.4%±1.87%,与对照组比较显著降低,差异有统计学意义(t=14.61,P<0.01)。IM急性期组CD19^+CD24^(high)CD27^+Breg细胞表达水平与EBV-DNA病毒载量呈负相关(r=-0.52,P<0.01)。经治疗后IM恢复期组CD19^+CD24^(high)CD27^+Breg细胞表达水平18.3%±2.11%与IM急性期组比较显著增高,差异有统计学意义(t=12.61,P<0.01)。IM急性期组血清IL-10较对照组明显降低,差异有统计学意义(t=11.50,P<0.01)。治疗后IM恢复期组IL-10较IM急性期组明显增高,差异有统计学意义(t=9.40,P<0.01)。结论IM急性期存在明显免疫失衡,即CD3^+CD8^+T细胞增多,CD4/CD8比值降低,可能与Breg细胞表达减低导致的免疫抑制功能不足有关。

Objective To investigate the biological function of regulatory B cells （Bregs） in children with infectious mononucleosis （IM）. Methods A total of 53 IM children and 50 healthy controls were enrolled. The T - cell subset and expressions of CD19 ＋ CD24high CD27 ＋ Bregs in peripheral blood mononuclear cells （PBMC） were evaluated by flow cytometry. The level of serum EBV - DNA copies was detected with fluorescent quantitative PCR. And the serum level of IL - 10,TGF -β was measured by enzyme - 1 inked immunosorbent as- say （ELISA）. Results IM patients in acute phase group had a significantly higher percentage of CD3 ＋ CD4 ＋ T cells （ t = 19.99, P 〈 0. 01 ） and lower percentage of CD3＋ CD8＋ T （ t = 17.47 ,P 〈 0.01 ） cells than control, corresponding to a low ratio of CD4/CD8 （ t = 16, 79,P 〈 0.01 ）. Compared with IM children in acute phase, the IM children in recovery phase had a higher expression of CD3 ＋ CD4＋ T cells（t=21.54,P 〈0.01） and lower expression of CD3 ＋CD8 ＋T cells（t = 17.47,P 〈0.01）, and higher ratio of CD4/CD8（t = 16.68,P 〈0.01 ）. The percentage of CD19 ~ CD24hlghCD27 ＋ Breg expression in PBMC of IM children in acute phase was 13.4% ＋ 1.87% , and it was lower than those in the health control group （ t = 14.61 ,P 〈 O. 01 ）. The expression level of CD19＋ CD24high CD27＋ Breg cells in the acute phase of IM was negatively correlated with EBV - DNA viral load （ r = - 0.52, P 〈 0.01 ）. The percentage of CD19＋ CD24highCD27 ＋ Breg expression in PBMC of post - treatment IM children in recovery phase was 18.3% ± 2. 11% , and it was higher than those in the IM children in acute phase（ t = 12.61 ,P 〈 0.01 ）. The level of IL - 10 significantly decreased in serum of IM pa- tients in acute phase compared with control（ t=11.50,P 〈 0. 01 ）. The level of IL- 10 significantly increased in serum of IM patients in recovery phase compared with IM patients in acute phase （ t = 9.40,P 〈 0. 01 ）. Conclusion In the acute phase of IM, there was obvious immune imbalance, that is, the increase of CD3 ＋ CD8 ＋ T cells and the decrease of CD4 / CD8 ratio, which may be result from the de- creased level of Breg cells and its insufficient of immunosuppression function.